RE: [PATCH 11/17] drm: renesas: rz-du: mipi_dsi: Add OF data support

Biju Das
2025-03-31T14:14:27Z

> -----Original Message-----
> From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> Sent: 31 March 2025 14:59
> To: Biju Das <biju.das.jz@bp.renesas.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>; Andrzej Hajda <andrzej.hajda@intel.com>; Neil
> Armstrong <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; laurent.pinchart
> <laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>; Jernej Skrabec
> <jernej.skrabec@gmail.com>; David Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Maarten
> Lankhorst <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>; Thomas Zimmermann
> <tzimmermann@suse.de>; Rob Herring <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor
> Dooley <conor+dt@kernel.org>; Mauro Carvalho Chehab <mchehab@kernel.org>; Kieran Bingham
> <kieran.bingham+renesas@ideasonboard.com>; Stephen Boyd <sboyd@kernel.org>; Philipp Zabel
> <p.zabel@pengutronix.de>; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-renesas-
> soc@vger.kernel.org; linux-media@vger.kernel.org; linux-clk@vger.kernel.org; Fabrizio Castro
> <fabrizio.castro.jz@renesas.com>; Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Subject: Re: [PATCH 11/17] drm: renesas: rz-du: mipi_dsi: Add OF data support
>
> Hi Biju,
>
> Thank you for the review.
>
> On Mon, Mar 31, 2025 at 1:38 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> >
> > Hi Prabhakar,
> >
> > Thanks for the patch.
> >
> > > -----Original Message-----
> > > From: Prabhakar <prabhakar.csengg@gmail.com>
> > > Sent: 30 March 2025 22:07
> > > Subject: [PATCH 11/17] drm: renesas: rz-du: mipi_dsi: Add OF data
> > > support
> > >
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > >
> > > In preparation for adding support for the Renesas RZ/V2H(P) SoC,
> > > this patch introduces a mechanism to pass SoC-specific information
> > > via OF data in the DSI driver. This enables the driver to adapt dynamically to various SoC-
> specific requirements without hardcoding configurations.
> > >
> > > The MIPI DSI interface on the RZ/V2H(P) SoC is nearly identical to
> > > the one on the RZ/G2L SoC. While the LINK registers are shared
> > > between the two SoCs, the D-PHY registers differ. Also the VCLK
> > > range differs on both these SoCs. To accommodate these differences `struct rzg2l_mipi_dsi_hw_info`
> is introduced and as now passed as OF data.
> > >
> > > These changes lay the groundwork for the upcoming RZ/V2H(P) SoC
> > > support by allowing SoC-specific data to be passed through OF.
> > >
> <snip>
> > > +
> > > ret = drm_of_get_data_lanes_count_ep(dsi->dev->of_node, 1, 0, 1, 4);
> > > if (ret < 0)
> > > return dev_err_probe(dsi->dev, ret, @@ -729,10 +750,12
> > > @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
> > > if (IS_ERR(dsi->vclk))
> > > return PTR_ERR(dsi->vclk);
> > >
> > > - dsi->rstc = devm_reset_control_get_exclusive(dsi->dev, "rst");
> > > - if (IS_ERR(dsi->rstc))
> > > - return dev_err_probe(dsi->dev, PTR_ERR(dsi->rstc),
> > > - "failed to get rst\n");
> > > + if (dsi->info->has_dphy_rstc) {
> > > + dsi->rstc = devm_reset_control_get_exclusive(dsi->dev,
> > > + "rst");
> >
> > Maybe use devm_reset_control_get_optional_exclusive by dropping has_dphy_rstc.
> >
> As the dtbs_check doesn't enforce this, `has_dphy_rstc` flag was added. Recently the same was done
> for the CRU [0] based on the recent comment received.
>

RZ/V2H has "arst" and "prst". So, If you add "rst" for RZ/V2H then you should get dtbs warning, right?

Cheers,
Biju