[PATCH 03/10] backlight: ti-lmu-backlight: Add LM3532 driver

[Milo Kim]

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 <jg1.han@xxxxxxxxxxx>
Cc: Bryan Wu <cooloney@xxxxxxxxx>
Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Milo Kim <milo.kim@xxxxxx>
---
 drivers/video/backlight/Kconfig     |    9 ++
 drivers/video/backlight/Makefile    |    1 +
 drivers/video/backlight/lm3532_bl.c |  240 +++++++++++++++++++++++++++++++++++
 3 files changed, 250 insertions(+)
 create mode 100644 drivers/video/backlight/lm3532_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 3641698..d841057 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -384,6 +384,15 @@ 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 || BACKLIGHT_LM3633 || BACKLIGHT_LM3695 || BACKLIGHT_LM3697
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index f80e046..51354d1 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_BACKLIGHT_HP700)		+= jornada720_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3533)		+= lm3533_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3630A)		+= lm3630a_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3639)		+= lm3639_bl.o
+obj-$(CONFIG_BACKLIGHT_LM3532)		+= lm3532_bl.o
 obj-$(CONFIG_TI_LMU_BACKLIGHT)		+= ti-lmu-backlight.o
 obj-$(CONFIG_BACKLIGHT_LOCOMO)		+= locomolcd.o
 obj-$(CONFIG_BACKLIGHT_LP855X)		+= lp855x_bl.o
diff --git a/drivers/video/backlight/lm3532_bl.c b/drivers/video/backlight/lm3532_bl.c
new file mode 100644
index 0000000..c4cf636
--- /dev/null
+++ b/drivers/video/backlight/lm3532_bl.c
@@ -0,0 +1,240 @@
+/*
+ * TI LM3532 Backlight Driver
+ *
+ * Copyright 2014 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.
+ *
+ * LM3532 backlight driver consists of three parts
+ *
+ *   1) LM3532 chip specific part: this file
+ *      Define device specific operations
+ *      Register LMU backlight driver
+ *
+ *   2) LMU backlight common driver: ti-lmu-backlight
+ *      General backlight subsystem control
+ *
+ *   3) LMU effect driver
+ *      Backlight ramp time configuration
+ *
+ */
+
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/mfd/ti-lmu.h>
+#include <linux/mfd/ti-lmu-effect.h>
+#include <linux/mfd/ti-lmu-register.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#include "ti-lmu-backlight.h"
+
+#define LM3532_PWM1			0
+#define LM3532_PWM2			1
+#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;
+	static int num_pwms;
+	u8 pwm_sel;
+	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, };
+
+	if (num_pwms > 0)
+		pwm_sel = LM3532_PWM2;
+	else
+		pwm_sel = LM3532_PWM1;
+
+	num_pwms++;
+
+	snprintf(lmu_bl->pwm_name, sizeof(lmu_bl->pwm_name), "%s:%d",
+		 LMU_BL_DEFAULT_PWM_NAME, pwm_sel);
+
+	return ti_lmu_update_bits(lmu, LM3532_REG_PWM_CFG_BASE + bank_id,
+				  mask[bank_id],
+				  (1 << shift[bank_id]) | pwm_sel);
+}
+
+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_pdata->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(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->bl_pdata->imax);
+}
+
+static void lm3532_bl_effect_request(struct ti_lmu_bl *lmu_bl)
+{
+	int i;
+	const char *name[] = {
+		[BL_EFFECT_RAMPUP] = LM3532_EFFECT_RAMPUP,
+		[BL_EFFECT_RAMPDN] = LM3532_EFFECT_RAMPDOWN,
+	};
+
+	for (i = BL_EFFECT_RAMPUP; i <= BL_EFFECT_RAMPDN; i++)
+		ti_lmu_effect_request(name[i],
+				      ti_lmu_backlight_effect_callback,
+				      i, lmu_bl);
+}
+
+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(lmu_bl);
+	if (ret)
+		return ret;
+
+	/* LMU effect is optional, checking return value is not required */
+	lm3532_bl_effect_request(lmu_bl);
+
+	return 0;
+}
+
+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,
+};
+
+static int lm3532_bl_probe(struct platform_device *pdev)
+{
+	struct ti_lmu *lmu = dev_get_drvdata(pdev->dev.parent);
+	struct ti_lmu_bl_chip *chip;
+	struct ti_lmu_bl *lmu_bl;
+
+	chip = ti_lmu_backlight_init_device(&pdev->dev, lmu, &lm3532_lmu_ops);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+
+	lmu_bl = ti_lmu_backlight_register(chip, lmu->pdata->bl_pdata,
+					   lmu->pdata->num_backlights);
+	if (IS_ERR(lmu_bl))
+		return PTR_ERR(lmu_bl);
+
+	platform_set_drvdata(pdev, lmu_bl);
+
+	return 0;
+}
+
+static int lm3532_bl_remove(struct platform_device *pdev)
+{
+	struct ti_lmu_bl *lmu_bl = platform_get_drvdata(pdev);
+
+	return ti_lmu_backlight_unregister(lmu_bl);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id lm3532_bl_of_match[] = {
+	{ .compatible = "ti,lm3532-backlight", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lm3532_bl_of_match);
+#endif
+
+static struct platform_driver lm3532_bl_driver = {
+	.probe = lm3532_bl_probe,
+	.remove = lm3532_bl_remove,
+	.driver = {
+		.name = "lm3532-backlight",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(lm3532_bl_of_match),
+	},
+};
+module_platform_driver(lm3532_bl_driver);
+
+MODULE_DESCRIPTION("TI LM3532 Backlight Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lm3532-backlight");
-- 
1.7.9.5

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