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Linus Walleij535f09c2014-05-22 00:34:16 +02001/*
2 * Generic Syscon LEDs Driver
3 *
4 * Copyright (c) 2014, Linaro Limited
5 * Author: Linus Walleij <linus.walleij@linaro.org>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
20 * MA 02111-1307 USA
Linus Walleij535f09c2014-05-22 00:34:16 +020021 */
22#include <linux/io.h>
Linus Walleija917d4b42015-03-03 10:08:19 +010023#include <linux/module.h>
Linus Walleij535f09c2014-05-22 00:34:16 +020024#include <linux/of_device.h>
25#include <linux/of_address.h>
26#include <linux/platform_device.h>
27#include <linux/stat.h>
28#include <linux/slab.h>
29#include <linux/mfd/syscon.h>
30#include <linux/regmap.h>
31#include <linux/leds.h>
32
33/**
34 * struct syscon_led - state container for syscon based LEDs
35 * @cdev: LED class device for this LED
36 * @map: regmap to access the syscon device backing this LED
37 * @offset: the offset into the syscon regmap for the LED register
38 * @mask: the bit in the register corresponding to the LED
39 * @state: current state of the LED
40 */
41struct syscon_led {
42 struct led_classdev cdev;
43 struct regmap *map;
44 u32 offset;
45 u32 mask;
46 bool state;
47};
48
49static void syscon_led_set(struct led_classdev *led_cdev,
50 enum led_brightness value)
51{
52 struct syscon_led *sled =
53 container_of(led_cdev, struct syscon_led, cdev);
54 u32 val;
55 int ret;
56
57 if (value == LED_OFF) {
58 val = 0;
59 sled->state = false;
60 } else {
61 val = sled->mask;
62 sled->state = true;
63 }
64
65 ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);
66 if (ret < 0)
67 dev_err(sled->cdev.dev, "error updating LED status\n");
68}
69
Linus Walleija917d4b42015-03-03 10:08:19 +010070static int syscon_led_probe(struct platform_device *pdev)
Linus Walleij535f09c2014-05-22 00:34:16 +020071{
Linus Walleija917d4b42015-03-03 10:08:19 +010072 struct device *dev = &pdev->dev;
73 struct device_node *np = dev->of_node;
74 struct device *parent;
75 struct regmap *map;
76 struct syscon_led *sled;
77 const char *state;
Linus Walleij535f09c2014-05-22 00:34:16 +020078 int ret;
79
Linus Walleija917d4b42015-03-03 10:08:19 +010080 parent = dev->parent;
81 if (!parent) {
82 dev_err(dev, "no parent for syscon LED\n");
83 return -ENODEV;
Linus Walleij535f09c2014-05-22 00:34:16 +020084 }
Linus Walleija917d4b42015-03-03 10:08:19 +010085 map = syscon_node_to_regmap(parent->of_node);
Bjorn Andersson991a3f62015-08-18 12:25:26 -070086 if (IS_ERR(map)) {
Linus Walleija917d4b42015-03-03 10:08:19 +010087 dev_err(dev, "no regmap for syscon LED parent\n");
Bjorn Andersson991a3f62015-08-18 12:25:26 -070088 return PTR_ERR(map);
Linus Walleija917d4b42015-03-03 10:08:19 +010089 }
90
91 sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
92 if (!sled)
93 return -ENOMEM;
94
95 sled->map = map;
96
97 if (of_property_read_u32(np, "offset", &sled->offset))
98 return -EINVAL;
99 if (of_property_read_u32(np, "mask", &sled->mask))
100 return -EINVAL;
101 sled->cdev.name =
102 of_get_property(np, "label", NULL) ? : np->name;
103 sled->cdev.default_trigger =
104 of_get_property(np, "linux,default-trigger", NULL);
105
106 state = of_get_property(np, "default-state", NULL);
107 if (state) {
108 if (!strcmp(state, "keep")) {
109 u32 val;
110
111 ret = regmap_read(map, sled->offset, &val);
112 if (ret < 0)
113 return ret;
114 sled->state = !!(val & sled->mask);
115 } else if (!strcmp(state, "on")) {
116 sled->state = true;
117 ret = regmap_update_bits(map, sled->offset,
118 sled->mask,
119 sled->mask);
120 if (ret < 0)
121 return ret;
122 } else {
123 sled->state = false;
124 ret = regmap_update_bits(map, sled->offset,
125 sled->mask, 0);
126 if (ret < 0)
127 return ret;
128 }
129 }
130 sled->cdev.brightness_set = syscon_led_set;
131
132 ret = led_classdev_register(dev, &sled->cdev);
133 if (ret < 0)
134 return ret;
135
136 platform_set_drvdata(pdev, sled);
137 dev_info(dev, "registered LED %s\n", sled->cdev.name);
138
Linus Walleij3f6e42c2014-10-24 03:57:19 -0700139 return 0;
140}
Linus Walleij535f09c2014-05-22 00:34:16 +0200141
Linus Walleija917d4b42015-03-03 10:08:19 +0100142static int syscon_led_remove(struct platform_device *pdev)
Linus Walleij3f6e42c2014-10-24 03:57:19 -0700143{
Linus Walleija917d4b42015-03-03 10:08:19 +0100144 struct syscon_led *sled = platform_get_drvdata(pdev);
Linus Walleij3f6e42c2014-10-24 03:57:19 -0700145
Linus Walleija917d4b42015-03-03 10:08:19 +0100146 led_classdev_unregister(&sled->cdev);
147 /* Turn it off */
148 regmap_update_bits(sled->map, sled->offset, sled->mask, 0);
Linus Walleij3f6e42c2014-10-24 03:57:19 -0700149 return 0;
Linus Walleij535f09c2014-05-22 00:34:16 +0200150}
Linus Walleija917d4b42015-03-03 10:08:19 +0100151
152static const struct of_device_id of_syscon_leds_match[] = {
153 { .compatible = "register-bit-led", },
154 {},
155};
156
157MODULE_DEVICE_TABLE(of, of_syscon_leds_match);
158
159static struct platform_driver syscon_led_driver = {
160 .probe = syscon_led_probe,
161 .remove = syscon_led_remove,
162 .driver = {
163 .name = "leds-syscon",
164 .of_match_table = of_syscon_leds_match,
165 },
166};
167module_platform_driver(syscon_led_driver);