[PATCH v2] backlight: pwm_bl: Fix uninitialized variable
From: Daniel Thompson <hidden>
Date: 2018-07-19 16:19:47
Also in:
dri-devel, linux-pwm, lkml
Subsystem:
backlight class/subsystem, framebuffer layer, the rest · Maintainers:
Lee Jones, Daniel Thompson, Jingoo Han, Helge Deller, Linus Torvalds
Currently, if the DT does not define num-interpolated-steps then
num_steps is undefined and the interpolation code will deploy randomly.
Fix this.
Additionally fix a small grammar error that was identified and
tighten up return code checking of DT properties, both of which came
up during review of this patch.
Fixes: 573fe6d1c25c ("backlight: pwm_bl: Linear interpolation between
brightness-levels")
Reported-by: Marcel Ziswiler <redacted>
Signed-off-by: Daniel Thompson <redacted>
Tested-by: Marcel Ziswiler <redacted>
---
Notes:
v2:
- Simplify SoB chain (with Marcel's permission)
- Separate complex if statement and make other similar calls use same
return code checking approach
- Tidy up comment formatting and fix pre-existing grammar error
drivers/video/backlight/pwm_bl.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 9ee4c1b735b2..f7799f62fea0 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c@@ -284,30 +284,29 @@ static int pwm_backlight_parse_dt(struct device *dev, ret = of_property_read_u32_array(node, "brightness-levels", data->levels, data->max_brightness); - if (ret < 0) + if (!ret) return ret; ret = of_property_read_u32(node, "default-brightness-level", &value); - if (ret < 0) + if (!ret) return ret; data->dft_brightness = value; /* * This property is optional, if is set enables linear - * interpolation between each of the values of brightness levels - * and creates a new pre-computed table. + * interpolation between each of the values of brightness + * levels and creates a new pre-computed table. */ - of_property_read_u32(node, "num-interpolated-steps", - &num_steps); - - /* - * Make sure that there is at least two entries in the - * brightness-levels table, otherwise we can't interpolate - * between two points. - */ - if (num_steps) { + ret = of_property_read_u32(node, "num-interpolated-steps", + &num_steps); + if (!ret || num_steps) { + /* + * Make sure that there are at least two entries in + * the brightness-levels table, otherwise we can't + * interpolate between two points. + */ if (data->max_brightness < 2) { dev_err(dev, "can't interpolate\n"); return -EINVAL; --
2.17.1