[PATCH RESEND 08/16] backlight: ti-lmu-backlight: add LM3532 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 08/16] backlight: ti-lmu-backlight: add LM3532 driver
Date: Mon, 2 Nov 2015 14:24:27 +0900	[thread overview]
Message-ID: <1446441875-1256-9-git-send-email-milo.kim@ti.com> (raw)
In-Reply-To: <1446441875-1256-1-git-send-email-milo.kim@ti.com>

LM3532 has 3 backlight strings and 8 bit dimming is supported.
PWM brightness control is also supported.

Common backlight driver is controlled by TI LMU backlight driver.
Only LM3532 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/lm3532_bl.c | 183 ++++++++++++++++++++++++++++++++++++
 3 files changed, 193 insertions(+)
 create mode 100644 drivers/video/backlight/lm3532_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index f26eb1c..86d7946 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -390,6 +390,15 @@ config BACKLIGHT_LM3639
 	help
 	  This supports TI LM3639 Backlight + 1.5A Flash LED Driver
 
+config BACKLIGHT_LM3532
+	tristate "Backlight driver for TI LM3532"
+	depends on BACKLIGHT_CLASS_DEVICE && MFD_TI_LMU
+	select TI_LMU_BACKLIGHT
+	help
+	  Say Y to enable the backlight driver for TI LM3532.
+	  Up to 3 backlight strings and 8 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 9e475dc..e037f57 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-$(CONFIG_BACKLIGHT_LM3532)		+= lm3532_bl.o
 obj-$(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/lm3532_bl.c b/drivers/video/backlight/lm3532_bl.c
new file mode 100644
index 0000000..fd21a3c
--- /dev/null
+++ b/drivers/video/backlight/lm3532_bl.c
@@ -0,0 +1,183 @@
+/*
+ * TI LM3532 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 LM3532_PWM1			0
+#define LM3532_BL_MAX_STRINGS		3
+#define LM3532_MAX_ZONE_CFG		3
+#define LM3532_MAX_BRIGHTNESS		255
+
+static int lm3532_bl_init(struct ti_lmu_bl_chip *chip)
+{
+	int i, ret;
+	u8 lm3532_regs[] = { LM3532_REG_ZONE_CFG_A, LM3532_REG_ZONE_CFG_B,
+			     LM3532_REG_ZONE_CFG_C, };
+
+	/*
+	 * Assign zone targets as below.
+	 *   Zone target 0 for control A
+	 *   Zone target 1 for control B
+	 *   Zone target 2 for control C
+	 */
+
+	for (i = 0; i < LM3532_MAX_ZONE_CFG; i++) {
+		ret = ti_lmu_update_bits(chip->lmu, lm3532_regs[i],
+					 LM3532_ZONE_CFG_MASK,
+					 i << LM3532_ZONE_CFG_SHIFT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int lm3532_bl_enable(struct ti_lmu_bl *lmu_bl, int enable)
+{
+	return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3532_REG_ENABLE,
+				  BIT(lmu_bl->bank_id),
+				  enable << lmu_bl->bank_id);
+}
+
+static int lm3532_bl_set_brightness(struct ti_lmu_bl *lmu_bl, int brightness)
+{
+	u8 reg[] = { LM3532_REG_BRT_A, LM3532_REG_BRT_B, LM3532_REG_BRT_C, };
+
+	return ti_lmu_write_byte(lmu_bl->chip->lmu, reg[lmu_bl->bank_id],
+				 brightness);
+}
+
+static int lm3532_bl_select_pwm_bank(struct ti_lmu_bl *lmu_bl, int bank_id)
+{
+	struct ti_lmu *lmu = lmu_bl->chip->lmu;
+	u8 mask[]  = { LM3532_PWM_SEL_A_MASK, LM3532_PWM_SEL_B_MASK,
+		       LM3532_PWM_SEL_C_MASK, };
