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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 | /* * LEDs driver for LT3593 controllers * * See the datasheet at http://cds.linear.com/docs/Datasheet/3593f.pdf * * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de> * * Based on leds-gpio.c, * * Copyright (C) 2007 8D Technologies inc. * Raphael Assenat <raph@8d.com> * Copyright (C) 2008 Freescale Semiconductor, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/leds.h> #include <linux/workqueue.h> #include <linux/delay.h> #include <linux/gpio.h> #include <linux/slab.h> #include <linux/module.h> struct lt3593_led_data { struct led_classdev cdev; unsigned gpio; struct work_struct work; u8 new_level; }; static void lt3593_led_work(struct work_struct *work) { int pulses; struct lt3593_led_data *led_dat = container_of(work, struct lt3593_led_data, work); /* * The LT3593 resets its internal current level register to the maximum * level on the first falling edge on the control pin. Each following * falling edge decreases the current level by 625uA. Up to 32 pulses * can be sent, so the maximum power reduction is 20mA. * After a timeout of 128us, the value is taken from the register and * applied is to the output driver. */ if (led_dat->new_level == 0) { gpio_set_value_cansleep(led_dat->gpio, 0); return; } pulses = 32 - (led_dat->new_level * 32) / 255; if (pulses == 0) { gpio_set_value_cansleep(led_dat->gpio, 0); mdelay(1); gpio_set_value_cansleep(led_dat->gpio, 1); return; } gpio_set_value_cansleep(led_dat->gpio, 1); while (pulses--) { gpio_set_value_cansleep(led_dat->gpio, 0); udelay(1); gpio_set_value_cansleep(led_dat->gpio, 1); udelay(1); } } static void lt3593_led_set(struct led_classdev *led_cdev, enum led_brightness value) { struct lt3593_led_data *led_dat = container_of(led_cdev, struct lt3593_led_data, cdev); led_dat->new_level = value; schedule_work(&led_dat->work); } static int create_lt3593_led(const struct gpio_led *template, struct lt3593_led_data *led_dat, struct device *parent) { int ret, state; /* skip leds on GPIOs that aren't available */ if (!gpio_is_valid(template->gpio)) { dev_info(parent, "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n", KBUILD_MODNAME, template->gpio, template->name); return 0; } led_dat->cdev.name = template->name; led_dat->cdev.default_trigger = template->default_trigger; led_dat->gpio = template->gpio; led_dat->cdev.brightness_set = lt3593_led_set; state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; if (!template->retain_state_suspended) led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; ret = devm_gpio_request_one(parent, template->gpio, state ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW, template->name); if (ret < 0) return ret; INIT_WORK(&led_dat->work, lt3593_led_work); ret = led_classdev_register(parent, &led_dat->cdev); if (ret < 0) return ret; dev_info(parent, "%s: registered LT3593 LED '%s' at GPIO %d\n", KBUILD_MODNAME, template->name, template->gpio); return 0; } static void delete_lt3593_led(struct lt3593_led_data *led) { if (!gpio_is_valid(led->gpio)) return; led_classdev_unregister(&led->cdev); cancel_work_sync(&led->work); } static int lt3593_led_probe(struct platform_device *pdev) { struct gpio_led_platform_data *pdata = pdev->dev.platform_data; struct lt3593_led_data *leds_data; int i, ret = 0; if (!pdata) return -EBUSY; leds_data = devm_kzalloc(&pdev->dev, sizeof(struct lt3593_led_data) * pdata->num_leds, GFP_KERNEL); if (!leds_data) return -ENOMEM; for (i = 0; i < pdata->num_leds; i++) { ret = create_lt3593_led(&pdata->leds[i], &leds_data[i], &pdev->dev); if (ret < 0) goto err; } platform_set_drvdata(pdev, leds_data); return 0; err: for (i = i - 1; i >= 0; i--) delete_lt3593_led(&leds_data[i]); return ret; } static int lt3593_led_remove(struct platform_device *pdev) { int i; struct gpio_led_platform_data *pdata = pdev->dev.platform_data; struct lt3593_led_data *leds_data; leds_data = platform_get_drvdata(pdev); for (i = 0; i < pdata->num_leds; i++) delete_lt3593_led(&leds_data[i]); return 0; } static struct platform_driver lt3593_led_driver = { .probe = lt3593_led_probe, .remove = lt3593_led_remove, .driver = { .name = "leds-lt3593", .owner = THIS_MODULE, }, }; module_platform_driver(lt3593_led_driver); MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); MODULE_DESCRIPTION("LED driver for LT3593 controllers"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:leds-lt3593"); |