Re: [PATCH] backlight: add new lm3509 backlight driver

This is a general driver for LM3509 backlgiht chip of TI.
LM3509 is High Efficiency Boost for White LED's and/or OLED Displays with Dual
Current Sinks. This driver supports OLED/White LED select, brightness control
sub/main conrtorl.
You can refer to the datasheet at http://www.ti.com/product/lm3509 for review.

Signed-off-by: Daniel Jeong <redacted>
---
 drivers/video/backlight/Kconfig     |    7 +
 drivers/video/backlight/Makefile    |    1 +
 drivers/video/backlight/lm3509_bl.c |  399 +++++++++++++++++++++++++++++++++++
 3 files changed, 407 insertions(+)
 create mode 100644 drivers/video/backlight/lm3509_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 8d03924..9dc119e 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig

@@ -366,6 +366,13 @@ config BACKLIGHT_AAT2870
 	  If you have a AnalogicTech AAT2870 say Y to enable the
 	  backlight driver.

+config BACKLIGHT_LM3509
+	tristate "Backlight Driver for LM3509"
+	depends on BACKLIGHT_CLASS_DEVICE && I2C
+	select REGMAP_I2C
+	help
+	  This supports TI LM3509 Backlight Driver
+
 config BACKLIGHT_LM3630A
 	tristate "Backlight Driver for LM3630A"
 	depends on BACKLIGHT_CLASS_DEVICE && I2C && PWM

diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index fcd50b73..c34ed98 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile

@@ -36,6 +36,7 @@ obj-$(CONFIG_BACKLIGHT_GPIO)		+= gpio_backlight.o
 obj-$(CONFIG_BACKLIGHT_HP680)		+= hp680_bl.o
 obj-$(CONFIG_BACKLIGHT_HP700)		+= jornada720_bl.o
 obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO)	+= ipaq_micro_bl.o
+obj-$(CONFIG_BACKLIGHT_LM3509)		+= lm3509_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3533)		+= lm3533_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3630A)		+= lm3630a_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3639)		+= lm3639_bl.o

diff --git a/drivers/video/backlight/lm3509_bl.c b/drivers/video/backlight/lm3509_bl.c
new file mode 100644
index 0000000..4f4fb85
--- /dev/null
+++ b/drivers/video/backlight/lm3509_bl.c

@@ -0,0 +1,399 @@
+/*
+ * Simple driver for Texas Instruments LM3509 Backlight driver chip
+ * Copyright (C) 2014 Texas Instruments
+ *
+ * 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/backlight.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#define LM3509_NAME "lm3509"
+
+#define REG_GP	0x10
+#define REG_BMAIN	0xa0
+#define REG_BSUB	0xb0
+#define REG_MAX		0xff

+
+#define LM3509_POR_BR_MAIN	0xe0
+#define LM3509_POR_BR_SUB	0xe0
+#define LM3509_MAX_BR		0xff

