blob: 2579678f97a6c8e02ca897c363e1b1d107d67715 [file] [log] [blame]
Daniel Macka8dd18f2009-10-15 02:59:35 +02001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/slab.h>
Daniel Macka8dd18f2009-10-15 02:59:35 +020027
28struct lt3593_led_data {
29 struct led_classdev cdev;
30 unsigned gpio;
31 struct work_struct work;
32 u8 new_level;
33};
34
35static 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
74static 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
84static int __devinit create_lt3593_led(const struct gpio_led *template,
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)) {
91 printk(KERN_INFO "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n",
92 KBUILD_MODNAME, template->gpio, template->name);
93 return 0;
94 }
95
96 ret = gpio_request(template->gpio, template->name);
97 if (ret < 0)
98 return ret;
99
100 led_dat->cdev.name = template->name;
101 led_dat->cdev.default_trigger = template->default_trigger;
102 led_dat->gpio = template->gpio;
103
104 led_dat->cdev.brightness_set = lt3593_led_set;
105
106 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
107 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
108
109 if (!template->retain_state_suspended)
110 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
111
112 ret = gpio_direction_output(led_dat->gpio, state);
113 if (ret < 0)
114 goto err;
115
116 INIT_WORK(&led_dat->work, lt3593_led_work);
117
118 ret = led_classdev_register(parent, &led_dat->cdev);
119 if (ret < 0)
120 goto err;
121
122 printk(KERN_INFO "%s: registered LT3593 LED '%s' at GPIO %d\n",
123 KBUILD_MODNAME, template->name, template->gpio);
124
125 return 0;
126
127err:
128 gpio_free(led_dat->gpio);
129 return ret;
130}
131
132static void delete_lt3593_led(struct lt3593_led_data *led)
133{
134 if (!gpio_is_valid(led->gpio))
135 return;
136
137 led_classdev_unregister(&led->cdev);
138 cancel_work_sync(&led->work);
139 gpio_free(led->gpio);
140}
141
142static int __devinit lt3593_led_probe(struct platform_device *pdev)
143{
144 struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
145 struct lt3593_led_data *leds_data;
146 int i, ret = 0;
147
148 if (!pdata)
149 return -EBUSY;
150
151 leds_data = kzalloc(sizeof(struct lt3593_led_data) * pdata->num_leds,
152 GFP_KERNEL);
153 if (!leds_data)
154 return -ENOMEM;
155
156 for (i = 0; i < pdata->num_leds; i++) {
157 ret = create_lt3593_led(&pdata->leds[i], &leds_data[i],
158 &pdev->dev);
159 if (ret < 0)
160 goto err;
161 }
162
163 platform_set_drvdata(pdev, leds_data);
164
165 return 0;
166
167err:
168 for (i = i - 1; i >= 0; i--)
169 delete_lt3593_led(&leds_data[i]);
170
171 kfree(leds_data);
172
173 return ret;
174}
175
176static int __devexit lt3593_led_remove(struct platform_device *pdev)
177{
178 int i;
179 struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
180 struct lt3593_led_data *leds_data;
181
182 leds_data = platform_get_drvdata(pdev);
183
184 for (i = 0; i < pdata->num_leds; i++)
185 delete_lt3593_led(&leds_data[i]);
186
187 kfree(leds_data);
188
189 return 0;
190}
191
192static struct platform_driver lt3593_led_driver = {
193 .probe = lt3593_led_probe,
194 .remove = __devexit_p(lt3593_led_remove),
195 .driver = {
196 .name = "leds-lt3593",
197 .owner = THIS_MODULE,
198 },
199};
200
201MODULE_ALIAS("platform:leds-lt3593");
202
203static int __init lt3593_led_init(void)
204{
205 return platform_driver_register(&lt3593_led_driver);
206}
207
208static void __exit lt3593_led_exit(void)
209{
210 platform_driver_unregister(&lt3593_led_driver);
211}
212
213module_init(lt3593_led_init);
214module_exit(lt3593_led_exit);
215
216MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
217MODULE_DESCRIPTION("LED driver for LT3593 controllers");
218MODULE_LICENSE("GPL");