// SPDX-License-Identifier: GPL-2.0
/*
* Nuvoton NPCM7xx I2C Controller driver
*
* Copyright (C) 2020 Nuvoton Technologies tali.perry@nuvoton.com
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
enum i2c_mode {
I2C_MASTER,
I2C_SLAVE,
};
/*
* External I2C Interface driver xfer indication values, which indicate status
* of the bus.
*/
enum i2c_state_ind {
I2C_NO_STATUS_IND = 0,
I2C_SLAVE_RCV_IND,
I2C_SLAVE_XMIT_IND,
I2C_SLAVE_XMIT_MISSING_DATA_IND,
I2C_SLAVE_RESTART_IND,
I2C_SLAVE_DONE_IND,
I2C_MASTER_DONE_IND,
I2C_NACK_IND,
I2C_BUS_ERR_IND,
I2C_WAKE_UP_IND,
I2C_BLOCK_BYTES_ERR_IND,
I2C_SLAVE_RCV_MISSING_DATA_IND,
};
/*
* Operation type values (used to define the operation currently running)
* module is interrupt driven, on each interrupt the current operation is
* checked to see if the module is currently reading or writing.
*/
enum i2c_oper {
I2C_NO_OPER = 0,
I2C_WRITE_OPER,
I2C_READ_OPER,
};
/* I2C Bank (module had 2 banks of registers) */
enum i2c_bank {
I2C_BANK_0 = 0,
I2C_BANK_1,
};
/* Internal I2C states values (for the I2C module state machine). */
enum i2c_state {
I2C_DISABLE = 0,
I2C_IDLE,
I2C_MASTER_START,
I2C_SLAVE_MATCH,
I2C_OPER_STARTED,
I2C_STOP_PENDING,
};
#if IS_ENABLED(CONFIG_I2C_SLAVE)
/* Module supports setting multiple own slave addresses */
enum i2c_addr {
I2C_SLAVE_ADDR1 = 0,
I2C_SLAVE_ADDR2,
I2C_SLAVE_ADDR3,
I2C_SLAVE_ADDR4,
I2C_SLAVE_ADDR5,
I2C_SLAVE_ADDR6,
I2C_SLAVE_ADDR7,
I2C_SLAVE_ADDR8,
I2C_SLAVE_ADDR9,
I2C_SLAVE_ADDR10,
I2C_GC_ADDR,
I2C_ARP_ADDR,
};
#endif
/* init register and default value required to enable module */
#define NPCM_I2CSEGCTL 0xE4
#define NPCM_I2CSEGCTL_INIT_VAL 0x0333F000
/* Common regs */
#define NPCM_I2CSDA 0x00
#define NPCM_I2CST 0x02
#define NPCM_I2CCST 0x04
#define NPCM_I2CCTL1 0x06
#define NPCM_I2CADDR1 0x08
#define NPCM_I2CCTL2 0x0A
#define NPCM_I2CADDR2 0x0C
#define NPCM_I2CCTL3 0x0E
#define NPCM_I2CCST2 0x18
#define NPCM_I2CCST3 0x19
#define I2C_VER 0x1F
/*BANK0 regs*/
#define NPCM_I2CADDR3 0x10
#define NPCM_I2CADDR7 0x11
#define NPCM_I2CADDR4 0x12
#define NPCM_I2CADDR8 0x13
#define NPCM_I2CADDR5 0x14
#define NPCM_I2CADDR9 0x15
#define NPCM_I2CADDR6 0x16
#define NPCM_I2CADDR10 0x17
#if IS_ENABLED(CONFIG_I2C_SLAVE)
/*
* npcm_i2caddr array:
* The module supports having multiple own slave addresses.
* Since the addr regs are sprinkled all over the address space,
* use this array to get the address or each register.
*/
#define I2C_NUM_OWN_ADDR 10
static const int npcm_i2caddr[I2C_NUM_OWN_ADDR] = {
NPCM_I2CADDR1, NPCM_I2CADDR2, NPCM_I2CADDR3, NPCM_I2CADDR4,
NPCM_I2CADDR5, NPCM_I2CADDR6, NPCM_I2CADDR7, NPCM_I2CADDR8,
NPCM_I2CADDR9, NPCM_I2CADDR10,
};
#endif
#define NPCM_I2CCTL4 0x1A
#define NPCM_I2CCTL5 0x1B
#define NPCM_I2CSCLLT 0x1C /* SCL Low Time */
#define NPCM_I2CFIF_CTL 0x1D /* FIFO Control */
#define NPCM_I2CSCLHT 0x1E /* SCL High Time */
/* BANK 1 regs */
#define NPCM_I2CFIF_CTS 0x10 /* Both FIFOs Control and Status */
#define NPCM_I2CTXF_CTL 0x12 /* Tx-FIFO Control */
#define NPCM_I2CT_OUT 0x14 /* Bus T.O. */
#define NPCM_I2CPEC 0x16 /* PEC Data */
#define NPCM_I2CTXF_STS 0x1A /* Tx-FIFO Status */
#define NPCM_I2CRXF_STS 0x1C /* Rx-FIFO Status */
#define NPCM_I2CRXF_CTL 0x1E /* Rx-FIFO Control */
/* NPCM_I2CST reg fields */
#define NPCM_I2CST_XMIT BIT(0)
#define NPCM_I2CST_MASTER BIT(1)
#define NPCM_I2CST_NMATCH BIT(2)
#define NPCM_I2CST_STASTR BIT(3)
#define NPCM_I2CST_NEGACK BIT(4)
#define NPCM_I2CST_BER BIT(5)
#define NPCM_I2CST_SDAST BIT(6)
#define NPCM_I2CST_SLVSTP BIT(7)
/* NPCM_I2CCST reg fields */
#define NPCM_I2CCST_BUSY BIT(0)
#define NPCM_I2CCST_BB BIT(1)
#define NPCM_I2CCST_MATCH BIT(2)
#define NPCM_I2CCST_GCMATCH BIT(3)
#define NPCM_I2CCST_TSDA BIT(4)
#define NPCM_I2CCST_TGSCL BIT(5)
#define NPCM_I2CCST_MATCHAF BIT(6)
#define NPCM_I2CCST_ARPMATCH BIT(7)
/* NPCM_I2CCTL1 reg fields */
#define NPCM_I2CCTL1_START BIT(0)
#define NPCM_I2CCTL1_STOP BIT(1)
#define NPCM_I2CCTL1_INTEN BIT(2)
#define NPCM_I2CCTL1_EOBINTE BIT(3)
#define NPCM_I2CCTL1_ACK BIT(4)
#define NPCM_I2CCTL1_GCMEN BIT(5)
#define NPCM_I2CCTL1_NMINTE BIT(6)
#define NPCM_I2CCTL1_STASTRE BIT(7)
/* RW1S fields (inside a RW reg): */
#define NPCM_I2CCTL1_RWS \
(NPCM_I2CCTL1_START | NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK)
/* npcm_i2caddr reg fields */
#define NPCM_I2CADDR_A GENMASK(6, 0)
#define NPCM_I2CADDR_SAEN BIT(7)
/* NPCM_I2CCTL2 reg fields */
#define I2CCTL2_ENABLE BIT(0)
#define I2CCTL2_SCLFRQ6_0 GENMASK(7, 1)
/* NPCM_I2CCTL3 reg fields */
#define I2CCTL3_SCLFRQ8_7 GENMASK(1, 0)
#define I2CCTL3_ARPMEN BIT(2)
#define I2CCTL3_IDL_START BIT(3)
#define I2CCTL3_400K_MODE BIT(4)
#define I2CCTL3_BNK_SEL BIT(5)
#define I2CCTL3_SDA_LVL BIT(6)
#define I2CCTL3_SCL_LVL BIT(7)
/* NPCM_I2CCST2 reg fields */
#define NPCM_I2CCST2_MATCHA1F BIT(0)
#define NPCM_I2CCST2_MATCHA2F BIT(1)
#define NPCM_I2CCST2_MATCHA3F BIT(2)
#define NPCM_I2CCST2_MATCHA4F BIT(3)
#define NPCM_I2CCST2_MATCHA5F BIT(4)
#define NPCM_I2CCST2_MATCHA6F BIT(5)
#define NPCM_I2CCST2_MATCHA7F BIT(5)
#define NPCM_I2CCST2_INTSTS BIT(7)
/* NPCM_I2CCST3 reg fields */
#define NPCM_I2CCST3_MATCHA8F BIT(0)
#define NPCM_I2CCST3_MATCHA9F BIT(1)
#define NPCM_I2CCST3_MATCHA10F BIT(2)
#define NPCM_I2CCST3_EO_BUSY BIT(7)
/* NPCM_I2CCTL4 reg fields */
#define I2CCTL4_HLDT GENMASK(5, 0)
#define I2CCTL4_LVL_WE BIT(7)
/* NPCM_I2CCTL5 reg fields */
#define I2CCTL5_DBNCT GENMASK(3, 0)
/* NPCM_I2CFIF_CTS reg fields */
#define NPCM_I2CFIF_CTS_RXF_TXE BIT(1)
#define NPCM_I2CFIF_CTS_RFTE_IE BIT(3)
#define NPCM_I2CFIF_CTS_CLR_FIFO BIT(6)
#define NPCM_I2CFIF_CTS_SLVRSTR BIT(7)
/* NPCM_I2CTXF_CTL reg fields */
#define NPCM_I2CTXF_CTL_TX_THR GENMASK(4, 0)
#define NPCM_I2CTXF_CTL_THR_TXIE BIT(6)
/* NPCM_I2CT_OUT reg fields */
#define NPCM_I2CT_OUT_TO_CKDIV GENMASK(5, 0)
#define NPCM_I2CT_OUT_T_OUTIE BIT(6)
#define NPCM_I2CT_OUT_T_OUTST BIT(7)
/* NPCM_I2CTXF_STS reg fields */
#define NPCM_I2CTXF_STS_TX_BYTES GENMASK(4, 0)
#define NPCM_I2CTXF_STS_TX_THST BIT(6)
/* NPCM_I2CRXF_STS reg fields */
#define NPCM_I2CRXF_STS_RX_BYTES GENMASK(4, 0)
#define NPCM_I2CRXF_STS_RX_THST BIT(6)
/* NPCM_I2CFIF_CTL reg fields */
#define NPCM_I2CFIF_CTL_FIFO_EN BIT(4)
/* NPCM_I2CRXF_CTL reg fields */
#define NPCM_I2CRXF_CTL_RX_THR GENMASK(4, 0)
#define NPCM_I2CRXF_CTL_LAST_PEC BIT(5)
#define NPCM_I2CRXF_CTL_THR_RXIE BIT(6)
#define I2C_HW_FIFO_SIZE 16
