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SubjectRe: Backlight in motorola Droid 4
Hi!

> >So now the backlight LED can be controlled. Good. (And thanks!)
> >
> >But I seem to remember that backlight had range from "is it really on?"
> >to "very bright"; now it seems to have range from "bright" to "very
> >bright".
> >
> >Any ideas what goes on there?
>
> In the LM3552 driver we are changing the Full scale brightness registers for
> the
>
> specific control bank.
>
> #define LM3532_REG_CTRL_A_BRT    0x17
> #define LM3532_REG_CTRL_B_BRT    0x19
> #define LM3532_REG_CTRL_C_BRT    0x1b
>
> In the ti-lmu code the ALS zones were being modified not the control bank
> brightness.
>
> #define LM3532_REG_BRT_A            0x70    /* zone 0 */
> #define LM3532_REG_BRT_B            0x76    /* zone 1 */
> #define LM3532_REG_BRT_C            0x7C    /* zone 2 */
>
> Not sure how the ALS is attached in the system if it reports to the host and
> the host manages
>
> the back light or if the the ALS is connected directly to the LM3532.
>
> Maybe the ALS zone targets need to be updated to allow a fuller range.  The
> LM3532 may be stuck
>
> in a certain zone.
>
> Probably should set up the ALS properties in the device tree.

I came with this so far.
Pavel

diff --git a/arch/arm/boot/dts/omap4-droid4-xt894.dts b/arch/arm/boot/dts/omap4-droid4-xt894.dts
index 62af1b8..752952e 100644
--- a/arch/arm/boot/dts/omap4-droid4-xt894.dts
+++ b/arch/arm/boot/dts/omap4-droid4-xt894.dts
@@ -422,6 +422,7 @@
led-sources = <2>;
ti,led-mode = <0>;
label = ":backlight";
+ default-state = "on";
linux,default-trigger = "backlight";
};

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index e5e1b3a..2baeacd 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -288,7 +288,7 @@ static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
count, ppos);
}

-#undef REGMAP_ALLOW_WRITE_DEBUGFS
+#define REGMAP_ALLOW_WRITE_DEBUGFS
#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
/*
* This can be dangerous especially when we have clients such as
diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
index bdc98dd..db6e382 100644
--- a/drivers/leds/leds-gpio.c
+++ b/drivers/leds/leds-gpio.c
@@ -172,6 +172,7 @@ static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
led.default_state = LEDS_GPIO_DEFSTATE_ON;
else
led.default_state = LEDS_GPIO_DEFSTATE_OFF;
+ /* FIXME: else ... warn about bad device tree */
}

if (fwnode_property_present(child, "retain-state-suspended"))
diff --git a/drivers/leds/leds-lm3532.c b/drivers/leds/leds-lm3532.c
index 180895b..365a22a5 100644
--- a/drivers/leds/leds-lm3532.c
+++ b/drivers/leds/leds-lm3532.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
// TI LM3532 LED driver
// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+// http://www.ti.com/lit/ds/symlink/lm3532.pdf

#include <linux/i2c.h>
#include <linux/leds.h>
@@ -23,7 +24,7 @@
#define LM3532_REG_PWM_B_CFG 0x14
#define LM3532_REG_PWM_C_CFG 0x15
#define LM3532_REG_ZONE_CFG_A 0x16
-#define LM3532_REG_CTRL_A_BRT 0x17
+#define LM3532_REG_CTRL_A_BRT 0x17 /* Called "Control A Full-Scale Current " in documentation */
#define LM3532_REG_ZONE_CFG_B 0x18
#define LM3532_REG_CTRL_B_BRT 0x19
#define LM3532_REG_ZONE_CFG_C 0x1a
@@ -38,6 +39,7 @@
#define LM3532_REG_ZN_2_LO 0x65
#define LM3532_REG_ZN_3_HI 0x66
#define LM3532_REG_ZN_3_LO 0x67
+#define LM3532_REG_ZN_TARGET 0x70
#define LM3532_REG_MAX 0x7e

/* Contorl Enable */
@@ -302,7 +304,7 @@ static int lm3532_led_disable(struct lm3532_led *led_data)
int ret;

ret = regmap_update_bits(led_data->priv->regmap, LM3532_REG_ENABLE,
- ctrl_en_val, ~ctrl_en_val);
+ ctrl_en_val, 0);
if (ret) {
dev_err(led_data->priv->dev, "Failed to set ctrl:%d\n", ret);
return ret;
@@ -321,6 +323,7 @@ static int lm3532_brightness_set(struct led_classdev *led_cdev,

mutex_lock(&led->priv->lock);

+ /* Actually, I don't think this is acceptable */
if (led->mode == LM3532_BL_MODE_ALS) {
if (brt_val > LED_OFF)
ret = lm3532_led_enable(led);
@@ -339,11 +342,23 @@ static int lm3532_brightness_set(struct led_classdev *led_cdev,
if (ret)
goto unlock;

