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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> | |
20 | #include <linux/init.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/leds.h> | |
23 | #include <linux/workqueue.h> | |
24 | #include <linux/delay.h> | |
25 | #include <linux/gpio.h> | |
5a0e3ad6 | 26 | #include <linux/slab.h> |
54f4dedb | 27 | #include <linux/module.h> |
a8dd18fe DM |
28 | |
29 | struct lt3593_led_data { | |
30 | struct led_classdev cdev; | |
31 | unsigned gpio; | |
32 | struct work_struct work; | |
33 | u8 new_level; | |
34 | }; | |
35 | ||
36 | static void lt3593_led_work(struct work_struct *work) | |
37 | { | |
38 | int pulses; | |
39 | struct lt3593_led_data *led_dat = | |
40 | container_of(work, struct lt3593_led_data, work); | |
41 | ||
42 | /* | |
43 | * The LT3593 resets its internal current level register to the maximum | |
44 | * level on the first falling edge on the control pin. Each following | |
45 | * falling edge decreases the current level by 625uA. Up to 32 pulses | |
46 | * can be sent, so the maximum power reduction is 20mA. | |
47 | * After a timeout of 128us, the value is taken from the register and | |
48 | * applied is to the output driver. | |
49 | */ | |
50 | ||
51 | if (led_dat->new_level == 0) { | |
52 | gpio_set_value_cansleep(led_dat->gpio, 0); | |
53 | return; | |
54 | } | |
55 | ||
56 | pulses = 32 - (led_dat->new_level * 32) / 255; | |
57 | ||
58 | if (pulses == 0) { | |
59 | gpio_set_value_cansleep(led_dat->gpio, 0); | |
60 | mdelay(1); | |
61 | gpio_set_value_cansleep(led_dat->gpio, 1); | |
62 | return; | |
63 | } | |
64 | ||
65 | gpio_set_value_cansleep(led_dat->gpio, 1); | |
66 | ||
67 | while (pulses--) { | |
68 | gpio_set_value_cansleep(led_dat->gpio, 0); | |
69 | udelay(1); | |
70 | gpio_set_value_cansleep(led_dat->gpio, 1); | |
71 | udelay(1); | |
72 | } | |
73 | } | |
74 | ||
75 | static void lt3593_led_set(struct led_classdev *led_cdev, | |
76 | enum led_brightness value) | |
77 | { | |
78 | struct lt3593_led_data *led_dat = | |
79 | container_of(led_cdev, struct lt3593_led_data, cdev); | |
80 | ||
81 | led_dat->new_level = value; | |
82 | schedule_work(&led_dat->work); | |
83 | } | |
84 | ||
85 | static int __devinit create_lt3593_led(const struct gpio_led *template, | |
86 | struct lt3593_led_data *led_dat, struct device *parent) | |
87 | { | |
88 | int ret, state; | |
89 | ||
90 | /* skip leds on GPIOs that aren't available */ | |
91 | if (!gpio_is_valid(template->gpio)) { | |
92 | printk(KERN_INFO "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n", | |
93 | KBUILD_MODNAME, template->gpio, template->name); | |
94 | return 0; | |
95 | } | |
96 | ||
97 | ret = gpio_request(template->gpio, template->name); | |
98 | if (ret < 0) | |
99 | return ret; | |
100 | ||
101 | led_dat->cdev.name = template->name; | |
102 | led_dat->cdev.default_trigger = template->default_trigger; | |
103 | led_dat->gpio = template->gpio; | |
104 | ||
105 | led_dat->cdev.brightness_set = lt3593_led_set; | |
106 | ||
107 | state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); | |
108 | led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; | |
109 | ||
110 | if (!template->retain_state_suspended) | |
111 | led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; | |
112 | ||
113 | ret = gpio_direction_output(led_dat->gpio, state); | |
114 | if (ret < 0) | |
115 | goto err; | |
116 | ||
117 | INIT_WORK(&led_dat->work, lt3593_led_work); | |
118 | ||
119 | ret = led_classdev_register(parent, &led_dat->cdev); | |
120 | if (ret < 0) | |
121 | goto err; | |
122 | ||
123 | printk(KERN_INFO "%s: registered LT3593 LED '%s' at GPIO %d\n", | |
124 | KBUILD_MODNAME, template->name, template->gpio); | |
125 | ||
126 | return 0; | |
127 | ||
128 | err: | |
129 | gpio_free(led_dat->gpio); | |
130 | return ret; | |
131 | } | |
132 | ||
133 | static void delete_lt3593_led(struct lt3593_led_data *led) | |
134 | { | |
135 | if (!gpio_is_valid(led->gpio)) | |
136 | return; | |
137 | ||
138 | led_classdev_unregister(&led->cdev); | |
139 | cancel_work_sync(&led->work); | |
140 | gpio_free(led->gpio); | |
141 | } | |
142 | ||
143 | static int __devinit lt3593_led_probe(struct platform_device *pdev) | |
144 | { | |
145 | struct gpio_led_platform_data *pdata = pdev->dev.platform_data; | |
146 | struct lt3593_led_data *leds_data; | |
147 | int i, ret = 0; | |
148 | ||
149 | if (!pdata) | |
150 | return -EBUSY; | |
151 | ||
152 | leds_data = kzalloc(sizeof(struct lt3593_led_data) * pdata->num_leds, | |
153 | GFP_KERNEL); | |
154 | if (!leds_data) | |
155 | return -ENOMEM; | |
156 | ||
157 | for (i = 0; i < pdata->num_leds; i++) { | |
158 | ret = create_lt3593_led(&pdata->leds[i], &leds_data[i], | |
159 | &pdev->dev); | |
160 | if (ret < 0) | |
161 | goto err; | |
162 | } | |
163 | ||
164 | platform_set_drvdata(pdev, leds_data); | |
165 | ||
166 | return 0; | |
167 | ||
168 | err: | |
169 | for (i = i - 1; i >= 0; i--) | |
170 | delete_lt3593_led(&leds_data[i]); | |
171 | ||
172 | kfree(leds_data); | |
173 | ||
174 | return ret; | |
175 | } | |
176 | ||
177 | static int __devexit lt3593_led_remove(struct platform_device *pdev) | |
178 | { | |
179 | int i; | |
180 | struct gpio_led_platform_data *pdata = pdev->dev.platform_data; | |
181 | struct lt3593_led_data *leds_data; | |
182 | ||
183 | leds_data = platform_get_drvdata(pdev); | |
184 | ||
185 | for (i = 0; i < pdata->num_leds; i++) | |
186 | delete_lt3593_led(&leds_data[i]); | |
187 | ||
188 | kfree(leds_data); | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
193 | static struct platform_driver lt3593_led_driver = { | |
194 | .probe = lt3593_led_probe, | |
195 | .remove = __devexit_p(lt3593_led_remove), | |
196 | .driver = { | |
197 | .name = "leds-lt3593", | |
198 | .owner = THIS_MODULE, | |
199 | }, | |
200 | }; | |
201 | ||
892a8843 | 202 | module_platform_driver(lt3593_led_driver); |
a8dd18fe DM |
203 | |
204 | MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); | |
205 | MODULE_DESCRIPTION("LED driver for LT3593 controllers"); | |
206 | MODULE_LICENSE("GPL"); | |
892a8843 | 207 | MODULE_ALIAS("platform:leds-lt3593"); |