Re: [PATCH v5 3/6] pwm: Add rockchip PWMv4 driver

Damon Ding
2026-04-26T12:07:31Z

Hi Nicolas,

On 4/20/2026 9:52 PM, Nicolas Frattaroli wrote:
> The Rockchip RK3576 brings with it a new PWM IP, in downstream code
> referred to as "v4". This new IP is different enough from the previous
> Rockchip IP that I felt it necessary to add a new driver for it, instead
> of shoehorning it in the old one.
>
> Add this new driver, based on the PWM core's waveform APIs. Its platform
> device is registered by the parent mfpwm driver, from which it also
> receives a little platform data struct, so that mfpwm can guarantee that
> all the platform device drivers spread across different subsystems for
> this specific hardware IP do not interfere with each other.
>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Tested-by: Damon Ding <damon.ding@rock-chips.com>

The continuous mode of all PWM channels has been preliminarily tested
and verified working on the RK3576 IoT board.

I have tested with several typical period and duty cycle configurations.

Following Uwe's suggestion [0], I also tested with libpwm using commands
similar to the following:

./pwmset -c 0 -p 0 -P 1000000 -D 500000 -s 5000

I was previously unaware of the existence of libpwm. I will continue to
follow its upstream development and updates going forward. :-)

Best regards,
Damon

[0]https://lore.kernel.org/all/fgu42esufq2x4fcccncqs3hlotih2gqmws5atotlaznuahoslw@34vblr6vboze/