// SPDX-License-Identifier: GPL-2.0
/*
* STIH4xx CEC driver
* Copyright (C) STMicroelectronics SA 2016
*
*/
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <media/cec.h>
#include <media/cec-notifier.h>
#define CEC_NAME "stih-cec"
/* CEC registers */
#define CEC_CLK_DIV 0x0
#define CEC_CTRL 0x4
#define CEC_IRQ_CTRL 0x8
#define CEC_STATUS 0xC
#define CEC_EXT_STATUS 0x10
#define CEC_TX_CTRL 0x14
#define CEC_FREE_TIME_THRESH 0x18
#define CEC_BIT_TOUT_THRESH 0x1C
#define CEC_BIT_PULSE_THRESH 0x20
#define CEC_DATA 0x24
#define CEC_TX_ARRAY_CTRL 0x28
#define CEC_CTRL2 0x2C
#define CEC_TX_ERROR_STS 0x30
#define CEC_ADDR_TABLE 0x34
#define CEC_DATA_ARRAY_CTRL 0x38
#define CEC_DATA_ARRAY_STATUS 0x3C
#define CEC_TX_DATA_BASE 0x40
#define CEC_TX_DATA_TOP 0x50
#define CEC_TX_DATA_SIZE 0x1
#define CEC_RX_DATA_BASE 0x54
#define CEC_RX_DATA_TOP 0x64
#define CEC_RX_DATA_SIZE 0x1
/* CEC_CTRL2 */
#define CEC_LINE_INACTIVE_EN BIT(0)
#define CEC_AUTO_BUS_ERR_EN BIT(1)
#define CEC_STOP_ON_ARB_ERR_EN BIT(2)
#define CEC_TX_REQ_WAIT_EN BIT(3)
/* CEC_DATA_ARRAY_CTRL */
#define CEC_TX_ARRAY_EN BIT(0)
#define CEC_RX_ARRAY_EN BIT(1)
#define CEC_TX_ARRAY_RESET BIT(2)
#define CEC_RX_ARRAY_RESET BIT(3)
#define CEC_TX_N_OF_BYTES_IRQ_EN BIT(4)
#define CEC_TX_STOP_ON_NACK BIT(7)
/* CEC_TX_ARRAY_CTRL */
#define CEC_TX_N_OF_BYTES 0x1F
#define CEC_TX_START BIT(5)
#define CEC_TX_AUTO_SOM_EN BIT(6)
#define CEC_TX_AUTO_EOM_EN BIT(7)
/* CEC_IRQ_CTRL */
#define CEC_TX_DONE_IRQ_EN BIT(0)
#define CEC_ERROR_IRQ_EN BIT(2)
#define CEC_RX_DONE_IRQ_EN BIT(3)
#define CEC_RX_SOM_IRQ_EN BIT(4)
#define CEC_RX_EOM_IRQ_EN BIT(5)
#define CEC_FREE_TIME_IRQ_EN BIT(6)
#define CEC_PIN_STS_IRQ_EN BIT(7)
/* CEC_CTRL */
#define CEC_IN_FILTER_EN BIT(0)
#define CEC_PWR_SAVE_EN BIT(1)
#define CEC_EN BIT(4)
#define CEC_ACK_CTRL BIT(5)
#define CEC_RX_RESET_EN BIT(6)
#define CEC_IGNORE_RX_ERROR BIT(7)
/* CEC_STATUS */
#define CEC_TX_DONE_STS BIT(0)
#define CEC_TX_ACK_GET_STS BIT(1)
#define CEC_ERROR_STS BIT(2)
#define CEC_RX_DONE_STS BIT(3)
#define CEC_RX_SOM_STS BIT(4)
#define CEC_RX_EOM_STS BIT(5)
#define CEC_FREE_TIME_IRQ_STS BIT(6)
#define CEC_PIN_STS BIT(7)
#define CEC_SBIT_TOUT_STS BIT(8)
#define CEC_DBIT_TOUT_STS BIT(9)
#define CEC_LPULSE_ERROR_STS BIT(10)
#define CEC_HPULSE_ERROR_STS BIT(11)
#define CEC_TX_ERROR BIT(12)
#define CEC_TX_ARB_ERROR BIT(13)
#define CEC_RX_ERROR_MIN BIT(14)
#define CEC_RX_ERROR_MAX BIT(15)
/* Signal free time in bit periods (2.4ms) */
#define CEC_PRESENT_INIT_SFT 7
#define CEC_NEW_INIT_SFT 5
#define CEC_RETRANSMIT_SFT 3
/* Constants for CEC_BIT_TOUT_THRESH register */
#define CEC_SBIT_TOUT_47MS BIT(1)
#define CEC_SBIT_TOUT_48MS (BIT(0) | BIT(1))
#define CEC_SBIT_TOUT_50MS BIT(2)
#define CEC_DBIT_TOUT_27MS BIT(0)
#define CEC_DBIT_TOUT_28MS BIT(1)
#define CEC_DBIT_TOUT_29MS (BIT(0) | BIT(1))
/* Constants for CEC_BIT_PULSE_THRESH register */
#define CEC_BIT_LPULSE_03MS BIT(1)
#define CEC_BIT_HPULSE_03MS BIT(3)
/* Constants for CEC_DATA_ARRAY_STATUS register */
#define CEC_RX_N_OF_BYTES 0x1F
#define CEC_TX_N_OF_BYTES_SENT BIT(5)
#define CEC_RX_OVERRUN BIT(6)
