1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * u-blox GNSS receiver driver
4  *
5  * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
6  */
7 
8 #include <linux/errno.h>
9 #include <linux/gnss.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/serdev.h>
16 
17 #include "serial.h"
18 
19 struct ubx_data {
20 	struct regulator *v_bckp;
21 	struct regulator *vcc;
22 };
23 
ubx_set_active(struct gnss_serial * gserial)24 static int ubx_set_active(struct gnss_serial *gserial)
25 {
26 	struct ubx_data *data = gnss_serial_get_drvdata(gserial);
27 	int ret;
28 
29 	ret = regulator_enable(data->vcc);
30 	if (ret)
31 		return ret;
32 
33 	return 0;
34 }
35 
ubx_set_standby(struct gnss_serial * gserial)36 static int ubx_set_standby(struct gnss_serial *gserial)
37 {
38 	struct ubx_data *data = gnss_serial_get_drvdata(gserial);
39 	int ret;
40 
41 	ret = regulator_disable(data->vcc);
42 	if (ret)
43 		return ret;
44 
45 	return 0;
46 }
47 
ubx_set_power(struct gnss_serial * gserial,enum gnss_serial_pm_state state)48 static int ubx_set_power(struct gnss_serial *gserial,
49 				enum gnss_serial_pm_state state)
50 {
51 	switch (state) {
52 	case GNSS_SERIAL_ACTIVE:
53 		return ubx_set_active(gserial);
54 	case GNSS_SERIAL_OFF:
55 	case GNSS_SERIAL_STANDBY:
56 		return ubx_set_standby(gserial);
57 	}
58 
59 	return -EINVAL;
60 }
61 
62 static const struct gnss_serial_ops ubx_gserial_ops = {
63 	.set_power = ubx_set_power,
64 };
65 
ubx_probe(struct serdev_device * serdev)66 static int ubx_probe(struct serdev_device *serdev)
67 {
68 	struct gnss_serial *gserial;
69 	struct ubx_data *data;
70 	int ret;
71 
72 	gserial = gnss_serial_allocate(serdev, sizeof(*data));
73 	if (IS_ERR(gserial)) {
74 		ret = PTR_ERR(gserial);
75 		return ret;
76 	}
77 
78 	gserial->ops = &ubx_gserial_ops;
79 
80 	gserial->gdev->type = GNSS_TYPE_UBX;
81 
82 	data = gnss_serial_get_drvdata(gserial);
83 
84 	data->vcc = devm_regulator_get(&serdev->dev, "vcc");
85 	if (IS_ERR(data->vcc)) {
86 		ret = PTR_ERR(data->vcc);
87 		goto err_free_gserial;
88 	}
89 
90 	data->v_bckp = devm_regulator_get_optional(&serdev->dev, "v-bckp");
91 	if (IS_ERR(data->v_bckp)) {
92 		ret = PTR_ERR(data->v_bckp);
93 		if (ret == -ENODEV)
94 			data->v_bckp = NULL;
95 		else
96 			goto err_free_gserial;
97 	}
98 
99 	if (data->v_bckp) {
100 		ret = regulator_enable(data->v_bckp);
101 		if (ret)
102 			goto err_free_gserial;
103 	}
104 
105 	ret = gnss_serial_register(gserial);
106 	if (ret)
107 		goto err_disable_v_bckp;
108 
109 	return 0;
110 
111 err_disable_v_bckp:
112 	if (data->v_bckp)
113 		regulator_disable(data->v_bckp);
114 err_free_gserial:
115 	gnss_serial_free(gserial);
116 
117 	return ret;
118 }
119 
ubx_remove(struct serdev_device * serdev)120 static void ubx_remove(struct serdev_device *serdev)
121 {
122 	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
123 	struct ubx_data *data = gnss_serial_get_drvdata(gserial);
124 
125 	gnss_serial_deregister(gserial);
126 	if (data->v_bckp)
127 		regulator_disable(data->v_bckp);
128 	gnss_serial_free(gserial);
129 };
130 
131 #ifdef CONFIG_OF
132 static const struct of_device_id ubx_of_match[] = {
133 	{ .compatible = "u-blox,neo-6m" },
134 	{ .compatible = "u-blox,neo-8" },
135 	{ .compatible = "u-blox,neo-m8" },
136 	{},
137 };
138 MODULE_DEVICE_TABLE(of, ubx_of_match);
139 #endif
140 
141 static struct serdev_device_driver ubx_driver = {
142 	.driver	= {
143 		.name		= "gnss-ubx",
144 		.of_match_table	= of_match_ptr(ubx_of_match),
145 		.pm		= &gnss_serial_pm_ops,
146 	},
147 	.probe	= ubx_probe,
148 	.remove	= ubx_remove,
149 };
150 module_serdev_device_driver(ubx_driver);
151 
152 MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
153 MODULE_DESCRIPTION("u-blox GNSS receiver driver");
154 MODULE_LICENSE("GPL v2");
155