drivers/nfc/s3fwrn5/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
  27 struct s3fwrn82_uart_phy {
  28         struct phy_common common;
  29         struct serdev_device *ser_dev;
  30         struct sk_buff *recv_skb;
  31 };
  32
  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
  54 static 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
  81 static const struct serdev_device_ops s3fwrn82_serdev_ops = {
  82         .receive_buf = s3fwrn82_uart_read,
  83         .write_wakeup = serdev_device_write_wakeup,
  84 };
  85
  86 static const struct of_device_id s3fwrn82_uart_of_match[] = {
  87         { .compatible = "samsung,s3fwrn82", },
  88         {},
  89 };
  90 MODULE_DEVICE_TABLE(of, s3fwrn82_uart_of_match);
  91
  92 static 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
 111 static 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
 166 err_serdev:
 167         serdev_device_close(serdev);
 168 err_skb:
 169         kfree_skb(phy->recv_skb);
 170 err_exit:
 171         return ret;
 172 }
 173
 174 static 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
 183 static 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
 192 module_serdev_device_driver(s3fwrn82_uart_driver);
 193
 194 MODULE_LICENSE("GPL");
 195 MODULE_DESCRIPTION("UART driver for Samsung NFC");
 196 MODULE_AUTHOR("Bongsu Jeon <bongsu.jeon@samsung.com>");