Date:	Wed,  2 Dec 2009 18:40:25 +0100
From:	Antonio Ospite <ospite@...denti.unina.it>
To:	Richard Purdie <rpurdie@...ys.net>
Cc:	Antonio Ospite <ospite@...denti.unina.it>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lrg@...mlogic.co.uk>,
	Daniel Ribeiro <drwyrm@...il.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	openezx-devel@...ts.openezx.org
Subject: [PATCH] leds: Add LED class driver for regulator driven LEDs.

This driver provides an interface for controlling LEDs (or vibrators)
connected to PMICs for which there is a regulator framework driver.

This driver can be used, for instance, to control vibrator on all Motorola EZX
phones using the pcap-regulator driver services.

Signed-off-by: Antonio Ospite <ospite@...denti.unina.it>
---
The patch is against:
git://git.o-hand.com/linux-rpurdie-leds for-mm

A doubt I had was about leaving the 'supply' variable configurable from
platform data, or relying on some fixed value like "vled", but leaving it
configurable covers the case when we have different regulators used for
different LEDs or vibrators.

Should I add a note in Documentation/ about how to use it? Tell me if so.

Thanks,
   Antonio

P.S.: for those who get the mail from LKML, please Cc me on reply.

 drivers/leds/Kconfig           |    6 +
 drivers/leds/Makefile          |    1 +
 drivers/leds/leds-regulator.c  |  214 ++++++++++++++++++++++++++++++++++++++++
 include/linux/leds-regulator.h |   20 ++++
 4 files changed, 241 insertions(+), 0 deletions(-)
 create mode 100644 drivers/leds/leds-regulator.c
 create mode 100644 include/linux/leds-regulator.h

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f12a996..8a0e1ec 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -229,6 +229,12 @@ config LEDS_PWM
 	help
 	  This option enables support for pwm driven LEDs
 
