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 ssize_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
  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
 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
 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>");