+
+enum lm3509_leds {
+	BLED_BMAIN = 0,
+	BLED_BSUB
+};
+
+struct lm3509_chip {
+	struct device *dev;
+	struct backlight_device *bmain;
+	struct backlight_device *bsub;
+	struct regmap *regmap;
+};
+
+/*
+ * enable main
+ * 0 : disables the main current sink and forces MAIN high impedence.
+ * 1 : enables the main current sink.
+ */
+static ssize_t lm3509_bmain_enable_store(struct device *dev,
+				      struct device_attribute *devAttr,
+				      const char *buf, size_t size)
+{
+	struct lm3509_chip *pchip = dev_get_drvdata(dev);
+	unsigned int state;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &state);
+	if (ret) {
+		dev_err(pchip->dev, "input conversion fail\n");
+		return ret;
+	}
+
+	if (!state)
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x1, 0x0);
+	else
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x1, 0x1);
+	if (ret < 0) {
+		dev_err(pchip->dev, "i2c access fail to register\n");
+		return ret;
+	}
+
+	return size;
+}
+
+static DEVICE_ATTR(main_enable, S_IWUSR, NULL, lm3509_bmain_enable_store);
+
+/*
+ * OLED mode control
+ * 0 : white led mode - main and sub current sinks are active
+ * 1 : OLED mode - sub current sink is idabled
+ */
+static ssize_t lm3509_oled_mode_store(struct device *dev,
+				      struct device_attribute *devAttr,
+				      const char *buf, size_t size)
+{
+	struct lm3509_chip *pchip = dev_get_drvdata(dev);
+	unsigned int state;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &state);
+	if (ret) {
+		dev_err(pchip->dev, "input conversion fail\n");
+		return ret;
+	}
+
+	if (!state)
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x20, 0x00);
+	else
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x20, 0x20);
+	if (ret < 0) {
+		dev_err(pchip->dev, "i2c access fail to register\n");
+		return ret;
+	}
+
+	return size;
+}
+
+static DEVICE_ATTR(oled_enable, S_IWUSR, NULL, lm3509_oled_mode_store);
+
+/*
+ * brightness rate of change
+ * set the rate of change of the LED current in to MAIN and SUB/FB
+ * in response to change in the contents of registers
+ * 0 - 51 us/step
+ * 1 - 13 ms/step
+ * 2 - 26 ms/step
+ * 3 - 52 ms/step
+ */
+static ssize_t lm3509_rate_store(struct device *dev,
+				      struct device_attribute *devAttr,
+				      const char *buf, size_t size)
+{
+	struct lm3509_chip *pchip = dev_get_drvdata(dev);
+	unsigned int state;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &state);
+	if (ret) {
+		dev_err(pchip->dev, "input conversion fail\n");
+		return ret;
+	}
+
+	ret = regmap_update_bits(pchip->regmap, REG_GP, 0x18, state << 3);
+	if (ret < 0) {
+		dev_err(pchip->dev, "i2c access fail to register\n");
+		return ret;
+	}
+
+	return size;
+}
+
+static DEVICE_ATTR(rate, S_IWUSR, NULL, lm3509_rate_store);
+
+/* update and get brightness */
+static int lm3509_bmain_update_status(struct backlight_device *bl)
+{
+	struct lm3509_chip *pchip = bl_get_data(bl);
+	int ret;
+
+	ret = regmap_write(pchip->regmap, REG_BMAIN, bl->props.brightness);
+	if (ret < 0)
+		dev_err(pchip->dev, "i2c access fail to register\n");
+	return bl->props.brightness;
+}
+
+static int lm3509_bmain_get_brightness(struct backlight_device *bl)
+{
+	return bl->props.brightness;
+}
+
+static const struct backlight_ops lm3509_bmain_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = lm3509_bmain_update_status,
+	.get_brightness = lm3509_bmain_get_brightness,

+};
+
+/*
+ * enable sub
+ * 0 : disables the secondary current sink and forces SUB/FB high impedence.
+ * 1 : enables the secondary current sink.
+ */
+static ssize_t lm3509_bsub_enable_store(struct device *dev,
+				      struct device_attribute *devAttr,
+				      const char *buf, size_t size)
+{
+	struct lm3509_chip *pchip = dev_get_drvdata(dev);
+	unsigned int state;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &state);
+	if (ret) {
+		dev_err(pchip->dev, "input conversion fail\n");
+		return ret;
+	}
+
+	if (!state)
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x2, 0x0);
+	else
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x2, 0x2);
+	if (ret < 0) {
+		dev_err(pchip->dev, "i2c access fail to register\n");
+		return ret;
+	}
+
+	return size;
+}
+
+static DEVICE_ATTR(sub_enable, S_IWUSR, NULL, lm3509_bsub_enable_store);
+
+/*
+ * uni mode select
+ * 0 : allows the current into MAIN and SUB/FB to be independently controlled
+ *     via the bmain and bsub.
+ * 1 : disables the bsub register and causes the contents of bmain to set
+ *     the current in both the MAIN and SUB/FB current sinks.
+ */
+static ssize_t lm3509_uni_mode_store(struct device *dev,
+				      struct device_attribute *devAttr,
+				      const char *buf, size_t size)
+{
+	struct lm3509_chip *pchip = dev_get_drvdata(dev);
+	unsigned int state;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &state);
+	if (ret) {
+		dev_err(pchip->dev, "input conversion fail\n");
+		return ret;
+	}
+
+	if (!state)
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x4, 0x0);
+	else
+		ret = regmap_update_bits(pchip->regmap, REG_GP, 0x4, 0x4);
+	if (ret < 0) {
+		dev_err(pchip->dev, "i2c access fail to register\n");
+		return ret;
+	}
+
+	return size;
+}
+
+static DEVICE_ATTR(uni_mode, S_IWUSR, NULL, lm3509_uni_mode_store);
+
+/* update and get brightness */
+static int lm3509_bsub_update_status(struct backlight_device *bl)
+{
+	struct lm3509_chip *pchip = bl_get_data(bl);
+	int ret;
+
+	ret = regmap_write(pchip->regmap, REG_BSUB, bl->props.brightness);
+	if (ret < 0)
+		dev_err(pchip->dev, "i2c access fail to register\n");
+	return bl->props.brightness;
+}
+
+static int lm3509_bsub_get_brightness(struct backlight_device *bl)
+{
+	return bl->props.brightness;
+}
+
+static const struct backlight_ops lm3509_bsub_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = lm3509_bsub_update_status,
+	.get_brightness = lm3509_bsub_get_brightness,
+};