/* I2C_VER reg fields */
#define I2C_VER_VERSION GENMASK(6, 0)
#define I2C_VER_FIFO_EN BIT(7)
/* stall/stuck timeout in us */
#define DEFAULT_STALL_COUNT 25
/* SCLFRQ field position */
#define SCLFRQ_0_TO_6 GENMASK(6, 0)
#define SCLFRQ_7_TO_8 GENMASK(8, 7)
/* supported clk settings. values in Hz. */
#define I2C_FREQ_MIN_HZ 10000
#define I2C_FREQ_MAX_HZ I2C_MAX_FAST_MODE_PLUS_FREQ
/* Status of one I2C module */
struct npcm_i2c {
struct i2c_adapter adap;
struct device *dev;
unsigned char __iomem *reg;
spinlock_t lock; /* IRQ synchronization */
struct completion cmd_complete;
int cmd_err;
struct i2c_msg *msgs;
int msgs_num;
int num;
u32 apb_clk;
struct i2c_bus_recovery_info rinfo;
enum i2c_state state;
enum i2c_oper operation;
enum i2c_mode master_or_slave;
enum i2c_state_ind stop_ind;
u8 dest_addr;
u8 *rd_buf;
u16 rd_size;
u16 rd_ind;
u8 *wr_buf;
u16 wr_size;
u16 wr_ind;
bool fifo_use;
u16 PEC_mask; /* PEC bit mask per slave address */
bool PEC_use;
bool read_block_use;
unsigned long int_time_stamp;
unsigned long bus_freq; /* in Hz */
#if IS_ENABLED(CONFIG_I2C_SLAVE)
u8 own_slave_addr;
struct i2c_client *slave;
int slv_rd_size;
int slv_rd_ind;
int slv_wr_size;
int slv_wr_ind;
u8 slv_rd_buf[I2C_HW_FIFO_SIZE];
u8 slv_wr_buf[I2C_HW_FIFO_SIZE];
#endif
struct dentry *debugfs; /* debugfs device directory */
u64 ber_cnt;
u64 rec_succ_cnt;
u64 rec_fail_cnt;
u64 nack_cnt;
u64 timeout_cnt;
u64 tx_complete_cnt;
};
static inline void npcm_i2c_select_bank(struct npcm_i2c *bus,
enum i2c_bank bank)
{
u8 i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3);
if (bank == I2C_BANK_0)
i2cctl3 = i2cctl3 & ~I2CCTL3_BNK_SEL;
else
i2cctl3 = i2cctl3 | I2CCTL3_BNK_SEL;
iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3);
}
static void npcm_i2c_init_params(struct npcm_i2c *bus)
{
bus->stop_ind = I2C_NO_STATUS_IND;
bus->rd_size = 0;
bus->wr_size = 0;
bus->rd_ind = 0;
bus->wr_ind = 0;
bus->read_block_use = false;
bus->int_time_stamp = 0;
bus->PEC_use = false;
bus->PEC_mask = 0;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
if (bus->slave)
bus->master_or_slave = I2C_SLAVE;
#endif
}
static inline void npcm_i2c_wr_byte(struct npcm_i2c *bus, u8 data)
{
iowrite8(data, bus->reg + NPCM_I2CSDA);
}
static inline u8 npcm_i2c_rd_byte(struct npcm_i2c *bus)
{
return ioread8(bus->reg + NPCM_I2CSDA);
}
static int npcm_i2c_get_SCL(struct i2c_adapter *_adap)
{
struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
return !!(I2CCTL3_SCL_LVL & ioread8(bus->reg + NPCM_I2CCTL3));
}
static int npcm_i2c_get_SDA(struct i2c_adapter *_adap)
{
struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
return !!(I2CCTL3_SDA_LVL & ioread8(bus->reg + NPCM_I2CCTL3));
}
static inline u16 npcm_i2c_get_index(struct npcm_i2c *bus)
{
if (bus->operation == I2C_READ_OPER)
return bus->rd_ind;
if (bus->operation == I2C_WRITE_OPER)
return bus->wr_ind;
return 0;
}
/* quick protocol (just address) */
static inline bool npcm_i2c_is_quick(struct npcm_i2c *bus)
{
return bus->wr_size == 0 && bus->rd_size == 0;
}
static void npcm_i2c_disable(struct npcm_i2c *bus)
{
u8 i2cctl2;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
int i;
/* select bank 0 for I2C addresses */
npcm_i2c_select_bank(bus, I2C_BANK_0);
/* Slave addresses removal */
for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR; i++)
iowrite8(0, bus->reg + npcm_i2caddr[i]);
npcm_i2c_select_bank(bus, I2C_BANK_1);
#endif
/* Disable module */
i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2);
i2cctl2 = i2cctl2 & ~I2CCTL2_ENABLE;
iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2);
bus->state = I2C_DISABLE;
}
static void npcm_i2c_enable(struct npcm_i2c *bus)
{
u8 i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2);
i2cctl2 = i2cctl2 | I2CCTL2_ENABLE;
iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2);
bus->state = I2C_IDLE;
}
/* enable\disable end of busy (EOB) interrupts */
static inline void npcm_i2c_eob_int(struct npcm_i2c *bus, bool enable)
{
u8 val;
/* Clear EO_BUSY pending bit: */
val = ioread8(bus->reg + NPCM_I2CCST3);
val = val | NPCM_I2CCST3_EO_BUSY;
iowrite8(val, bus->reg + NPCM_I2CCST3);
val = ioread8(bus->reg + NPCM_I2CCTL1);
val &= ~NPCM_I2CCTL1_RWS;
if (enable)
val |= NPCM_I2CCTL1_EOBINTE;
else
val &= ~NPCM_I2CCTL1_EOBINTE;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
}
static inline bool npcm_i2c_tx_fifo_empty(struct npcm_i2c *bus)
{
u8 tx_fifo_sts;
tx_fifo_sts = ioread8(bus->reg + NPCM_I2CTXF_STS);
/* check if TX FIFO is not empty */
if ((tx_fifo_sts & NPCM_I2CTXF_STS_TX_BYTES) == 0)
return false;
/* check if TX FIFO status bit is set: */
return !!FIELD_GET(NPCM_I2CTXF_STS_TX_THST, tx_fifo_sts);
}
static inline bool npcm_i2c_rx_fifo_full(struct npcm_i2c *bus)
{
u8 rx_fifo_sts;
rx_fifo_sts = ioread8(bus->reg + NPCM_I2CRXF_STS);
/* check if RX FIFO is not empty: */
if ((rx_fifo_sts & NPCM_I2CRXF_STS_RX_BYTES) == 0)
return false;
/* check if rx fifo full status is set: */
return !!FIELD_GET(NPCM_I2CRXF_STS_RX_THST, rx_fifo_sts);
}
static inline void npcm_i2c_clear_fifo_int(struct npcm_i2c *bus)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CFIF_CTS);
val = (val & NPCM_I2CFIF_CTS_SLVRSTR) | NPCM_I2CFIF_CTS_RXF_TXE;
iowrite8(val, bus->reg + NPCM_I2CFIF_CTS);
}
static inline void npcm_i2c_clear_tx_fifo(struct npcm_i2c *bus)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CTXF_STS);
val = val | NPCM_I2CTXF_STS_TX_THST;
iowrite8(val, bus->reg + NPCM_I2CTXF_STS);
}
static inline void npcm_i2c_clear_rx_fifo(struct npcm_i2c *bus)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CRXF_STS);
val = val | NPCM_I2CRXF_STS_RX_THST;
iowrite8(val, bus->reg + NPCM_I2CRXF_STS);
}
static void npcm_i2c_int_enable(struct npcm_i2c *bus, bool enable)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CCTL1);
val &= ~NPCM_I2CCTL1_RWS;
if (enable)
val |= NPCM_I2CCTL1_INTEN;
else
val &= ~NPCM_I2CCTL1_INTEN;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
}
static inline void npcm_i2c_master_start(struct npcm_i2c *bus)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CCTL1);
val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK);
val |= NPCM_I2CCTL1_START;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
}
static inline void npcm_i2c_master_stop(struct npcm_i2c *bus)
{
u8 val;
/*
* override HW issue: I2C may fail to supply stop condition in Master
* Write operation.
