[PATCH 07/10] backlight: ti-lmu-backlight: Add LM3697 driver

From: Milo Kim
Date: Fri Feb 14 2014 - 01:32:28 EST

LM3697 has 3 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 LM3697 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/lm3697_bl.c | 224 +++++++++++++++++++++++++++++++++++
3 files changed, 234 insertions(+)
create mode 100644 drivers/video/backlight/lm3697_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index b169c8d..3c39b30 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -419,6 +419,15 @@ config BACKLIGHT_LM3695
Say Y to enable the backlight driver for TI LM3695.
Up to 2 backlight strings and 11 bit dimming is supported.

+config BACKLIGHT_LM3697
+ tristate "Backlight driver for TI LM3697"
+ depends on BACKLIGHT_CLASS_DEVICE && MFD_TI_LMU
+ select TI_LMU_BACKLIGHT
+ help
+ Say Y to enable the backlight driver for TI LM3697.
+ 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 || BACKLIGHT_LM3633 || BACKLIGHT_LM3695 || BACKLIGHT_LM3697
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 5427162..16e6ad7 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_BACKLIGHT_LM3532) += lm3532_bl.o
obj-$(CONFIG_BACKLIGHT_LM3631) += lm3631_bl.o
obj-$(CONFIG_BACKLIGHT_LM3633) += lm3633_bl.o
obj-$(CONFIG_BACKLIGHT_LM3695) += lm3695_bl.o
+obj-$(CONFIG_BACKLIGHT_LM3697) += lm3697_bl.o
obj-$(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/lm3697_bl.c b/drivers/video/backlight/lm3697_bl.c
new file mode 100644
index 0000000..18b866a
--- /dev/null
+++ b/drivers/video/backlight/lm3697_bl.c
@@ -0,0 +1,224 @@
+/*
+ * TI LM3697 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.
+ *
+ * LM3697 backlight driver consists of three parts
+ *
+ * 1) LM3697 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 LM3697_BL_MAX_STRINGS 3
+#define LM3697_MAX_BRIGHTNESS 2047
+
+static int lm3697_bl_init(struct ti_lmu_bl_chip *chip)
+{
+ /* Configure ramp selection for each bank */
+ return ti_lmu_update_bits(chip->lmu, LM3697_REG_RAMP_CONF,
+ LM3697_RAMP_MASK, LM3697_RAMP_EACH);
+}
+
+static int lm3697_bl_enable(struct ti_lmu_bl *lmu_bl, int enable)
+{
+ return ti_lmu_update_bits(lmu_bl->chip->lmu, LM3697_REG_ENABLE,
+ BIT(lmu_bl->bank_id),
+ enable << lmu_bl->bank_id);
+}
+
+static int lm3697_bl_set_brightness(struct ti_lmu_bl *lmu_bl, int brightness)
+{
+ int ret;
+ u8 data;
+ u8 reg_lsb[] = { LM3697_REG_BRT_A_LSB, LM3697_REG_BRT_B_LSB, };
+ u8 reg_msb[] = { LM3697_REG_BRT_A_MSB, LM3697_REG_BRT_B_MSB, };
+
+ data = brightness & LM3697_BRT_LSB_MASK;
+ ret = ti_lmu_update_bits(lmu_bl->chip->lmu, reg_lsb[lmu_bl->bank_id],
+ LM3697_BRT_LSB_MASK, data);
+ if (ret)
+ return ret;
+
+ data = (brightness >> LM3697_BRT_MSB_SHIFT) & 0xFF;
+ return ti_lmu_write_byte(lmu_bl->chip->lmu, reg_msb[lmu_bl->bank_id],
+ data);
+}
+
+static int lm3697_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,
+ LM3697_REG_PWM_CFG,
+ BIT(bank_id), 1 << bank_id);
+
+ return 0;
+}
+
