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/*
* I2C Link Layer for ST21NFCB NCI based Driver
* Copyright (C) 2014 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/st21nfcb.h>
#include "ndlc.h"
#define DRIVER_DESC "NCI NFC driver for ST21NFCB"
/* ndlc header */
#define ST21NFCB_FRAME_HEADROOM 1
#define ST21NFCB_FRAME_TAILROOM 0
#define ST21NFCB_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
{ST21NFCB_NCI_DRIVER_NAME, 0},
{}
};
MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
struct st21nfcb_i2c_phy {
struct i2c_client *i2c_dev;
struct llt_ndlc *ndlc;
unsigned int gpio_irq;
unsigned int gpio_reset;
unsigned int irq_polarity;
int powered;
/*
* < 0 if hardware error occured (e.g. i2c err)
* and prevents normal operation.
*/
int hard_fault;
};
#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 st21nfcb_nci_i2c_enable(void *phy_id)
{
struct st21nfcb_i2c_phy *phy = phy_id;
gpio_set_value(phy->gpio_reset, 0);
usleep_range(10000, 15000);
gpio_set_value(phy->gpio_reset, 1);
phy->powered = 1;
usleep_range(80000, 85000);
return 0;
}
static void st21nfcb_nci_i2c_disable(void *phy_id)
{
struct st21nfcb_i2c_phy *phy = phy_id;
pr_info("\n");
phy->powered = 0;
/* reset chip in order to flush clf */
gpio_set_value(phy->gpio_reset, 0);
usleep_range(10000, 15000);
gpio_set_value(phy->gpio_reset, 1);
}
static void st21nfcb_nci_remove_header(struct sk_buff *skb)
{
skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
}
/*
* 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 st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
{
int r = -1;
struct st21nfcb_i2c_phy *phy = phy_id;
struct i2c_client *client = phy->i2c_dev;
I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
if (phy->hard_fault != 0)
return phy->hard_fault;
r = i2c_master_send(client, skb->data, skb->len);
if (r == -EREMOTEIO) { /* 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;
}
st21nfcb_nci_remove_header(skb);
return r;
}
/*
* Reads an ndlc frame and returns it in a newly allocated sk_buff.
* returns:
* frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
* end of read)
* -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
* at end of read)
* -EREMOTEIO : i2c read error (fatal)
* -EBADMSG : frame was incorrect and discarded
* (value returned from st21nfcb_nci_i2c_repack)
* -EIO : if no ST21NFCB_SOF_EOF is found after reaching
* the read length end sequence
*/
static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
struct sk_buff **skb)
{
int r;
u8 len;
u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
struct i2c_client *client = phy->i2c_dev;
r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
if (r == -EREMOTEIO) { /* Retry, chip was in standby */
usleep_range(1000, 4000);
r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
}
if (r != ST21NFCB_NCI_I2C_MIN_SIZE) {
nfc_err(&client->dev, "cannot read ndlc & nci header\n");
return -EREMOTEIO;
}
len = be16_to_cpu(*(__be16 *) (buf + 2));
if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
nfc_err(&client->dev, "invalid frame len\n");
return -EBADMSG;
}
*skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
if (*skb == NULL)
return -ENOMEM;
skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
memcpy((*skb)->data, buf, ST21NFCB_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 + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
I2C_DUMP_SKB("i2c frame read", *skb);
return 0;
}
/*
* Reads an ndlc frame from the chip.
*
* On ST21NFCB, IRQ goes in idle state when read starts.
*/
static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
{
struct st21nfcb_i2c_phy *phy = phy_id;
struct i2c_client *client;
struct sk_buff *skb = NULL;
int r;
if (!phy || irq != phy->i2c_dev->irq) {
WARN_ON_ONCE(1);
return IRQ_NONE;
}
client = phy->i2c_dev;
dev_dbg(&client->dev, "IRQ\n");
if (phy->hard_fault)
return IRQ_HANDLED;
if (!phy->powered) {
st21nfcb_nci_i2c_disable(phy);
return IRQ_HANDLED;
}
r = st21nfcb_nci_i2c_read(phy, &skb);
if (r == -EREMOTEIO) {
phy->hard_fault = r;
ndlc_recv(phy->ndlc, NULL);
return IRQ_HANDLED;
} else if (r == -ENOMEM || r == -EBADMSG) {
return IRQ_HANDLED;
}
ndlc_recv(phy->ndlc, skb);
return IRQ_HANDLED;
}
static struct nfc_phy_ops i2c_phy_ops = {
.write = st21nfcb_nci_i2c_write,
.enable = st21nfcb_nci_i2c_enable,
.disable = st21nfcb_nci_i2c_disable,
};
#ifdef CONFIG_OF
static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
{
struct st21nfcb_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 -ENODEV;
}
phy->gpio_reset = gpio;
/* IRQ */
r = irq_of_parse_and_map(pp, 0);
if (r < 0) {
nfc_err(&client->dev, "Unable to get irq, error: %d\n", r);
return r;
}
phy->irq_polarity = irq_get_trigger_type(r);
client->irq = r;
return 0;
}
#else
static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
{
return -ENODEV;
}
#endif
static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
{
struct st21nfcb_nfc_platform_data *pdata;
struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(<
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