diff options
author | Loys Ollivier <lollivier@baylibre.com> | 2019-02-13 16:09:29 +0100 |
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committer | Johan Hovold <johan@kernel.org> | 2019-02-15 16:54:38 +0100 |
commit | d4584bbfcf2a8f5b6605be9eba465bba59ce68c8 (patch) | |
tree | 9daa1ff36cd537850fd7a910135849a84851ce6b /drivers/gnss/mtk.c | |
parent | 625239d4ad43590f6639737ee900884f7d801411 (diff) | |
download | linux-d4584bbfcf2a8f5b6605be9eba465bba59ce68c8.tar.bz2 |
gnss: add driver for mediatek receivers
Add driver for serial-connected Mediatek-based GNSS receivers.
These devices typically boot transmitting vendor specific NMEA output
sequences. The serial port bit rate is read from the device tree
"current-speed".
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 mediatek 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 the timepulse-support is left unimplemented.
Signed-off-by: Loys Ollivier <lollivier@baylibre.com>
[ johan: rename backup supply ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/gnss/mtk.c')
-rw-r--r-- | drivers/gnss/mtk.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/drivers/gnss/mtk.c b/drivers/gnss/mtk.c new file mode 100644 index 000000000000..d1fc55560daf --- /dev/null +++ b/drivers/gnss/mtk.c @@ -0,0 +1,152 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Mediatek 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 mtk_data { + struct regulator *vbackup; + struct regulator *vcc; +}; + +static int mtk_set_active(struct gnss_serial *gserial) +{ + struct mtk_data *data = gnss_serial_get_drvdata(gserial); + int ret; + + ret = regulator_enable(data->vcc); + if (ret) + return ret; + + return 0; +} + +static int mtk_set_standby(struct gnss_serial *gserial) +{ + struct mtk_data *data = gnss_serial_get_drvdata(gserial); + int ret; + + ret = regulator_disable(data->vcc); + if (ret) + return ret; + + return 0; +} + +static int mtk_set_power(struct gnss_serial *gserial, + enum gnss_serial_pm_state state) +{ + switch (state) { + case GNSS_SERIAL_ACTIVE: + return mtk_set_active(gserial); + case GNSS_SERIAL_OFF: + case GNSS_SERIAL_STANDBY: + return mtk_set_standby(gserial); + } + + return -EINVAL; +} + +static const struct gnss_serial_ops mtk_gserial_ops = { + .set_power = mtk_set_power, +}; + +static int mtk_probe(struct serdev_device *serdev) +{ + struct gnss_serial *gserial; + struct mtk_data *data; + int ret; + + gserial = gnss_serial_allocate(serdev, sizeof(*data)); + if (IS_ERR(gserial)) { + ret = PTR_ERR(gserial); + return ret; + } + + gserial->ops = &mtk_gserial_ops; + + gserial->gdev->type = GNSS_TYPE_MTK; + + 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->vbackup = devm_regulator_get_optional(&serdev->dev, "vbackup"); + if (IS_ERR(data->vbackup)) { + ret = PTR_ERR(data->vbackup); + if (ret == -ENODEV) + data->vbackup = NULL; + else + goto err_free_gserial; + } + + if (data->vbackup) { + ret = regulator_enable(data->vbackup); + if (ret) + goto err_free_gserial; + } + + ret = gnss_serial_register(gserial); + if (ret) + goto err_disable_vbackup; + + return 0; + +err_disable_vbackup: + if (data->vbackup) + regulator_disable(data->vbackup); +err_free_gserial: + gnss_serial_free(gserial); + + return ret; +} + +static void mtk_remove(struct serdev_device *serdev) +{ + struct gnss_serial *gserial = serdev_device_get_drvdata(serdev); + struct mtk_data *data = gnss_serial_get_drvdata(gserial); + + gnss_serial_deregister(gserial); + if (data->vbackup) + regulator_disable(data->vbackup); + gnss_serial_free(gserial); +}; + +#ifdef CONFIG_OF +static const struct of_device_id mtk_of_match[] = { + { .compatible = "globaltop,pa6h" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mtk_of_match); +#endif + +static struct serdev_device_driver mtk_driver = { + .driver = { + .name = "gnss-mtk", + .of_match_table = of_match_ptr(mtk_of_match), + .pm = &gnss_serial_pm_ops, + }, + .probe = mtk_probe, + .remove = mtk_remove, +}; +module_serdev_device_driver(mtk_driver); + +MODULE_AUTHOR("Loys Ollivier <lollivier@baylibre.com>"); +MODULE_DESCRIPTION("Mediatek GNSS receiver driver"); +MODULE_LICENSE("GPL v2"); |