struct stih_cec {
struct cec_adapter *adap;
struct device *dev;
struct clk *clk;
void __iomem *regs;
int irq;
u32 irq_status;
struct cec_notifier *notifier;
};
static int stih_cec_adap_enable(struct cec_adapter *adap, bool enable)
{
struct stih_cec *cec = cec_get_drvdata(adap);
if (enable) {
/* The doc says (input TCLK_PERIOD * CEC_CLK_DIV) = 0.1ms */
unsigned long clk_freq = clk_get_rate(cec->clk);
u32 cec_clk_div = clk_freq / 10000;
writel(cec_clk_div, cec->regs + CEC_CLK_DIV);
/* Configuration of the durations activating a timeout */
writel(CEC_SBIT_TOUT_47MS | (CEC_DBIT_TOUT_28MS << 4),
cec->regs + CEC_BIT_TOUT_THRESH);
/* Configuration of the smallest allowed duration for pulses */
writel(CEC_BIT_LPULSE_03MS | CEC_BIT_HPULSE_03MS,
cec->regs + CEC_BIT_PULSE_THRESH);
/* Minimum received bit period threshold */
writel(BIT(5) | BIT(7), cec->regs + CEC_TX_CTRL);
/* Configuration of transceiver data arrays */
writel(CEC_TX_ARRAY_EN | CEC_RX_ARRAY_EN | CEC_TX_STOP_ON_NACK,
cec->regs + CEC_DATA_ARRAY_CTRL);
/* Configuration of the control bits for CEC Transceiver */
writel(CEC_IN_FILTER_EN | CEC_EN | CEC_RX_RESET_EN,
cec->regs + CEC_CTRL);
/* Clear logical addresses */
writel(0, cec->regs + CEC_ADDR_TABLE);
/* Clear the status register */
writel(0x0, cec->regs + CEC_STATUS);
/* Enable the interrupts */
writel(CEC_TX_DONE_IRQ_EN | CEC_RX_DONE_IRQ_EN |
CEC_RX_SOM_IRQ_EN | CEC_RX_EOM_IRQ_EN |
CEC_ERROR_IRQ_EN,
cec->regs + CEC_IRQ_CTRL);
} else {
/* Clear logical addresses */
writel(0, cec->regs + CEC_ADDR_TABLE);
/* Clear the status register */
writel(0x0, cec->regs + CEC_STATUS);
/* Disable the interrupts */
writel(0, cec->regs + CEC_IRQ_CTRL);
}
return 0;
}
static int stih_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
{
struct stih_cec *cec = cec_get_drvdata(adap);
u32 reg = readl(cec->regs + CEC_ADDR_TABLE);
reg |= 1 << logical_addr;
if (logical_addr == CEC_LOG_ADDR_INVALID)
reg = 0;
writel(reg, cec->regs + CEC_ADDR_TABLE);
return 0;
}
static int stih_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
u32 signal_free_time, struct cec_msg *msg)
{
struct stih_cec *cec = cec_get_drvdata(adap);
int i;
/* Copy message into registers */
for (i = 0; i < msg->len; i++)
writeb(msg->msg[i], cec->regs + CEC_TX_DATA_BASE + i);
/*
* Start transmission, configure hardware to add start and stop bits
* Signal free time is handled by the hardware
*/
writel(CEC_TX_AUTO_SOM_EN | CEC_TX_AUTO_EOM_EN | CEC_TX_START |
msg->len, cec->regs + CEC_TX_ARRAY_CTRL);
return 0;
}
static void stih_tx_done(struct stih_cec *cec, u32 status)
{
if (status & CEC_TX_ERROR) {
cec_transmit_attempt_done(cec->adap, CEC_TX_STATUS_ERROR);
return;
}
if (status & CEC_TX_ARB_ERROR) {
cec_transmit_attempt_done(cec->adap, CEC_TX_STATUS_ARB_LOST);
return;
}
if (!(status & CEC_TX_ACK_GET_STS)) {
cec_transmit_attempt_done(cec->adap, CEC_TX_STATUS_NACK);
return;
}
cec_transmit_attempt_done(cec->adap, CEC_TX_STATUS_OK);
}
static void stih_rx_done(struct stih_cec *cec, u32 status)
{
struct cec_msg msg = {};
u8 i;
if (status & CEC_RX_ERROR_MIN)
