Re: [PATCH v4 12/14] drm/tidss: Add support for AM62P display subsystem

[Aradhya Bhatia <aradhya.bhatia@linux.dev>]

Hi Tomi,

On 29/10/26 10:18, Tomi Valkeinen wrote:
> From: Swamil Jain <s-jain1@ti.com>
> 
> The DSS controller on TI's AM62P SoC features two instances of the TI
> DSS. Each DSS instance supports two video ports, similar to the DSS
> controller found on the TI AM62X SoC. This allows three independent
> video streams to be supported: OLDI, DPI, and DSI.
> 
> Since the DSS instances on AM62P are architecturally similar to those
> on the AM62X DSS controller, the existing dispc_am625_feats
> configuration can be reused for the AM62P DSS support.
> 
> This commit adds the necessary device tree compatibility entry for
> "ti,am62p-dss" in the tidss driver, pointing to dispc_am625_feats,
> thereby enabling DSS support on AM62P devices.
> 
> Signed-off-by: Swamil Jain <s-jain1@ti.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Reviewed-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>

> ---
>  drivers/gpu/drm/tidss/tidss_drv.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/tidss/tidss_drv.c b/drivers/gpu/drm/tidss/tidss_drv.c
> index 44b0b009c29a..8e3cbfb5ef87 100644
> --- a/drivers/gpu/drm/tidss/tidss_drv.c
> +++ b/drivers/gpu/drm/tidss/tidss_drv.c
> @@ -240,6 +240,7 @@ static const struct of_device_id tidss_of_table[] = {
>  	{ .compatible = "ti,am625-dss", .data = &dispc_am625_feats, },
>  	{ .compatible = "ti,am62a7-dss", .data = &dispc_am62a7_feats, },

On a separate note,

Now that `vp_bus_type` support has been dropped, the only thing
different `dispc_am62a7_feats` has from `dispc_am625_feats` is the
subrev macro.

The DSS in AM62A7 SoC is functionally same with that in AM625 SoC; the
only difference being the absence of both the OLDI TXes in AM62A7.

The dt-bindings enforce that rule.

The only place subrev DISPC_AM625 is used, and subrev DISPC_AM62A7 is
not, is for an OLDI reset done log print.

if (dispc->feat->subrev == DISPC_AM625 ||
    dispc->feat->subrev == DISPC_AM65X)
	dev_dbg(dispc->dev, "OLDI RESETDONE %d,%d,%d\n",
		REG_GET(dispc, DSS_SYSSTATUS, GENMASK(5, 5)),
		REG_GET(dispc, DSS_SYSSTATUS, GENMASK(6, 6)),
		REG_GET(dispc, DSS_SYSSTATUS, GENMASK(7, 7)));

Should we consider some workaround for this print, so that we can
entirely drop `dispc_am62a7_feats`?


--
Regards
Aradhya