linux/drivers/gnss/mtk.c
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   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
  19struct mtk_data {
  20        struct regulator *vbackup;
  21        struct regulator *vcc;
  22};
  23
  24static 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
  36static 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
  48static 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
  62static const struct gnss_serial_ops mtk_gserial_ops = {
  63        .set_power = mtk_set_power,
  64};
  65
  66static 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
 111err_disable_vbackup:
 112        if (data->vbackup)
 113                regulator_disable(data->vbackup);
 114err_free_gserial:
 115        gnss_serial_free(gserial);
 116
 117        return ret;
 118}
 119
 120static 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
 132static const struct of_device_id mtk_of_match[] = {
 133        { .compatible = "globaltop,pa6h" },
 134        {},
 135};
 136MODULE_DEVICE_TABLE(of, mtk_of_match);
 137#endif
 138
 139static 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};
 148module_serdev_device_driver(mtk_driver);
 149
 150MODULE_AUTHOR("Loys Ollivier <lollivier@baylibre.com>");
 151MODULE_DESCRIPTION("Mediatek GNSS receiver driver");
 152MODULE_LICENSE("GPL v2");
 153