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Commit 1ad69f10 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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gnss: add driver for u-blox receivers 



Add driver for serial-connected u-blox GNSS receivers.

Note that the driver uses the generic GNSS serial implementation and
therefore essentially only manages power abstracted into three power
states: ACTIVE, STANDBY, and OFF.

For u-blox receivers with a main supply and no enable-gpios, this simply
means that the main supply is disabled in STANDBY and OFF (the optional
backup supply is kept enabled while the driver is bound).

Note that timepulse-support is not yet implemented.

Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cf408372

drivers/gnss/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -15,4 +15,17 @@ if GNSS 
config GNSS_SERIAL

	tristate



config GNSS_UBX_SERIAL

	tristate "u-blox GNSS receiver support"

	depends on SERIAL_DEV_BUS

	select GNSS_SERIAL

	---help---

	  Say Y here if you have a u-blox GNSS receiver which uses a serial

	  interface.



	  To compile this driver as a module, choose M here: the module will

	  be called gnss-ubx.



	  If unsure, say N.



endif # GNSS

drivers/gnss/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -8,3 +8,6 @@ gnss-y := core.o 


obj-$(CONFIG_GNSS_SERIAL)		+= gnss-serial.o

gnss-serial-y := serial.o



obj-$(CONFIG_GNSS_UBX_SERIAL)		+= gnss-ubx.o

gnss-ubx-y := ubx.o

drivers/gnss/ubx.c

0 → 100644
+151 −0
Original line number Diff line number Diff line 
// 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/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 *v_bckp;

	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;

}



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 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;



	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;

	}



	data->v_bckp = devm_regulator_get_optional(&serdev->dev, "v-bckp");

	if (IS_ERR(data->v_bckp)) {

		ret = PTR_ERR(data->v_bckp);

		if (ret == -ENODEV)

			data->v_bckp = NULL;

		else

			goto err_free_gserial;

	}



	if (data->v_bckp) {

		ret = regulator_enable(data->v_bckp);

		if (ret)

			goto err_free_gserial;

	}



	ret = gnss_serial_register(gserial);

	if (ret)

		goto err_disable_v_bckp;



	return 0;



err_disable_v_bckp:

	if (data->v_bckp)

		regulator_disable(data->v_bckp);

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);

	struct ubx_data *data = gnss_serial_get_drvdata(gserial);



	gnss_serial_deregister(gserial);

	if (data->v_bckp)

		regulator_disable(data->v_bckp);

	gnss_serial_free(gserial);

};



#ifdef CONFIG_OF

static const struct of_device_id ubx_of_match[] = {

	{ .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");