[PATCH 10/16] backlight: ti-lmu-backlight: add LM3632 driver

[Milo Kim]

LM3632 has 2 backlight strings and 11 bit dimming is supported.
PWM brightness control is also supported.

Common backlight driver is controlled by TI LMU backlight driver.
Only LM3632 specific code is implemented here.

Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Milo Kim <milo.kim@xxxxxx>
---
 drivers/video/backlight/Kconfig     |   9 +++
 drivers/video/backlight/Makefile    |   1 +
 drivers/video/backlight/lm3632_bl.c | 125 ++++++++++++++++++++++++++++++++++++
 3 files changed, 135 insertions(+)
 create mode 100644 drivers/video/backlight/lm3632_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 986842e..e3bf905 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -408,6 +408,15 @@ config BACKLIGHT_LM3631
 	  Up to 2 backlight strings and 11 bit dimming is supported.
 	  PWM brightness control is also supported.
 
+config BACKLIGHT_LM3632
+	tristate "Backlight driver for TI LM3632"
+	depends on BACKLIGHT_CLASS_DEVICE && MFD_TI_LMU
+	select TI_LMU_BACKLIGHT
+	help
+	  Say Y to enable the backlight driver for TI LM3632.
+	  Up to 2 backlight strings and 11 bit dimming is supported.
+	  PWM brightness control is also supported.
+
 config TI_LMU_BACKLIGHT
 	tristate "Backlight driver for TI LMU"
 	depends on BACKLIGHT_LM3532 || BACKLIGHT_LM3631 || \
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index e8891e8..6cd5232 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_BACKLIGHT_LM3532)		+= lm3532_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3533)		+= lm3533_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3630A)		+= lm3630a_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3631)		+= lm3631_bl.o
+obj-$(CONFIG_BACKLIGHT_LM3632)		+= lm3632_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3639)		+= lm3639_bl.o
 obj-$(CONFIG_BACKLIGHT_LOCOMO)		+= locomolcd.o
 obj-$(CONFIG_BACKLIGHT_LP855X)		+= lp855x_bl.o
diff --git a/drivers/video/backlight/lm3632_bl.c b/drivers/video/backlight/lm3632_bl.c
new file mode 100644
index 0000000..7a3eb73
--- /dev/null
+++ b/drivers/video/backlight/lm3632_bl.c
@@ -0,0 +1,125 @@
+/*
+ * TI LM3632 Backlight Driver
+ *
+ * Copyright 2015 Texas Instruments
+ *
+ * Author: Milo Kim <milo.kim@xxxxxx>
+ *
+ * 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/kernel.h>
+#include <linux/mfd/ti-lmu.h>
+#include <linux/mfd/ti-lmu-register.h>
+#include <linux/module.h>
+
+#include "ti-lmu-backlight.h"
+
+#define LM3632_DEFAULT_OVP		LM3632_OVP_25V
+#define LM3632_FULL_STRINGS		(LMU_HVLED1 | LMU_HVLED2)
+#define LM3632_MAX_BRIGHTNESS		2047
+
+static int lm3632_bl_enable(struct ti_lmu_bl *lmu_bl, int enable)
+{
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3632_REG_ENABLE,
+				  LM3632_BL_EN_MASK, enable);
+}
+
+static int lm3632_bl_set_brightness(struct ti_lmu_bl *lmu_bl, int brightness)
+{
+	u8 data;
+	int ret;
+
+	if (lmu_bl->mode == BL_PWM_BASED)
+		return 0;
+
+	data = brightness & LM3632_BRT_LSB_MASK;
+	ret = ti_lmu_update_bits(lmu_bl->chip->lmu, LM3632_REG_BRT_LSB,
+				 LM3632_BRT_LSB_MASK, data);
+	if (ret)
+		return ret;
+
+	data = (brightness >> LM3632_BRT_MSB_SHIFT) & 0xFF;
+	return ti_lmu_write_byte(lmu_bl->chip->lmu, LM3632_REG_BRT_MSB,
+				 data);
+}
+
+static int lm3632_bl_string_configure(struct ti_lmu_bl *lmu_bl)
+{
+	u8 val;
+
+	if (lmu_bl->bl_string == LM3632_FULL_STRINGS)
+		val = LM3632_BL_TWO_STRINGS;
+	else
+		val = LM3632_BL_ONE_STRING;
+
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3632_REG_ENABLE,
+				  LM3632_BL_STRING_MASK, val);
+}
+
+static int lm3632_bl_set_ovp(struct ti_lmu_bl *lmu_bl)
+{
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3632_REG_CONFIG1,
+				  LM3632_OVP_MASK, LM3632_DEFAULT_OVP);
+}
+
+static int lm3632_bl_set_swfreq(struct ti_lmu_bl *lmu_bl)
+{
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3632_REG_CONFIG2,
+				  LM3632_SWFREQ_MASK, LM3632_SWFREQ_1MHZ);
+}
+
+static int lm3632_bl_set_ctrl_mode(struct ti_lmu_bl *lmu_bl)
+{
+	u8 val;
+
+	if (lmu_bl->mode == BL_PWM_BASED)
+		val = LM3632_PWM_MODE;
+	else
+		val = LM3632_I2C_MODE;
+
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3632_REG_IO_CTRL,
+				  LM3632_PWM_MASK, val);
+}
+
+static int lm3632_bl_configure(struct ti_lmu_bl *lmu_bl)
+{
+	int ret;
+
+	ret = lm3632_bl_string_configure(lmu_bl);
+	if (ret)
+		return ret;
+
+	/* Select OVP level */
+	ret = lm3632_bl_set_ovp(lmu_bl);
+	if (ret)
+		return ret;
+
+	/* Select switching frequency */
+	ret = lm3632_bl_set_swfreq(lmu_bl);
+	if (ret)
+		return ret;
+
+	/* Backlight control mode - PWM or I2C */
+	return lm3632_bl_set_ctrl_mode(lmu_bl);
+}
+
+static const struct ti_lmu_bl_ops lm3632_lmu_ops = {
+	.configure		= lm3632_bl_configure,
+	.update_brightness	= lm3632_bl_set_brightness,
+	.bl_enable		= lm3632_bl_enable,
+	.max_brightness		= LM3632_MAX_BRIGHTNESS,
+};
+
+/* LM3632 backlight of_device_id */
+TI_LMU_BL_OF_DEVICE(lm3632, "ti,lm3632-backlight");
+
+/* LM3632 backlight platform driver */
+TI_LMU_BL_PLATFORM_DRIVER(lm3632, "lm3632-backlight");
+
+MODULE_DESCRIPTION("TI LM3632 Backlight Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:lm3632-backlight");
-- 
1.9.1

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