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535f09cc LW |
1 | /* |
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 | |
535f09cc LW |
21 | */ |
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 | */ | |
40 | struct syscon_led { | |
41 | struct led_classdev cdev; | |
42 | struct regmap *map; | |
43 | u32 offset; | |
44 | u32 mask; | |
45 | bool state; | |
46 | }; | |
47 | ||
48 | static 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 | ||
3f6e42c8 LW |
69 | static int __init syscon_leds_spawn(struct device_node *np, |
70 | struct device *dev, | |
71 | struct regmap *map) | |
535f09cc | 72 | { |
535f09cc | 73 | struct device_node *child; |
535f09cc LW |
74 | int ret; |
75 | ||
535f09cc LW |
76 | 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 | } | |
535f09cc LW |
123 | } |
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 | } | |
3f6e42c8 LW |
132 | return 0; |
133 | } | |
134 | ||
135 | static 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 | } | |
535f09cc | 164 | |
3f6e42c8 | 165 | return 0; |
535f09cc LW |
166 | } |
167 | device_initcall(syscon_leds_init); |