Hi, Xinlei:
On Fri, 2022-05-20 at 10:00 +0800, xinlei.lee@xxxxxxxxxxxx wrote:
> From: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
>
> In order to match the changes of "Use the drm_panel_bridge API",
> the poweron/poweroff of dsi is extracted from enable/disable and
> defined as new funcs (atomic_pre_enable/atomic_post_disable).
>
> Since dsi_poweron is moved from dsi_enable to pre_enable function, in
> order to avoid poweron failure, the operation of dsi register fails
> to
> cause bus hang. Therefore, the protection mechanism is added to the
> dsi_enable function.
Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>
>
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge
> API")
>
> Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
> Signed-off-by: Xinlei Lee <xinlei.lee@xxxxxxxxxxxx>
> Reviewed-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@xxxxxxxxxxxxx>
> Reviewed-by: Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 53 +++++++++++++++++++---------
> --
> 1 file changed, 34 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index f880136cec09..d9a6b928dba8 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -691,16 +691,6 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> *dsi)
> if (--dsi->refcount != 0)
> return;
>
> - /*
> - * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
> - * mtk_dsi_stop() should be called after
> mtk_drm_crtc_atomic_disable(),
> - * which needs irq for vblank, and mtk_dsi_stop() will disable
> irq.
> - * mtk_dsi_start() needs to be called in
> mtk_output_dsi_enable(),
> - * after dsi is fully set.
> - */
> - mtk_dsi_stop(dsi);
> -
> - mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
> mtk_dsi_reset_engine(dsi);
> mtk_dsi_lane0_ulp_mode_enter(dsi);
> mtk_dsi_clk_ulp_mode_enter(dsi);
> @@ -715,17 +705,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> *dsi)
>
> static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
> {
> - int ret;
> -
> if (dsi->enabled)
> return;
>
> - ret = mtk_dsi_poweron(dsi);
> - if (ret < 0) {
> - DRM_ERROR("failed to power on dsi\n");
> - return;
> - }
> -
> mtk_dsi_set_mode(dsi);
> mtk_dsi_clk_hs_mode(dsi, 1);
>
> @@ -739,7 +721,16 @@ static void mtk_output_dsi_disable(struct
> mtk_dsi *dsi)
> if (!dsi->enabled)
> return;
>
> - mtk_dsi_poweroff(dsi);
> + /*
> + * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
> + * mtk_dsi_stop() should be called after
> mtk_drm_crtc_atomic_disable(),
> + * which needs irq for vblank, and mtk_dsi_stop() will disable
> irq.
> + * mtk_dsi_start() needs to be called in
> mtk_output_dsi_enable(),
> + * after dsi is fully set.
> + */
> + mtk_dsi_stop(dsi);
> +
> + mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
>
> dsi->enabled = false;
> }
> @@ -776,13 +767,37 @@ static void mtk_dsi_bridge_atomic_enable(struct
> drm_bridge *bridge,
> {
> struct mtk_dsi *dsi = bridge_to_dsi(bridge);
>
> + if (dsi->refcount == 0)
> + return;
> +
> mtk_output_dsi_enable(dsi);
> }
>
> +static void mtk_dsi_bridge_atomic_pre_enable(struct drm_bridge
> *bridge,
> + struct drm_bridge_state
> *old_bridge_state)
> +{
> + struct mtk_dsi *dsi = bridge_to_dsi(bridge);
> + int ret;
> +
> + ret = mtk_dsi_poweron(dsi);
> + if (ret < 0)
> + DRM_ERROR("failed to power on dsi\n");
> +}
> +
> +static void mtk_dsi_bridge_atomic_post_disable(struct drm_bridge
> *bridge,
> + struct drm_bridge_state
> *old_bridge_state)
> +{
> + struct mtk_dsi *dsi = bridge_to_dsi(bridge);
> +
> + mtk_dsi_poweroff(dsi);
> +}
> +
> static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
> .attach = mtk_dsi_bridge_attach,
> .atomic_disable = mtk_dsi_bridge_atomic_disable,
> .atomic_enable = mtk_dsi_bridge_atomic_enable,
> + .atomic_pre_enable = mtk_dsi_bridge_atomic_pre_enable,
> + .atomic_post_disable = mtk_dsi_bridge_atomic_post_disable,
> .mode_set = mtk_dsi_bridge_mode_set,
> };
>
