Re: [PATCH v6 13/21] drm: renesas: rz-du: mipi_dsi: Add RZ_MIPI_DSI_FEATURE_GPO0R feature

From: Laurent Pinchart

Date: Wed Apr 08 2026 - 10:17:30 EST

On Wed, Apr 08, 2026 at 04:12:22PM +0200, Tommaso Merciai wrote:
> Hi Laurent,
> Thanks for your review.
>
> On 4/8/26 14:31, Laurent Pinchart wrote:
> > On Wed, Apr 08, 2026 at 12:36:58PM +0200, Tommaso Merciai wrote:
> >> The MIPI DSI ip found in the RZ/G3E SoC select the video input clock
> >> based on the DU instance actually connected using the GPO0R register.
> >>
> >> Add this feature to the driver using `RZ_MIPI_DSI_FEATURE_GPO0R`, update
> >> the code accordingly to manage the vclk selection with the introduction
> >> of `rzg2l_mipi_dsi_get_input_port()`.
> >>
> >> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@xxxxxxxxxxxxxx>
> >> ---
> >> v5->v6:
> >> - Moved rzg2l_mipi_dsi_link_write() into rzv2h_mipi_dsi_dphy_init()
> >> + comments from HW Manual.
> >>
> >> v4->v5:
> >> - No changes.
> >>
> >> v3->v4:
> >> - No changes.
> >>
> >> v2->v3:
> >> - No changes.
> >>
> >> v1->v2:
> >> - No changes.
> >>
> >> .../gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 71 +++++++++++++++++--
> >> .../drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h | 3 +
> >> 2 files changed, 68 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> >> index be6dbf19a24e..947c8e15fc4b 100644
> >> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> >> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> >> @@ -37,7 +37,9 @@ MODULE_IMPORT_NS("RZV2H_CPG");
> >>
> >> #define RZG2L_DCS_BUF_SIZE 128 /* Maximum DCS buffer size in external memory. */
> >>
> >> +#define RZ_MIPI_DSI_MAX_INPUT 2
> >> #define RZ_MIPI_DSI_FEATURE_16BPP BIT(0)
> >> +#define RZ_MIPI_DSI_FEATURE_GPO0R BIT(1)
> >>
> >> struct rzg2l_mipi_dsi;
> >>
> >> @@ -81,13 +83,14 @@ struct rzg2l_mipi_dsi {
> >> struct drm_bridge bridge;
> >> struct drm_bridge *next_bridge;
> >>
> >> - struct clk *vclk;
> >> + struct clk *vclk[RZ_MIPI_DSI_MAX_INPUT];
> >> struct clk *lpclk;
> >>
> >> enum mipi_dsi_pixel_format format;
> >> unsigned int num_data_lanes;
> >> unsigned int lanes;
> >> unsigned long mode_flags;
> >> + u8 vclk_idx;
> >>
> >> struct rzv2h_dsi_mode_calc mode_calc;
> >>
> >> @@ -543,8 +546,8 @@ static int rzg2l_dphy_conf_clks(struct rzg2l_mipi_dsi *dsi, unsigned long mode_f
> >> unsigned long vclk_rate;
> >> unsigned int bpp;
> >>
> >> - clk_set_rate(dsi->vclk, mode_freq * KILO);
> >> - vclk_rate = clk_get_rate(dsi->vclk);
> >> + clk_set_rate(dsi->vclk[dsi->vclk_idx], mode_freq * KILO);
> >> + vclk_rate = clk_get_rate(dsi->vclk[dsi->vclk_idx]);
> >> if (vclk_rate != mode_freq * KILO)
> >> dev_dbg(dsi->dev, "Requested vclk rate %lu, actual %lu mismatch\n",
> >> mode_freq * KILO, vclk_rate);
> >> @@ -687,6 +690,19 @@ static int rzv2h_mipi_dsi_dphy_init(struct rzg2l_mipi_dsi *dsi,
> >> rzg2l_mipi_dsi_phy_write(dsi, PLLCLKSET1R,
> >> FIELD_PREP(PLLCLKSET1R_PLL_K, dsi_parameters->k));
> >>
> >> + /*
> >> + * From RZ/G3E HW manual (Rev.1.15) section 9.5.3 Operation,
> >> + * 9.5.3.1 Power on Reset and Initial Settings for All Operations.
> >> + * Figure 9.5-4 Power On/Off Sequence show that after writing to
> >> + * GPO0R.VICH register we need to wait for more than 1 x tp before
> >> + * writing to PLLENR.PLLEN.
> >> + *
> >> + * Note: GPO0R is a link register, not a PHY register. This setting
> >> + * is specific to RZ/G3E.
> >> + */
> >> + if (dsi->info->features & RZ_MIPI_DSI_FEATURE_GPO0R)
> >> + rzg2l_mipi_dsi_link_write(dsi, GPO0R, dsi->vclk_idx);
> >> +
> >> /*
> >> * From RZ/V2H HW manual (Rev.1.20) section 9.5.3 Operation,
> >> * (C) After write to D-PHY registers we need to wait for more than 1 x tp
> >> @@ -1005,6 +1021,37 @@ static int rzg2l_mipi_dsi_stop_video(struct rzg2l_mipi_dsi *dsi)
> >> return ret;
> >> }
> >>
> >> +static int rzg2l_mipi_dsi_get_input_port(struct rzg2l_mipi_dsi *dsi)
> >> +{
> >> + struct device_node *np = dsi->dev->of_node;
> >> + struct device_node *remote_ep, *ep_node;
> >> + struct of_endpoint ep;
> >> + bool ep_enabled;
> >> + int in_port;
> >> +
> >> + /* DSI can have only one port enabled */
> >
> > Why is that ? The hardware supports dynamic input selection, why can't
> > it be supported at runtime ?
>
> For runtime/dynamic you mean using DT overlay??
> like, remove:
>
> Removing - DU0 --> DSI (input 0 | port@0 ) overlay and
> install - DU1 --> DSI (input 1 | port@1 ) overlay and
> viceversa?

