linux/drivers/gnss/ubx.c
Wolfram Sang 0cbbbe09d4 gnss: ubx: add support for the reset gpio
The Renesas KingFisher board includes a U-Blox Neo-M8 chip. This chip
has a reset pin which is also wired on the board. When Linux starts,
reset is asserted by the firmware. Deassert the reset pin when probing
this driver.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
[ johan: rename gpio descriptor variable ]
Signed-off-by: Johan Hovold <johan@kernel.org>
2023-12-15 09:29:54 +01:00

146 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* u-blox GNSS receiver driver
*
* Copyright (C) 2018 Johan Hovold <johan@kernel.org>
*/
#include <linux/errno.h>
#include <linux/gnss.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/serdev.h>
#include "serial.h"
struct ubx_data {
struct regulator *vcc;
};
static int ubx_set_active(struct gnss_serial *gserial)
{
struct ubx_data *data = gnss_serial_get_drvdata(gserial);
int ret;
ret = regulator_enable(data->vcc);
if (ret)
return ret;
return 0;
}
static int ubx_set_standby(struct gnss_serial *gserial)
{
struct ubx_data *data = gnss_serial_get_drvdata(gserial);
int ret;
ret = regulator_disable(data->vcc);
if (ret)
return ret;
return 0;
}
static int ubx_set_power(struct gnss_serial *gserial,
enum gnss_serial_pm_state state)
{
switch (state) {
case GNSS_SERIAL_ACTIVE:
return ubx_set_active(gserial);
case GNSS_SERIAL_OFF:
case GNSS_SERIAL_STANDBY:
return ubx_set_standby(gserial);
}
return -EINVAL;
}
static const struct gnss_serial_ops ubx_gserial_ops = {
.set_power = ubx_set_power,
};
static int ubx_probe(struct serdev_device *serdev)
{
struct gnss_serial *gserial;
struct gpio_desc *reset;
struct ubx_data *data;
int ret;
gserial = gnss_serial_allocate(serdev, sizeof(*data));
if (IS_ERR(gserial)) {
ret = PTR_ERR(gserial);
return ret;
}
gserial->ops = &ubx_gserial_ops;
gserial->gdev->type = GNSS_TYPE_UBX;
data = gnss_serial_get_drvdata(gserial);
data->vcc = devm_regulator_get(&serdev->dev, "vcc");
if (IS_ERR(data->vcc)) {
ret = PTR_ERR(data->vcc);
goto err_free_gserial;
}
ret = devm_regulator_get_enable_optional(&serdev->dev, "v-bckp");
if (ret < 0 && ret != -ENODEV)
goto err_free_gserial;
/* Deassert reset */
reset = devm_gpiod_get_optional(&serdev->dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(reset)) {
ret = PTR_ERR(reset);
goto err_free_gserial;
}
ret = gnss_serial_register(gserial);
if (ret)
goto err_free_gserial;
return 0;
err_free_gserial:
gnss_serial_free(gserial);
return ret;
}
static void ubx_remove(struct serdev_device *serdev)
{
struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
gnss_serial_deregister(gserial);
gnss_serial_free(gserial);
}
#ifdef CONFIG_OF
static const struct of_device_id ubx_of_match[] = {
{ .compatible = "u-blox,neo-6m" },
{ .compatible = "u-blox,neo-8" },
{ .compatible = "u-blox,neo-m8" },
{},
};
MODULE_DEVICE_TABLE(of, ubx_of_match);
#endif
static struct serdev_device_driver ubx_driver = {
.driver = {
.name = "gnss-ubx",
.of_match_table = of_match_ptr(ubx_of_match),
.pm = &gnss_serial_pm_ops,
},
.probe = ubx_probe,
.remove = ubx_remove,
};
module_serdev_device_driver(ubx_driver);
MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
MODULE_DESCRIPTION("u-blox GNSS receiver driver");
MODULE_LICENSE("GPL v2");