/* * Copyright 2008 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de> * * This file is subject to the terms and conditions of version 2 of * the GNU General Public License. See the file COPYING in the main * directory of this archive for more details. * * LED driver for the DAC124S085 SPI DAC */ #include <linux/leds.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/workqueue.h> #include <linux/spi/spi.h> struct dac124s085_led { struct led_classdev ldev; struct spi_device *spi; int id; int brightness; char name[sizeof("dac124s085-3")]; struct mutex mutex; struct work_struct work; spinlock_t lock; }; struct dac124s085 { struct dac124s085_led leds[4]; }; #define REG_WRITE (0 << 12) #define REG_WRITE_UPDATE (1 << 12) #define ALL_WRITE_UPDATE (2 << 12) #define POWER_DOWN_OUTPUT (3 << 12) static void dac124s085_led_work(struct work_struct *work) { struct dac124s085_led *led = container_of(work, struct dac124s085_led, work); u16 word; mutex_lock(&led->mutex); word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE | (led->brightness & 0xfff)); spi_write(led->spi, (const u8 *)&word, sizeof(word)); mutex_unlock(&led->mutex); } static void dac124s085_set_brightness(struct led_classdev *ldev, enum led_brightness brightness) { struct dac124s085_led *led = container_of(ldev, struct dac124s085_led, ldev); spin_lock(&led->lock); led->brightness = brightness; schedule_work(&led->work); spin_unlock(&led->lock); } static int dac124s085_probe(struct spi_device *spi) { struct dac124s085 *dac; struct dac124s085_led *led; int i, ret; dac = kzalloc(sizeof(*dac), GFP_KERNEL); if (!dac) return -ENOMEM; spi->bits_per_word = 16; for (i = 0; i < ARRAY_SIZE(dac->leds); i++) { led = dac->leds + i; led->id = i; led->brightness = LED_OFF; led->spi = spi; snprintf(led->name, sizeof(led->name), "dac124s085-%d", i); spin_lock_init(&led->lock); INIT_WORK(&led->work, dac124s085_led_work); mutex_init(&led->mutex); led->ldev.name = led->name; led->ldev.brightness = LED_OFF; led->ldev.max_brightness = 0xfff; led->ldev.brightness_set = dac124s085_set_brightness; ret = led_classdev_register(&spi->dev, &led->ldev); if (ret < 0) goto eledcr; } spi_set_drvdata(spi, dac); return 0; eledcr: while (i--) led_classdev_unregister(&dac->leds[i].ldev); spi_set_drvdata(spi, NULL); kfree(dac); return ret; } static int dac124s085_remove(struct spi_device *spi) { struct dac124s085 *dac = spi_get_drvdata(spi); int i; for (i = 0; i < ARRAY_SIZE(dac->leds); i++) { led_classdev_unregister(&dac->leds[i].ldev); cancel_work_sync(&dac->leds[i].work); } spi_set_drvdata(spi, NULL); kfree(dac); return 0; } static struct spi_driver dac124s085_driver = { .probe = dac124s085_probe, .remove = dac124s085_remove, .driver = { .name = "dac124s085", .owner = THIS_MODULE, }, }; static int __init dac124s085_leds_init(void) { return spi_register_driver(&dac124s085_driver); } static void __exit dac124s085_leds_exit(void) { spi_unregister_driver(&dac124s085_driver); } module_init(dac124s085_leds_init); module_exit(dac124s085_leds_exit); MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>"); MODULE_DESCRIPTION("DAC124S085 LED driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("spi:dac124s085");