drivers/gnss/mtk.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Mediatek 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/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/serdev.h>
  16
  17 #include "serial.h"
  18
  19 struct mtk_data {
  20         struct regulator *vbackup;
  21         struct regulator *vcc;
  22 };
  23
  24 static int mtk_set_active(struct gnss_serial *gserial)
  25 {
  26         struct mtk_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 mtk_set_standby(struct gnss_serial *gserial)
  37 {
  38         struct mtk_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 mtk_set_power(struct gnss_serial *gserial,
  49                          enum gnss_serial_pm_state state)
  50 {
  51         switch (state) {
  52         case GNSS_SERIAL_ACTIVE:
  53                 return mtk_set_active(gserial);
  54         case GNSS_SERIAL_OFF:
  55         case GNSS_SERIAL_STANDBY:
  56                 return mtk_set_standby(gserial);
  57         }
  58
  59         return -EINVAL;
  60 }
  61
  62 static const struct gnss_serial_ops mtk_gserial_ops = {
  63         .set_power = mtk_set_power,
  64 };
  65
  66 static int mtk_probe(struct serdev_device *serdev)
  67 {
  68         struct gnss_serial *gserial;
  69         struct mtk_data *data;
  70         int ret;
  71
  72         gserial = gnss_serial_allocate(serdev, sizeof(*data));
  73         if (IS_ERR(gserial)) {
  74                 ret = PTR_ERR(gserial);
  75                 return ret;
  76         }
  77
  78         gserial->ops = &mtk_gserial_ops;
  79
  80         gserial->gdev->type = GNSS_TYPE_MTK;
  81
  82         data = gnss_serial_get_drvdata(gserial);
  83
  84         data->vcc = devm_regulator_get(&serdev->dev, "vcc");
  85         if (IS_ERR(data->vcc)) {
  86                 ret = PTR_ERR(data->vcc);
  87                 goto err_free_gserial;
  88         }
  89
  90         data->vbackup = devm_regulator_get_optional(&serdev->dev, "vbackup");
  91         if (IS_ERR(data->vbackup)) {
  92                 ret = PTR_ERR(data->vbackup);
  93                 if (ret == -ENODEV)
  94                         data->vbackup = NULL;
  95                 else
  96                         goto err_free_gserial;
  97         }
  98
  99         if (data->vbackup) {
 100                 ret = regulator_enable(data->vbackup);
 101                 if (ret)
 102                         goto err_free_gserial;
 103         }
 104
 105         ret = gnss_serial_register(gserial);
 106         if (ret)
 107                 goto err_disable_vbackup;
 108
 109         return 0;
 110
 111 err_disable_vbackup:
 112         if (data->vbackup)
 113                 regulator_disable(data->vbackup);
 114 err_free_gserial:
 115         gnss_serial_free(gserial);
 116
 117         return ret;
 118 }
 119
 120 static void mtk_remove(struct serdev_device *serdev)
 121 {
 122         struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
 123         struct mtk_data *data = gnss_serial_get_drvdata(gserial);
 124
 125         gnss_serial_deregister(gserial);
 126         if (data->vbackup)
 127                 regulator_disable(data->vbackup);
 128         gnss_serial_free(gserial);
 129 };
 130
 131 #ifdef CONFIG_OF
 132 static const struct of_device_id mtk_of_match[] = {
 133         { .compatible = "globaltop,pa6h" },
 134         {},
 135 };
 136 MODULE_DEVICE_TABLE(of, mtk_of_match);
 137 #endif
 138
 139 static struct serdev_device_driver mtk_driver = {
 140         .driver = {
 141                 .name           = "gnss-mtk",
 142                 .of_match_table = of_match_ptr(mtk_of_match),
 143                 .pm             = &gnss_serial_pm_ops,
 144         },
 145         .probe  = mtk_probe,
 146         .remove = mtk_remove,
 147 };
 148 module_serdev_device_driver(mtk_driver);
 149
 150 MODULE_AUTHOR("Loys Ollivier <lollivier@baylibre.com>");
 151 MODULE_DESCRIPTION("Mediatek GNSS receiver driver");
 152 MODULE_LICENSE("GPL v2");