[PATCH AUTOSEL 4.20 001/105] backlight: pwm_bl: Fix devicetree parsing with auto-generated brightness tables

Sasha Levin
2019-02-13T02:33:40Z

From: Heiko Stuebner <heiko.stuebner@bq.com>

[ Upstream commit 61170ee9386888f1e6f7e9cc58e8d9a8c2a3c1dd ]

Commit 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly
to human eye") made the parse-dt function return early when using an auto-
generated brightness-table, but didn't take into account that some more
settings were handled below the brightness handling, like power-on-delays
and also setting the pdata enable-gpio to -EINVAL.

This surfaces for example in the case of a backlight without any
enable-gpio which then tries to use gpio-0 in error.

Fix this by simply moving the trailing settings above the brightness
handling.

Fixes: 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")
Signed-off-by: Heiko Stuebner <heiko.stuebner@bq.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/video/backlight/pwm_bl.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index f9ef0673a083..aded3213bfb5 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -268,6 +268,16 @@ static int pwm_backlight_parse_dt(struct device *dev,

memset(data, 0, sizeof(*data));

+ /*
+ * These values are optional and set as 0 by default, the out values
+ * are modified only if a valid u32 value can be decoded.
+ */
+ of_property_read_u32(node, "post-pwm-on-delay-ms",
+ &data->post_pwm_on_delay);
+ of_property_read_u32(node, "pwm-off-delay-ms", &data->pwm_off_delay);
+
+ data->enable_gpio = -EINVAL;
+
/*
* Determine the number of brightness levels, if this property is not
* set a default table of brightness levels will be used.
@@ -380,15 +390,6 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->max_brightness--;
}

- /*
- * These values are optional and set as 0 by default, the out values
- * are modified only if a valid u32 value can be decoded.
- */
- of_property_read_u32(node, "post-pwm-on-delay-ms",
- &data->post_pwm_on_delay);
- of_property_read_u32(node, "pwm-off-delay-ms", &data->pwm_off_delay);
-
- data->enable_gpio = -EINVAL;
return 0;
}

--
2.19.1