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 marcel.ziswiler@toradex.com Signed-off-by: Daniel Thompson daniel.thompson@linaro.org Tested-by: Marcel Ziswiler marcel.ziswiler@toradex.com ---
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