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a8dd18fe DM |
1 | /* |
2 | * LEDs driver for LT3593 controllers | |
3 | * | |
4 | * See the datasheet at http://cds.linear.com/docs/Datasheet/3593f.pdf | |
5 | * | |
6 | * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de> | |
7 | * | |
8 | * Based on leds-gpio.c, | |
9 | * | |
10 | * Copyright (C) 2007 8D Technologies inc. | |
11 | * Raphael Assenat <raph@8d.com> | |
12 | * Copyright (C) 2008 Freescale Semiconductor, Inc. | |
13 | * | |
14 | * This program is free software; you can redistribute it and/or modify | |
15 | * it under the terms of the GNU General Public License version 2 as | |
16 | * published by the Free Software Foundation. | |
17 | */ | |
18 | ||
19 | #include <linux/kernel.h> | |
a8dd18fe DM |
20 | #include <linux/platform_device.h> |
21 | #include <linux/leds.h> | |
22 | #include <linux/workqueue.h> | |
23 | #include <linux/delay.h> | |
24 | #include <linux/gpio.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
54f4dedb | 26 | #include <linux/module.h> |
a8dd18fe DM |
27 | |
28 | struct lt3593_led_data { | |
29 | struct led_classdev cdev; | |
30 | unsigned gpio; | |
31 | struct work_struct work; | |
32 | u8 new_level; | |
33 | }; | |
34 | ||
35 | static void lt3593_led_work(struct work_struct *work) | |
36 | { | |
37 | int pulses; | |
38 | struct lt3593_led_data *led_dat = | |
39 | container_of(work, struct lt3593_led_data, work); | |
40 | ||
41 | /* | |
42 | * The LT3593 resets its internal current level register to the maximum | |
43 | * level on the first falling edge on the control pin. Each following | |
44 | * falling edge decreases the current level by 625uA. Up to 32 pulses | |
45 | * can be sent, so the maximum power reduction is 20mA. | |
46 | * After a timeout of 128us, the value is taken from the register and | |
47 | * applied is to the output driver. | |
48 | */ | |
49 | ||
50 | if (led_dat->new_level == 0) { | |
51 | gpio_set_value_cansleep(led_dat->gpio, 0); | |
52 | return; | |
53 | } | |
54 | ||
55 | pulses = 32 - (led_dat->new_level * 32) / 255; | |
56 | ||
57 | if (pulses == 0) { | |
58 | gpio_set_value_cansleep(led_dat->gpio, 0); | |
59 | mdelay(1); | |
60 | gpio_set_value_cansleep(led_dat->gpio, 1); | |
61 | return; | |
62 | } | |
63 | ||
64 | gpio_set_value_cansleep(led_dat->gpio, 1); | |
65 | ||
66 | while (pulses--) { | |
67 | gpio_set_value_cansleep(led_dat->gpio, 0); | |
68 | udelay(1); | |
69 | gpio_set_value_cansleep(led_dat->gpio, 1); | |
70 | udelay(1); | |
71 | } | |
72 | } | |
73 | ||
74 | static void lt3593_led_set(struct led_classdev *led_cdev, | |
75 | enum led_brightness value) | |
76 | { | |
77 | struct lt3593_led_data *led_dat = | |
78 | container_of(led_cdev, struct lt3593_led_data, cdev); | |
79 | ||
80 | led_dat->new_level = value; | |
81 | schedule_work(&led_dat->work); | |
82 | } | |
83 | ||
98ea1ea2 | 84 | static int create_lt3593_led(const struct gpio_led *template, |
a8dd18fe DM |
85 | struct lt3593_led_data *led_dat, struct device *parent) |
86 | { | |
87 | int ret, state; | |
88 | ||
89 | /* skip leds on GPIOs that aren't available */ | |
90 | if (!gpio_is_valid(template->gpio)) { | |
30e5c3e6 | 91 | dev_info(parent, "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n", |
a8dd18fe DM |
92 | KBUILD_MODNAME, template->gpio, template->name); |
93 | return 0; | |
94 | } | |
95 | ||
a8dd18fe DM |
96 | led_dat->cdev.name = template->name; |
