[Intel-gfx] [PATCH v2 09/15] pwm: crc: Enable/disable PWM output on enable/disable

[Uwe Kleine-König]

On Sun, Jun 07, 2020 at 08:18:34PM +0200, Hans de Goede wrote:
> The pwm-crc code is using 2 different enable bits:
> 1. bit 7 of the PWM0_CLK_DIV (PWM_OUTPUT_ENABLE)
> 2. bit 0 of the BACKLIGHT_EN register
> 
> So far we've kept the PWM_OUTPUT_ENABLE bit set when disabling the PWM,
> this commit makes crc_pwm_disable() clear it on disable and makes
> crc_pwm_enable() set it again on re-enable.
> 
> This should disable the internal (divided) PWM clock and tri-state the
> PWM output pin when disabled, saving some power.

It would be great if you could also document that disabling the PWM
makes the output tri-state. There are a few drivers that have a
"Limitations" section at their top. Describing that there (in the same
format) would be the right place.

Also note that according to Thierry's conception getting a (driven)
inactive output is the right thing for a disabled PWM.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
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