* Need to delay at least 5 us from the last int, before issueing a stop
*/
udelay(10); /* function called from interrupt, can't sleep */
val = ioread8(bus->reg + NPCM_I2CCTL1);
val &= ~(NPCM_I2CCTL1_START | NPCM_I2CCTL1_ACK);
val |= NPCM_I2CCTL1_STOP;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
if (!bus->fifo_use)
return;
npcm_i2c_select_bank(bus, I2C_BANK_1);
if (bus->operation == I2C_READ_OPER)
npcm_i2c_clear_rx_fifo(bus);
else
npcm_i2c_clear_tx_fifo(bus);
npcm_i2c_clear_fifo_int(bus);
iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
}
static inline void npcm_i2c_stall_after_start(struct npcm_i2c *bus, bool stall)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CCTL1);
val &= ~NPCM_I2CCTL1_RWS;
if (stall)
val |= NPCM_I2CCTL1_STASTRE;
else
val &= ~NPCM_I2CCTL1_STASTRE;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
}
static inline void npcm_i2c_nack(struct npcm_i2c *bus)
{
u8 val;
val = ioread8(bus->reg + NPCM_I2CCTL1);
val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_START);
val |= NPCM_I2CCTL1_ACK;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
}
static inline void npcm_i2c_clear_master_status(struct npcm_i2c *bus)
{
u8 val;
/* Clear NEGACK, STASTR and BER bits */
val = NPCM_I2CST_BER | NPCM_I2CST_NEGACK | NPCM_I2CST_STASTR;
iowrite8(val, bus->reg + NPCM_I2CST);
}
#if IS_ENABLED(CONFIG_I2C_SLAVE)
static void npcm_i2c_slave_int_enable(struct npcm_i2c *bus, bool enable)
{
u8 i2cctl1;
/* enable interrupt on slave match: */
i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1);
i2cctl1 &= ~NPCM_I2CCTL1_RWS;
if (enable)
i2cctl1 |= NPCM_I2CCTL1_NMINTE;
else
i2cctl1 &= ~NPCM_I2CCTL1_NMINTE;
iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
}
static int npcm_i2c_slave_enable(struct npcm_i2c *bus, enum i2c_addr addr_type,
u8 addr, bool enable)
{
u8 i2cctl1;
u8 i2cctl3;
u8 sa_reg;
sa_reg = (addr & 0x7F) | FIELD_PREP(NPCM_I2CADDR_SAEN, enable);
if (addr_type == I2C_GC_ADDR) {
i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1);
if (enable)
i2cctl1 |= NPCM_I2CCTL1_GCMEN;
else
i2cctl1 &= ~NPCM_I2CCTL1_GCMEN;
iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
return 0;
}
if (addr_type == I2C_ARP_ADDR) {
i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3);
if (enable)
i2cctl3 |= I2CCTL3_ARPMEN;
else
i2cctl3 &= ~I2CCTL3_ARPMEN;
iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3);
return 0;
}
if (addr_type >= I2C_ARP_ADDR)
return -EFAULT;
/* select bank 0 for address 3 to 10 */
if (addr_type > I2C_SLAVE_ADDR2)
npcm_i2c_select_bank(bus, I2C_BANK_0);
/* Set and enable the address */
iowrite8(sa_reg, bus->reg + npcm_i2caddr[addr_type]);
npcm_i2c_slave_int_enable(bus, enable);
if (addr_type > I2C_SLAVE_ADDR2)
npcm_i2c_select_bank(bus, I2C_BANK_1);
return 0;
}
#endif
static void npcm_i2c_reset(struct npcm_i2c *bus)
{
/*
* Save I2CCTL1 relevant bits. It is being cleared when the module
* is disabled.
*/
u8 i2cctl1;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
u8 addr;
#endif
i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1);
npcm_i2c_disable(bus);
npcm_i2c_enable(bus);
/* Restore NPCM_I2CCTL1 Status */
i2cctl1 &= ~NPCM_I2CCTL1_RWS;
iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
/* Clear BB (BUS BUSY) bit */
iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
iowrite8(0xFF, bus->reg + NPCM_I2CST);
/* Clear and disable EOB */
npcm_i2c_eob_int(bus, false);
/* Clear all fifo bits: */
iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
#if IS_ENABLED(CONFIG_I2C_SLAVE)
if (bus->slave) {
addr = bus->slave->addr;
npcm_i2c_slave_enable(bus, I2C_SLAVE_ADDR1, addr, true);
}
#endif
/* clear status bits for spurious interrupts */
npcm_i2c_clear_master_status(bus);
bus->state = I2C_IDLE;
}
static inline bool npcm_i2c_is_master(struct npcm_i2c *bus)
{
return !!FIELD_GET(NPCM_I2CST_MASTER, ioread8(bus->reg + NPCM_I2CST));
}
static void npcm_i2c_callback(struct npcm_i2c *bus,
enum i2c_state_ind op_status, u16 info)
{
struct i2c_msg *msgs;
int msgs_num;
msgs = bus->msgs;
msgs_num = bus->msgs_num;
/*
* check that transaction was not timed-out, and msgs still
* holds a valid value.
*/
if (!msgs)
return;
if (completion_done(&bus->cmd_complete))
return;
switch (op_status) {
case I2C_MASTER_DONE_IND:
bus->cmd_err = bus->msgs_num;
if (bus->tx_complete_cnt < ULLONG_MAX)
bus->tx_complete_cnt++;
fallthrough;
case I2C_BLOCK_BYTES_ERR_IND:
/* Master tx finished and all transmit bytes were sent */
if (bus->msgs) {
if (msgs[0].flags & I2C_M_RD)
msgs[0].len = info;
else if (msgs_num == 2 &&
msgs[1].flags & I2C_M_RD)
msgs[1].len = info;
}
if (completion_done(&bus->cmd_complete) == false)
complete(&bus->cmd_complete);
break;
case I2C_NACK_IND:
/* MASTER transmit got a NACK before tx all bytes */
bus->cmd_err = -ENXIO;
if (bus->master_or_slave == I2C_MASTER)
complete(&bus->cmd_complete);
break;
case I2C_BUS_ERR_IND:
/* Bus error */
bus->cmd_err = -EAGAIN;
if (bus->master_or_slave == I2C_MASTER)
complete(&bus->cmd_complete);
break;
case I2C_WAKE_UP_IND:
/* I2C wake up */
break;
default:
break;
}
bus->operation = I2C_NO_OPER;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
if (bus->slave)
bus->master_or_slave = I2C_SLAVE;
#endif
}
static u8 npcm_i2c_fifo_usage(struct npcm_i2c *bus)
{
if (bus->operation == I2C_WRITE_OPER)
return FIELD_GET(NPCM_I2CTXF_STS_TX_BYTES,
ioread8(bus->reg + NPCM_I2CTXF_STS));
if (bus->operation == I2C_READ_OPER)
return FIELD_GET(NPCM_I2CRXF_STS_RX_BYTES,
ioread8(bus->reg + NPCM_I2CRXF_STS));
return 0;
}
static void npcm_i2c_write_to_fifo_master(struct npcm_i2c *bus, u16 max_bytes)
{
u8 size_free_fifo;
/*
* Fill the FIFO, while the FIFO is not full and there are more bytes
* to write
*/
size_free_fifo = I2C_HW_FIFO_SIZE - npcm_i2c_fifo_usage(bus);
while (max_bytes-- && size_free_fifo) {
if (bus->wr_ind < bus->wr_size)
npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]);
else
npcm_i2c_wr_byte(bus, 0xFF);
size_free_fifo = I2C_HW_FIFO_SIZE - npcm_i2c_fifo_usage(bus);
}
}
/*
* npcm_i2c_set_fifo:
* configure the FIFO before using it. If nread is -1 RX FIFO will not be
* configured. same for nwrite
*/
static void npcm_i2c_set_fifo(struct npcm_i2c *bus, int nread, int nwrite)
{
u8 rxf_ctl = 0;
if (!bus->fifo_use)
return;
npcm_i2c_select_bank(bus, I2C_BANK_1);
npcm_i2c_clear_tx_fifo(bus);
npcm_i2c_clear_rx_fifo(bus);
/* configure RX FIFO */
if (nread > 0) {
rxf_ctl = min_t(int, nread, I2C_HW_FIFO_SIZE);
/* set LAST bit. if LAST is set next FIFO packet is nacked */
if (nread <= I2C_HW_FIFO_SIZE)
rxf_ctl |= NPCM_I2CRXF_CTL_LAST_PEC;
/*
* if we are about to read the first byte in blk rd mode,
* don't NACK it. If slave returns zero size HW can't NACK
* it immediately, it will read extra byte and then NACK.
