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* I2C Link Layer for ST NCI NFC controller familly based Driver
* Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/nfc.h>
#include <linux/platform_data/st-nci.h>
#include "ndlc.h"
#define DRIVER_DESC "NCI NFC driver for ST_NCI"
/* ndlc header */
#define ST_NCI_FRAME_HEADROOM 1
#define ST_NCI_FRAME_TAILROOM 0
#define ST_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
#define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
#define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
static struct i2c_device_id st_nci_i2c_id_table[] = {
{ST_NCI_DRIVER_NAME, 0},
{}
};
MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
struct st_nci_i2c_phy {
struct i2c_client *i2c_dev;
struct llt_ndlc *ndlc;
unsigned int gpio_reset;
unsigned int irq_polarity;
};
#define I2C_DUMP_SKB(info, skb) \
do { \
pr_debug("%s:\n", info); \
print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
16, 1, (skb)->data, (skb)->len, 0); \
} while (0)
static int st_nci_i2c_enable(void *phy_id)
{
struct st_nci_i2c_phy *phy = phy_id;
gpio_set_value(phy->gpio_reset, 0);
usleep_range(10000, 15000);
gpio_set_value(phy->gpio_reset, 1);
usleep_range(80000, 85000);
if (phy->ndlc->powered == 0)
enable_irq(phy->i2c_dev->irq);
return 0;
}
static void st_nci_i2c_disable(void *phy_id)
{
struct st_nci_i2c_phy *phy = phy_id;
disable_irq_nosync(phy->i2c_dev->irq);
}
/*
* Writing a frame must not return the number of written bytes.
* It must return either zero for success, or <0 for error.
* In addition, it must not alter the skb
*/
static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
{
int r = -1;
struct st_nci_i2c_phy *phy = phy_id;
struct i2c_client *client = phy->i2c_dev;
I2C_DUMP_SKB("st_nci_i2c_write", skb);
if (phy->ndlc->hard_fault != 0)
return phy->ndlc->hard_fault;
r = i2c_master_send(client, skb->data, skb->len);
if (r < 0) { /* Retry, chip was in standby */
usleep_range(1000, 4000);
r = i2c_master_send(client, skb->data, skb->len);
}
if (r >= 0) {
if (r != skb->len)
r = -EREMOTEIO;
else
r = 0;
}
return r;
}
/*
* Reads an ndlc frame and returns it in a newly allocated sk_buff.
* returns:
* 0 : if received frame is complete
* -EREMOTEIO : i2c read error (fatal)
* -EBADMSG : frame was incorrect and discarded
* -ENOMEM : cannot allocate skb, frame dropped
*/
static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
struct sk_buff **skb)
{
int r;
u8 len;
u8 buf[ST_NCI_I2C_MAX_SIZE];
struct i2c_client *client = phy->i2c_dev;
r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
if (r < 0) { /* Retry, chip was in standby */
usleep_range(1000, 4000);
r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
}
if (r != ST_NCI_I2C_MIN_SIZE)
return -EREMOTEIO;
len = be16_to_cpu(*(__be16 *) (buf + 2));
if (len > ST_NCI_I2C_MAX_SIZE) {
nfc_err(&client->dev, "invalid frame len\n");
return -EBADMSG;
}
*skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
if (*skb == NULL)
return -ENOMEM;
skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
if (!len)
return 0;
r = i2c_master_recv(client, buf, len);
if (r != len) {
kfree_skb(*skb);
return -EREMOTEIO;
}
skb_put(*skb, len);
memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
I2C_DUMP_SKB("i2c frame read", *skb);
return 0;
}
/*
* Reads an ndlc frame from the chip.
*
* On ST_NCI, IRQ goes in idle state when read starts.
