backlight: add driver for DA9052/53 PMIC v1

DA9052/53 PMIC has capability to supply power for upto 3 banks of 6
white serial LEDS.  It can also control intensity of independent banks
and to drive these banks boost converter will provide up to 24V and
forward current of max 50mA.

This patch allows to control intensity of the individual WLEDs bank
through DA9052/53 PMIC.

This patch is functionally tested on Samsung SMDKV6410.

Signed-off-by: David Dajun Chen <dchen@diasemi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/backlight/Kconfig

@@ -245,6 +245,12 @@ config BACKLIGHT_DA903X
 	  If you have a LCD backlight connected to the WLED output of DA9030
 	  or DA9034 WLED output, say Y here to enable this driver.
 
+config BACKLIGHT_DA9052
+	tristate "Dialog DA9052/DA9053 WLED"
+	depends on PMIC_DA9052
+	help
+	  Enable the Backlight Driver for DA9052-BC and DA9053-AA/Bx PMICs.
+
 config BACKLIGHT_MAX8925
 	tristate "Backlight driver for MAX8925"
 	depends on MFD_MAX8925

drivers/video/backlight/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
 obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
 obj-$(CONFIG_BACKLIGHT_PWM)	+= pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_DA903X)	+= da903x_bl.o
+obj-$(CONFIG_BACKLIGHT_DA9052)	+= da9052_bl.o
 obj-$(CONFIG_BACKLIGHT_MAX8925)	+= max8925_bl.o
 obj-$(CONFIG_BACKLIGHT_APPLE)	+= apple_bl.o
 obj-$(CONFIG_BACKLIGHT_TOSA)	+= tosa_bl.o

drivers/video/backlight/da9052_bl.c

@@ -0,0 +1,187 @@
+/*
+ * Backlight Driver for Dialog DA9052 PMICs
+ *
+ * Copyright(c) 2012 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@diasemi.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/fb.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/da9052/da9052.h>
+#include <linux/mfd/da9052/reg.h>
+
+#define DA9052_MAX_BRIGHTNESS		0xFF
+
+enum {
+	DA9052_WLEDS_OFF,
+	DA9052_WLEDS_ON,
+};
+
+enum {
+	DA9052_TYPE_WLED1,
+	DA9052_TYPE_WLED2,
+	DA9052_TYPE_WLED3,
+};
+
+static unsigned char wled_bank[] = {
+	DA9052_LED1_CONF_REG,
+	DA9052_LED2_CONF_REG,
+	DA9052_LED3_CONF_REG,
+};
+
+struct da9052_bl {
+	struct da9052 *da9052;
+	uint brightness;
+	uint state;
+	uint led_reg;
+};
+
+static int da9052_adjust_wled_brightness(struct da9052_bl *wleds)
+{
+	unsigned char boost_en;
+	unsigned char i_sink;
+	int ret;
+
+	boost_en = 0x3F;
+	i_sink = 0xFF;
+	if (wleds->state == DA9052_WLEDS_OFF) {
+		boost_en = 0x00;
+		i_sink = 0x00;
+	}
+
+	ret = da9052_reg_write(wleds->da9052, DA9052_BOOST_REG, boost_en);
+	if (ret < 0)
+		return ret;
+
+	ret = da9052_reg_write(wleds->da9052, DA9052_LED_CONT_REG, i_sink);
+	if (ret < 0)
+		return ret;
+
+	ret = da9052_reg_write(wleds->da9052, wled_bank[wleds->led_reg], 0x0);
+	if (ret < 0)
+		return ret;
+
+	msleep(10);
+
+	if (wleds->brightness) {
+		ret = da9052_reg_write(wleds->da9052, wled_bank[wleds->led_reg],
+				       wleds->brightness);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int da9052_backlight_update_status(struct backlight_device *bl)
+{
+	int brightness = bl->props.brightness;
+	struct da9052_bl *wleds = bl_get_data(bl);
+
+	wleds->brightness = brightness;
+	wleds->state = DA9052_WLEDS_ON;
+
+	return da9052_adjust_wled_brightness(wleds);
+}
+
+static int da9052_backlight_get_brightness(struct backlight_device *bl)
+{
+	struct da9052_bl *wleds = bl_get_data(bl);
+
+	return wleds->brightness;
+}
+
+static const struct backlight_ops da9052_backlight_ops = {
+	.update_status = da9052_backlight_update_status,
+	.get_brightness = da9052_backlight_get_brightness,
+};
+
+static int da9052_backlight_probe(struct platform_device *pdev)
+{
+	struct backlight_device *bl;
+	struct backlight_properties props;
+	struct da9052_bl *wleds;
+
+	wleds = devm_kzalloc(&pdev->dev, sizeof(struct da9052_bl), GFP_KERNEL);
+	if (!wleds)
+		return -ENOMEM;
+
+	wleds->da9052 = dev_get_drvdata(pdev->dev.parent);
+	wleds->brightness = 0;
+	wleds->led_reg = platform_get_device_id(pdev)->driver_data;
+	wleds->state = DA9052_WLEDS_OFF;
+
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = DA9052_MAX_BRIGHTNESS;
+
+	bl = backlight_device_register(pdev->name, wleds->da9052->dev, wleds,
+				       &da9052_backlight_ops, &props);
+	if (IS_ERR(bl)) {
+		dev_err(&pdev->dev, "Failed to register backlight\n");
+		devm_kfree(&pdev->dev, wleds);
+		return PTR_ERR(bl);
+	}
+
+	bl->props.max_brightness = DA9052_MAX_BRIGHTNESS;
+	bl->props.brightness = 0;
+	platform_set_drvdata(pdev, bl);
+
+	return da9052_adjust_wled_brightness(wleds);
+}
+
+static int da9052_backlight_remove(struct platform_device *pdev)
+{
+	struct backlight_device *bl = platform_get_drvdata(pdev);
+	struct da9052_bl *wleds = bl_get_data(bl);
+
+	wleds->brightness = 0;
+	wleds->state = DA9052_WLEDS_OFF;
+	da9052_adjust_wled_brightness(wleds);
+	backlight_device_unregister(bl);
+	devm_kfree(&pdev->dev, wleds);
+
+	return 0;
+}
+
+static struct platform_device_id da9052_wled_ids[] = {
+	{
+		.name		= "da9052-wled1",
+		.driver_data	= DA9052_TYPE_WLED1,
+	},
+	{
+		.name		= "da9052-wled2",
+		.driver_data	= DA9052_TYPE_WLED2,
+	},
+	{
+		.name		= "da9052-wled3",
+		.driver_data	= DA9052_TYPE_WLED3,
+	},
+};
+
+static struct platform_driver da9052_wled_driver = {
+	.probe		= da9052_backlight_probe,
+	.remove		= da9052_backlight_remove,
+	.id_table	= da9052_wled_ids,
+	.driver	= {
+		.name	= "da9052-wled",
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_platform_driver(da9052_wled_driver);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
+MODULE_DESCRIPTION("Backlight driver for DA9052 PMIC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9052-backlight");