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