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");