*/
if (bus->rd_ind == 0 && bus->read_block_use) {
/* set fifo to read one byte, no last: */
rxf_ctl = 1;
}
/* set fifo size: */
iowrite8(rxf_ctl, bus->reg + NPCM_I2CRXF_CTL);
}
/* configure TX FIFO */
if (nwrite > 0) {
if (nwrite > I2C_HW_FIFO_SIZE)
/* data to send is more then FIFO size. */
iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CTXF_CTL);
else
iowrite8(nwrite, bus->reg + NPCM_I2CTXF_CTL);
npcm_i2c_clear_tx_fifo(bus);
}
}
static void npcm_i2c_read_fifo(struct npcm_i2c *bus, u8 bytes_in_fifo)
{
u8 data;
while (bytes_in_fifo--) {
data = npcm_i2c_rd_byte(bus);
if (bus->rd_ind < bus->rd_size)
bus->rd_buf[bus->rd_ind++] = data;
}
}
static void npcm_i2c_master_abort(struct npcm_i2c *bus)
{
/* Only current master is allowed to issue a stop condition */
if (!npcm_i2c_is_master(bus))
return;
npcm_i2c_eob_int(bus, true);
npcm_i2c_master_stop(bus);
npcm_i2c_clear_master_status(bus);
}
#if IS_ENABLED(CONFIG_I2C_SLAVE)
static u8 npcm_i2c_get_slave_addr(struct npcm_i2c *bus, enum i2c_addr addr_type)
{
u8 slave_add;
/* select bank 0 for address 3 to 10 */
if (addr_type > I2C_SLAVE_ADDR2)
npcm_i2c_select_bank(bus, I2C_BANK_0);
slave_add = ioread8(bus->reg + npcm_i2caddr[(int)addr_type]);
if (addr_type > I2C_SLAVE_ADDR2)
npcm_i2c_select_bank(bus, I2C_BANK_1);
return slave_add;
}
static int npcm_i2c_remove_slave_addr(struct npcm_i2c *bus, u8 slave_add)
{
int i;
/* Set the enable bit */
slave_add |= 0x80;
npcm_i2c_select_bank(bus, I2C_BANK_0);
for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR; i++) {
if (ioread8(bus->reg + npcm_i2caddr[i]) == slave_add)
iowrite8(0, bus->reg + npcm_i2caddr[i]);
}
npcm_i2c_select_bank(bus, I2C_BANK_1);
return 0;
}
static void npcm_i2c_write_fifo_slave(struct npcm_i2c *bus, u16 max_bytes)
{
/*
* Fill the FIFO, while the FIFO is not full and there are more bytes
* to write
*/
npcm_i2c_clear_fifo_int(bus);
npcm_i2c_clear_tx_fifo(bus);
iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
while (max_bytes-- && I2C_HW_FIFO_SIZE != npcm_i2c_fifo_usage(bus)) {
if (bus->slv_wr_size <= 0)
break;
bus->slv_wr_ind = bus->slv_wr_ind % I2C_HW_FIFO_SIZE;
npcm_i2c_wr_byte(bus, bus->slv_wr_buf[bus->slv_wr_ind]);
bus->slv_wr_ind++;
bus->slv_wr_ind = bus->slv_wr_ind % I2C_HW_FIFO_SIZE;
bus->slv_wr_size--;
}
}
static void npcm_i2c_read_fifo_slave(struct npcm_i2c *bus, u8 bytes_in_fifo)
{
u8 data;
if (!bus->slave)
return;
while (bytes_in_fifo--) {
data = npcm_i2c_rd_byte(bus);
bus->slv_rd_ind = bus->slv_rd_ind % I2C_HW_FIFO_SIZE;
bus->slv_rd_buf[bus->slv_rd_ind] = data;
bus->slv_rd_ind++;
/* 1st byte is length in block protocol: */
if (bus->slv_rd_ind == 1 && bus->read_block_use)
bus->slv_rd_size = data + bus->PEC_use + 1;
}
}
static int npcm_i2c_slave_get_wr_buf(struct npcm_i2c *bus)
{
int i;
u8 value;
int ind;
int ret = bus->slv_wr_ind;
/* fill a cyclic buffer */
for (i = 0; i < I2C_HW_FIFO_SIZE; i++) {
if (bus->slv_wr_size >= I2C_HW_FIFO_SIZE)
break;
i2c_slave_event(bus->slave, I2C_SLAVE_READ_REQUESTED, &value);
ind = (bus->slv_wr_ind + bus->slv_wr_size) % I2C_HW_FIFO_SIZE;
bus->slv_wr_buf[ind] = value;
bus->slv_wr_size++;
i2c_slave_event(bus->slave, I2C_SLAVE_READ_PROCESSED, &value);
}
return I2C_HW_FIFO_SIZE - ret;
}
static void npcm_i2c_slave_send_rd_buf(struct npcm_i2c *bus)
{
int i;
for (i = 0; i < bus->slv_rd_ind; i++)
i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_RECEIVED,
&bus->slv_rd_buf[i]);
/*
* once we send bytes up, need to reset the counter of the wr buf
* got data from master (new offset in device), ignore wr fifo:
*/
if (bus->slv_rd_ind) {
bus->slv_wr_size = 0;
bus->slv_wr_ind = 0;
}
bus->slv_rd_ind = 0;
bus->slv_rd_size = bus->adap.quirks->max_read_len;
npcm_i2c_clear_fifo_int(bus);
npcm_i2c_clear_rx_fifo(bus);
}
static void npcm_i2c_slave_receive(struct npcm_i2c *bus, u16 nread,
u8 *read_data)
{
bus->state = I2C_OPER_STARTED;
bus->operation = I2C_READ_OPER;
bus->slv_rd_size = nread;
bus->slv_rd_ind = 0;
iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CRXF_CTL);
npcm_i2c_clear_tx_fifo(bus);
npcm_i2c_clear_rx_fifo(bus);
}
static void npcm_i2c_slave_xmit(struct npcm_i2c *bus, u16 nwrite,
u8 *write_data)
{
if (nwrite == 0)
return;
bus->state = I2C_OPER_STARTED;
bus->operation = I2C_WRITE_OPER;
/* get the next buffer */
npcm_i2c_slave_get_wr_buf(bus);
npcm_i2c_write_fifo_slave(bus, nwrite);
}
/*
* npcm_i2c_slave_wr_buf_sync:
* currently slave IF only supports single byte operations.
* in order to utilize the npcm HW FIFO, the driver will ask for 16 bytes
* at a time, pack them in buffer, and then transmit them all together
* to the FIFO and onward to the bus.
* NACK on read will be once reached to bus->adap->quirks->max_read_len.
* sending a NACK wherever the backend requests for it is not supported.
* the next two functions allow reading to local buffer before writing it all
* to the HW FIFO.
*/
static void npcm_i2c_slave_wr_buf_sync(struct npcm_i2c *bus)
{
int left_in_fifo;
left_in_fifo = FIELD_GET(NPCM_I2CTXF_STS_TX_BYTES,
ioread8(bus->reg + NPCM_I2CTXF_STS));
/* fifo already full: */
if (left_in_fifo >= I2C_HW_FIFO_SIZE ||
bus->slv_wr_size >= I2C_HW_FIFO_SIZE)
return;
/* update the wr fifo index back to the untransmitted bytes: */
bus->slv_wr_ind = bus->slv_wr_ind - left_in_fifo;
bus->slv_wr_size = bus->slv_wr_size + left_in_fifo;
if (bus->slv_wr_ind < 0)
bus->slv_wr_ind += I2C_HW_FIFO_SIZE;
}
static void npcm_i2c_slave_rd_wr(struct npcm_i2c *bus)
{
if (NPCM_I2CST_XMIT & ioread8(bus->reg + NPCM_I2CST)) {
/*
* Slave got an address match with direction bit 1 so it should
* transmit data. Write till the master will NACK
*/
bus->operation = I2C_WRITE_OPER;
npcm_i2c_slave_xmit(bus, bus->adap.quirks->max_write_len,
bus->slv_wr_buf);
} else {
/*
* Slave got an address match with direction bit 0 so it should
* receive data.
* this module does not support saying no to bytes.
* it will always ACK.
*/
bus->operation = I2C_READ_OPER;
npcm_i2c_read_fifo_slave(bus, npcm_i2c_fifo_usage(bus));
bus->stop_ind = I2C_SLAVE_RCV_IND;
npcm_i2c_slave_send_rd_buf(bus);
npcm_i2c_slave_receive(bus, bus->adap.quirks->max_read_len,
bus->slv_rd_buf);
}
}
static irqreturn_t npcm_i2c_int_slave_handler(struct npcm_i2c *bus)
{
u8 val;
irqreturn_t ret = IRQ_NONE;
u8 i2cst = ioread8(bus->reg + NPCM_I2CST);
/* Slave: A NACK has occurred */
if (NPCM_I2CST_NEGACK & i2cst) {
bus->stop_ind = I2C_NACK_IND;
npcm_i2c_slave_wr_buf_sync(bus);
if (bus->fifo_use)
/* clear the FIFO */
iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO,
bus->reg + NPCM_I2CFIF_CTS);
/* In slave write, NACK is OK, otherwise it is a problem */
bus->stop_ind = I2C_NO_STATUS_IND;
bus->operation = I2C_NO_OPER;
bus->own_slave_addr = 0xFF;
/*
* Slave has to wait for STOP to decide this is the end
* of the transaction. tx is not yet considered as done
*/
iowrite8(NPCM_I2CST_NEGACK, bus->reg + NPCM_I2CST);
ret = IRQ_HANDLED;
}
/* Slave mode: a Bus Error (BER) has been identified */
if (NPCM_I2CST_BER & i2cst) {
/*
* Check whether bus arbitration or Start or Stop during data
* xfer bus arbitration problem should not result in recovery
*/
bus->stop_ind = I2C_BUS_ERR_IND;
/* wait for bus busy before clear fifo */
iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
bus->state = I2C_IDLE;
/*
* in BER case we might get 2 interrupts: one for slave one for
* master ( for a channel which is master\slave switching)
*/
if (completion_done(&bus->cmd_complete) == false) {
bus->cmd_err = -EIO;
complete(&bus->cmd_complete);
}
bus->own_slave_addr = 0xFF;
iowrite8(NPCM_I2CST_BER, bus->reg + NPCM_I2CST);
ret = IRQ_HANDLED;
}
/* A Slave Stop Condition has been identified */
if (NPCM_I2CST_SLVSTP & i2cst) {
u8 bytes_in_fifo = npcm_i2c_fifo_usage(bus);
bus->stop_ind = I2C_SLAVE_DONE_IND;
if (bus->operation == I2C_READ_OPER)
npcm_i2c_read_fifo_slave(bus, bytes_in_fifo);
/* if the buffer is empty nothing will be sent */
npcm_i2c_slave_send_rd_buf(bus);
/* Slave done transmitting or receiving */
bus->stop_ind = I2C_NO_STATUS_IND;
/*
* Note, just because we got here, it doesn't mean we through
* away the wr buffer.
* we keep it until the next received offset.
*/
bus->operation = I2C_NO_OPER;
bus->own_slave_addr = 0xFF;
i2c_slave_event(bus->slave, I2C_SLAVE_STOP, 0);
iowrite8(NPCM_I2CST_SLVSTP, bus->reg + NPCM_I2CST);
if (bus->fifo_use) {
npcm_i2c_clear_fifo_int(bus);
npcm_i2c_clear_rx_fifo(bus);
npcm_i2c_clear_tx_fifo(bus);
iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO,
bus->reg + NPCM_I2CFIF_CTS);
}
bus->state = I2C_IDLE;
ret = IRQ_HANDLED;
}
/* restart condition occurred and Rx-FIFO was not empty */
if (bus->fifo_use && FIELD_GET(NPCM_I2CFIF_CTS_SLVRSTR,
ioread8(bus->reg + NPCM_I2CFIF_CTS))) {
bus->stop_ind = I2C_SLAVE_RESTART_IND;
bus->master_or_slave = I2C_SLAVE;
if (bus->operation == I2C_READ_OPER)
npcm_i2c_read_fifo_slave(bus, npcm_i2c_fifo_usage(bus));
bus->operation = I2C_WRITE_OPER;
iowrite8(0, bus->reg + NPCM_I2CRXF_CTL);
val = NPCM_I2CFIF_CTS_CLR_FIFO | NPCM_I2CFIF_CTS_SLVRSTR |
NPCM_I2CFIF_CTS_RXF_TXE;
iowrite8(val, bus->reg + NPCM_I2CFIF_CTS);
npcm_i2c_slave_rd_wr(bus);
ret = IRQ_HANDLED;
}
/* A Slave Address Match has been identified */
if (NPCM_I2CST_NMATCH & i2cst) {
u8 info = 0;
/* Address match automatically implies slave mode */
bus->master_or_slave = I2C_SLAVE;
npcm_i2c_clear_fifo_int(bus);
npcm_i2c_clear_rx_fifo(bus);
npcm_i2c_clear_tx_fifo(bus);
iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CRXF_CTL);
if (NPCM_I2CST_XMIT & i2cst) {
bus->operation = I2C_WRITE_OPER;
} else {
i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_REQUESTED,
&info);
bus->operation = I2C_READ_OPER;
}
if (bus->own_slave_addr == 0xFF) {
/* Check which type of address match */
val = ioread8(bus->reg + NPCM_I2CCST);
if (NPCM_I2CCST_MATCH & val) {
u16 addr;
enum i2c_addr eaddr;
u8 i2ccst2;
u8 i2ccst3;
i2ccst3 = ioread8(bus->reg + NPCM_I2CCST3);
i2ccst2 = ioread8(bus->reg + NPCM_I2CCST2);
/*
* the i2c module can response to 10 own SA.
