backlight: max8831: Add backlight support for MAX8831

Added backlight driver support for MAX8831.

Bug 1034472

Change-Id: I648f9fbd18dd596da835e492f8802cc28a9619fd
Signed-off-by: Chaitanya Bandi <bandik@nvidia.com>
Reviewed-on: http://git-master/r/131326
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
GVS: Gerrit_Virtual_Submit

Rebase-Id: R8d4886e0083dd83cd604af07d9338815001b00da

3 files changed, 166 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index c6d7fc9aa7bf..bd836b2815eb 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -435,6 +435,13 @@ config BACKLIGHT_AS3711
 	  If you have an Austrian Microsystems AS3711 say Y to enable the
 	  backlight driver.
 
+config BACKLIGHT_MAX8831
+	tristate "Backlight driver for Maxim MAX8831"
+	depends on MFD_MAX8831
+	help
+	  If you have a MAX8831 for backlight, say Y to enable the
+	  backlight driver.
+
 endif # BACKLIGHT_CLASS_DEVICE
 
 endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 0a228729557a..178f671c0700 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_BACKLIGHT_LM3639)		+= lm3639_bl.o
 obj-$(CONFIG_BACKLIGHT_LOCOMO)		+= locomolcd.o
 obj-$(CONFIG_BACKLIGHT_LP855X)		+= lp855x_bl.o
 obj-$(CONFIG_BACKLIGHT_LP8788)		+= lp8788_bl.o
+obj-$(CONFIG_BACKLIGHT_MAX8831)		+= max8831_bl.o
 obj-$(CONFIG_BACKLIGHT_MAX8925)		+= max8925_bl.o
 obj-$(CONFIG_BACKLIGHT_OMAP1)		+= omap1_bl.o
 obj-$(CONFIG_BACKLIGHT_OT200)		+= ot200_bl.o
diff --git a/drivers/video/backlight/max8831_bl.c b/drivers/video/backlight/max8831_bl.c
new file mode 100644
index 000000000000..3b38e104c1f1
--- /dev/null
+++ b/drivers/video/backlight/max8831_bl.c
@@ -0,0 +1,158 @@
+/*
+ * Backlight LEDs driver for MAX8831
+ *
+ * Copyright (c) 2008-2012, NVIDIA Corporation.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mfd/max8831.h>
+
+struct max8831_backlight_data {
+	struct device		*max8831_dev;
+	int			id;
+	int			current_brightness;
+};
+
+static int max8831_backlight_set(struct backlight_device *bl, int brightness)
+{
+	struct max8831_backlight_data *data = bl_get_data(bl);
+	struct device *dev = data->max8831_dev;
+
+	if (data->id == MAX8831_BL_LEDS) {
+
+		if (brightness == 0) {
+			max8831_update_bits(dev, MAX8831_CTRL,
+			(MAX8831_CTRL_LED1_ENB | MAX8831_CTRL_LED2_ENB), 0);
+		} else {
+			max8831_update_bits(dev, MAX8831_CTRL,
+			(MAX8831_CTRL_LED1_ENB | MAX8831_CTRL_LED2_ENB),
+			(MAX8831_CTRL_LED1_ENB | MAX8831_CTRL_LED2_ENB));
+
+			max8831_write(dev, MAX8831_CURRENT_CTRL_LED1,
+								brightness);
+			max8831_write(dev, MAX8831_CURRENT_CTRL_LED2,
+								brightness);
+		}
+	}
+	data->current_brightness = brightness;
+	return 0;
+}
+static int max8831_backlight_update_status(struct backlight_device *bl)
+{
+	int brightness = bl->props.brightness;
+
+	if (bl->props.power != FB_BLANK_UNBLANK)
+		brightness = 0;
+
+	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+		brightness = 0;
+
+	return max8831_backlight_set(bl, brightness);
+}
+
+static int max8831_backlight_get_brightness(struct backlight_device *bl)
+{
+	struct max8831_backlight_data *data = bl_get_data(bl);
+	return data->current_brightness;
+}
+
+static const struct backlight_ops max8831_backlight_ops = {
+	.update_status	= max8831_backlight_update_status,
+	.get_brightness	= max8831_backlight_get_brightness,
+};
+
+static int max8831_bl_probe(struct platform_device *pdev)
+{
+	struct max8831_backlight_data *data;
+	struct backlight_device *bl;
+	struct backlight_properties props;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (data == NULL)
+		return -ENOMEM;
+
+	data->max8831_dev = pdev->dev.parent;
+	data->current_brightness = 0;
+	data->id = pdev->id;
+
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = MAX8831_BL_LEDS_MAX_CURR;
+	bl = backlight_device_register(pdev->name, data->max8831_dev, data,
+				       &max8831_backlight_ops, &props);
+	if (IS_ERR(bl)) {
+		dev_err(&pdev->dev, "failed to register backlight\n");
+		return PTR_ERR(bl);
+	}
+
+	bl->props.brightness = MAX8831_BL_LEDS_MAX_CURR;
+
+	platform_set_drvdata(pdev, bl);
+	backlight_update_status(bl);
+	return 0;
+}
+
+static int max8831_bl_remove(struct platform_device *pdev)
+{
+	struct backlight_device *bl = platform_get_drvdata(pdev);
+	backlight_device_unregister(bl);
+	return 0;
+}
+#ifdef CONFIG_PM
+static int max8831_bl_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct backlight_device *bl = platform_get_drvdata(pdev);
+	return max8831_backlight_set(bl, 0);
+}
+
+static int max8831_bl_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct backlight_device *bl = platform_get_drvdata(pdev);
+	backlight_update_status(bl);
+	return 0;
+}
+
+static const struct dev_pm_ops max8831_bl_pm_ops = {
+	.suspend	= max8831_bl_suspend,
+	.resume		= max8831_bl_resume,
+};
+#endif
+
+static struct platform_driver max8831_bl_driver = {
+	.driver = {
+		.name	= "max8831_display_bl",
+		.owner	= THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm	= &max8831_bl_pm_ops,
+#endif
+	},
+	.probe	= max8831_bl_probe,
+	.remove	= max8831_bl_remove,
+};
+module_platform_driver(max8831_bl_driver);
+
+MODULE_AUTHOR("Chaitanya Bandi <bandik@nvidia.com>");
+MODULE_DESCRIPTION("MAX8831 Backlight display driver");
+MODULE_LICENSE("GPL v2");