*/
static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
{
struct st_nci_i2c_phy *phy = phy_id;
struct i2c_client *client;
struct sk_buff *skb = NULL;
int r;
if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
WARN_ON_ONCE(1);
return IRQ_NONE;
}
client = phy->i2c_dev;
dev_dbg(&client->dev, "IRQ\n");
if (phy->ndlc->hard_fault)
return IRQ_HANDLED;
if (!phy->ndlc->powered) {
st_nci_i2c_disable(phy);
return IRQ_HANDLED;
}
r = st_nci_i2c_read(phy, &skb);
if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
return IRQ_HANDLED;
ndlc_recv(phy->ndlc, skb);
return IRQ_HANDLED;
}
static struct nfc_phy_ops i2c_phy_ops = {
.write = st_nci_i2c_write,
.enable = st_nci_i2c_enable,
.disable = st_nci_i2c_disable,
};
#ifdef CONFIG_OF
static int st_nci_i2c_of_request_resources(struct i2c_client *client)
{
struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
struct device_node *pp;
int gpio;
int r;
pp = client->dev.of_node;
if (!pp)
return -ENODEV;
/* Get GPIO from device tree */
gpio = of_get_named_gpio(pp, "reset-gpios", 0);
if (gpio < 0) {
nfc_err(&client->dev,
"Failed to retrieve reset-gpios from device tree\n");
return gpio;
}
/* GPIO request and configuration */
r = devm_gpio_request_one(&client->dev, gpio,
GPIOF_OUT_INIT_HIGH, "clf_reset");
if (r) {
nfc_err(&client->dev, "Failed to request reset pin\n");
return r;
}
phy->gpio_reset = gpio;
phy->irq_polarity = irq_get_trigger_type(client->irq);
return 0;
}
#else
static int st_nci_i2c_of_request_resources(struct i2c_client *client)
{
return -ENODEV;
}
#endif
static int st_nci_i2c_request_resources(struct i2c_client *client)
{
struct st_nci_nfc_platform_data *pdata;
struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
int r;
pdata = client->dev.platform_data;
if (pdata == NULL) {
nfc_err(&client->dev, "No platform data\n");
return -EINVAL;
}
/* store for later use */
phy->gpio_reset = pdata->gpio_reset;
phy->irq_polarity = pdata->irq_polarity;
r = devm_gpio_request_one(&client->dev,
phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
if (r) {
pr_err("%s : reset gpio_request failed\n", __FILE__);
return r;
}
return 0;
}
static int st_nci_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct st_nci_i2c_phy *phy;
struct st_nci_nfc_platform_data *pdata;
int r;
dev_dbg(&client->dev, "%s\n", __func__);
dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
return -ENODEV;
}
phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy),
GFP_KERNEL);
if (!phy)
return -ENOMEM;
phy->i2c_dev = client;
i2c_set_clientdata(client, phy);
pdata = client->dev.platform_data;
if (!pdata && client->dev.of_node) {
r = st_nci_i2c_of_request_resources(client);
if (r) {
nfc_err(&client->dev, "No platform data\n");
return r;
}
} else if (pdata) {
r = st_nci_i2c_request_resources(client);
if (r) {
nfc_err(&client->dev,
"Cannot get platform resources\n");
return r;
}
} else {
nfc_err(&client->dev,
"st_nci platform resources not available\n");
return -ENODEV;
}
r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
&phy->ndlc);
if (r < 0) {
nfc_err(&client->dev, "Unable to register ndlc layer\n");
return r;
}
r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
st_nci_irq_thread_fn,
phy->irq_polarity | IRQF_ONESHOT,
ST_NCI_DRIVER_NAME, phy);
if (r < 0)
nfc_err(&client->dev, "Unable to register IRQ handler\n");
return r;
}
static int st_nci_i2c_remove(struct i2c_client *client)
{
struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
dev_dbg(&client->dev, "%s\n", __func__);
ndlc_remove(phy->ndlc);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id of_st_nci_i2c_match[] = {
{ .compatible = "st,st21nfcb-i2c", },
{ .compatible = "st,st21nfcb_i2c", },
{ .compatible = "st,st21nfcc-i2c", },
{}
};
MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
#endif
static struct i2c_driver st_nci_i2c_driver = {
.driver = {
.owner = THIS_MODULE,
.name = ST_NCI_I2C_DRIVER_NAME,
.of_match_table = of_match_ptr(of_st_nci_i2c_match),
},
.probe = st_nci_i2c_probe,
.id_table = st_nci_i2c_id_table,
.remove = st_nci_i2c_remove,
};
module_i2c_driver(st_nci_i2c_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);
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