Daniel Mack | a8dd18f | 2009-10-15 02:59:35 +0200 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 26 | #include <linux/slab.h> |
Paul Gortmaker | 54f4ded | 2011-07-03 13:56:03 -0400 | [diff] [blame^] | 27 | #include <linux/module.h> |
Daniel Mack | a8dd18f | 2009-10-15 02:59:35 +0200 | [diff] [blame] | 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 | |
| 202 | MODULE_ALIAS("platform:leds-lt3593"); |
| 203 | |
| 204 | static int __init lt3593_led_init(void) |
| 205 | { |
| 206 | return platform_driver_register(<3593_led_driver); |
| 207 | } |
| 208 | |
| 209 | static void __exit lt3593_led_exit(void) |
| 210 | { |
| 211 | platform_driver_unregister(<3593_led_driver); |
| 212 | } |
| 213 | |
| 214 | module_init(lt3593_led_init); |
| 215 | module_exit(lt3593_led_exit); |
| 216 | |
| 217 | MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); |
| 218 | MODULE_DESCRIPTION("LED driver for LT3593 controllers"); |
| 219 | MODULE_LICENSE("GPL"); |