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leds: Add dac124s085 driver
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Add an LED driver using the DAC124S085 DAC from NatSemi

[[email protected]: use header files for interfaces]
Signed-off-by: Guennadi Liakhovetski <[email protected]>
Signed-off-by: Randy Dunlap <[email protected]>
Signed-off-by: Richard Purdie <[email protected]>
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Guennadi Liakhovetski authored and rpurdie committed Apr 6, 2009
1 parent 1bd465e commit ac2dd0f
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7 changes: 7 additions & 0 deletions drivers/leds/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -190,6 +190,13 @@ config LEDS_DA903X
This option enables support for on-chip LED drivers found
on Dialog Semiconductor DA9030/DA9034 PMICs.

config LEDS_DAC124S085
tristate "LED Support for DAC124S085 SPI DAC"
depends on LEDS_CLASS && SPI
help
This option enables support for DAC124S085 SPI DAC from NatSemi,
which can be used to control up to four LEDs.

comment "LED Triggers"

config LEDS_TRIGGERS
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3 changes: 3 additions & 0 deletions drivers/leds/Makefile
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Expand Up @@ -25,6 +25,9 @@ obj-$(CONFIG_LEDS_PCA955X) += leds-pca955x.o
obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o
obj-$(CONFIG_LEDS_WM8350) += leds-wm8350.o

# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o

# LED Triggers
obj-$(CONFIG_LEDS_TRIGGER_TIMER) += ledtrig-timer.o
obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK) += ledtrig-ide-disk.o
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150 changes: 150 additions & 0 deletions drivers/leds/leds-dac124s085.c
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@@ -0,0 +1,150 @@
/*
* Copyright 2008
* Guennadi Liakhovetski, DENX Software Engineering, <[email protected]>
*
* 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/gfp.h>
#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 <[email protected]>");
MODULE_DESCRIPTION("DAC124S085 LED driver");
MODULE_LICENSE("GPL v2");

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