+	u8 shift[] = { LM3532_PWM_SEL_A_SHIFT, LM3532_PWM_SEL_B_SHIFT,
+		       LM3532_PWM_SEL_C_SHIFT, };
+
+	/* Limitation: only PWM1 is supported. PWM2 is not supported. */
+
+	return ti_lmu_update_bits(lmu, LM3532_REG_PWM_CFG_BASE + bank_id,
+				  mask[bank_id],
+				  (1 << shift[bank_id]) | LM3532_PWM1);
+}
+
+static int lm3532_bl_string_configure(struct ti_lmu_bl *lmu_bl)
+{
+	struct ti_lmu *lmu = lmu_bl->chip->lmu;
+	int bank_id = lmu_bl->bank_id;
+	int is_detected = 0;
+	int i, ret;
+	u8 mask[]  = { LM3532_ILED1_CFG_MASK, LM3532_ILED2_CFG_MASK,
+		       LM3532_ILED3_CFG_MASK, };
+	u8 shift[]  = { LM3532_ILED1_CFG_SHIFT, LM3532_ILED2_CFG_SHIFT,
+			LM3532_ILED3_CFG_SHIFT, };
+
+	/* Assign control bank from backlight string configuration */
+	for (i = 0; i < LM3532_BL_MAX_STRINGS; i++) {
+		if (test_bit(i, &lmu_bl->bl_string)) {
+			ret = ti_lmu_update_bits(lmu, LM3532_REG_OUTPUT_CFG,
+						 mask[i], bank_id << shift[i]);
+			if (ret)
+				return ret;
+
+			is_detected = 1;
+		}
+	}
+
+	if (!is_detected) {
+		dev_err(lmu_bl->chip->dev, "No backlight string found\n");
+		return -EINVAL;
+	}
+
+	if (lmu_bl->mode == BL_PWM_BASED)
+		return lm3532_bl_select_pwm_bank(lmu_bl, bank_id);
+
+	return 0;
+}
+
+static int lm3532_bl_set_current_limit(struct ti_lmu_bl *lmu_bl)
+{
+	u8 reg[] = { LM3532_REG_IMAX_A, LM3532_REG_IMAX_B, LM3532_REG_IMAX_C };
+
+	return ti_lmu_write_byte(lmu_bl->chip->lmu, reg[lmu_bl->bank_id],
+				 lmu_bl->imax);
+}
+
+static int lm3532_bl_set_ramp(struct ti_lmu_bl *lmu_bl)
+{
+	int ret, index;
+
+	index = ti_lmu_backlight_get_ramp_index(lmu_bl, BL_RAMP_UP);
+	if (index > 0) {
+		ret = ti_lmu_update_bits(lmu_bl->chip->lmu, LM3532_REG_RAMPUP,
+					 LM3532_RAMPUP_MASK,
+					 index << LM3532_RAMPUP_SHIFT);
+		if (ret)
+			return ret;
+	}
+
+	index = ti_lmu_backlight_get_ramp_index(lmu_bl, BL_RAMP_DOWN);
+	if (index > 0) {
+		ret = ti_lmu_update_bits(lmu_bl->chip->lmu, LM3532_REG_RAMPDN,
+					 LM3532_RAMPDN_MASK,
+					 index << LM3532_RAMPDN_SHIFT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int lm3532_bl_configure(struct ti_lmu_bl *lmu_bl)
+{
+	int ret;
+
+	ret = lm3532_bl_string_configure(lmu_bl);
+	if (ret)
+		return ret;
+
+	ret = lm3532_bl_set_current_limit(lmu_bl);
+	if (ret)
+		return ret;
+
+	return lm3532_bl_set_ramp(lmu_bl);
+}
+
+/* Backlight ramp up/down time. Unit is msec. */
+static const int lm3532_ramp_table[] = { 0, 1, 2, 4, 8, 16, 32, 65 };
+
+static const struct ti_lmu_bl_ops lm3532_lmu_ops = {
+	.init			= lm3532_bl_init,
+	.configure		= lm3532_bl_configure,
+	.update_brightness	= lm3532_bl_set_brightness,
+	.bl_enable		= lm3532_bl_enable,
+	.max_brightness		= LM3532_MAX_BRIGHTNESS,
+	.ramp_table		= lm3532_ramp_table,
+	.size_ramp		= ARRAY_SIZE(lm3532_ramp_table),
+};
+
+/* LM3532 backlight of_device_id */
+TI_LMU_BL_OF_DEVICE(lm3532, "ti,lm3532-backlight");
+
+/* LM3532 backlight platform driver */
+TI_LMU_BL_PLATFORM_DRIVER(lm3532, "lm3532-backlight");
+
+MODULE_DESCRIPTION("TI LM3532 Backlight Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:lm3532-backlight");
-- 
1.9.1

