[PATCH RESEND 11/16] backlight: ti-lmu-backlight: add LM3633 driver

From: Milo Kim <milo.kim@ti.com>
To: <devicetree@vger.kernel.org>, <lee.jones@linaro.org>,
	<linux-kernel@vger.kernel.org>
Cc: Milo Kim <milo.kim@ti.com>, Jingoo Han <jingoohan1@gmail.com>
Subject: [PATCH RESEND 11/16] backlight: ti-lmu-backlight: add LM3633 driver
Date: Mon, 2 Nov 2015 14:24:30 +0900	[thread overview]
Message-ID: <1446441875-1256-12-git-send-email-milo.kim@ti.com> (raw)
In-Reply-To: <1446441875-1256-1-git-send-email-milo.kim@ti.com>

LM3633 has 3 backlight strings and 11 bit dimming is supported.
PWM brightness control is also supported.

LM3633 MFD has HWMON driver which monitors hardware fault detection.
After this monitoring is done, LM3633 backlight device should be
reinitialized. To enable this, 'hwmon_notifier_used' is set to true.
Then, TI LMU backlight handles LMU HWMON event in
ti_lmu_backlight_hwmon_notifier().

Common backlight driver is controlled by TI LMU backlight driver.
Only LM3633 specific code is implemented here.

Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Milo Kim <milo.kim@ti.com>
---
 drivers/video/backlight/Kconfig     |   9 ++
 drivers/video/backlight/Makefile    |   1 +
 drivers/video/backlight/lm3633_bl.c | 210 ++++++++++++++++++++++++++++++++++++
 3 files changed, 220 insertions(+)
 create mode 100644 drivers/video/backlight/lm3633_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index e3bf905..e3c4adb 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -417,6 +417,15 @@ config BACKLIGHT_LM3632
 	  Up to 2 backlight strings and 11 bit dimming is supported.
 	  PWM brightness control is also supported.
 
