[PATCH v2 3/8] drm: verisilicon: add a driver for Verisilicon display controllers
Icenowy Zheng
uwu at icenowy.me
Mon Sep 22 18:10:28 PDT 2025
在 2025-09-23星期二的 03:53 +0300，Dmitry Baryshkov写道：
> On Sun, Sep 21, 2025 at 04:34:41PM +0800, Icenowy Zheng wrote:
> > This is a from-scratch driver targeting Verisilicon DC-series
> > display
> > controllers, which feature self-identification functionality like
> > their
> > GC-series GPUs.
> >
> > Only DC8200 is being supported now, and only the main framebuffer
> > is set
> > up (as the DRM primary plane). Support for more DC models and more
> > features is my further targets.
> >
> > As the display controller is delivered to SoC vendors as a whole
> > part,
> > this driver does not use component framework and extra bridges
> > inside a
> > SoC is expected to be implemented as dedicated bridges (this driver
> > properly supports bridge chaining).
> >
> > Signed-off-by: Icenowy Zheng <uwu at icenowy.me>
> > ---
> > Changes in v2:
> > - Changed some Control flows according to previous reviews.
> > - Added missing of_node_put when checking of endpoints for output
> > type.
> > - Switched all userspace-visible modeset objects to be managed by
> > drmm
> > instead of devm.
> > - Utilize devm_drm_bridge_alloc() in internal bridge.
> > - Prevented the usage of simple encoder helpers by passing a NULL
> > funcs pointer.
> > - Let devm enable clocks when getting them.
> > - Removed explicit `.cache_type = REGCACHE_NONE` in regmap config.
> > - Fixed a debug print using a variable before initialization.
> > - Fixed a wrong index when using bulk to handle resets.
> > - Added missing configuration for DPI format (currently fixed
> > RGB888).
> >
> > drivers/gpu/drm/Kconfig | 2 +
> > drivers/gpu/drm/Makefile | 1 +
> > drivers/gpu/drm/verisilicon/Kconfig | 15 +
> > drivers/gpu/drm/verisilicon/Makefile | 5 +
> > drivers/gpu/drm/verisilicon/vs_bridge.c | 330
> > ++++++++++++++++++
> > drivers/gpu/drm/verisilicon/vs_bridge.h | 40 +++
> > drivers/gpu/drm/verisilicon/vs_bridge_regs.h | 54 +++
> > drivers/gpu/drm/verisilicon/vs_crtc.c | 217 ++++++++++++
> > drivers/gpu/drm/verisilicon/vs_crtc.h | 29 ++
> > drivers/gpu/drm/verisilicon/vs_crtc_regs.h | 60 ++++
> > drivers/gpu/drm/verisilicon/vs_dc.c | 205 +++++++++++
> > drivers/gpu/drm/verisilicon/vs_dc.h | 39 +++
> > drivers/gpu/drm/verisilicon/vs_dc_top_regs.h | 27 ++
> > drivers/gpu/drm/verisilicon/vs_drm.c | 177 ++++++++++
> > drivers/gpu/drm/verisilicon/vs_drm.h | 29 ++
> > drivers/gpu/drm/verisilicon/vs_hwdb.c | 150 ++++++++
> > drivers/gpu/drm/verisilicon/vs_hwdb.h | 29 ++
> > drivers/gpu/drm/verisilicon/vs_plane.c | 102 ++++++
> > drivers/gpu/drm/verisilicon/vs_plane.h | 68 ++++
> > .../gpu/drm/verisilicon/vs_primary_plane.c | 157 +++++++++
> > .../drm/verisilicon/vs_primary_plane_regs.h | 53 +++
> > 21 files changed, 1789 insertions(+)
> > create mode 100644 drivers/gpu/drm/verisilicon/Kconfig
> > create mode 100644 drivers/gpu/drm/verisilicon/Makefile
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_bridge.c
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_bridge.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_bridge_regs.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_crtc.c
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_crtc.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_crtc_regs.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_dc.c
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_dc.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_dc_top_regs.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_drm.c
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_drm.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_hwdb.c
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_hwdb.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_plane.c
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_plane.h
> > create mode 100644 drivers/gpu/drm/verisilicon/vs_primary_plane.c
> > create mode 100644
> > drivers/gpu/drm/verisilicon/vs_primary_plane_regs.h
> >
> > +
> > +static int vs_bridge_atomic_check(struct drm_bridge *bridge,
> > + struct drm_bridge_state
> > *bridge_state,
> > + struct drm_crtc_state
> > *crtc_state,
> > + struct drm_connector_state
> > *conn_state)
> > +{
> > + struct vs_bridge *vbridge =
> > drm_bridge_to_vs_bridge(bridge);
> > +
> > + if (vbridge->intf == VSDC_OUTPUT_INTERFACE_DP &&
> > + !vs_bridge_out_dp_fmt_supported(bridge_state-
> > >output_bus_cfg.format))
> > + return -EINVAL;
>
> I still think that it's better to have per-interface type bridge
> funcs
> rather than checking for the interface type inside the function.
>
> > +
> > + vbridge->output_bus_fmt = bridge_state-
> > >output_bus_cfg.format;
> > +
> > + return 0;
> > +}
> > +
> > +
> > + bridge = devm_drm_bridge_alloc(drm_dev->dev, struct
> > vs_bridge, base,
> > + &vs_bridge_funcs);
> > + if (!bridge)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + bridge->crtc = crtc;
> > + bridge->intf = intf;
> > + bridge->next = next;
> > +
> > + if (intf == VSDC_OUTPUT_INTERFACE_DPI)
> > + enctype = DRM_MODE_ENCODER_DPI;
> > + else
> > + enctype = DRM_MODE_ENCODER_NONE;
>
> Nit: DRM_MODE_ENCODER_TMDS ?
The DC it self never encodes TMDS, and although most SoC connect the DP
interface to HDMI TX controllers, it's theortically to use other
bridges here (e.g. DP TX controllers).
>
> > +
> > + bridge->enc = drmm_plain_encoder_alloc(drm_dev, NULL,
> > enctype, NULL);
> > + if (IS_ERR(bridge->enc)) {
> > + dev_err(drm_dev->dev,
> > + "Cannot initialize encoder for output
> > %u\n", output);
> > + ret = PTR_ERR(bridge->enc);
> > + return ERR_PTR(ret);
> > + }
> > +
> > + bridge->enc->possible_crtcs = drm_crtc_mask(&crtc->base);
> > +
> > + ret = drm_bridge_attach(bridge->enc, &bridge->base, NULL,
> > + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > + if (ret) {
> > + dev_err(drm_dev->dev,
> > + "Cannot attach bridge for output %u\n",
> > output);
> > + return ERR_PTR(ret);
> > + }
> > +
> > + bridge->conn = drm_bridge_connector_init(drm_dev, bridge-
> > >enc);
> > + if (IS_ERR(bridge->conn)) {
> > + dev_err(drm_dev->dev,
> > + "Cannot create connector for output %u\n",
> > output);
> > + ret = PTR_ERR(bridge->conn);
> > + return ERR_PTR(ret);
> > + }
> > + drm_connector_attach_encoder(bridge->conn, bridge->enc);
> > +
> > + return bridge;
> > +}
>
> Other than that LGTM.
>
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