drivers/gnss/mtk.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Mediatek GNSS receiver driver
0004  *
0005  * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
0006  */
0007
0008 #include <linux/errno.h>
0009 #include <linux/gnss.h>
0010 #include <linux/init.h>
0011 #include <linux/kernel.h>
0012 #include <linux/module.h>
0013 #include <linux/of.h>
0014 #include <linux/regulator/consumer.h>
0015 #include <linux/serdev.h>
0016
0017 #include "serial.h"
0018
0019 struct mtk_data {
0020     struct regulator *vbackup;
0021     struct regulator *vcc;
0022 };
0023
0024 static int mtk_set_active(struct gnss_serial *gserial)
0025 {
0026     struct mtk_data *data = gnss_serial_get_drvdata(gserial);
0027     int ret;
0028
0029     ret = regulator_enable(data->vcc);
0030     if (ret)
0031         return ret;
0032
0033     return 0;
0034 }
0035
0036 static int mtk_set_standby(struct gnss_serial *gserial)
0037 {
0038     struct mtk_data *data = gnss_serial_get_drvdata(gserial);
0039     int ret;
0040
0041     ret = regulator_disable(data->vcc);
0042     if (ret)
0043         return ret;
0044
0045     return 0;
0046 }
0047
0048 static int mtk_set_power(struct gnss_serial *gserial,
0049              enum gnss_serial_pm_state state)
0050 {
0051     switch (state) {
0052     case GNSS_SERIAL_ACTIVE:
0053         return mtk_set_active(gserial);
0054     case GNSS_SERIAL_OFF:
0055     case GNSS_SERIAL_STANDBY:
0056         return mtk_set_standby(gserial);
0057     }
0058
0059     return -EINVAL;
0060 }
0061
0062 static const struct gnss_serial_ops mtk_gserial_ops = {
0063     .set_power = mtk_set_power,
0064 };
0065
0066 static int mtk_probe(struct serdev_device *serdev)
0067 {
0068     struct gnss_serial *gserial;
0069     struct mtk_data *data;
0070     int ret;
0071
0072     gserial = gnss_serial_allocate(serdev, sizeof(*data));
0073     if (IS_ERR(gserial)) {
0074         ret = PTR_ERR(gserial);
0075         return ret;
0076     }
0077
0078     gserial->ops = &mtk_gserial_ops;
0079
0080     gserial->gdev->type = GNSS_TYPE_MTK;
0081
0082     data = gnss_serial_get_drvdata(gserial);
0083
0084     data->vcc = devm_regulator_get(&serdev->dev, "vcc");
0085     if (IS_ERR(data->vcc)) {
0086         ret = PTR_ERR(data->vcc);
0087         goto err_free_gserial;
0088     }
0089
0090     data->vbackup = devm_regulator_get_optional(&serdev->dev, "vbackup");
0091     if (IS_ERR(data->vbackup)) {
0092         ret = PTR_ERR(data->vbackup);
0093         if (ret == -ENODEV)
0094             data->vbackup = NULL;
0095         else
0096             goto err_free_gserial;
0097     }
0098
0099     if (data->vbackup) {
0100         ret = regulator_enable(data->vbackup);
0101         if (ret)
0102             goto err_free_gserial;
0103     }
0104
0105     ret = gnss_serial_register(gserial);
0106     if (ret)
0107         goto err_disable_vbackup;
0108
0109     return 0;
0110
0111 err_disable_vbackup:
0112     if (data->vbackup)
0113         regulator_disable(data->vbackup);
0114 err_free_gserial:
0115     gnss_serial_free(gserial);
0116
0117     return ret;
0118 }
0119
0120 static void mtk_remove(struct serdev_device *serdev)
0121 {
0122     struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
0123     struct mtk_data *data = gnss_serial_get_drvdata(gserial);
0124
0125     gnss_serial_deregister(gserial);
0126     if (data->vbackup)
0127         regulator_disable(data->vbackup);
0128     gnss_serial_free(gserial);
0129 }
0130
0131 #ifdef CONFIG_OF
0132 static const struct of_device_id mtk_of_match[] = {
0133     { .compatible = "globaltop,pa6h" },
0134     {},
0135 };
0136 MODULE_DEVICE_TABLE(of, mtk_of_match);
0137 #endif
0138
0139 static struct serdev_device_driver mtk_driver = {
0140     .driver = {
0141         .name       = "gnss-mtk",
0142         .of_match_table = of_match_ptr(mtk_of_match),
0143         .pm     = &gnss_serial_pm_ops,
0144     },
0145     .probe  = mtk_probe,
0146     .remove = mtk_remove,
0147 };
0148 module_serdev_device_driver(mtk_driver);
0149
0150 MODULE_AUTHOR("Loys Ollivier <lollivier@baylibre.com>");
0151 MODULE_DESCRIPTION("Mediatek GNSS receiver driver");
0152 MODULE_LICENSE("GPL v2");