[PATCH v6 09/23] drm/rockchip: dw_hdmi: Add support for hclk

[Dmitry Osipenko]

17.02.2022 18:00, Sascha Hauer пишет:
> On Thu, Feb 17, 2022 at 03:35:08PM +0300, Dmitry Osipenko wrote:
>> 17.02.2022 11:29, Sascha Hauer пишет:
>>> The rk3568 HDMI has an additional clock that needs to be enabled for the
>>> HDMI controller to work. The purpose of that clock is not clear. It is
>>> named "hclk" in the downstream driver, so use the same name.
>>
>> Have you checked that DSI works without the enabled hclk? I'd expect the
>> whole VOP to be clock-gated.
> 
> No, I haven't checked that.
> 
> I am not sure where you aiming at. The HCLK_VOP is supplied to the vop2
> as well and the vop2 driver also enables this clock. Still, when the
> HDMI registers are accessed before the vop2 driver enables HCLK_VOP then
> the system hangs, so the HDMI needs it also.

HDMI, MIPI and etc are a part of VOP. I'm curious whether MIPI should
also hang, at least datasheet suggests that it should since hclk ungates
the AHB part of the VOP's h/w module, which is used for registers access.