From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Dunn Date: Sun, 22 Sep 2013 16:59:56 +0000 Subject: [PATCH v2] pwm-backlight: allow for non-increasing brightness levels Message-Id: <1379869196-19377-1-git-send-email-mikedunn@newsguy.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: Mike Dunn , Richard Purdie , Jingoo Han , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Grant Likely , Rob Herring , linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Robert Jarzmik , Marek Vasut Currently the driver assumes that the values specified in the brightness-levels device tree property increase as they are parsed from left to right. But boards that invert the signal between the PWM output and the backlight will need to specify decreasing brightness-levels. This patch removes the assumption that the last element of the array is the maximum value, and instead searches the array for the maximum value and uses that in the duty cycle calculation. Signed-off-by: Mike Dunn --- Changelog: v2: - commit message reworded; correct line wrap used - 'max_level' variable renamed to 'scale' - loop counter variable type changed to unsigned int - value held in scale changed from array index to actual maximum level - blank lines added around loop for readability drivers/video/backlight/pwm_bl.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 1fea627..5e99b88 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -27,6 +27,7 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + unsigned int scale; int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -57,7 +58,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) if (pb->levels) { duty_cycle = pb->levels[brightness]; - max = pb->levels[max]; + max = pb->scale; } else { duty_cycle = brightness; } @@ -195,7 +196,14 @@ static int pwm_backlight_probe(struct platform_device *pdev) } if (data->levels) { - max = data->levels[data->max_brightness]; + unsigned int i; + + for (i = 0; i <= data->max_brightness; i++) { + if (data->levels[i] > pb->scale) + pb->scale = data->levels[i]; + } + + max = pb->scale; pb->levels = data->levels; } else max = data->max_brightness; -- 1.8.1.5