No, I mean configurable by userspace, with two CRTCs sharing one DSI
encoder.

> >> + for_each_endpoint_of_node(np, ep_node) {
> >> + of_graph_parse_endpoint(ep_node, &ep);
> >> + if (ep.port >= RZ_MIPI_DSI_MAX_INPUT)
> >> + break;
> >> +
> >> + remote_ep = of_graph_get_remote_endpoint(ep_node);
> >> + ep_enabled = of_device_is_available(remote_ep);
> >> + of_node_put(remote_ep);
> >> +
> >> + if (ep_enabled) {
> >> + in_port = ep.port;
> >> + break;
> >> + }
> >> + }
> >> +
> >> + if (!ep_enabled)
> >> + return -EINVAL;
> >> +
> >> + dev_dbg(dsi->dev, "input port@%d\n", in_port);
> >> + return in_port;
> >> +}
> >> +
> >> /* -----------------------------------------------------------------------------
> >> * Bridge
> >> */
> >> @@ -1425,9 +1472,21 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
> >> if (IS_ERR(dsi->mmio))
> >> return PTR_ERR(dsi->mmio);
> >>
> >> - dsi->vclk = devm_clk_get(dsi->dev, "vclk");
> >> - if (IS_ERR(dsi->vclk))
> >> - return PTR_ERR(dsi->vclk);
> >> + dsi->vclk[0] = devm_clk_get(dsi->dev, "vclk");
> >> + if (IS_ERR(dsi->vclk[0]))
> >> + return PTR_ERR(dsi->vclk[0]);
> >> +
> >> + if (dsi->info->features & RZ_MIPI_DSI_FEATURE_GPO0R) {
> >> + dsi->vclk[1] = devm_clk_get(dsi->dev, "vclk2");
> >> + if (IS_ERR(dsi->vclk[1]))
> >> + return PTR_ERR(dsi->vclk[1]);
> >> +
> >> + ret = rzg2l_mipi_dsi_get_input_port(dsi);
> >> + if (ret < 0)
> >> + return dev_err_probe(dsi->dev, -EINVAL,
> >> + "No available input port\n");
> >> + dsi->vclk_idx = ret;
> >> + }
> >>
> >> dsi->lpclk = devm_clk_get(dsi->dev, "lpclk");
> >> if (IS_ERR(dsi->lpclk))
> >> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h
> >> index 2bef20566648..cee2e0bc5dc5 100644
> >> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h
> >> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h
> >> @@ -83,6 +83,9 @@
> >> #define LINKSR_SQCHRUN1 BIT(4)
> >> #define LINKSR_SQCHRUN0 BIT(0)
> >>
> >> +/* RZ/G3E General Purpose Output 0 Register */
> >> +#define GPO0R 0xc0
> >> +
> >> /* Tx Set Register */
> >> #define TXSETR 0x100
> >> #define TXSETR_NUMLANECAP (0x3 << 16)

--
Regards,

Laurent Pinchart