Re: [PATCH v2 2/2] backlight: add new lp8788 backlight driver
From: Thierry Reding
Date: Thu Jan 03 2013 - 04:05:49 EST
On Thu, Jan 03, 2013 at 08:54:27AM +0000, Kim, Milo wrote:
> Hi Thierry,
> > > (Platform data)
> > > Configurable data can be defined in the platform side.
> > > name : backlight driver name. (default: "lcd-
> > backlight")
> > > initial_brightness : initial value of backlight brightness
> > > bl_mode : brightness control by PWM or lp8788 register
> > > dim_mode : dimming mode selection
> > > full_scale : full scale current setting
> > > rise_time : brightness ramp up step time
> > > fall_time : brightness ramp down step time
> > > pwm_pol : PWM polarity setting when bl_mode is PWM
> > based
> > You might want to consider using enum pwm_polarity from linux/pwm.h
> > instead and convert to the driver representation internally.
> > I'm saying this because I'm thinking about extending the PWM framework
> > to allow PWM polarity and period to be specified in the PWM lookup
> > table
> > so that they can be treated transparently, independent of whether they
> > are obtained from DT or the lookup table.
> > That would allow the polarity and period to be retrieved with accessors
> > like pwm_get_polarity() and pwm_get_period().
> OK, pwm_pol will be replaced with pwm_get_polarity() in the next patch.
No, you can't do that yet because it will only work if you get the PWM
from DT. I meant that once the pieces in the PWM framework are there we
could encode the polarity in the PWM lookup table and *then* use
pwm_get_polarity() to obtain it instead of via platform data.
For now, I think you should only convert it to enum pwm_polarity so that
at least the data type is the same as the one used in the PWM framework.
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