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 int s3fwrn82_uart_read(struct serdev_device *serdev,
 55			      const unsigned char *data,
 56			      size_t count)
 57{
 58	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
 59	size_t i;
 60
 61	for (i = 0; i < count; i++) {
 62		skb_put_u8(phy->recv_skb, *data++);
 63
 64		if (phy->recv_skb->len < S3FWRN82_NCI_HEADER)
 65			continue;
 66
 67		if ((phy->recv_skb->len - S3FWRN82_NCI_HEADER)
 68				< phy->recv_skb->data[S3FWRN82_NCI_IDX])
 69			continue;
 70
 71		s3fwrn5_recv_frame(phy->common.ndev, phy->recv_skb,
 72				   phy->common.mode);
 73		phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
 74		if (!phy->recv_skb)
 75			return 0;
 76	}
 77
 78	return i;
 79}
 80
 81static const struct serdev_device_ops s3fwrn82_serdev_ops = {
 82	.receive_buf = s3fwrn82_uart_read,
 83	.write_wakeup = serdev_device_write_wakeup,
 84};
 85
 86static const struct of_device_id s3fwrn82_uart_of_match[] = {
 87	{ .compatible = "samsung,s3fwrn82", },
 88	{},
 89};
 90MODULE_DEVICE_TABLE(of, s3fwrn82_uart_of_match);
 91
 92static int s3fwrn82_uart_parse_dt(struct serdev_device *serdev)
 93{
 94	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
 95	struct device_node *np = serdev->dev.of_node;
 96
 97	if (!np)
 98		return -ENODEV;
 99
100	phy->common.gpio_en = of_get_named_gpio(np, "en-gpios", 0);
101	if (!gpio_is_valid(phy->common.gpio_en))
102		return -ENODEV;
103
104	phy->common.gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
105	if (!gpio_is_valid(phy->common.gpio_fw_wake))
106		return -ENODEV;
107
108	return 0;
109}
110
111static int s3fwrn82_uart_probe(struct serdev_device *serdev)
112{
113	struct s3fwrn82_uart_phy *phy;
114	int ret = -ENOMEM;
115
116	phy = devm_kzalloc(&serdev->dev, sizeof(*phy), GFP_KERNEL);
117	if (!phy)
118		goto err_exit;
119
120	phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
121	if (!phy->recv_skb)
122		goto err_exit;
123
124	mutex_init(&phy->common.mutex);
125	phy->common.mode = S3FWRN5_MODE_COLD;
126
127	phy->ser_dev = serdev;
128	serdev_device_set_drvdata(serdev, phy);
129	serdev_device_set_client_ops(serdev, &s3fwrn82_serdev_ops);
130	ret = serdev_device_open(serdev);
131	if (ret) {
132		dev_err(&serdev->dev, "Unable to open device\n");
133		goto err_skb;
134	}
135
136	ret = serdev_device_set_baudrate(serdev, 115200);
137	if (ret != 115200) {
138		ret = -EINVAL;
139		goto err_serdev;
140	}
141
142	serdev_device_set_flow_control(serdev, false);
143
144	ret = s3fwrn82_uart_parse_dt(serdev);
145	if (ret < 0)
146		goto err_serdev;
147
148	ret = devm_gpio_request_one(&phy->ser_dev->dev, phy->common.gpio_en,
149				    GPIOF_OUT_INIT_HIGH, "s3fwrn82_en");
150	if (ret < 0)
151		goto err_serdev;
152
153	ret = devm_gpio_request_one(&phy->ser_dev->dev,
154				    phy->common.gpio_fw_wake,
155				    GPIOF_OUT_INIT_LOW, "s3fwrn82_fw_wake");
156	if (ret < 0)
157		goto err_serdev;
158
159	ret = s3fwrn5_probe(&phy->common.ndev, phy, &phy->ser_dev->dev,
160			    &uart_phy_ops);
161	if (ret < 0)
162		goto err_serdev;
163
164	return ret;
165
166err_serdev:
167	serdev_device_close(serdev);
168err_skb:
169	kfree_skb(phy->recv_skb);
170err_exit:
171	return ret;
172}
173
174static void s3fwrn82_uart_remove(struct serdev_device *serdev)
175{
176	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
177
178	s3fwrn5_remove(phy->common.ndev);
179	serdev_device_close(serdev);
180	kfree_skb(phy->recv_skb);
181}
182
183static struct serdev_device_driver s3fwrn82_uart_driver = {
184	.probe = s3fwrn82_uart_probe,
185	.remove = s3fwrn82_uart_remove,
186	.driver = {
187		.name = "s3fwrn82_uart",
188		.of_match_table = s3fwrn82_uart_of_match,
189	},
190};
191
192module_serdev_device_driver(s3fwrn82_uart_driver);
193
194MODULE_LICENSE("GPL");
195MODULE_DESCRIPTION("UART driver for Samsung NFC");
196MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>");