Re: [PATCH 3/4] clk: qcom: Add support for Display Clock Controller on Shikra

[Dmitry Baryshkov]

On Tue, May 19, 2026 at 09:34:09AM +0530, Imran Shaik wrote:
> 
> 
> On 13-05-2026 08:38 pm, Dmitry Baryshkov wrote:
> > On Wed, May 13, 2026 at 04:51:03PM +0200, Konrad Dybcio wrote:
> > > On 5/13/26 4:06 PM, Dmitry Baryshkov wrote:
> > > > On Wed, May 13, 2026 at 05:01:16PM +0300, Dmitry Baryshkov wrote:
> > > > > On Wed, May 13, 2026 at 07:10:38PM +0530, Imran Shaik wrote:
> > > > > > Add a driver for the Display clock controller on Qualcomm Shikra SoC.
> > > > > > 
> > > > > > Signed-off-by: Imran Shaik <imran.shaik@xxxxxxxxxxxxxxxx>
> > > > > > ---
> > > > > >   drivers/clk/qcom/Kconfig         |  10 +
> > > > > >   drivers/clk/qcom/Makefile        |   1 +
> > > > > >   drivers/clk/qcom/dispcc-shikra.c | 565 +++++++++++++++++++++++++++++++++++++++
> > > > > >   3 files changed, 576 insertions(+)
> > > > > > 
> > > > > 
> > > > > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > > > 
> > > > After comparing the files...
> > > > 
> > > > Can we use dispcc-qcm2290.c instead? It uses clock-names instead of
> > > > clock-indices, but I think it should be fine to use clock-names as a
> > > > one-off.
> > > 
> > > Or we can convert it to use indices, since those are stable for agatti
> > > too - the names would remain in the binding, just unused by the driver
> > 
> > Either is fine for me.
> > 
> 
> Hi,
> 
> In Agatti, apart from the clock-names difference, I see that the AHB/XO
> clocks are not handled as always-on via the probe and instead rely on pm_clk

There is no pm_clk handling in Agatti driver.

> style handling, whereas Shikra follows the newer pattern by marking required
> CBCRs as critical during probe. I think that attempting to modify this
> approach into Agatti may introduce unnecessary complexity.

Well, you can start by explaining what caused the difference and the
result of those differences.

> 
> And the Agatti DISPCC doesn't have the DT_DSI1 bindings exposed, and
> updating this might break the ABI with respect to bindings, and DT.

You can add Shikra-specific bindings. See how it's handled for other
dispcc drivers.

> Given these and considering that Agatti is already stable, keeping the
> Shikra as separate GPUCC/DISPCC drivers is better to avoid the risk of
> regressions and complexity.

I think you've provided arguments for merging two drivers. It would
allow us to modernize Agatti driver and also to make sure that both
platforms use the well-tested code pattern.

-- 
With best wishes
Dmitry