* check which one was addressed by the master.
* respond to the first one.
*/
addr = ((i2ccst3 & 0x07) << 7) |
(i2ccst2 & 0x7F);
info = ffs(addr);
eaddr = (enum i2c_addr)info;
addr = npcm_i2c_get_slave_addr(bus, eaddr);
addr &= 0x7F;
bus->own_slave_addr = addr;
if (bus->PEC_mask & BIT(info))
bus->PEC_use = true;
else
bus->PEC_use = false;
} else {
if (NPCM_I2CCST_GCMATCH & val)
bus->own_slave_addr = 0;
if (NPCM_I2CCST_ARPMATCH & val)
bus->own_slave_addr = 0x61;
}
} else {
/*
* Slave match can happen in two options:
* 1. Start, SA, read (slave read without further ado)
* 2. Start, SA, read, data, restart, SA, read, ...
* (slave read in fragmented mode)
* 3. Start, SA, write, data, restart, SA, read, ..
* (regular write-read mode)
*/
if ((bus->state == I2C_OPER_STARTED &&
bus->operation == I2C_READ_OPER &&
bus->stop_ind == I2C_SLAVE_XMIT_IND) ||
bus->stop_ind == I2C_SLAVE_RCV_IND) {
/* slave tx after slave rx w/o STOP */
bus->stop_ind = I2C_SLAVE_RESTART_IND;
}
}
if (NPCM_I2CST_XMIT & i2cst)
bus->stop_ind = I2C_SLAVE_XMIT_IND;
else
bus->stop_ind = I2C_SLAVE_RCV_IND;
bus->state = I2C_SLAVE_MATCH;
npcm_i2c_slave_rd_wr(bus);
iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST);
ret = IRQ_HANDLED;
}
/* Slave SDA status is set - tx or rx */
if ((NPCM_I2CST_SDAST & i2cst) ||
(bus->fifo_use &&
(npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) {
npcm_i2c_slave_rd_wr(bus);
iowrite8(NPCM_I2CST_SDAST, bus->reg + NPCM_I2CST);
ret = IRQ_HANDLED;
} /* SDAST */
/*
* if irq is not one of the above, make sure EOB is disabled and all
* status bits are cleared.
*/
if (ret == IRQ_NONE) {
npcm_i2c_eob_int(bus, false);
npcm_i2c_clear_master_status(bus);
}
return IRQ_HANDLED;
}
static int npcm_i2c_reg_slave(struct i2c_client *client)
{
unsigned long lock_flags;
struct npcm_i2c *bus = i2c_get_adapdata(client->adapter);
bus->slave = client;
if (!bus->slave)
return -EINVAL;
if (client->flags & I2C_CLIENT_TEN)
return -EAFNOSUPPORT;
spin_lock_irqsave(&bus->lock, lock_flags);
npcm_i2c_init_params(bus);
bus->slv_rd_size = 0;
bus->slv_wr_size = 0;
bus->slv_rd_ind = 0;
bus->slv_wr_ind = 0;
if (client->flags & I2C_CLIENT_PEC)
bus->PEC_use = true;
dev_info(bus->dev, "i2c%d register slave SA=0x%x, PEC=%d\n", bus->num,
client->addr, bus->PEC_use);
npcm_i2c_slave_enable(bus, I2C_SLAVE_ADDR1, client->addr, true);
npcm_i2c_clear_fifo_int(bus);
npcm_i2c_clear_rx_fifo(bus);
npcm_i2c_clear_tx_fifo(bus);
npcm_i2c_slave_int_enable(bus, true);
spin_unlock_irqrestore(&bus->lock, lock_flags);
return 0;
}
static int npcm_i2c_unreg_slave(struct i2c_client *client)
{
struct npcm_i2c *bus = client->adapter->algo_data;
unsigned long lock_flags;
spin_lock_irqsave(&bus->lock, lock_flags);
if (!bus->slave) {
spin_unlock_irqrestore(&bus->lock, lock_flags);
return -EINVAL;
}
npcm_i2c_slave_int_enable(bus, false);
npcm_i2c_remove_slave_addr(bus, client->addr);
bus->slave = NULL;
spin_unlock_irqrestore(&bus->lock, lock_flags);
return 0;
}
#endif /* CONFIG_I2C_SLAVE */
static void npcm_i2c_master_fifo_read(struct npcm_i2c *bus)
{
int rcount;
int fifo_bytes;
enum i2c_state_ind ind = I2C_MASTER_DONE_IND;
fifo_bytes = npcm_i2c_fifo_usage(bus);
rcount = bus->rd_size - bus->rd_ind;
/*
* In order not to change the RX_TRH during transaction (we found that
* this might be problematic if it takes too much time to read the FIFO)
* we read the data in the following way. If the number of bytes to
* read == FIFO Size + C (where C < FIFO Size)then first read C bytes
* and in the next int we read rest of the data.
*/
if (rcount < (2 * I2C_HW_FIFO_SIZE) && rcount > I2C_HW_FIFO_SIZE)
fifo_bytes = rcount - I2C_HW_FIFO_SIZE;
if (rcount <= fifo_bytes) {
/* last bytes are about to be read - end of tx */
bus->state = I2C_STOP_PENDING;
bus->stop_ind = ind;
npcm_i2c_eob_int(bus, true);
/* Stop should be set before reading last byte. */
npcm_i2c_master_stop(bus);
npcm_i2c_read_fifo(bus, fifo_bytes);
} else {
npcm_i2c_read_fifo(bus, fifo_bytes);
rcount = bus->rd_size - bus->rd_ind;
npcm_i2c_set_fifo(bus, rcount, -1);
}
}
static void npcm_i2c_irq_master_handler_write(struct npcm_i2c *bus)
{
u16 wcount;
if (bus->fifo_use)
npcm_i2c_clear_tx_fifo(bus); /* clear the TX fifo status bit */
/* Master write operation - last byte handling */
if (bus->wr_ind == bus->wr_size) {
if (bus->fifo_use && npcm_i2c_fifo_usage(bus) > 0)
/*
* No more bytes to send (to add to the FIFO),
* however the FIFO is not empty yet. It is
* still in the middle of tx. Currently there's nothing
* to do except for waiting to the end of the tx
* We will get an int when the FIFO will get empty.
*/
return;
if (bus->rd_size == 0) {
/* all bytes have been written, in wr only operation */
npcm_i2c_eob_int(bus, true);
bus->state = I2C_STOP_PENDING;
bus->stop_ind = I2C_MASTER_DONE_IND;
npcm_i2c_master_stop(bus);
/* Clear SDA Status bit (by writing dummy byte) */
npcm_i2c_wr_byte(bus, 0xFF);
} else {
/* last write-byte written on previous int - restart */
npcm_i2c_set_fifo(bus, bus->rd_size, -1);
/* Generate repeated start upon next write to SDA */
npcm_i2c_master_start(bus);
/*
* Receiving one byte only - stall after successful
* completion of send address byte. If we NACK here, and
* slave doesn't ACK the address, we might
* unintentionally NACK the next multi-byte read.
*/
if (bus->rd_size == 1)
npcm_i2c_stall_after_start(bus, true);
/* Next int will occur on read */
bus->operation = I2C_READ_OPER;
/* send the slave address in read direction */
npcm_i2c_wr_byte(bus, bus->dest_addr | 0x1);
}
} else {
/* write next byte not last byte and not slave address */
if (!bus->fifo_use || bus->wr_size == 1) {
npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]);
} else {
wcount = bus->wr_size - bus->wr_ind;
npcm_i2c_set_fifo(bus, -1, wcount);
if (wcount)
npcm_i2c_write_to_fifo_master(bus, wcount);
}
}
}
static void npcm_i2c_irq_master_handler_read(struct npcm_i2c *bus)
{
u16 block_extra_bytes_size;
u8 data;
/* added bytes to the packet: */
block_extra_bytes_size = bus->read_block_use + bus->PEC_use;
/*
* Perform master read, distinguishing between last byte and the rest of
* the bytes. The last byte should be read when the clock is stopped
*/
if (bus->rd_ind == 0) { /* first byte handling: */
if (bus->read_block_use) {
/* first byte in block protocol is the size: */
data = npcm_i2c_rd_byte(bus);
data = clamp_val(data, 1, I2C_SMBUS_BLOCK_MAX);
bus->rd_size = data + block_extra_bytes_size;
bus->rd_buf[bus->rd_ind++] = data;
/* clear RX FIFO interrupt status: */
if (bus->fifo_use) {
data = ioread8(bus->reg + NPCM_I2CFIF_CTS);
data = data | NPCM_I2CFIF_CTS_RXF_TXE;
iowrite8(data, bus->reg + NPCM_I2CFIF_CTS);
}
npcm_i2c_set_fifo(bus, bus->rd_size - 1, -1);
npcm_i2c_stall_after_start(bus, false);
} else {
npcm_i2c_clear_tx_fifo(bus);
npcm_i2c_master_fifo_read(bus);
}
} else {
if (bus->rd_size == block_extra_bytes_size &&
bus->read_block_use) {
bus->state = I2C_STOP_PENDING;
bus->stop_ind = I2C_BLOCK_BYTES_ERR_IND;
bus->cmd_err = -EIO;
npcm_i2c_eob_int(bus, true);
npcm_i2c_master_stop(bus);
npcm_i2c_read_fifo(bus, npcm_i2c_fifo_usage(bus));
} else {
npcm_i2c_master_fifo_read(bus);
}
}
}
static void npcm_i2c_irq_handle_nmatch(struct npcm_i2c *bus)
{
iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST);
npcm_i2c_nack(bus);
bus->stop_ind = I2C_BUS_ERR_IND;
npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus));
}
/* A NACK has occurred */
static void npcm_i2c_irq_handle_nack(struct npcm_i2c *bus)
{
u8 val;
if (bus->nack_cnt < ULLONG_MAX)
bus->nack_cnt++;
if (bus->fifo_use) {
/*
* if there are still untransmitted bytes in TX FIFO
* reduce them from wr_ind
*/
if (bus->operation == I2C_WRITE_OPER)
bus->wr_ind -= npcm_i2c_fifo_usage(bus);
/* clear the FIFO */
iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
}
/* In master write operation, got unexpected NACK */
bus->stop_ind = I2C_NACK_IND;
/* Only current master is allowed to issue Stop Condition */
if (npcm_i2c_is_master(bus)) {
/* stopping in the middle */
npcm_i2c_eob_int(bus, false);
npcm_i2c_master_stop(bus);
/* Clear SDA Status bit (by reading dummy byte) */
npcm_i2c_rd_byte(bus);
/*
* The bus is released from stall only after the SW clears
* NEGACK bit. Then a Stop condition is sent.
