Re: [PATCH v3 13/38] drm/msm/dp: introduce stream_id for each DP panel

[Yongxing Mou]

On 8/26/2025 1:56 AM, Dmitry Baryshkov wrote:
> On Mon, Aug 25, 2025 at 10:15:59PM +0800, Yongxing Mou wrote:
> > From: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> >
> > With MST, each DP controller can handle multiple streams.
> > There shall be one dp_panel for each stream but the dp_display
> > object shall be shared among them. To represent this abstraction,
> > create a stream_id for each DP panel which shall be set by the
> > MST stream. For SST, default this to stream 0.
> >
> > Use the stream ID to control the pixel clock of that respective
> > stream by extending the clock handles and state tracking of the
> > DP pixel clock to an array of max supported streams. The maximum
> > streams currently is 4.
> >
> > Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> > Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/dp/dp_ctrl.c    | 58 ++++++++++++++++++++++---------------
> >   drivers/gpu/drm/msm/dp/dp_ctrl.h    |  3 +-
> >   drivers/gpu/drm/msm/dp/dp_display.c | 27 +++++++++++++++--
> >   drivers/gpu/drm/msm/dp/dp_display.h |  2 ++
> >   drivers/gpu/drm/msm/dp/dp_panel.h   | 11 +++++++
> >   5 files changed, 73 insertions(+), 28 deletions(-)
>
> > @@ -2677,10 +2675,11 @@ static const char *ctrl_clks[] = {
> >   	"ctrl_link_iface",
> >   };
> >   
> > -static int msm_dp_ctrl_clk_init(struct msm_dp_ctrl *msm_dp_ctrl)
> > +static int msm_dp_ctrl_clk_init(struct msm_dp_ctrl *msm_dp_ctrl, int max_stream)
> >   {
> >   	struct msm_dp_ctrl_private *ctrl;
> >   	struct device *dev;
> > +	char stream_id_str[15];
>
> A comment would be nice. Or better replace this with the array lookup,
> it's much easier than snprintf.
Thanks, will replace this with the array lookup.
> >   	int i, rc;
> >   
> >   	ctrl = container_of(msm_dp_ctrl, struct msm_dp_ctrl_private, msm_dp_ctrl);
> > @@ -2710,9 +2709,19 @@ static int msm_dp_ctrl_clk_init(struct msm_dp_ctrl *msm_dp_ctrl)
> >   	if (rc)
> >   		return rc;
> >   
> > -	ctrl->pixel_clk = devm_clk_get(dev, "stream_pixel");
> > -	if (IS_ERR(ctrl->pixel_clk))
> > -		return PTR_ERR(ctrl->pixel_clk);
> > +	ctrl->pixel_clk[DP_STREAM_0] = devm_clk_get(dev, "stream_pixel");
> > +	if (IS_ERR(ctrl->pixel_clk[DP_STREAM_0]))
> > +		return PTR_ERR(ctrl->pixel_clk[DP_STREAM_0]);
> > +
> > +	for (i = DP_STREAM_1; i < max_stream; i++) {
> > +		sprintf(stream_id_str, "stream_%d_pixel", i);
> > +		ctrl->pixel_clk[i] = devm_clk_get(dev, stream_id_str);
> > +
> > +		if (IS_ERR(ctrl->pixel_clk[i])) {
> > +			DRM_DEBUG_DP("failed to get stream %d pixel clock", i);
> > +			break;
> > +		}
> > +	}
> >   
> >   	return 0;
> >   }