xref: /linux/drivers/nfc/s3fwrn5/uart.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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 
27 struct s3fwrn82_uart_phy {
28 	struct phy_common common;
29 	struct serdev_device *ser_dev;
30 	struct sk_buff *recv_skb;
31 };
32 
s3fwrn82_uart_write(void * phy_id,struct sk_buff * out)33 static 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 
47 static 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 
s3fwrn82_uart_read(struct serdev_device * serdev,const u8 * data,size_t count)54 static 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 		skb_put_u8(phy->recv_skb, *data++);
62 
63 		if (phy->recv_skb->len < S3FWRN82_NCI_HEADER)
64 			continue;
65 
66 		if ((phy->recv_skb->len - S3FWRN82_NCI_HEADER)
67 				< phy->recv_skb->data[S3FWRN82_NCI_IDX])
68 			continue;
69 
70 		s3fwrn5_recv_frame(phy->common.ndev, phy->recv_skb,
71 				   phy->common.mode);
72 		phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
73 		if (!phy->recv_skb)
74 			return 0;
75 	}
76 
77 	return i;
78 }
79 
80 static const struct serdev_device_ops s3fwrn82_serdev_ops = {
81 	.receive_buf = s3fwrn82_uart_read,
82 	.write_wakeup = serdev_device_write_wakeup,
83 };
84 
85 static const struct of_device_id s3fwrn82_uart_of_match[] = {
86 	{ .compatible = "samsung,s3fwrn82", },
87 	{},
88 };
89 MODULE_DEVICE_TABLE(of, s3fwrn82_uart_of_match);
90 
s3fwrn82_uart_parse_dt(struct serdev_device * serdev)91 static int s3fwrn82_uart_parse_dt(struct serdev_device *serdev)
92 {
93 	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
94 	struct device_node *np = serdev->dev.of_node;
95 
96 	if (!np)
97 		return -ENODEV;
98 
99 	phy->common.gpio_en = of_get_named_gpio(np, "en-gpios", 0);
100 	if (!gpio_is_valid(phy->common.gpio_en))
101 		return -ENODEV;
102 
103 	phy->common.gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
104 	if (!gpio_is_valid(phy->common.gpio_fw_wake))
105 		return -ENODEV;
106 
107 	return 0;
108 }
109 
s3fwrn82_uart_probe(struct serdev_device * serdev)110 static int s3fwrn82_uart_probe(struct serdev_device *serdev)
111 {
112 	struct s3fwrn82_uart_phy *phy;
113 	int ret = -ENOMEM;
114 
115 	phy = devm_kzalloc(&serdev->dev, sizeof(*phy), GFP_KERNEL);
116 	if (!phy)
117 		goto err_exit;
118 
119 	phy->recv_skb = alloc_skb(NCI_SKB_BUFF_LEN, GFP_KERNEL);
120 	if (!phy->recv_skb)
121 		goto err_exit;
122 
123 	mutex_init(&phy->common.mutex);
124 	phy->common.mode = S3FWRN5_MODE_COLD;
125 
126 	phy->ser_dev = serdev;
127 	serdev_device_set_drvdata(serdev, phy);
128 	serdev_device_set_client_ops(serdev, &s3fwrn82_serdev_ops);
129 	ret = serdev_device_open(serdev);
130 	if (ret) {
131 		dev_err(&serdev->dev, "Unable to open device\n");
132 		goto err_skb;
133 	}
134 
135 	ret = serdev_device_set_baudrate(serdev, 115200);
136 	if (ret != 115200) {
137 		ret = -EINVAL;
138 		goto err_serdev;
139 	}
140 
141 	serdev_device_set_flow_control(serdev, false);
142 
143 	ret = s3fwrn82_uart_parse_dt(serdev);
144 	if (ret < 0)
145 		goto err_serdev;
146 
147 	ret = devm_gpio_request_one(&phy->ser_dev->dev, phy->common.gpio_en,
148 				    GPIOF_OUT_INIT_HIGH, "s3fwrn82_en");
149 	if (ret < 0)
150 		goto err_serdev;
151 
152 	ret = devm_gpio_request_one(&phy->ser_dev->dev,
153 				    phy->common.gpio_fw_wake,
154 				    GPIOF_OUT_INIT_LOW, "s3fwrn82_fw_wake");
155 	if (ret < 0)
156 		goto err_serdev;
157 
158 	ret = s3fwrn5_probe(&phy->common.ndev, phy, &phy->ser_dev->dev,
159 			    &uart_phy_ops);
160 	if (ret < 0)
161 		goto err_serdev;
162 
163 	return ret;
164 
165 err_serdev:
166 	serdev_device_close(serdev);
167 err_skb:
168 	kfree_skb(phy->recv_skb);
169 err_exit:
170 	return ret;
171 }
172 
s3fwrn82_uart_remove(struct serdev_device * serdev)173 static void s3fwrn82_uart_remove(struct serdev_device *serdev)
174 {
175 	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
176 
177 	s3fwrn5_remove(phy->common.ndev);
178 	serdev_device_close(serdev);
179 	kfree_skb(phy->recv_skb);
180 }
181 
182 static struct serdev_device_driver s3fwrn82_uart_driver = {
183 	.probe = s3fwrn82_uart_probe,
184 	.remove = s3fwrn82_uart_remove,
185 	.driver = {
186 		.name = "s3fwrn82_uart",
187 		.of_match_table = s3fwrn82_uart_of_match,
188 	},
189 };
190 
191 module_serdev_device_driver(s3fwrn82_uart_driver);
192 
193 MODULE_LICENSE("GPL");
194 MODULE_DESCRIPTION("UART driver for Samsung NFC");
195 MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>");
196