[PATCH v2 2/9] drm/bridge: synopsys: dw-mipi-dsi: Add input bus format negotiation support

[Jagan Teki]

On Thu, Jul 20, 2023 at 12:40 PM Ying Liu <victor.liu at nxp.com> wrote:
>
> Introduce ->get_input_bus_fmts() callback to struct dw_mipi_dsi_plat_data
> so that vendor drivers can implement specific methods to get input bus
> formats for Synopsys DW MIPI DSI.
>
> While at it, implement a generic callback for ->atomic_get_input_bus_fmts(),
> where we try to get the input bus formats through pdata->get_input_bus_fmts()
> first.  If it's unavailable, fall back to the only format - MEDIA_BUS_FMT_FIXED,
> which matches the default behavior if ->atomic_get_input_bus_fmts() is not
> implemented as ->atomic_get_input_bus_fmts()'s kerneldoc indicates.
>
> Signed-off-by: Liu Ying <victor.liu at nxp.com>
> ---
> v1->v2:
> * No change.
>
>  drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 30 +++++++++++++++++++
>  include/drm/bridge/dw_mipi_dsi.h              | 11 +++++++
>  2 files changed, 41 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index 57eae0fdd970..8580b8a97fb1 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -12,6 +12,7 @@
>  #include <linux/component.h>
>  #include <linux/debugfs.h>
>  #include <linux/iopoll.h>
> +#include <linux/media-bus-format.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/pm_runtime.h>
> @@ -536,6 +537,34 @@ static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>         .transfer = dw_mipi_dsi_host_transfer,
>  };
>
> +static u32 *
> +dw_mipi_dsi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> +                                            struct drm_bridge_state *bridge_state,
> +                                            struct drm_crtc_state *crtc_state,
> +                                            struct drm_connector_state *conn_state,
> +                                            u32 output_fmt,
> +                                            unsigned int *num_input_fmts)
> +{
> +       struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> +       const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
> +       u32 *input_fmts;
> +
> +       if (pdata->get_input_bus_fmts)
> +               return pdata->get_input_bus_fmts(pdata->priv_data,
> +                                                bridge, bridge_state,
> +                                                crtc_state, conn_state,
> +                                                output_fmt, num_input_fmts);

Why do we need platform-controlled bus formats? The supported bridge
formats are common across all platforms and it is specific to the list
of formats supported by DW-MIPI DSI. isn't it?

Thanks,
Jagan.