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
 20struct ubx_data {
 21	struct regulator *vcc;
 22};
 23
 24static 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
 36static 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
 48static 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
 62static const struct gnss_serial_ops ubx_gserial_ops = {
 63	.set_power = ubx_set_power,
 64};
 65
 66static 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
108err_free_gserial:
109	gnss_serial_free(gserial);
110
111	return ret;
112}
113
114static 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
123static 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};
129MODULE_DEVICE_TABLE(of, ubx_of_match);
130#endif
131
132static 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};
141module_serdev_device_driver(ubx_driver);
142
143MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
144MODULE_DESCRIPTION("u-blox GNSS receiver driver");
145MODULE_LICENSE("GPL v2");