Re: [PATCH v8 2/2] drm/bridge: anx7625: Add anx7625 MIPI DSI/DPI to DP bridge driver

[Xin Ji <xji@analogixsemi.com>]

On Wed, Apr 29, 2020 at 10:10:05AM +0800, Nicolas Boichat wrote:
> On Mon, Apr 27, 2020 at 2:18 PM Xin Ji <xji@analogixsemi.com> wrote:
> >
> > The ANX7625 is an ultra-low power 4K Mobile HD Transmitter designed
> > for portable device. It converts MIPI DSI/DPI to DisplayPort 1.3 4K.
> >
> > The ANX7625 can support both USB Type-C PD feature and MIPI DSI/DPI
> > to DP feature. This driver only enabled MIPI DSI/DPI to DP feature.
> >
> > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > ---
> >  drivers/gpu/drm/bridge/Makefile           |    2 +-
> >  drivers/gpu/drm/bridge/analogix/Kconfig   |    6 +
> >  drivers/gpu/drm/bridge/analogix/Makefile  |    1 +
> >  drivers/gpu/drm/bridge/analogix/anx7625.c | 2158 +++++++++++++++++++++++++++++
> >  drivers/gpu/drm/bridge/analogix/anx7625.h |  410 ++++++
> >  5 files changed, 2576 insertions(+), 1 deletion(-)
> >  create mode 100644 drivers/gpu/drm/bridge/analogix/anx7625.c
> >  create mode 100644 drivers/gpu/drm/bridge/analogix/anx7625.h
> >
> > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > index 4934fcf..bcd388a 100644
> > --- a/drivers/gpu/drm/bridge/Makefile
> > +++ b/drivers/gpu/drm/bridge/Makefile
> > @@ -12,8 +12,8 @@ obj-$(CONFIG_DRM_SII9234) += sii9234.o
> >  obj-$(CONFIG_DRM_THINE_THC63LVD1024) += thc63lvd1024.o
> >  obj-$(CONFIG_DRM_TOSHIBA_TC358764) += tc358764.o
> >  obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
> > -obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/
> >  obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/
> >  obj-$(CONFIG_DRM_TI_SN65DSI86) += ti-sn65dsi86.o
> >  obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o
> > +obj-y += analogix/
> >  obj-y += synopsys/
> > diff --git a/drivers/gpu/drm/bridge/analogix/Kconfig b/drivers/gpu/drm/bridge/analogix/Kconfig
> > index e930ff9..b2f127e 100644
> > --- a/drivers/gpu/drm/bridge/analogix/Kconfig
> > +++ b/drivers/gpu/drm/bridge/analogix/Kconfig
> > @@ -2,3 +2,9 @@
> >  config DRM_ANALOGIX_DP
> >         tristate
> >         depends on DRM
> > +
> > +config ANALOGIX_ANX7625
> > +       tristate "Analogix MIPI to DP interface support"
> > +       help
> > +               ANX7625 is an ultra-low power 4K mobile HD transmitter designed
> > +               for portable devices. It converts MIPI/DPI to DisplayPort1.3 4K.
> > diff --git a/drivers/gpu/drm/bridge/analogix/Makefile b/drivers/gpu/drm/bridge/analogix/Makefile
> > index fdbf3fd..8a52867 100644
> > --- a/drivers/gpu/drm/bridge/analogix/Makefile
> > +++ b/drivers/gpu/drm/bridge/analogix/Makefile
> > @@ -1,3 +1,4 @@
> >  # SPDX-License-Identifier: GPL-2.0-only
> > +obj-$(CONFIG_ANALOGIX_ANX7625) += anx7625.o
> >  analogix_dp-objs := analogix_dp_core.o analogix_dp_reg.o
> >  obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix_dp.o
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > new file mode 100644
> > index 0000000..fff7a49
> > [snip]
> > +static int anx7625_attach_dsi(struct anx7625_data *ctx)
> > +{
> > +       struct mipi_dsi_host *host;
> > +       struct mipi_dsi_device *dsi;
> > +       struct device_node *mipi_host_node;
> > +       struct device *dev = &ctx->client->dev;
> > +       const struct mipi_dsi_device_info info = {
> > +               .type = "anx7625",
> > +               .channel = 0,
> > +               .node = NULL,
> > +       };
> > +
> > +       DRM_DEV_DEBUG_DRIVER(dev, "attach dsi\n");
> > +
> > +       if (ctx->pdata.dsi_supported)
> > +               mipi_host_node = ctx->pdata.node.mipi_dsi_host_node;
> > +       else
> > +               mipi_host_node = ctx->pdata.node.mipi_dpi_host_node;
> > +
> > +       if (!mipi_host_node) {
> > +               DRM_ERROR("dsi host is not configured.\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       host = of_find_mipi_dsi_host_by_node(mipi_host_node);
> 
> I tried this driver when connected to a dpi interface, and this fails,
> as of_find_mipi_dsi_host_by_node is not able to find the dpi interface
> from the SoC.