+ /* This driver is sick. It manipulates maximum current register (5-bit),
+ but fails to control 8-bit brightness register... which is exponential
+ so it allows >8 bit of control */
+
brightness_reg = LM3532_REG_CTRL_A_BRT + led->control_bank * 2;
- brt_val = brt_val / LM3532_BRT_VAL_ADJUST;
+ brt_val = 255 / LM3532_BRT_VAL_ADJUST;

ret = regmap_write(led->priv->regmap, brightness_reg, brt_val);

+ brightness_reg = 0x70 + led->control_bank * 5;
+
+ ret = regmap_write(led->priv->regmap, brightness_reg, brt_val);
+ ret = regmap_write(led->priv->regmap, brightness_reg+1, brt_val);
+ ret = regmap_write(led->priv->regmap, brightness_reg+2, brt_val);
+ ret = regmap_write(led->priv->regmap, brightness_reg+3, brt_val);
+ ret = regmap_write(led->priv->regmap, brightness_reg+4, brt_val);
+
unlock:
mutex_unlock(&led->priv->lock);
return ret;
@@ -382,7 +397,7 @@ static int lm3532_als_configure(struct lm3532_data *priv,
struct lm3532_als_data *als = priv->als_data;
u32 als_vmin, als_vmax, als_vstep;
int zone_reg = LM3532_REG_ZN_0_HI;
- int brightnes_config_reg;
+ int brightness_config_reg;
int ret;
int i;

@@ -415,10 +430,10 @@ static int lm3532_als_configure(struct lm3532_data *priv,
if (ret)
return ret;

- brightnes_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;
+ brightness_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;

- return regmap_update_bits(priv->regmap, brightnes_config_reg,
- LM3532_I2C_CTRL, LM3532_ALS_CTRL);
+ return regmap_update_bits(priv->regmap, brightness_config_reg,
+ LM3532_I2C_CTRL | LM3532_ALS_CTRL, LM3532_ALS_CTRL);
}

static int lm3532_parse_als(struct lm3532_data *priv)
@@ -483,6 +498,34 @@ static int lm3532_parse_als(struct lm3532_data *priv)
return ret;
}

+static void init_default_brightness(struct led_classdev *cdev, const char *tmp)
+{
+ if (!strcmp(tmp, "on")) {
+ cdev->brightness_set_blocking(cdev, cdev->max_brightness);
+ return;
+ }
+ if (!strcmp(tmp, "off")) {
+ cdev->brightness_set_blocking(cdev, 0);
+ return;
+ }
+ if (!strcmp(tmp, "keep"))
+ return;
+ printk("Invalid value for default brightness\n");
+}
+
+static void fwnode_default_brightness(struct led_classdev *cdev, struct fwnode_handle *child)
+{
+ const char *tmp;
+
+ if (!fwnode_property_read_string(child, "default-state", &tmp)) {
+ printk("Do not have default state\n");
+ init_default_brightness(cdev, "on");
+ return;
+ }
+
+ init_default_brightness(cdev, tmp);
+}
+
static int lm3532_parse_node(struct lm3532_data *priv)
{
struct fwnode_handle *child = NULL;
@@ -536,11 +579,13 @@ static int lm3532_parse_node(struct lm3532_data *priv)
ret = fwnode_property_read_u32(child, "ti,led-mode",
&led->mode);
if (ret) {
+ /* FIXME: should just default to non-als mod */
dev_err(&priv->client->dev, "ti,led-mode property missing\n");
fwnode_handle_put(child);
goto child_out;
}

+ /* FIXME: check for invalid ti,led-mode s? */
if (led->mode == LM3532_BL_MODE_ALS) {
ret = lm3532_parse_als(priv);
if (ret)
@@ -554,7 +599,7 @@ static int lm3532_parse_node(struct lm3532_data *priv)
NULL, 0);

if (led->num_leds > LM3532_MAX_LED_STRINGS) {
- dev_err(&priv->client->dev, "To many LED string defined\n");
+ dev_err(&priv->client->dev, "Too many LED strings defined\n");
continue;
}

@@ -582,6 +627,8 @@ static int lm3532_parse_node(struct lm3532_data *priv)
led->led_dev.name = led->label;
led->led_dev.brightness_set_blocking = lm3532_brightness_set;

+ lm3532_init_registers(led);
+
ret = devm_led_classdev_register(priv->dev, &led->led_dev);
if (ret) {
dev_err(&priv->client->dev, "led register err: %d\n",
@@ -590,7 +637,7 @@ static int lm3532_parse_node(struct lm3532_data *priv)
goto child_out;
}

- lm3532_init_registers(led);
+ fwnode_default_brightness(&led->led_dev, child);

i++;
}
diff --git a/drivers/leds/leds-spi-byte.c b/drivers/leds/leds-spi-byte.c
index b231b56..692e10d 100644
--- a/drivers/leds/leds-spi-byte.c
+++ b/drivers/leds/leds-spi-byte.c
@@ -118,6 +118,7 @@ static int spi_byte_probe(struct spi_device *spi)
led->ldev.brightness = led->ldev.max_brightness;
} else if (strcmp(state, "off")) {
/* all other cases except "off" */
+ /* Wrong; want keep, too */
dev_err(dev, "default-state can only be 'on' or 'off'");
return -EINVAL;
}
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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