*/
npcm_i2c_clear_master_status(bus);
readx_poll_timeout_atomic(ioread8, bus->reg + NPCM_I2CCST, val,
!(val & NPCM_I2CCST_BUSY), 10, 200);
/* verify no status bits are still set after bus is released */
npcm_i2c_clear_master_status(bus);
}
bus->state = I2C_IDLE;
/*
* In Master mode, NACK should be cleared only after STOP.
* In such case, the bus is released from stall only after the
* software clears NACK bit. Then a Stop condition is sent.
*/
npcm_i2c_callback(bus, bus->stop_ind, bus->wr_ind);
}
/* Master mode: a Bus Error has been identified */
static void npcm_i2c_irq_handle_ber(struct npcm_i2c *bus)
{
if (bus->ber_cnt < ULLONG_MAX)
bus->ber_cnt++;
bus->stop_ind = I2C_BUS_ERR_IND;
if (npcm_i2c_is_master(bus)) {
npcm_i2c_master_abort(bus);
} else {
npcm_i2c_clear_master_status(bus);
/* Clear BB (BUS BUSY) bit */
iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
bus->cmd_err = -EAGAIN;
npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus));
}
bus->state = I2C_IDLE;
}
/* EOB: a master End Of Busy (meaning STOP completed) */
static void npcm_i2c_irq_handle_eob(struct npcm_i2c *bus)
{
npcm_i2c_eob_int(bus, false);
bus->state = I2C_IDLE;
npcm_i2c_callback(bus, bus->stop_ind, bus->rd_ind);
}
/* Address sent and requested stall occurred (Master mode) */
static void npcm_i2c_irq_handle_stall_after_start(struct npcm_i2c *bus)
{
if (npcm_i2c_is_quick(bus)) {
bus->state = I2C_STOP_PENDING;
bus->stop_ind = I2C_MASTER_DONE_IND;
npcm_i2c_eob_int(bus, true);
npcm_i2c_master_stop(bus);
} else if ((bus->rd_size == 1) && !bus->read_block_use) {
/*
* Receiving one byte only - set NACK after ensuring
* slave ACKed the address byte.
*/
npcm_i2c_nack(bus);
}
/* Reset stall-after-address-byte */
npcm_i2c_stall_after_start(bus, false);
/* Clear stall only after setting STOP */
iowrite8(NPCM_I2CST_STASTR, bus->reg + NPCM_I2CST);
}
/* SDA status is set - TX or RX, master */
static void npcm_i2c_irq_handle_sda(struct npcm_i2c *bus, u8 i2cst)
{
u8 fif_cts;
if (!npcm_i2c_is_master(bus))
return;
if (bus->state == I2C_IDLE) {
bus->stop_ind = I2C_WAKE_UP_IND;
if (npcm_i2c_is_quick(bus) || bus->read_block_use)
/*
* Need to stall after successful
* completion of sending address byte
*/
npcm_i2c_stall_after_start(bus, true);
else
npcm_i2c_stall_after_start(bus, false);
/*
* Receiving one byte only - stall after successful completion
* of sending address byte If we NACK here, and slave doesn't
* ACK the address, we might unintentionally NACK the next
* multi-byte read
*/
if (bus->wr_size == 0 && bus->rd_size == 1)
npcm_i2c_stall_after_start(bus, true);
/* Initiate I2C master tx */
/* select bank 1 for FIFO regs */
npcm_i2c_select_bank(bus, I2C_BANK_1);
fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS);
fif_cts = fif_cts & ~NPCM_I2CFIF_CTS_SLVRSTR;
/* clear FIFO and relevant status bits. */
fif_cts = fif_cts | NPCM_I2CFIF_CTS_CLR_FIFO;
iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS);
/* re-enable */
fif_cts = fif_cts | NPCM_I2CFIF_CTS_RXF_TXE;
iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS);
/*
* Configure the FIFO threshold:
* according to the needed # of bytes to read.
* Note: due to HW limitation can't config the rx fifo before it
* got and ACK on the restart. LAST bit will not be reset unless
* RX completed. It will stay set on the next tx.
*/
if (bus->wr_size)
npcm_i2c_set_fifo(bus, -1, bus->wr_size);
else
npcm_i2c_set_fifo(bus, bus->rd_size, -1);
bus->state = I2C_OPER_STARTED;
if (npcm_i2c_is_quick(bus) || bus->wr_size)
npcm_i2c_wr_byte(bus, bus->dest_addr);
else
npcm_i2c_wr_byte(bus, bus->dest_addr | BIT(0));
/* SDA interrupt, after start\restart */
} else {
if (NPCM_I2CST_XMIT & i2cst) {
bus->operation = I2C_WRITE_OPER;
npcm_i2c_irq_master_handler_write(bus);
} else {
bus->operation = I2C_READ_OPER;
npcm_i2c_irq_master_handler_read(bus);
}
}
}
static int npcm_i2c_int_master_handler(struct npcm_i2c *bus)
{
u8 i2cst;
int ret = -EIO;
i2cst = ioread8(bus->reg + NPCM_I2CST);
if (FIELD_GET(NPCM_I2CST_NMATCH, i2cst)) {
npcm_i2c_irq_handle_nmatch(bus);
return 0;
}
/* A NACK has occurred */
if (FIELD_GET(NPCM_I2CST_NEGACK, i2cst)) {
npcm_i2c_irq_handle_nack(bus);
return 0;
}
/* Master mode: a Bus Error has been identified */
if (FIELD_GET(NPCM_I2CST_BER, i2cst)) {
npcm_i2c_irq_handle_ber(bus);
return 0;
}
/* EOB: a master End Of Busy (meaning STOP completed) */
if ((FIELD_GET(NPCM_I2CCTL1_EOBINTE,
ioread8(bus->reg + NPCM_I2CCTL1)) == 1) &&
(FIELD_GET(NPCM_I2CCST3_EO_BUSY,
ioread8(bus->reg + NPCM_I2CCST3)))) {
npcm_i2c_irq_handle_eob(bus);
return 0;
}
/* Address sent and requested stall occurred (Master mode) */
if (FIELD_GET(NPCM_I2CST_STASTR, i2cst)) {
npcm_i2c_irq_handle_stall_after_start(bus);
ret = 0;
}
/* SDA status is set - TX or RX, master */
if (FIELD_GET(NPCM_I2CST_SDAST, i2cst) ||
(bus->fifo_use &&
(npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) {
npcm_i2c_irq_handle_sda(bus, i2cst);
ret = 0;
}
return ret;
}
/* recovery using TGCLK functionality of the module */
static int npcm_i2c_recovery_tgclk(struct i2c_adapter *_adap)
{
u8 val;
u8 fif_cts;
bool done = false;
int status = -ENOTRECOVERABLE;
struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
/* Allow 3 bytes (27 toggles) to be read from the slave: */
int iter = 27;
if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1)) {
dev_dbg(bus->dev, "bus%d-0x%x recovery skipped, bus not stuck",
bus->num, bus->dest_addr);
npcm_i2c_reset(bus);
return 0;
}
npcm_i2c_int_enable(bus, false);
npcm_i2c_disable(bus);
npcm_i2c_enable(bus);
iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
npcm_i2c_clear_tx_fifo(bus);
npcm_i2c_clear_rx_fifo(bus);
iowrite8(0, bus->reg + NPCM_I2CRXF_CTL);
iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
npcm_i2c_stall_after_start(bus, false);
/* select bank 1 for FIFO regs */
npcm_i2c_select_bank(bus, I2C_BANK_1);
/* clear FIFO and relevant status bits. */
fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS);
fif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR;
fif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO;
iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS);
npcm_i2c_set_fifo(bus, -1, 0);
/* Repeat the following sequence until SDA is released */
do {
/* Issue a single SCL toggle */
iowrite8(NPCM_I2CCST_TGSCL, bus->reg + NPCM_I2CCST);
usleep_range(20, 30);
/* If SDA line is inactive (high), stop */
if (npcm_i2c_get_SDA(_adap)) {
done = true;
status = 0;
}
} while (!done && iter--);
/* If SDA line is released: send start-addr-stop, to re-sync. */
if (npcm_i2c_get_SDA(_adap)) {
/* Send an address byte in write direction: */
npcm_i2c_wr_byte(bus, bus->dest_addr);
npcm_i2c_master_start(bus);
/* Wait until START condition is sent */
status = readx_poll_timeout(npcm_i2c_get_SCL, _adap, val, !val,
20, 200);
/* If START condition was sent */
if (npcm_i2c_is_master(bus) > 0) {
usleep_range(20, 30);
npcm_i2c_master_stop(bus);
usleep_range(200, 500);
}
}
npcm_i2c_reset(bus);
npcm_i2c_int_enable(bus, true);
if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1))
status = 0;
else
status = -ENOTRECOVERABLE;
if (status) {
if (bus->rec_fail_cnt < ULLONG_MAX)
bus->rec_fail_cnt++;
} else {
if (bus->rec_succ_cnt < ULLONG_MAX)
bus->rec_succ_cnt++;
}
return status;
}
/* recovery using bit banging functionality of the module */
static void npcm_i2c_recovery_init(struct i2c_adapter *_adap)
{
struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
struct i2c_bus_recovery_info *rinfo = &bus->rinfo;
rinfo->recover_bus = npcm_i2c_recovery_tgclk;
/*
* npcm i2c HW allows direct reading of SCL and SDA.
