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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 | |
21 | * | |
22 | * This driver provides system reboot functionality for APM X-Gene SoC. | |
23 | * For system shutdown, this is board specify. If a board designer | |
24 | * implements GPIO shutdown, use the gpio-poweroff.c driver. | |
25 | */ | |
26 | #include <linux/io.h> | |
27 | #include <linux/of_device.h> | |
28 | #include <linux/of_address.h> | |
29 | #include <linux/platform_device.h> | |
30 | #include <linux/stat.h> | |
31 | #include <linux/slab.h> | |
32 | #include <linux/mfd/syscon.h> | |
33 | #include <linux/regmap.h> | |
34 | #include <linux/leds.h> | |
35 | ||
36 | /** | |
37 | * struct syscon_led - state container for syscon based LEDs | |
38 | * @cdev: LED class device for this LED | |
39 | * @map: regmap to access the syscon device backing this LED | |
40 | * @offset: the offset into the syscon regmap for the LED register | |
41 | * @mask: the bit in the register corresponding to the LED | |
42 | * @state: current state of the LED | |
43 | */ | |
44 | struct syscon_led { | |
45 | struct led_classdev cdev; | |
46 | struct regmap *map; | |
47 | u32 offset; | |
48 | u32 mask; | |
49 | bool state; | |
50 | }; | |
51 | ||
52 | static void syscon_led_set(struct led_classdev *led_cdev, | |
53 | enum led_brightness value) | |
54 | { | |
55 | struct syscon_led *sled = | |
56 | container_of(led_cdev, struct syscon_led, cdev); | |
57 | u32 val; | |
58 | int ret; | |
59 | ||
60 | if (value == LED_OFF) { | |
61 | val = 0; | |
62 | sled->state = false; | |
63 | } else { | |
64 | val = sled->mask; | |
65 | sled->state = true; | |
66 | } | |
67 | ||
68 | ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val); | |
69 | if (ret < 0) | |
70 | dev_err(sled->cdev.dev, "error updating LED status\n"); | |
71 | } | |
72 | ||
73 | static const struct of_device_id syscon_match[] = { | |
74 | { .compatible = "syscon", }, | |
75 | {}, | |
76 | }; | |
77 | ||
78 | static int __init syscon_leds_init(void) | |
79 | { | |
80 | const struct of_device_id *devid; | |
81 | struct device_node *np; | |
82 | struct device_node *child; | |
83 | struct regmap *map; | |
84 | struct platform_device *pdev; | |
85 | struct device *dev; | |
86 | int ret; | |
87 | ||
88 | np = of_find_matching_node_and_match(NULL, syscon_match, | |
89 | &devid); | |
90 | if (!np) | |
91 | return -ENODEV; | |
92 | ||
93 | map = syscon_node_to_regmap(np); | |
94 | if (IS_ERR(map)) | |
95 | return PTR_ERR(map); | |
96 | ||
97 | /* | |
98 | * If the map is there, the device should be there, we allocate | |
99 | * memory on the syscon device's behalf here. | |
100 | */ | |
101 | pdev = of_find_device_by_node(np); | |
102 | if (!pdev) | |
103 | return -ENODEV; | |
104 | dev = &pdev->dev; | |
105 | ||
106 | for_each_available_child_of_node(np, child) { | |
107 | struct syscon_led *sled; | |
108 | const char *state; | |
109 | ||
110 | /* Only check for register-bit-leds */ | |
111 | if (of_property_match_string(child, "compatible", | |
112 | "register-bit-led") < 0) | |
113 | continue; | |
114 | ||
115 | sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL); | |
116 | if (!sled) | |
117 | return -ENOMEM; | |
118 | ||
119 | sled->map = map; | |
120 | ||
121 | if (of_property_read_u32(child, "offset", &sled->offset)) | |
122 | return -EINVAL; | |
123 | if (of_property_read_u32(child, "mask", &sled->mask)) | |
124 | return -EINVAL; | |
125 | sled->cdev.name = | |
126 | of_get_property(child, "label", NULL) ? : child->name; | |
127 | sled->cdev.default_trigger = | |
128 | of_get_property(child, "linux,default-trigger", NULL); | |
129 | ||
130 | state = of_get_property(child, "default-state", NULL); | |
131 | if (state) { | |
132 | if (!strcmp(state, "keep")) { | |
133 | u32 val; | |
134 | ||
135 | ret = regmap_read(map, sled->offset, &val); | |
136 | if (ret < 0) | |
137 | return ret; | |
138 | sled->state = !!(val & sled->mask); | |
139 | } else if (!strcmp(state, "on")) { | |
140 | sled->state = true; | |
141 | ret = regmap_update_bits(map, sled->offset, | |
142 | sled->mask, | |
143 | sled->mask); | |
144 | if (ret < 0) | |
145 | return ret; | |
146 | } else { | |
147 | sled->state = false; | |
148 | ret = regmap_update_bits(map, sled->offset, | |
149 | sled->mask, 0); | |
150 | if (ret < 0) | |
151 | return ret; | |
152 | } | |
153 | ||
154 | } | |
155 | sled->cdev.brightness_set = syscon_led_set; | |
156 | ||
157 | ret = led_classdev_register(dev, &sled->cdev); | |
158 | if (ret < 0) | |
159 | return ret; | |
160 | ||
161 | dev_info(dev, "registered LED %s\n", sled->cdev.name); | |
162 | } | |
163 | ||
164 | return 0; | |
165 | } | |
166 | device_initcall(syscon_leds_init); |