Re: [PATCH 2/3] arm64: dts: qcom: glymur: Add videocc sleep clock

[Shawn Guo <shengchao.guo@oss.qualcomm.com>]

On Fri, Sep 25, 2026 at 09:19:49PM +0530, Jagadeesh Kona wrote:
> 
> On 9/24/2026 9:41 PM, Shawn Guo wrote:
> > The videocc node supplies only the two XO inputs. videocc-glymur.c
> > expects a third input, DT_SLEEP_CLK, and uses it as the parent of
> > video_cc_sleep_clk_src, so that RCG cannot resolve its parent and ends
> > up as an orphan clock: any clk_set_rate() on it fails, and it shows up
> > parentless in /sys/kernel/debug/clk/clk_summary.
> > 
> > Nothing is broken at runtime today because VIDEO_CC_SLEEP_CLK (0x8138)
> > is listed in video_cc_glymur_critical_cbcrs and is therefore force
> > enabled through regmap, bypassing the clock framework; the sleep source
> > simply keeps whatever rate the bootloader left. The orphan still blocks
> > any future rate management of the video sleep path.
> > 
> 
> Hi Shawn,
> 
> The sleep clock supports only a fixed 32KHz frequency and does not support
> any other frequencies. Additionally, this clock is not currently used or voted
> on by any consumers. Therefore, leaving it in its default bootloader configured
> rate should be sufficient, and this change isn't really required.

Hi Jagadeesh,

Agreed on both facts, and the commit message says as much: nothing is
broken at runtime and there is no rate to manage.  The patch is not
about fixing a functional failure though, it is about the DT describing
the hardware inputs the block actually has.

video_cc_sleep_clk_src's parent_map contains P_SLEEP_CLK and its
freq_tbl has F(32000, P_SLEEP_CLK, 1, 0, 0), so the RCG really does
take a sleep clock input in hardware, and videocc-glymur.c asks the DT
for it via DT_SLEEP_CLK.  A DT that stops at two inputs leaves that
input undescribed regardless of whether anyone votes on it today.

It also matters for the binding.  The schema currently documents two
inputs for every compatible, which is wrong for qcom,glymur-videocc,
and I am fixing that in the preceding patch of this series.  If the
DTS keeps only two entries it no longer matches its own binding.

Shawn