uart.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * UART Link Layer for S3FWRN82 NCI based Driver
  4 *
  5 * Copyright (C) 2015 Samsung Electronics
  6 * Robert Baldyga <r.baldyga@samsung.com>
  7 * Copyright (C) 2020 Samsung Electronics
  8 * Bongsu Jeon <bongsu.jeon@samsung.com>
  9 */
 10
 11#include <linux/device.h>
 12#include <linux/kernel.h>
 13#include <linux/module.h>
 14#include <linux/nfc.h>
 15#include <linux/netdevice.h>
 16#include <linux/of.h>
 17#include <linux/serdev.h>
 18#include <linux/gpio.h>
 19#include <linux/of_gpio.h>
 20
 21#include "phy_common.h"
 22
 23#define S3FWRN82_NCI_HEADER 3
 24#define S3FWRN82_NCI_IDX 2
 25#define NCI_SKB_BUFF_LEN 258
 26
 27struct s3fwrn82_uart_phy {
 28	struct phy_common common;
 29	struct serdev_device *ser_dev;
 30	struct sk_buff *recv_skb;
 31};
 32
 33static int s3fwrn82_uart_write(void *phy_id, struct sk_buff *out)
 34{
 35	struct s3fwrn82_uart_phy *phy = phy_id;
 36	int err;
 37
 38	err = serdev_device_write(phy->ser_dev,
 39				  out->data, out->len,
 40				  MAX_SCHEDULE_TIMEOUT);
 41	if (err < 0)
 42		return err;
 43
 44	return 0;
 45}
 46
 47static const struct s3fwrn5_phy_ops uart_phy_ops = {
 48	.set_wake = s3fwrn5_phy_set_wake,
 49	.set_mode = s3fwrn5_phy_set_mode,
 50	.get_mode = s3fwrn5_phy_get_mode,
 51	.write = s3fwrn82_uart_write,
 52};
 53
 54static size_t s3fwrn82_uart_read(struct serdev_device *serdev,
 55				 const u8 *data, size_t count)
 56{
 57	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
 58	size_t i;
 59
 60	for (i = 0; i < count; i++) {
 61		if (!phy->recv_skb) {
 62			phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
 63			if (!phy->recv_skb)
 64				return i;
 65		}
 66
 67		skb_put_u8(phy->recv_skb, *data++);
 68
 69		if (phy->recv_skb->len < S3FWRN82_NCI_HEADER)
 70			continue;
 71
 72		if ((phy->recv_skb->len - S3FWRN82_NCI_HEADER)
 73				< phy->recv_skb->data[S3FWRN82_NCI_IDX])
 74			continue;
 75
 76		s3fwrn5_recv_frame(phy->common.ndev, phy->recv_skb,
 77				   phy->common.mode);
 78		phy->recv_skb = NULL;
 79	}
 80
 81	return i;
 82}
 83
 84static const struct serdev_device_ops s3fwrn82_serdev_ops = {
 85	.receive_buf = s3fwrn82_uart_read,
 86	.write_wakeup = serdev_device_write_wakeup,
 87};
 88
 89static const struct of_device_id s3fwrn82_uart_of_match[] = {
 90	{ .compatible = "samsung,s3fwrn82", },
 91	{},
 92};
 93MODULE_DEVICE_TABLE(of, s3fwrn82_uart_of_match);
 94
 95static int s3fwrn82_uart_parse_dt(struct serdev_device *serdev)
 96{
 97	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
 98	struct device_node *np = serdev->dev.of_node;
 99
100	if (!np)
101		return -ENODEV;
102
103	phy->common.gpio_en = of_get_named_gpio(np, "en-gpios", 0);
104	if (!gpio_is_valid(phy->common.gpio_en))
105		return -ENODEV;
106
107	phy->common.gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
108	if (!gpio_is_valid(phy->common.gpio_fw_wake))
109		return -ENODEV;
110
111	return 0;
112}
113
114static int s3fwrn82_uart_probe(struct serdev_device *serdev)
115{
116	struct s3fwrn82_uart_phy *phy;
117	int ret = -ENOMEM;
118
119	phy = devm_kzalloc(&serdev->dev, sizeof(*phy), GFP_KERNEL);
120	if (!phy)
121		goto err_exit;
122
123	phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
124	if (!phy->recv_skb)
125		goto err_exit;
126
127	mutex_init(&phy->common.mutex);
128	phy->common.mode = S3FWRN5_MODE_COLD;
129
130	phy->ser_dev = serdev;
131	serdev_device_set_drvdata(serdev, phy);
132	serdev_device_set_client_ops(serdev, &s3fwrn82_serdev_ops);
133	ret = serdev_device_open(serdev);
134	if (ret) {
135		dev_err(&serdev->dev, "Unable to open device\n");
136		goto err_skb;
137	}
138
139	ret = serdev_device_set_baudrate(serdev, 115200);
140	if (ret != 115200) {
141		ret = -EINVAL;
142		goto err_serdev;
143	}
144
145	serdev_device_set_flow_control(serdev, false);
146
147	ret = s3fwrn82_uart_parse_dt(serdev);
148	if (ret < 0)
149		goto err_serdev;
150
151	ret = devm_gpio_request_one(&phy->ser_dev->dev, phy->common.gpio_en,
152				    GPIOF_OUT_INIT_HIGH, "s3fwrn82_en");
153	if (ret < 0)
154		goto err_serdev;
155
156	ret = devm_gpio_request_one(&phy->ser_dev->dev,
157				    phy->common.gpio_fw_wake,
158				    GPIOF_OUT_INIT_LOW, "s3fwrn82_fw_wake");
159	if (ret < 0)
160		goto err_serdev;
161
162	ret = s3fwrn5_probe(&phy->common.ndev, phy, &phy->ser_dev->dev,
163			    &uart_phy_ops);
164	if (ret < 0)
165		goto err_serdev;
166
167	return ret;
168
169err_serdev:
170	serdev_device_close(serdev);
171err_skb:
172	kfree_skb(phy->recv_skb);
173err_exit:
174	return ret;
175}
176
177static void s3fwrn82_uart_remove(struct serdev_device *serdev)
178{
179	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
180
181	s3fwrn5_remove(phy->common.ndev);
182	serdev_device_close(serdev);
183	kfree_skb(phy->recv_skb);
184}
185
186static struct serdev_device_driver s3fwrn82_uart_driver = {
187	.probe = s3fwrn82_uart_probe,
188	.remove = s3fwrn82_uart_remove,
189	.driver = {
190		.name = "s3fwrn82_uart",
191		.of_match_table = s3fwrn82_uart_of_match,
192	},
193};
194
195module_serdev_device_driver(s3fwrn82_uart_driver);
196
197MODULE_LICENSE("GPL");
198MODULE_DESCRIPTION("UART driver for Samsung NFC");
199MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>");