+static int lm3697_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;
+
+ /* Assign control bank from backlight string configuration */
+ for (i = 0; i < LM3697_BL_MAX_STRINGS; i++) {
+ if (test_bit(i, &lmu_bl->bl_pdata->bl_string)) {
+ ret = ti_lmu_update_bits(lmu,
+ LM3697_REG_HVLED_OUTPUT_CFG,
+ BIT(i), 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;
+ }
+
+ if (lmu_bl->mode == BL_PWM_BASED) {
+ snprintf(lmu_bl->pwm_name, sizeof(lmu_bl->pwm_name),
+ "%s", LMU_BL_DEFAULT_PWM_NAME);
+
+ return ti_lmu_update_bits(lmu, LM3697_REG_PWM_CFG,
+ BIT(bank_id), 1 << bank_id);
+ }
+
+ return 0;
+}
+
+static int lm3697_bl_set_current(struct ti_lmu_bl *lmu_bl)
+{
+ u8 reg[] = { LM3697_REG_IMAX_A, LM3697_REG_IMAX_B, };
+
+ return ti_lmu_write_byte(lmu_bl->chip->lmu, reg[lmu_bl->bank_id],
+ lmu_bl->bl_pdata->imax);
+}
+
+static void lm3697_bl_effect_request(enum lmu_effect_request_id id,
+ struct ti_lmu_bl *lmu_bl)
+{
+ const char *name[][2] = {
+ { LM3697_EFFECT_BL0_RAMPUP, LM3697_EFFECT_BL0_RAMPDOWN },
+ { LM3697_EFFECT_BL1_RAMPUP, LM3697_EFFECT_BL1_RAMPDOWN },
+ };
+
+ ti_lmu_effect_request(name[lmu_bl->bank_id][id],
+ ti_lmu_backlight_effect_callback, id, lmu_bl);
+}
+
+static int lm3697_bl_configure(struct ti_lmu_bl *lmu_bl)
+{
+ int ret;
+
+ ret = lm3697_bl_set_ctrl_mode(lmu_bl);
+ if (ret)
+ return ret;
+
+ ret = lm3697_bl_string_configure(lmu_bl);
+ if (ret)
+ return ret;
+
+ ret = lm3697_bl_set_current(lmu_bl);
+ if (ret)
+ return ret;
+
+ /* LMU effect is optional, checking return value is not required */
+ if (lmu_bl->bl_pdata->ramp_up_ms)
+ lm3697_bl_effect_request(BL_EFFECT_RAMPUP, lmu_bl);
+
+ if (lmu_bl->bl_pdata->ramp_down_ms)
+ lm3697_bl_effect_request(BL_EFFECT_RAMPDN, lmu_bl);
+
+ return 0;
+}
+
+static const struct ti_lmu_bl_ops lm3697_lmu_ops = {
+ .init = lm3697_bl_init,
+ .configure = lm3697_bl_configure,
+ .update_brightness = lm3697_bl_set_brightness,
+ .bl_enable = lm3697_bl_enable,
+ .max_brightness = LM3697_MAX_BRIGHTNESS,
+};
+
+static int lm3697_bl_probe(struct platform_device *pdev)
+{
+ struct ti_lmu *lmu = dev_get_drvdata(pdev->dev.parent);
+ struct ti_lmu_bl *lmu_bl;
+ struct ti_lmu_bl_chip *chip;
+
+ chip = ti_lmu_backlight_init_device(&pdev->dev, lmu, &lm3697_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 lm3697_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 lm3697_bl_of_match[] = {
+ { .compatible = "ti,lm3697-backlight", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, lm3697_bl_of_match);
+#endif
+
+static struct platform_driver lm3697_bl_driver = {
+ .probe = lm3697_bl_probe,
+ .remove = lm3697_bl_remove,
+ .driver = {
+ .name = "lm3697-backlight",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(lm3697_bl_of_match),
+ },
+};
+module_platform_driver(lm3697_bl_driver);
+
+MODULE_DESCRIPTION("TI LM3697 Backlight Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lm3697-backlight");
--
1.7.9.5

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