return;
if (status & CEC_RX_ERROR_MAX)
return;
msg.len = readl(cec->regs + CEC_DATA_ARRAY_STATUS) & 0x1f;
if (!msg.len)
return;
if (msg.len > 16)
msg.len = 16;
for (i = 0; i < msg.len; i++)
msg.msg[i] = readl(cec->regs + CEC_RX_DATA_BASE + i);
cec_received_msg(cec->adap, &msg);
}
static irqreturn_t stih_cec_irq_handler_thread(int irq, void *priv)
{
struct stih_cec *cec = priv;
if (cec->irq_status & CEC_TX_DONE_STS)
stih_tx_done(cec, cec->irq_status);
if (cec->irq_status & CEC_RX_DONE_STS)
stih_rx_done(cec, cec->irq_status);
cec->irq_status = 0;
return IRQ_HANDLED;
}
static irqreturn_t stih_cec_irq_handler(int irq, void *priv)
{
struct stih_cec *cec = priv;
cec->irq_status = readl(cec->regs + CEC_STATUS);
writel(cec->irq_status, cec->regs + CEC_STATUS);
return IRQ_WAKE_THREAD;
}
static const struct cec_adap_ops sti_cec_adap_ops = {
.adap_enable = stih_cec_adap_enable,
.adap_log_addr = stih_cec_adap_log_addr,
.adap_transmit = stih_cec_adap_transmit,
};
static int stih_cec_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
struct stih_cec *cec;
struct device_node *np;
struct platform_device *hdmi_dev;
int ret;
cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
if (!cec)
return -ENOMEM;
np = of_parse_phandle(pdev->dev.of_node, "hdmi-phandle", 0);
if (!np) {
dev_err(&pdev->dev, "Failed to find hdmi node in device tree\n");
return -ENODEV;
}
hdmi_dev = of_find_device_by_node(np);
if (!hdmi_dev)
return -EPROBE_DEFER;
cec->notifier = cec_notifier_get(&hdmi_dev->dev);
if (!cec->notifier)
return -ENOMEM;
cec->dev = dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
cec->regs = devm_ioremap_resource(dev, res);
if (IS_ERR(cec->regs))
return PTR_ERR(cec->regs);
cec->irq = platform_get_irq(pdev, 0);
if (cec->irq < 0)
return cec->irq;
ret = devm_request_threaded_irq(dev, cec->irq, stih_cec_irq_handler,
stih_cec_irq_handler_thread, 0,
pdev->name, cec);
if (ret)
return ret;
cec->clk = devm_clk_get(dev, "cec-clk");
if (IS_ERR(cec->clk)) {
dev_err(dev, "Cannot get cec clock\n");
return PTR_ERR(cec->clk);
}
cec->adap = cec_allocate_adapter(&sti_cec_adap_ops, cec,
CEC_NAME, CEC_CAP_DEFAULTS, CEC_MAX_LOG_ADDRS);
ret = PTR_ERR_OR_ZERO(cec->adap);
if (ret)
return ret;
ret = cec_register_adapter(cec->adap, &pdev->dev);
if (ret) {
cec_delete_adapter(cec->adap);
return ret;
}
cec_register_cec_notifier(cec->adap, cec->notifier);
platform_set_drvdata(pdev, cec);
return 0;
}
static int stih_cec_remove(struct platform_device *pdev)
{
struct stih_cec *cec = platform_get_drvdata(pdev);
cec_unregister_adapter(cec->adap);
cec_notifier_put(cec->notifier);
return 0;
}
static const struct of_device_id stih_cec_match[] = {
{
.compatible = "st,stih-cec",
},
{},
};
MODULE_DEVICE_TABLE(of, stih_cec_match);
static struct platform_driver stih_cec_pdrv = {
.probe = stih_cec_probe,
.remove = stih_cec_remove,
.driver = {
.name = CEC_NAME,
.of_match_table = stih_cec_match,
},
};
module_platform_driver(stih_cec_pdrv);
MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@linaro.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("STIH4xx CEC driver");