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
 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 *safeboot;
 70	struct gpio_desc *reset;
 71	struct ubx_data *data;
 72	int ret;
 73
 74	gserial = gnss_serial_allocate(serdev, sizeof(*data));
 75	if (IS_ERR(gserial)) {
 76		ret = PTR_ERR(gserial);
 77		return ret;
 78	}
 79
 80	gserial->ops = &ubx_gserial_ops;
 81
 82	gserial->gdev->type = GNSS_TYPE_UBX;
 83
 84	data = gnss_serial_get_drvdata(gserial);
 85
 86	data->vcc = devm_regulator_get(&serdev->dev, "vcc");
 87	if (IS_ERR(data->vcc)) {
 88		ret = PTR_ERR(data->vcc);
 89		goto err_free_gserial;
 90	}
 91
 92	ret = devm_regulator_get_enable_optional(&serdev->dev, "v-bckp");
 93	if (ret < 0 && ret != -ENODEV)
 94		goto err_free_gserial;
 95
 96	/* Deassert safeboot */
 97	safeboot = devm_gpiod_get_optional(&serdev->dev, "safeboot", GPIOD_OUT_LOW);
 98	if (IS_ERR(safeboot)) {
 99		ret = PTR_ERR(safeboot);
100		goto err_free_gserial;
101	}
102
103	/* Deassert reset */
104	reset = devm_gpiod_get_optional(&serdev->dev, "reset", GPIOD_OUT_LOW);
105	if (IS_ERR(reset)) {
106		ret = PTR_ERR(reset);
107		goto err_free_gserial;
108	}
109
110	ret = gnss_serial_register(gserial);
111	if (ret)
112		goto err_free_gserial;
113
114	return 0;
115
116err_free_gserial:
117	gnss_serial_free(gserial);
118
119	return ret;
120}
121
122static void ubx_remove(struct serdev_device *serdev)
123{
124	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
125
126	gnss_serial_deregister(gserial);
127	gnss_serial_free(gserial);
128}
129
130#ifdef CONFIG_OF
131static const struct of_device_id ubx_of_match[] = {
132	{ .compatible = "u-blox,neo-6m" },
133	{ .compatible = "u-blox,neo-8" },
134	{ .compatible = "u-blox,neo-m8" },
135	{},
136};
137MODULE_DEVICE_TABLE(of, ubx_of_match);
138#endif
139
140static struct serdev_device_driver ubx_driver = {
141	.driver	= {
142		.name		= "gnss-ubx",
143		.of_match_table	= of_match_ptr(ubx_of_match),
144		.pm		= &gnss_serial_pm_ops,
145	},
146	.probe	= ubx_probe,
147	.remove	= ubx_remove,
148};
149module_serdev_device_driver(ubx_driver);
150
151MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
152MODULE_DESCRIPTION("u-blox GNSS receiver driver");
153MODULE_LICENSE("GPL v2");