97 | led_dat->cdev.default_trigger = template->default_trigger; | |
98 | led_dat->gpio = template->gpio; | |
99 | ||
100 | led_dat->cdev.brightness_set = lt3593_led_set; | |
101 | ||
102 | state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); | |
103 | led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; | |
104 | ||
105 | if (!template->retain_state_suspended) | |
106 | led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; | |
107 | ||
84f6942c JH |
108 | ret = devm_gpio_request_one(parent, template->gpio, state ? |
109 | GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW, | |
110 | template->name); | |
a8dd18fe | 111 | if (ret < 0) |
507d967b | 112 | return ret; |
a8dd18fe DM |
113 | |
114 | INIT_WORK(&led_dat->work, lt3593_led_work); | |
115 | ||
116 | ret = led_classdev_register(parent, &led_dat->cdev); | |
117 | if (ret < 0) | |
95a8ff83 | 118 | return ret; |
a8dd18fe | 119 | |
30e5c3e6 | 120 | dev_info(parent, "%s: registered LT3593 LED '%s' at GPIO %d\n", |
a8dd18fe DM |
121 | KBUILD_MODNAME, template->name, template->gpio); |
122 | ||
123 | return 0; | |
a8dd18fe DM |
124 | } |
125 | ||
126 | static void delete_lt3593_led(struct lt3593_led_data *led) | |
127 | { | |
128 | if (!gpio_is_valid(led->gpio)) | |
129 | return; | |
130 | ||
131 | led_classdev_unregister(&led->cdev); | |
132 | cancel_work_sync(&led->work); | |
a8dd18fe DM |
133 | } |
134 | ||
98ea1ea2 | 135 | static int lt3593_led_probe(struct platform_device *pdev) |
a8dd18fe | 136 | { |
87aae1ea | 137 | struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev); |
a8dd18fe DM |
138 | struct lt3593_led_data *leds_data; |
139 | int i, ret = 0; | |
140 | ||
141 | if (!pdata) | |
142 | return -EBUSY; | |
143 | ||
0a8d9d4a BW |
144 | leds_data = devm_kzalloc(&pdev->dev, |
145 | sizeof(struct lt3593_led_data) * pdata->num_leds, | |
146 | GFP_KERNEL); | |
a8dd18fe DM |
147 | if (!leds_data) |
148 | return -ENOMEM; | |
149 | ||
150 | for (i = 0; i < pdata->num_leds; i++) { | |
151 | ret = create_lt3593_led(&pdata->leds[i], &leds_data[i], | |
152 | &pdev->dev); | |
153 | if (ret < 0) | |
154 | goto err; | |
155 | } | |
156 | ||
157 | platform_set_drvdata(pdev, leds_data); | |
158 | ||
159 | return 0; | |
160 | ||
161 | err: | |
162 | for (i = i - 1; i >= 0; i--) | |
163 | delete_lt3593_led(&leds_data[i]); | |
164 | ||
a8dd18fe DM |
165 | return ret; |
166 | } | |
167 | ||
678e8a6b | 168 | static int lt3593_led_remove(struct platform_device *pdev) |
a8dd18fe DM |
169 | { |
170 | int i; | |
87aae1ea | 171 | struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev); |
a8dd18fe DM |
172 | struct lt3593_led_data *leds_data; |
173 | ||
174 | leds_data = platform_get_drvdata(pdev); | |
175 | ||
176 | for (i = 0; i < pdata->num_leds; i++) | |
177 | delete_lt3593_led(&leds_data[i]); | |
178 | ||
a8dd18fe DM |
179 | return 0; |
180 | } | |
181 | ||
182 | static struct platform_driver lt3593_led_driver = { | |
183 | .probe = lt3593_led_probe, | |
df07cf81 | 184 | .remove = lt3593_led_remove, |
a8dd18fe DM |
185 | .driver = { |
186 | .name = "leds-lt3593", | |
187 | .owner = THIS_MODULE, | |
188 | }, | |
189 | }; | |
190 | ||
892a8843 | 191 | module_platform_driver(lt3593_led_driver); |
a8dd18fe DM |
192 | |
193 | MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); | |
194 | MODULE_DESCRIPTION("LED driver for LT3593 controllers"); | |
195 | MODULE_LICENSE("GPL"); | |
892a8843 | 196 | MODULE_ALIAS("platform:leds-lt3593"); |