* However, it does not support setting SCL and SDA directly.
* The recovery function can toggle SCL when SDA is low (but not set)
* Getter functions used internally, and can be used externally.
*/
rinfo->get_scl = npcm_i2c_get_SCL;
rinfo->get_sda = npcm_i2c_get_SDA;
_adap->bus_recovery_info = rinfo;
}
/* SCLFRQ min/max field values */
#define SCLFRQ_MIN 10
#define SCLFRQ_MAX 511
#define clk_coef(freq, mul) DIV_ROUND_UP((freq) * (mul), 1000000)
/*
* npcm_i2c_init_clk: init HW timing parameters.
* NPCM7XX i2c module timing parameters are dependent on module core clk (APB)
* and bus frequency.
* 100kHz bus requires tSCL = 4 * SCLFRQ * tCLK. LT and HT are symmetric.
* 400kHz bus requires asymmetric HT and LT. A different equation is recommended
* by the HW designer, given core clock range (equations in comments below).
*
*/
static int npcm_i2c_init_clk(struct npcm_i2c *bus, u32 bus_freq_hz)
{
u32 k1 = 0;
u32 k2 = 0;
u8 dbnct = 0;
u32 sclfrq = 0;
u8 hldt = 7;
u8 fast_mode = 0;
u32 src_clk_khz;
u32 bus_freq_khz;
src_clk_khz = bus->apb_clk / 1000;
bus_freq_khz = bus_freq_hz / 1000;
bus->bus_freq = bus_freq_hz;
/* 100KHz and below: */
if (bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ) {
sclfrq = src_clk_khz / (bus_freq_khz * 4);
if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX)
return -EDOM;
if (src_clk_khz >= 40000)
hldt = 17;
else if (src_clk_khz >= 12500)
hldt = 15;
else
hldt = 7;
}
/* 400KHz: */
else if (bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ) {
sclfrq = 0;
fast_mode = I2CCTL3_400K_MODE;
if (src_clk_khz < 7500)
/* 400KHZ cannot be supported for core clock < 7.5MHz */
return -EDOM;
else if (src_clk_khz >= 50000) {
k1 = 80;
k2 = 48;
hldt = 12;
dbnct = 7;
}
/* Master or Slave with frequency > 25MHz */
else if (src_clk_khz > 25000) {
hldt = clk_coef(src_clk_khz, 300) + 7;
k1 = clk_coef(src_clk_khz, 1600);
k2 = clk_coef(src_clk_khz, 900);
}
}
/* 1MHz: */
else if (bus_freq_hz <= I2C_MAX_FAST_MODE_PLUS_FREQ) {
sclfrq = 0;
fast_mode = I2CCTL3_400K_MODE;
/* 1MHZ cannot be supported for core clock < 24 MHz */
if (src_clk_khz < 24000)
return -EDOM;
k1 = clk_coef(src_clk_khz, 620);
k2 = clk_coef(src_clk_khz, 380);
/* Core clk > 40 MHz */
if (src_clk_khz > 40000) {
/*
* Set HLDT:
* SDA hold time: (HLDT-7) * T(CLK) >= 120
* HLDT = 120/T(CLK) + 7 = 120 * FREQ(CLK) + 7
*/
hldt = clk_coef(src_clk_khz, 120) + 7;
} else {
hldt = 7;
dbnct = 2;
}
}
/* Frequency larger than 1 MHz is not supported */
else
return -EINVAL;
if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) {
k1 = round_up(k1, 2);
k2 = round_up(k2 + 1, 2);
if (k1 < SCLFRQ_MIN || k1 > SCLFRQ_MAX ||
k2 < SCLFRQ_MIN || k2 > SCLFRQ_MAX)
return -EDOM;
}
/* write sclfrq value. bits [6:0] are in I2CCTL2 reg */
iowrite8(FIELD_PREP(I2CCTL2_SCLFRQ6_0, sclfrq & 0x7F),
bus->reg + NPCM_I2CCTL2);
/* bits [8:7] are in I2CCTL3 reg */
iowrite8(fast_mode | FIELD_PREP(I2CCTL3_SCLFRQ8_7, (sclfrq >> 7) & 0x3),
bus->reg + NPCM_I2CCTL3);
/* Select Bank 0 to access NPCM_I2CCTL4/NPCM_I2CCTL5 */
npcm_i2c_select_bank(bus, I2C_BANK_0);
if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) {
/*
* Set SCL Low/High Time:
* k1 = 2 * SCLLT7-0 -> Low Time = k1 / 2
* k2 = 2 * SCLLT7-0 -> High Time = k2 / 2
*/
iowrite8(k1 / 2, bus->reg + NPCM_I2CSCLLT);
iowrite8(k2 / 2, bus->reg + NPCM_I2CSCLHT);
iowrite8(dbnct, bus->reg + NPCM_I2CCTL5);
}
iowrite8(hldt, bus->reg + NPCM_I2CCTL4);
/* Return to Bank 1, and stay there by default: */
npcm_i2c_select_bank(bus, I2C_BANK_1);
return 0;
}
static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
u32 bus_freq_hz)
{
u8 val;
int ret;
/* Check whether module already enabled or frequency is out of bounds */
if ((bus->state != I2C_DISABLE && bus->state != I2C_IDLE) ||
bus_freq_hz < I2C_FREQ_MIN_HZ || bus_freq_hz > I2C_FREQ_MAX_HZ)
return -EINVAL;
npcm_i2c_int_enable(bus, false);
npcm_i2c_disable(bus);
/* Configure FIFO mode : */
if (FIELD_GET(I2C_VER_FIFO_EN, ioread8(bus->reg + I2C_VER))) {
bus->fifo_use = true;
npcm_i2c_select_bank(bus, I2C_BANK_0);
val = ioread8(bus->reg + NPCM_I2CFIF_CTL);
val |= NPCM_I2CFIF_CTL_FIFO_EN;
iowrite8(val, bus->reg + NPCM_I2CFIF_CTL);
npcm_i2c_select_bank(bus, I2C_BANK_1);
} else {
bus->fifo_use = false;
}
/* Configure I2C module clock frequency */
ret = npcm_i2c_init_clk(bus, bus_freq_hz);
if (ret) {
dev_err(bus->dev, "npcm_i2c_init_clk failed\n");
return ret;
}
/* Enable module (before configuring CTL1) */
npcm_i2c_enable(bus);
bus->state = I2C_IDLE;
val = ioread8(bus->reg + NPCM_I2CCTL1);
val = (val | NPCM_I2CCTL1_NMINTE) & ~NPCM_I2CCTL1_RWS;
iowrite8(val, bus->reg + NPCM_I2CCTL1);
npcm_i2c_reset(bus);
/* check HW is OK: SDA and SCL should be high at this point. */
if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
npcm_i2c_get_SCL(&bus->adap));
return -ENXIO;
}
npcm_i2c_int_enable(bus, true);
return 0;
}
static int __npcm_i2c_init(struct npcm_i2c *bus, struct platform_device *pdev)
{
u32 clk_freq_hz;
int ret;
/* Initialize the internal data structures */
bus->state = I2C_DISABLE;
bus->master_or_slave = I2C_SLAVE;
bus->int_time_stamp = 0;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
bus->slave = NULL;
#endif
ret = device_property_read_u32(&pdev->dev, "clock-frequency",
&clk_freq_hz);
if (ret) {
dev_info(&pdev->dev, "Could not read clock-frequency property");
clk_freq_hz = I2C_MAX_STANDARD_MODE_FREQ;
}
ret = npcm_i2c_init_module(bus, I2C_MASTER, clk_freq_hz);
if (ret) {
dev_err(&pdev->dev, "npcm_i2c_init_module failed\n");
return ret;
}
return 0;
}
static irqreturn_t npcm_i2c_bus_irq(int irq, void *dev_id)
{
struct npcm_i2c *bus = dev_id;
if (npcm_i2c_is_master(bus))
bus->master_or_slave = I2C_MASTER;
if (bus->master_or_slave == I2C_MASTER) {
bus->int_time_stamp = jiffies;
if (!npcm_i2c_int_master_handler(bus))
return IRQ_HANDLED;
}
#if IS_ENABLED(CONFIG_I2C_SLAVE)
if (bus->slave) {
bus->master_or_slave = I2C_SLAVE;
if (npcm_i2c_int_slave_handler(bus))
return IRQ_HANDLED;
}
#endif
/* clear status bits for spurious interrupts */
npcm_i2c_clear_master_status(bus);
return IRQ_HANDLED;
}
static bool npcm_i2c_master_start_xmit(struct npcm_i2c *bus,
u8 slave_addr, u16 nwrite, u16 nread,
u8 *write_data, u8 *read_data,
bool use_PEC, bool use_read_block)
{
if (bus->state != I2C_IDLE) {
bus->cmd_err = -EBUSY;
return false;
}
bus->dest_addr = slave_addr << 1;
bus->wr_buf = write_data;
bus->wr_size = nwrite;
bus->wr_ind = 0;
bus->rd_buf = read_data;
bus->rd_size = nread;
bus->rd_ind = 0;
bus->PEC_use = 0;
/* for tx PEC is appended to buffer from i2c IF. PEC flag is ignored */
if (nread)
bus->PEC_use = use_PEC;
bus->read_block_use = use_read_block;
if (nread && !nwrite)
bus->operation = I2C_READ_OPER;
else
bus->operation = I2C_WRITE_OPER;
if (bus->fifo_use) {
u8 i2cfif_cts;
npcm_i2c_select_bank(bus, I2C_BANK_1);
/* clear FIFO and relevant status bits. */
i2cfif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS);
i2cfif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR;
i2cfif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO;
iowrite8(i2cfif_cts, bus->reg + NPCM_I2CFIF_CTS);
}
bus->state = I2C_IDLE;
npcm_i2c_stall_after_start(bus, true);
npcm_i2c_master_start(bus);
return true;
}
static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
struct npcm_i2c *bus = container_of(adap, struct npcm_i2c, adap);
struct i2c_msg *msg0, *msg1;
unsigned long time_left, flags;
u16 nwrite, nread;
u8 *write_data, *read_data;
u8 slave_addr;
unsigned long timeout;
bool read_block = false;
bool read_PEC = false;
u8 bus_busy;
unsigned long timeout_usec;
if (bus->state == I2C_DISABLE) {
dev_err(bus->dev, "I2C%d module is disabled", bus->num);
return -EINVAL;
}
msg0 = &msgs[0];
slave_addr = msg0->addr;
if (msg0->flags & I2C_M_RD) { /* read */
nwrite = 0;
write_data = NULL;
read_data = msg0->buf;
if (msg0->flags & I2C_M_RECV_LEN) {
nread = 1;
read_block = true;
if (msg0->flags & I2C_CLIENT_PEC)
read_PEC = true;
} else {
nread = msg0->len;
}
} else { /* write */
nwrite = msg0->len;
write_data = msg0->buf;
nread = 0;
read_data = NULL;
if (num == 2) {
msg1 = &msgs[1];
read_data = msg1->buf;
if (msg1->flags & I2C_M_RECV_LEN) {
nread = 1;
read_block = true;
if (msg1->flags & I2C_CLIENT_PEC)
read_PEC = true;
} else {
nread = msg1->len;
read_block = false;
}
}
}
/*
* Adaptive TimeOut: estimated time in usec + 100% margin:
* 2: double the timeout for clock stretching case
* 9: bits per transaction (including the ack/nack)
*/
timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite);
timeout = max_t(unsigned long, bus->adap.timeout, usecs_to_jiffies(timeout_usec));
if (nwrite >= 32 * 1024 || nread >= 32 * 1024) {
dev_err(bus->dev, "i2c%d buffer too big\n", bus->num);
return -EINVAL;
}
time_left = jiffies + timeout + 1;
do {
/*
* we must clear slave address immediately when the bus is not
* busy, so we spinlock it, but we don't keep the lock for the
* entire while since it is too long.
