[PATCH RESEND 08/16] backlight: ti-lmu-backlight: add LM3532 driver

Milo Kim
2015-11-02T05:24:27Z

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-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Signed-off-by: Milo Kim <milo.kim-l0cyMroinI0@public.gmane.org>
---
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-l0cyMroinI0@public.gmane.org>
+ *
+ * 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

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