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U-Blox M8/M9 chip have a pin to start it in safeboot mode, to be used to recover from situations where the flash content has become corrupted and needs to be restored. If this pin is asserted at power up/reset, the receiver starts in safeboot mode and GNSS operation is disabled. Deassert the safeboot pin when probing this driver. Signed-off-by: Alejandro Enrique <alejandroe1@geotab.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20250911-ubx-safeboot-v3-2-32fe6b882a3c@geotab.com [ johan: deassert after requesting supplies ] Signed-off-by: Johan Hovold <johan@kernel.org>
154 lines
3.1 KiB
C
154 lines
3.1 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 *safeboot;
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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 safeboot */
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safeboot = devm_gpiod_get_optional(&serdev->dev, "safeboot", GPIOD_OUT_LOW);
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if (IS_ERR(safeboot)) {
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ret = PTR_ERR(safeboot);
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goto err_free_gserial;
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}
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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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