*/
spin_lock_irqsave(&bus->lock, flags);
bus_busy = ioread8(bus->reg + NPCM_I2CCST) & NPCM_I2CCST_BB;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
if (!bus_busy && bus->slave)
iowrite8((bus->slave->addr & 0x7F),
bus->reg + NPCM_I2CADDR1);
#endif
spin_unlock_irqrestore(&bus->lock, flags);
} while (time_is_after_jiffies(time_left) && bus_busy);
if (bus_busy) {
iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
npcm_i2c_reset(bus);
i2c_recover_bus(adap);
return -EAGAIN;
}
npcm_i2c_init_params(bus);
bus->dest_addr = slave_addr;
bus->msgs = msgs;
bus->msgs_num = num;
bus->cmd_err = 0;
bus->read_block_use = read_block;
reinit_completion(&bus->cmd_complete);
npcm_i2c_int_enable(bus, true);
if (npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread,
write_data, read_data, read_PEC,
read_block)) {
time_left = wait_for_completion_timeout(&bus->cmd_complete,
timeout);
if (time_left == 0) {
if (bus->timeout_cnt < ULLONG_MAX)
bus->timeout_cnt++;
if (bus->master_or_slave == I2C_MASTER) {
i2c_recover_bus(adap);
bus->cmd_err = -EIO;
bus->state = I2C_IDLE;
}
}
}
/* if there was BER, check if need to recover the bus: */
if (bus->cmd_err == -EAGAIN)
bus->cmd_err = i2c_recover_bus(adap);
/*
* After any type of error, check if LAST bit is still set,
* due to a HW issue.
* It cannot be cleared without resetting the module.
*/
else if (bus->cmd_err &&
(NPCM_I2CRXF_CTL_LAST_PEC & ioread8(bus->reg + NPCM_I2CRXF_CTL)))
npcm_i2c_reset(bus);
/* after any xfer, successful or not, stall and EOB must be disabled */
npcm_i2c_stall_after_start(bus, false);
npcm_i2c_eob_int(bus, false);
#if IS_ENABLED(CONFIG_I2C_SLAVE)
/* reenable slave if it was enabled */
if (bus->slave)
iowrite8((bus->slave->addr & 0x7F) | NPCM_I2CADDR_SAEN,
bus->reg + NPCM_I2CADDR1);
#else
npcm_i2c_int_enable(bus, false);
#endif
return bus->cmd_err;
}
static u32 npcm_i2c_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C |
I2C_FUNC_SMBUS_EMUL |
I2C_FUNC_SMBUS_BLOCK_DATA |
I2C_FUNC_SMBUS_PEC |
I2C_FUNC_SLAVE;
}
static const struct i2c_adapter_quirks npcm_i2c_quirks = {
.max_read_len = 32768,
.max_write_len = 32768,
.flags = I2C_AQ_COMB_WRITE_THEN_READ,
};
static const struct i2c_algorithm npcm_i2c_algo = {
.master_xfer = npcm_i2c_master_xfer,
.functionality = npcm_i2c_functionality,
#if IS_ENABLED(CONFIG_I2C_SLAVE)
.reg_slave = npcm_i2c_reg_slave,
.unreg_slave = npcm_i2c_unreg_slave,
#endif
};
/* i2c debugfs directory: used to keep health monitor of i2c devices */
static struct dentry *npcm_i2c_debugfs_dir;
static void npcm_i2c_init_debugfs(struct platform_device *pdev,
struct npcm_i2c *bus)
{
struct dentry *d;
if (!npcm_i2c_debugfs_dir)
return;
d = debugfs_create_dir(dev_name(&pdev->dev), npcm_i2c_debugfs_dir);
if (IS_ERR_OR_NULL(d))
return;
debugfs_create_u64("ber_cnt", 0444, d, &bus->ber_cnt);
debugfs_create_u64("nack_cnt", 0444, d, &bus->nack_cnt);
debugfs_create_u64("rec_succ_cnt", 0444, d, &bus->rec_succ_cnt);
debugfs_create_u64("rec_fail_cnt", 0444, d, &bus->rec_fail_cnt);
debugfs_create_u64("timeout_cnt", 0444, d, &bus->timeout_cnt);
debugfs_create_u64("tx_complete_cnt", 0444, d, &bus->tx_complete_cnt);
bus->debugfs = d;
}
static int npcm_i2c_probe_bus(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
static struct regmap *gcr_regmap;
struct i2c_adapter *adap;
struct npcm_i2c *bus;
struct clk *i2c_clk;
int irq;
int ret;
bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
if (!bus)
return -ENOMEM;
bus->dev = &pdev->dev;
bus->num = of_alias_get_id(pdev->dev.of_node, "i2c");
/* core clk must be acquired to calculate module timing settings */
i2c_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(i2c_clk))
return PTR_ERR(i2c_clk);
bus->apb_clk = clk_get_rate(i2c_clk);
gcr_regmap = syscon_regmap_lookup_by_phandle(np, "nuvoton,sys-mgr");
if (IS_ERR(gcr_regmap))
gcr_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr");
if (IS_ERR(gcr_regmap))
return PTR_ERR(gcr_regmap);
regmap_write(gcr_regmap, NPCM_I2CSEGCTL, NPCM_I2CSEGCTL_INIT_VAL);
bus->reg = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(bus->reg))
return PTR_ERR(bus->reg);
spin_lock_init(&bus->lock);
init_completion(&bus->cmd_complete);
adap = &bus->adap;
adap->owner = THIS_MODULE;
adap->retries = 3;
adap->timeout = msecs_to_jiffies(35);
adap->algo = &npcm_i2c_algo;
adap->quirks = &npcm_i2c_quirks;
adap->algo_data = bus;
adap->dev.parent = &pdev->dev;
adap->dev.of_node = pdev->dev.of_node;
adap->nr = pdev->id;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
ret = devm_request_irq(bus->dev, irq, npcm_i2c_bus_irq, 0,
dev_name(bus->dev), bus);
if (ret)
return ret;
ret = __npcm_i2c_init(bus, pdev);
if (ret)
return ret;
npcm_i2c_recovery_init(adap);
i2c_set_adapdata(adap, bus);
snprintf(bus->adap.name, sizeof(bus->adap.name), "npcm_i2c_%d",
bus->num);
ret = i2c_add_numbered_adapter(&bus->adap);
if (ret)
return ret;
platform_set_drvdata(pdev, bus);
npcm_i2c_init_debugfs(pdev, bus);
return 0;
}
static int npcm_i2c_remove_bus(struct platform_device *pdev)
{
unsigned long lock_flags;
struct npcm_i2c *bus = platform_get_drvdata(pdev);
debugfs_remove_recursive(bus->debugfs);
spin_lock_irqsave(&bus->lock, lock_flags);
npcm_i2c_disable(bus);
spin_unlock_irqrestore(&bus->lock, lock_flags);
i2c_del_adapter(&bus->adap);
return 0;
}
static const struct of_device_id npcm_i2c_bus_of_table[] = {
{ .compatible = "nuvoton,npcm750-i2c", },
{}
};
MODULE_DEVICE_TABLE(of, npcm_i2c_bus_of_table);
static struct platform_driver npcm_i2c_bus_driver = {
.probe = npcm_i2c_probe_bus,
.remove = npcm_i2c_remove_bus,
.driver = {
.name = "nuvoton-i2c",
.of_match_table = npcm_i2c_bus_of_table,
}
};
static int __init npcm_i2c_init(void)
{
npcm_i2c_debugfs_dir = debugfs_create_dir("npcm_i2c", NULL);
return platform_driver_register(&npcm_i2c_bus_driver);
}
module_init(npcm_i2c_init);
static void __exit npcm_i2c_exit(void)
{
platform_driver_unregister(&npcm_i2c_bus_driver);
debugfs_remove_recursive(npcm_i2c_debugfs_dir);
}
module_exit(npcm_i2c_exit);
MODULE_AUTHOR("Avi Fishman <avi.fishman@gmail.com>");
MODULE_AUTHOR("Tali Perry <tali.perry@nuvoton.com>");
MODULE_AUTHOR("Tyrone Ting <kfting@nuvoton.com>");
MODULE_DESCRIPTION("Nuvoton I2C Bus Driver");
MODULE_LICENSE("GPL v2");