> 
> I'm not too familiar with how dpi bridges are supposed to work in the
> kernel, but should we even call "anx7625_attach_dsi" for DPI
> interface?
DPI needs hardware support, and I don't know how to register DPI interface
in the driver too, I'll remove the DPI support in the next serial.
> 
> > +       if (!host) {
> > +               DRM_ERROR("failed to find dsi host.\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       dsi = mipi_dsi_device_register_full(host, &info);
> > +       if (IS_ERR(dsi)) {
> > +               DRM_ERROR("failed to create dsi device.\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       dsi->lanes = 4;
> > +       dsi->format = MIPI_DSI_FMT_RGB888;
> > +       dsi->mode_flags = MIPI_DSI_MODE_VIDEO   |
> > +               MIPI_DSI_MODE_VIDEO_SYNC_PULSE  |
> > +               MIPI_DSI_MODE_EOT_PACKET        |
> > +               MIPI_DSI_MODE_VIDEO_HSE;
> > +
> > +       if (mipi_dsi_attach(dsi) < 0) {
> > +               DRM_ERROR("failed to attach dsi to host.\n");
> > +               mipi_dsi_device_unregister(dsi);
> > +               return -EINVAL;
> > +       }
> > +
> > +       ctx->dsi = dsi;
> > +
> > +       DRM_DEV_DEBUG_DRIVER(dev, "attach dsi succeeded.\n");
> > +
> > +       return 0;
> > +}
> > +
> > [snip]
> > +static int anx7625_bridge_attach(struct drm_bridge *bridge)
> > +{
> > +       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > +       int err;
> > +       struct device *dev = &ctx->client->dev;
> > +
> > +       DRM_DEV_DEBUG_DRIVER(dev, "drm attach\n");
> > +       if (!bridge->encoder) {
> > +               DRM_ERROR("Parent encoder object not found");
> > +               return -ENODEV;
> > +       }
> > +
> > +       err = drm_connector_init(bridge->dev, &ctx->connector,
> > +                                &anx7625_connector_funcs,
> > +                                ctx->pdata.internal_panel ?
> > +                                       DRM_MODE_CONNECTOR_eDP :
> > +                                       DRM_MODE_CONNECTOR_DisplayPort);
> > +       if (err) {
> > +               DRM_ERROR("Failed to initialize connector: %d\n", err);
> > +               return err;
> > +       }
> > +
> > +       drm_connector_helper_add(&ctx->connector,
> > +                                &anx7625_connector_helper_funcs);
> > +
> > +       err = drm_connector_register(&ctx->connector);
> > +       if (err) {
> > +               DRM_ERROR("Failed to register connector: %d\n", err);
> > +               return err;
> > +       }
> > +
> > +       ctx->connector.polled = DRM_CONNECTOR_POLL_HPD;
> > +
> > +       err = drm_connector_attach_encoder(&ctx->connector, bridge->encoder);
> > +       if (err) {
> > +               DRM_ERROR("Failed to link up connector to encoder: %d\n", err);
> > +               drm_connector_unregister(&ctx->connector);
> > +               return err;
> > +       }
> > +
> > +       err = anx7625_attach_dsi(ctx);
> > +       if (err) {
> > +               DRM_ERROR("Failed to attach to dsi : %d\n", err);
> > +               drm_connector_unregister(&ctx->connector);
> > +               return err;
> > +       }
> > +
> > +       ctx->bridge_attached = 1;
> > +
> > +       return 0;
> > +}
> > +