leds: Add dac124s085 driver

Add an LED driver using the DAC124S085 DAC from NatSemi

[randy.dunlap@oracle.com: use header files for interfaces]
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

3 files changed, 160 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 90d39e5803cd..16a94088beee 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -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
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 9d76f0f160a4..4157e86b9747 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -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
diff --git a/drivers/leds/leds-dac124s085.c b/drivers/leds/leds-dac124s085.c
new file mode 100644
index 000000000000..098d9aae7259
--- /dev/null
+++ b/drivers/leds/leds-dac124s085.c
@@ -0,0 +1,150 @@
+/*
+ * 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/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 <lg@denx.de>");
+MODULE_DESCRIPTION("DAC124S085 LED driver");
+MODULE_LICENSE("GPL v2");