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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>
23#include <linux/of_device.h>
24#include <linux/of_address.h>
25#include <linux/platform_device.h>
26#include <linux/stat.h>
27#include <linux/slab.h>
28#include <linux/mfd/syscon.h>
29#include <linux/regmap.h>
30#include <linux/leds.h>
31
32/**
33 * struct syscon_led - state container for syscon based LEDs
34 * @cdev: LED class device for this LED
35 * @map: regmap to access the syscon device backing this LED
36 * @offset: the offset into the syscon regmap for the LED register
37 * @mask: the bit in the register corresponding to the LED
38 * @state: current state of the LED
39 */
40struct syscon_led {
41 struct led_classdev cdev;
42 struct regmap *map;
43 u32 offset;
44 u32 mask;
45 bool state;
46};
47
48static void syscon_led_set(struct led_classdev *led_cdev,
49 enum led_brightness value)
50{
51 struct syscon_led *sled =
52 container_of(led_cdev, struct syscon_led, cdev);
53 u32 val;
54 int ret;
55
56 if (value == LED_OFF) {
57 val = 0;
58 sled->state = false;
59 } else {
60 val = sled->mask;
61 sled->state = true;
62 }
63
64 ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);
65 if (ret < 0)
66 dev_err(sled->cdev.dev, "error updating LED status\n");
67}
68
Linus Walleij3f6e42c2014-10-24 03:57:19 -070069static int __init syscon_leds_spawn(struct device_node *np,
70 struct device *dev,
71 struct regmap *map)
Linus Walleij535f09c2014-05-22 00:34:16 +020072{
Linus Walleij535f09c2014-05-22 00:34:16 +020073 struct device_node *child;
Linus Walleij535f09c2014-05-22 00:34:16 +020074 int ret;
75
Linus Walleij535f09c2014-05-22 00:34:16 +020076 for_each_available_child_of_node(np, child) {
77 struct syscon_led *sled;
78 const char *state;
79
80 /* Only check for register-bit-leds */
81 if (of_property_match_string(child, "compatible",
82 "register-bit-led") < 0)
83 continue;
84
85 sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
86 if (!sled)
87 return -ENOMEM;
88
89 sled->map = map;
90
91 if (of_property_read_u32(child, "offset", &sled->offset))
92 return -EINVAL;
93 if (of_property_read_u32(child, "mask", &sled->mask))
94 return -EINVAL;
95 sled->cdev.name =
96 of_get_property(child, "label", NULL) ? : child->name;
97 sled->cdev.default_trigger =
98 of_get_property(child, "linux,default-trigger", NULL);
99
100 state = of_get_property(child, "default-state", NULL);
101 if (state) {
102 if (!strcmp(state, "keep")) {
103 u32 val;
104
105 ret = regmap_read(map, sled->offset, &val);
106 if (ret < 0)
107 return ret;
108 sled->state = !!(val & sled->mask);
109 } else if (!strcmp(state, "on")) {
110 sled->state = true;
111 ret = regmap_update_bits(map, sled->offset,
112 sled->mask,
113 sled->mask);
114 if (ret < 0)
115 return ret;
116 } else {
117 sled->state = false;
118 ret = regmap_update_bits(map, sled->offset,
119 sled->mask, 0);
120 if (ret < 0)
121 return ret;
122 }
Linus Walleij535f09c2014-05-22 00:34:16 +0200123 }
124 sled->cdev.brightness_set = syscon_led_set;
125
126 ret = led_classdev_register(dev, &sled->cdev);
127 if (ret < 0)
128 return ret;
129
130 dev_info(dev, "registered LED %s\n", sled->cdev.name);
131 }
Linus Walleij3f6e42c2014-10-24 03:57:19 -0700132 return 0;
133}
Linus Walleij535f09c2014-05-22 00:34:16 +0200134
Linus Walleij3f6e42c2014-10-24 03:57:19 -0700135static int __init syscon_leds_init(void)
136{
137 struct device_node *np;
138
139 for_each_of_allnodes(np) {
140 struct platform_device *pdev;
141 struct regmap *map;
142 int ret;
143
144 if (!of_device_is_compatible(np, "syscon"))
145 continue;
146
147 map = syscon_node_to_regmap(np);
148 if (IS_ERR(map)) {
149 pr_err("error getting regmap for syscon LEDs\n");
150 continue;
151 }
152
153 /*
154 * If the map is there, the device should be there, we allocate
155 * memory on the syscon device's behalf here.
156 */
157 pdev = of_find_device_by_node(np);
158 if (!pdev)
159 return -ENODEV;
160 ret = syscon_leds_spawn(np, &pdev->dev, map);
161 if (ret)
162 dev_err(&pdev->dev, "could not spawn syscon LEDs\n");
163 }
164
165 return 0;
Linus Walleij535f09c2014-05-22 00:34:16 +0200166}
167device_initcall(syscon_leds_init);