+config BACKLIGHT_LM3633
+	tristate "Backlight driver for TI LM3633"
+	depends on BACKLIGHT_CLASS_DEVICE && MFD_TI_LMU
+	select TI_LMU_BACKLIGHT
+	help
+	  Say Y to enable the backlight driver for TI LM3633.
+	  Up to 3 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 6cd5232..364b854 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -41,6 +41,7 @@ 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-$(CONFIG_BACKLIGHT_LM3633)		+= lm3633_bl.o
 obj-$(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/lm3633_bl.c b/drivers/video/backlight/lm3633_bl.c
new file mode 100644
index 0000000..6e01746
--- /dev/null
+++ b/drivers/video/backlight/lm3633_bl.c
@@ -0,0 +1,210 @@
+/*
+ * TI LM3633 Backlight Driver
+ *
+ * Copyright 2015 Texas Instruments
+ *
+ * Author: Milo Kim <milo.kim@ti.com>
+ *
+ * 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 LM3633_DEFAULT_OVP		LM3633_BOOST_OVP_40V
+#define LM3633_BL_MAX_STRINGS		3
+#define LM3633_BL_MAX_BRIGHTNESS	2047
+
+static int lm3633_bl_init(struct ti_lmu_bl_chip *chip)
+{
+	/* Configure ramp selection for each bank */
+	return ti_lmu_update_bits(chip->lmu, LM3633_REG_BL_RAMP_CONF,
+				  LM3633_BL_RAMP_MASK, LM3633_BL_RAMP_EACH);
+}
+
+static int lm3633_bl_enable(struct ti_lmu_bl *lmu_bl, int enable)
+{
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3633_REG_ENABLE,
+				  BIT(lmu_bl->bank_id),
+				  enable << lmu_bl->bank_id);
+}
+
+static int lm3633_bl_set_brightness(struct ti_lmu_bl *lmu_bl, int brightness)
+{
+	int ret;
+	u8 data;
+	u8 reg_lsb[] = { LM3633_REG_BRT_HVLED_A_LSB,
+			 LM3633_REG_BRT_HVLED_B_LSB, };
+	u8 reg_msb[] = { LM3633_REG_BRT_HVLED_A_MSB,
+			 LM3633_REG_BRT_HVLED_B_MSB, };
+
+	if (lmu_bl->mode == BL_PWM_BASED) {
+		/*
+		 * PWM can start from any non-zero code and dim down to zero.
+		 * So, brightness register should be updated even in PWM mode.
+		 */
+		if (brightness > 0)
+			brightness = LM3633_BL_MAX_BRIGHTNESS;
+		else
+			brightness = 0;
+	}
+
+	data = brightness & LM3633_BRT_HVLED_LSB_MASK;
+	ret = ti_lmu_update_bits(lmu_bl->chip->lmu, reg_lsb[lmu_bl->bank_id],
+				 LM3633_BRT_HVLED_LSB_MASK, data);
+	if (ret)
+		return ret;
+
+	data = (brightness >> LM3633_BRT_HVLED_MSB_SHIFT) & 0xFF;
+	return ti_lmu_write_byte(lmu_bl->chip->lmu, reg_msb[lmu_bl->bank_id],
+				 data);
+}
+
+static int lm3633_bl_boost_configure(struct ti_lmu_bl *lmu_bl)
+{
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3633_REG_BOOST_CFG,
+				  LM3633_BOOST_OVP_MASK, LM3633_DEFAULT_OVP);
+}
+
+static int lm3633_bl_set_ctrl_mode(struct ti_lmu_bl *lmu_bl)
+{
+	int bank_id = lmu_bl->bank_id;
+
+	if (lmu_bl->mode == BL_PWM_BASED)
+		return ti_lmu_update_bits(lmu_bl->chip->lmu,
+					  LM3633_REG_PWM_CFG,
+					  BIT(bank_id), 1 << bank_id);
+
+	return 0;
+}
+
+static int lm3633_bl_string_configure(struct ti_lmu_bl *lmu_bl)
+{
+	struct ti_lmu *lmu = lmu_bl->chip->lmu;
+	int is_detected = 0;
+	int i, ret;
+
+	/* Assign control bank from backlight string configuration */
+	for (i = 0; i < LM3633_BL_MAX_STRINGS; i++) {
+		if (test_bit(i, &lmu_bl->bl_string)) {
+			ret = ti_lmu_update_bits(lmu,
+						 LM3633_REG_HVLED_OUTPUT_CFG,
+						 BIT(i), lmu_bl->bank_id << i);
+			if (ret)
+				return ret;
+
+			is_detected = 1;
+		}
+	}
+
+	if (!is_detected) {
+		dev_err(lmu_bl->chip->dev, "No backlight string found\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int lm3633_bl_set_current_limit(struct ti_lmu_bl *lmu_bl)
+{
+	u8 reg[] = { LM3633_REG_IMAX_HVLED_A, LM3633_REG_IMAX_HVLED_B, };
+
+	return ti_lmu_write_byte(lmu_bl->chip->lmu, reg[lmu_bl->bank_id],
+				 lmu_bl->imax);
+}
+
+static int lm3633_bl_set_ramp(struct ti_lmu_bl *lmu_bl)
+{
+	int ret, index;
+	u8 reg;
+
+	index = ti_lmu_backlight_get_ramp_index(lmu_bl, BL_RAMP_UP);
+	if (index > 0) {
+		if (lmu_bl->bank_id == 0)
+			reg = LM3633_REG_BL0_RAMPUP;
+		else
+			reg = LM3633_REG_BL1_RAMPUP;
+
+		ret = ti_lmu_update_bits(lmu_bl->chip->lmu, reg,
+					 LM3633_BL_RAMPUP_MASK,
+					 index << LM3633_BL_RAMPUP_SHIFT);
+		if (ret)
+			return ret;
+	}
+
+	index = ti_lmu_backlight_get_ramp_index(lmu_bl, BL_RAMP_DOWN);
+	if (index > 0) {
+		if (lmu_bl->bank_id == 0)
+			reg = LM3633_REG_BL0_RAMPDN;
+		else
+			reg = LM3633_REG_BL1_RAMPDN;
+
+		ret = ti_lmu_update_bits(lmu_bl->chip->lmu, reg,
+					 LM3633_BL_RAMPDN_MASK,
+					 index << LM3633_BL_RAMPDN_SHIFT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int lm3633_bl_configure(struct ti_lmu_bl *lmu_bl)
+{
+	int ret;
+
+	ret = lm3633_bl_boost_configure(lmu_bl);
+	if (ret)
+		return ret;
+
+	ret = lm3633_bl_set_ctrl_mode(lmu_bl);
+	if (ret)
+		return ret;
+
+	ret = lm3633_bl_string_configure(lmu_bl);
+	if (ret)
+		return ret;
+
+	ret = lm3633_bl_set_current_limit(lmu_bl);
+	if (ret)
+		return ret;
+
+	ret = lm3633_bl_set_ramp(lmu_bl);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/* Backlight ramp up/down time. Unit is msec. */
+static const int lm3633_ramp_table[] = {
+	   2, 250, 500, 1000, 2000, 4000, 8000, 16000,
+};
+
+static const struct ti_lmu_bl_ops lm3633_lmu_ops = {
+	.init			= lm3633_bl_init,
+	.configure		= lm3633_bl_configure,
+	.update_brightness	= lm3633_bl_set_brightness,
+	.bl_enable		= lm3633_bl_enable,
+	.hwmon_notifier_used	= true,
+	.max_brightness		= LM3633_BL_MAX_BRIGHTNESS,
+	.ramp_table		= lm3633_ramp_table,
+	.size_ramp		= ARRAY_SIZE(lm3633_ramp_table),
+};
+
+/* LM3633 backlight of_device_id */
+TI_LMU_BL_OF_DEVICE(lm3633, "ti,lm3633-backlight");
+
+/* LM3633 backlight platform driver */
+TI_LMU_BL_PLATFORM_DRIVER(lm3633, "lm3633-backlight");
+
+MODULE_DESCRIPTION("TI LM3633 Backlight Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:lm3633-backlight");
-- 
1.9.1

