Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756093AbZJHJD2 (ORCPT ); Thu, 8 Oct 2009 05:03:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755719AbZJHJD2 (ORCPT ); Thu, 8 Oct 2009 05:03:28 -0400 Received: from buzzloop.caiaq.de ([212.112.241.133]:43086 "EHLO buzzloop.caiaq.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755572AbZJHJD0 (ORCPT ); Thu, 8 Oct 2009 05:03:26 -0400 From: Daniel Mack To: linux-kernel@vger.kernel.org Cc: Daniel Mack , Richard Purdie Subject: [PATCH] LED: add driver for LT3593 controlled LEDs Date: Wed, 7 Oct 2009 05:41:00 +0800 Message-Id: <1254865260-13570-1-git-send-email-daniel@caiaq.de> X-Mailer: git-send-email 1.6.0.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7639 Lines: 284 The LT3593 is a step-up DC/DC converter designed to drive up to ten white LEDs in series. The current flow can be set with a control pin. This driver controls any number of such devices connected on generic GPIOs and exports the function as as platform_driver. The gpio_led platform data struct definition is reused for this purpose. Successfully tested on a PXA embedded board. Signed-off-by: Daniel Mack Cc: Richard Purdie Signed-off-by: Daniel Mack --- drivers/leds/Kconfig | 8 ++ drivers/leds/Makefile | 1 + drivers/leds/leds-lt3593.c | 218 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 227 insertions(+), 0 deletions(-) create mode 100644 drivers/leds/leds-lt3593.c diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index 7c8e712..80a183f 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -229,6 +229,14 @@ config LEDS_BD2802 This option enables support for BD2802GU RGB LED driver chips accessed via the I2C bus. +config LEDS_LT3593 + tristate "LED driver for LT3593 controllers" + depends on LEDS_CLASS && GENERIC_GPIO + help + This option enables support for LEDs driven by a Linear Technology + LT3593 controller. This controller uses a special one-wire pulse + coding protocol to set the brightness. + comment "LED Triggers" config LEDS_TRIGGERS diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index e8cdcf7..3d79287 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -28,6 +28,7 @@ obj-$(CONFIG_LEDS_PCA955X) += leds-pca955x.o obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o obj-$(CONFIG_LEDS_PWM) += leds-pwm.o +obj-$(CONFIG_LEDS_LT3593) += leds-lt3593.o # LED SPI Drivers obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o diff --git a/drivers/leds/leds-lt3593.c b/drivers/leds/leds-lt3593.c new file mode 100644 index 0000000..de69a5f --- /dev/null +++ b/drivers/leds/leds-lt3593.c @@ -0,0 +1,218 @@ +/* + * LEDs driver for LT3593 controllers + * + * See the datasheet at http://cds.linear.com/docs/Datasheet/3593f.pdf + * + * Copyright (c) 2009 Daniel Mack + * + * Based on leds-gpio.c, + * + * Copyright (C) 2007 8D Technologies inc. + * Raphael Assenat + * 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 +#include +#include +#include +#include +#include + +#include + +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 __devinit 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)) { + printk(KERN_INFO "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n", + KBUILD_MODNAME, template->gpio, template->name); + return 0; + } + + ret = gpio_request(template->gpio, template->name); + if (ret < 0) + return ret; + + 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 = gpio_direction_output(led_dat->gpio, state); + if (ret < 0) + goto err; + + INIT_WORK(&led_dat->work, lt3593_led_work); + + ret = led_classdev_register(parent, &led_dat->cdev); + if (ret < 0) + goto err; + + printk(KERN_INFO "%s: registered LT3593 LED '%s' at GPIO %d\n", + KBUILD_MODNAME, template->name, template->gpio); + + return 0; + +err: + gpio_free(led_dat->gpio); + return ret; +} + +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); + gpio_free(led->gpio); +} + +static int __devinit 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 = kzalloc(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]); + + kfree(leds_data); + + return ret; +} + +static int __devexit 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]); + + kfree(leds_data); + + return 0; +} + +static struct platform_driver lt3593_led_driver = { + .probe = lt3593_led_probe, + .remove = __devexit_p(lt3593_led_remove), + .driver = { + .name = "leds-lt3593", + .owner = THIS_MODULE, + }, +}; + +MODULE_ALIAS("platform:leds-lt3593"); + +static int __init lt3593_led_init(void) +{ + return platform_driver_register(<3593_led_driver); +} + +static void __exit lt3593_led_exit(void) +{ + platform_driver_unregister(<3593_led_driver); +} + +module_init(lt3593_led_init); +module_exit(lt3593_led_exit); + +MODULE_AUTHOR("Daniel Mack "); +MODULE_DESCRIPTION("LED driver for LT3593 controllers"); +MODULE_LICENSE("GPL"); -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/