Re: [PATCH v3 09/15] pwm: crc: Enable/disable PWM output on enable/disable

Uwe Kleine-König
2020-06-22T07:55:26Z

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Hello,

[adding Shobhit Kumar <shobhit.kumar@intel.com> to Cc who is the author
of this driver according to the comment on the top of the driver]

On Sat, Jun 20, 2020 at 02:17:52PM +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.
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> Changes in v3:
> - Remove paragraph about tri-stating the output from the commit message,
> we don't have a datasheet so this was just an unfounded guess

I have the impression you spend quite some time with this driver trying
to understand it. What I still think is a bit unfortunate is that there
is quite some guesswork involved. I wonder if it would be possible to
get the manual of that PWM. Do I understand correctly that this is IP
from Intel? There are quite some Intel people on Cc; maybe someone can
help/put in a good word/check and ack the changes?

Best regards
Uwe

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

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