uart.c
// SPDX-License-Identifier: GPL-2.0+
/*
* UART Link Layer for S3FWRN82 NCI based Driver
*
* Copyright (C) 2015 Samsung Electronics
* Robert Baldyga <r.baldyga@samsung.com>
* Copyright (C) 2020 Samsung Electronics
* Bongsu Jeon <bongsu.jeon@samsung.com>
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/nfc.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/serdev.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include "phy_common.h"
#define S3FWRN82_NCI_HEADER 3
#define S3FWRN82_NCI_IDX 2
#define NCI_SKB_BUFF_LEN 258
struct s3fwrn82_uart_phy {
struct phy_common common;
struct serdev_device *ser_dev;
struct sk_buff *recv_skb;
};
static int s3fwrn82_uart_write(void *phy_id, struct sk_buff *out)
{
struct s3fwrn82_uart_phy *phy = phy_id;
int err;
err = serdev_device_write(phy->ser_dev,
out->data, out->len,
MAX_SCHEDULE_TIMEOUT);
if (err < 0)
return err;
return 0;
}
static const struct s3fwrn5_phy_ops uart_phy_ops = {
.set_wake = s3fwrn5_phy_set_wake,
.set_mode = s3fwrn5_phy_set_mode,
.get_mode = s3fwrn5_phy_get_mode,
.write = s3fwrn82_uart_write,
};
static size_t s3fwrn82_uart_read(struct serdev_device *serdev,
const u8 *data, size_t count)
{
struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
size_t i;
for (i = 0; i < count; i++) {
skb_put_u8(phy->recv_skb, *data++);
if (phy->recv_skb->len < S3FWRN82_NCI_HEADER)
continue;
if ((phy->recv_skb->len - S3FWRN82_NCI_HEADER)
< phy->recv_skb->data[S3FWRN82_NCI_IDX])
continue;
s3fwrn5_recv_frame(phy->common.ndev, phy->recv_skb,
phy->common.mode);
phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
if (!phy->recv_skb)
return 0;
}
return i;
}
static const struct serdev_device_ops s3fwrn82_serdev_ops = {
.receive_buf = s3fwrn82_uart_read,
.write_wakeup = serdev_device_write_wakeup,
};
static const struct of_device_id s3fwrn82_uart_of_match[] = {
{ .compatible = "samsung,s3fwrn82", },
{},
};
MODULE_DEVICE_TABLE(of, s3fwrn82_uart_of_match);
static int s3fwrn82_uart_parse_dt(struct serdev_device *serdev)
{
struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
struct device_node *np = serdev->dev.of_node;
if (!np)
return -ENODEV;
phy->common.gpio_en = of_get_named_gpio(np, "en-gpios", 0);
if (!gpio_is_valid(phy->common.gpio_en))
return -ENODEV;
phy->common.gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
if (!gpio_is_valid(phy->common.gpio_fw_wake))
return -ENODEV;
return 0;
}
static int s3fwrn82_uart_probe(struct serdev_device *serdev)
{
struct s3fwrn82_uart_phy *phy;
int ret = -ENOMEM;
phy = devm_kzalloc(&serdev->dev, sizeof(*phy), GFP_KERNEL);
if (!phy)
goto err_exit;
phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
if (!phy->recv_skb)
goto err_exit;
mutex_init(&phy->common.mutex);
phy->common.mode = S3FWRN5_MODE_COLD;
phy->ser_dev = serdev;
serdev_device_set_drvdata(serdev, phy);
serdev_device_set_client_ops(serdev, &s3fwrn82_serdev_ops);
ret = serdev_device_open(serdev);
if (ret) {
dev_err(&serdev->dev, "Unable to open device\n");
goto err_skb;
}
ret = serdev_device_set_baudrate(serdev, 115200);
if (ret != 115200) {
ret = -EINVAL;
goto err_serdev;
}
serdev_device_set_flow_control(serdev, false);
ret = s3fwrn82_uart_parse_dt(serdev);
if (ret < 0)
goto err_serdev;
ret = devm_gpio_request_one(&phy->ser_dev->dev, phy->common.gpio_en,
GPIOF_OUT_INIT_HIGH, "s3fwrn82_en");
if (ret < 0)
goto err_serdev;
ret = devm_gpio_request_one(&phy->ser_dev->dev,
phy->common.gpio_fw_wake,
GPIOF_OUT_INIT_LOW, "s3fwrn82_fw_wake");
if (ret < 0)
goto err_serdev;
ret = s3fwrn5_probe(&phy->common.ndev, phy, &phy->ser_dev->dev,
&uart_phy_ops);
if (ret < 0)
goto err_serdev;
return ret;
err_serdev:
serdev_device_close(serdev);
err_skb:
kfree_skb(phy->recv_skb);
err_exit:
return ret;
}
static void s3fwrn82_uart_remove(struct serdev_device *serdev)
{
struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
s3fwrn5_remove(phy->common.ndev);
serdev_device_close(serdev);
kfree_skb(phy->recv_skb);
}
static struct serdev_device_driver s3fwrn82_uart_driver = {
.probe = s3fwrn82_uart_probe,
.remove = s3fwrn82_uart_remove,
.driver = {
.name = "s3fwrn82_uart",
.of_match_table = s3fwrn82_uart_of_match,
},
};
module_serdev_device_driver(s3fwrn82_uart_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("UART driver for Samsung NFC");
MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>");