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Date: Thu, 18 Dec 2008 13:51:06 +0100 (CET)
From: Guennadi Liakhovetski <lg@...x.de>
To: Ben Dooks <ben-linux@...ff.org>
cc: linux-kernel@...r.kernel.org, rpurdie@...ys.net
Subject: [PATCH v2] leds: add a dac124s085 SPI LED driver
A simple LED driver using the DAC124S085 DAC from NatSemi
Signed-off-by: Guennadi Liakhovetski <lg@...x.de>
---
Changes since v1: implemented corrections by Ben Dooks: macro instead of a
magic constant, endianness conversion, ARRAY_SIZE instead of a hard-coded
constant.
Still needs a previous patch making maximum brightness configurable:
http://marc.info/?l=linux-kernel&m=122771446123369&w=2
drivers/leds/Kconfig | 7 ++
drivers/leds/Makefile | 3 +
drivers/leds/leds-dac124s085.c | 147 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 157 insertions(+), 0 deletions(-)
create mode 100644 drivers/leds/leds-dac124s085.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a4a1ae2..a28635f 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -178,6 +178,13 @@ 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 bc247cb..8780152 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -26,6 +26,9 @@ obj-$(CONFIG_LEDS_DA903X) += leds-da903x.o
obj-$(CONFIG_LEDS_HP_DISK) += leds-hp-disk.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 0000000..9bd25c1
--- /dev/null
+++ b/drivers/leds/leds-dac124s085.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright 2008
+ * Guennadi Liakhovetski, DENX Software Engineering, <lg@...x.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/mutex.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@...x.de>");
+MODULE_DESCRIPTION("DAC124S085 LED driver");
+MODULE_LICENSE("GPL v2");
--
1.5.4
--
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