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