drivers/gnss/ubx.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * u-blox GNSS receiver driver
   4  *
   5  * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
   6  */
   7
   8 #include <linux/errno.h>
   9 #include <linux/gnss.h>
  10 #include <linux/gpio/consumer.h>
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/serdev.h>
  17
  18 #include "serial.h"
  19
  20 struct ubx_data {
  21         struct regulator *vcc;
  22 };
  23
  24 static int ubx_set_active(struct gnss_serial *gserial)
  25 {
  26         struct ubx_data *data = gnss_serial_get_drvdata(gserial);
  27         int ret;
  28
  29         ret = regulator_enable(data->vcc);
  30         if (ret)
  31                 return ret;
  32
  33         return 0;
  34 }
  35
  36 static int ubx_set_standby(struct gnss_serial *gserial)
  37 {
  38         struct ubx_data *data = gnss_serial_get_drvdata(gserial);
  39         int ret;
  40
  41         ret = regulator_disable(data->vcc);
  42         if (ret)
  43                 return ret;
  44
  45         return 0;
  46 }
  47
  48 static int ubx_set_power(struct gnss_serial *gserial,
  49                                 enum gnss_serial_pm_state state)
  50 {
  51         switch (state) {
  52         case GNSS_SERIAL_ACTIVE:
  53                 return ubx_set_active(gserial);
  54         case GNSS_SERIAL_OFF:
  55         case GNSS_SERIAL_STANDBY:
  56                 return ubx_set_standby(gserial);
  57         }
  58
  59         return -EINVAL;
  60 }
  61
  62 static const struct gnss_serial_ops ubx_gserial_ops = {
  63         .set_power = ubx_set_power,
  64 };
  65
  66 static int ubx_probe(struct serdev_device *serdev)
  67 {
  68         struct gnss_serial *gserial;
  69         struct gpio_desc *reset;
  70         struct ubx_data *data;
  71         int ret;
  72
  73         gserial = gnss_serial_allocate(serdev, sizeof(*data));
  74         if (IS_ERR(gserial)) {
  75                 ret = PTR_ERR(gserial);
  76                 return ret;
  77         }
  78
  79         gserial->ops = &ubx_gserial_ops;
  80
  81         gserial->gdev->type = GNSS_TYPE_UBX;
  82
  83         data = gnss_serial_get_drvdata(gserial);
  84
  85         data->vcc = devm_regulator_get(&serdev->dev, "vcc");
  86         if (IS_ERR(data->vcc)) {
  87                 ret = PTR_ERR(data->vcc);
  88                 goto err_free_gserial;
  89         }
  90
  91         ret = devm_regulator_get_enable_optional(&serdev->dev, "v-bckp");
  92         if (ret < 0 && ret != -ENODEV)
  93                 goto err_free_gserial;
  94
  95         /* Deassert reset */
  96         reset = devm_gpiod_get_optional(&serdev->dev, "reset", GPIOD_OUT_LOW);
  97         if (IS_ERR(reset)) {
  98                 ret = PTR_ERR(reset);
  99                 goto err_free_gserial;
 100         }
 101
 102         ret = gnss_serial_register(gserial);
 103         if (ret)
 104                 goto err_free_gserial;
 105
 106         return 0;
 107
 108 err_free_gserial:
 109         gnss_serial_free(gserial);
 110
 111         return ret;
 112 }
 113
 114 static void ubx_remove(struct serdev_device *serdev)
 115 {
 116         struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
 117
 118         gnss_serial_deregister(gserial);
 119         gnss_serial_free(gserial);
 120 }
 121
 122 #ifdef CONFIG_OF
 123 static const struct of_device_id ubx_of_match[] = {
 124         { .compatible = "u-blox,neo-6m" },
 125         { .compatible = "u-blox,neo-8" },
 126         { .compatible = "u-blox,neo-m8" },
 127         {},
 128 };
 129 MODULE_DEVICE_TABLE(of, ubx_of_match);
 130 #endif
 131
 132 static struct serdev_device_driver ubx_driver = {
 133         .driver = {
 134                 .name           = "gnss-ubx",
 135                 .of_match_table = of_match_ptr(ubx_of_match),
 136                 .pm             = &gnss_serial_pm_ops,
 137         },
 138         .probe  = ubx_probe,
 139         .remove = ubx_remove,
 140 };
 141 module_serdev_device_driver(ubx_driver);
 142
 143 MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
 144 MODULE_DESCRIPTION("u-blox GNSS receiver driver");
 145 MODULE_LICENSE("GPL v2");