+config LEDS_REGULATOR
+	tristate "REGULATOR driven LED support"
+	depends on LEDS_CLASS && REGULATOR
+	help
+	  This option enables support for regulator driven LEDs.
+
 config LEDS_BD2802
 	tristate "LED driver for BD2802 RGB LED"
 	depends on LEDS_CLASS && I2C
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 176f0c6..9e63869 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_LEDS_DA903X)		+= leds-da903x.o
 obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
 obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o
 obj-$(CONFIG_LEDS_PWM)			+= leds-pwm.o
+obj-$(CONFIG_LEDS_REGULATOR)		+= leds-regulator.o
 obj-$(CONFIG_LEDS_INTEL_SS4200)		+= leds-ss4200.o
 obj-$(CONFIG_LEDS_LT3593)		+= leds-lt3593.o
 obj-$(CONFIG_LEDS_ADP5520)		+= leds-adp5520.o
diff --git a/drivers/leds/leds-regulator.c b/drivers/leds/leds-regulator.c
new file mode 100644
index 0000000..fca5d42
--- /dev/null
+++ b/drivers/leds/leds-regulator.c
@@ -0,0 +1,214 @@
+/*
+ * leds-regulator.c - LED class driver for regulator driven LEDs.
+ *
+ * Copyright (C) 2009 Antonio Ospite <ospite@...denti.unina.it>
+ *
+ * Inspired by leds-wm8350 driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/workqueue.h>
+#include <linux/leds.h>
+#include <linux/leds-regulator.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define to_regulator_led(led_cdev) \
+	container_of(led_cdev, struct regulator_led, cdev)
+
+struct regulator_led {
+	struct led_classdev cdev;
+	enum led_brightness value;
+	int enabled;
+	struct mutex mutex;
+	struct work_struct work;
+
+	struct regulator *vcc;
+};
+
+static inline int led_regulator_get_max_brightness(struct regulator *supply)
+{
+	return regulator_count_voltages(supply);
+}
+
+static int led_regulator_get_vdd(struct regulator *supply,
+		enum led_brightness brightness)
+{
+	if (brightness == 0)
+		return 0;
+
+	return regulator_list_voltage(supply, brightness - 1);
+}
+
+
+static void regulator_led_enable(struct regulator_led *led)
+{
+	int ret;
+
+	if (led->enabled)
+		return;
+
+	ret = regulator_enable(led->vcc);
+	if (ret != 0) {
+		dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret);
+		return;
+	}
+
+	led->enabled = 1;
+}
+
+static void regulator_led_disable(struct regulator_led *led)
+{
+	int ret;
+
+	if (!led->enabled)
+		return;
+
+	ret = regulator_disable(led->vcc);
+	if (ret != 0) {
+		dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret);
+		return;
+	}
+
+	led->enabled = 0;
+}
+
+static void led_work(struct work_struct *work)
+{
+	struct regulator_led *led;
+	int voltage;
+	int ret;
+
+	led = container_of(work, struct regulator_led, work);
+
+	mutex_lock(&led->mutex);
+
+	if (led->value == 0) {
+		regulator_led_disable(led);
+		goto out;
+	}
+
+	voltage = led_regulator_get_vdd(led->vcc, led->value);
+	dev_dbg(led->cdev.dev, "brightness: %d voltage: %d",
+			led->value, voltage);
+
+	ret = regulator_set_voltage(led->vcc, voltage, voltage);
+	if (ret != 0)
+		dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n",
+			voltage, ret);
+
+	regulator_led_enable(led);
+
+out:
+	mutex_unlock(&led->mutex);
+}
+
+static void regulator_led_brightness_set(struct led_classdev *led_cdev,
+			   enum led_brightness value)
+{
+	struct regulator_led *led = to_regulator_led(led_cdev);
+
+	led->value = value;
+	schedule_work(&led->work);
+}
+
+static int regulator_led_probe(struct platform_device *pdev)
+{
+	struct led_regulator_platform_data *pdata = pdev->dev.platform_data;
+	struct regulator_led *led;
+	struct regulator *vcc;
+	int ret;
+
+	if (pdata == NULL) {
+		dev_err(&pdev->dev, "no platform data\n");
+		return -ENODEV;
+	}
+
+	vcc = regulator_get(&pdev->dev, pdata->supply);
+	if (IS_ERR(vcc)) {
+		dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name);
+		return PTR_ERR(vcc);;
+	}
+
+	led = kzalloc(sizeof(*led), GFP_KERNEL);
+	if (led == NULL) {
+		ret = -ENOMEM;
+		goto err_vcc;
+	}
+
+	ret = led_regulator_get_max_brightness(vcc);
+	if (ret < 0)
+		goto err_led;
+
+	led->cdev.max_brightness = ret;
+
+	led->cdev.brightness_set = regulator_led_brightness_set;
+	led->cdev.name = pdata->name;
+	led->cdev.flags |= LED_CORE_SUSPENDRESUME;
+	led->enabled = regulator_is_enabled(vcc);
+	led->vcc = vcc;
+
+	mutex_init(&led->mutex);
+	INIT_WORK(&led->work, led_work);
+
+	led->value = LED_OFF;
+	platform_set_drvdata(pdev, led);
+
+	ret = led_classdev_register(&pdev->dev, &led->cdev);
+	if (ret < 0) {
+		cancel_work_sync(&led->work);
+		goto err_led;
+	}
+
+	return 0;
+
+err_led:
+	kfree(led);
+err_vcc:
+	regulator_put(vcc);
+	return ret;
+}
+
+static int regulator_led_remove(struct platform_device *pdev)
+{
+	struct regulator_led *led = platform_get_drvdata(pdev);
+
+	led_classdev_unregister(&led->cdev);
+	cancel_work_sync(&led->work);
+	regulator_led_disable(led);
+	regulator_put(led->vcc);
+	kfree(led);
+	return 0;
+}
+
+static struct platform_driver regulator_led_driver = {
+	.driver = {
+		   .name  = "leds-regulator",
+		   .owner = THIS_MODULE,
+		   },
+	.probe  = regulator_led_probe,
+	.remove = regulator_led_remove,
+};
+
+static int __devinit regulator_led_init(void)
+{
+	return platform_driver_register(&regulator_led_driver);
+}
+module_init(regulator_led_init);
+
+static void regulator_led_exit(void)
+{
+	platform_driver_unregister(&regulator_led_driver);
+}
+module_exit(regulator_led_exit);
+
+MODULE_AUTHOR("Antonio Ospite <ospite@...denti.unina.it>");
+MODULE_DESCRIPTION("Regulator driven LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-regulator");
diff --git a/include/linux/leds-regulator.h b/include/linux/leds-regulator.h
new file mode 100644
index 0000000..a5850fd
--- /dev/null
+++ b/include/linux/leds-regulator.h
@@ -0,0 +1,20 @@
+/*
+ * leds-regulator.h - platform data structure for regulator driven LEDs.
+ *
+ * Copyright (C) 2009 Antonio Ospite <ospite@...denti.unina.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#ifndef __LINUX_LEDS_REGULATOR_H
+#define __LINUX_LEDS_REGULATOR_H
+
+struct led_regulator_platform_data {
+	char *name;	/* LED name as expected by LED class */
+	char *supply;
+};
+
+#endif /* __LINUX_LEDS_REGULATOR_H */
-- 
1.6.5.3

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