| From 96905f7f9eacf843bf235dca638eddf776c6c0fa Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 27 Jan 2021 12:07:56 +0100 |
| Subject: drm/stm: Fix bus_flags handling |
| |
| From: Marek Vasut <marex@denx.de> |
| |
| [ Upstream commit 99e360442f223dd40fc23ae07c7a263836fd27e6 ] |
| |
| The drm_display_mode_to_videomode() does not populate DISPLAY_FLAGS_DE_LOW |
| or DISPLAY_FLAGS_PIXDATA_NEGEDGE flags in struct videomode. Therefore, no |
| matter what polarity the next bridge or display might require, these flags |
| are never set, and thus the LTDC GCR_DEPOL and GCR_PCPOL bits are never set |
| and the LTDC behaves as if both DISPLAY_FLAGS_PIXDATA_POSEDGE and |
| DISPLAY_FLAGS_DE_HIGH were always set. |
| |
| The fix for this problem is taken almost verbatim from MXSFB driver. In |
| case there is a bridge attached to the LTDC, the bridge might have extra |
| polarity requirements, so extract bus_flags from the bridge and use them |
| for LTDC configuration. Otherwise, extract bus_flags from the connector, |
| which is the display. |
| |
| Fixes: b759012c5fa7 ("drm/stm: Add STM32 LTDC driver") |
| Signed-off-by: Marek Vasut <marex@denx.de> |
| Signed-off-by: Yannick Fertre <yannick.fertre@st.com> |
| Cc: Alexandre Torgue <alexandre.torgue@st.com> |
| Cc: Antonio Borneo <antonio.borneo@st.com> |
| Cc: Benjamin Gaignard <benjamin.gaignard@st.com> |
| Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> |
| Cc: Philippe Cornu <philippe.cornu@st.com> |
| Cc: Sam Ravnborg <sam@ravnborg.org> |
| Cc: Vincent Abriou <vincent.abriou@st.com> |
| Cc: Yannick Fertre <yannick.fertre@st.com> |
| Cc: linux-arm-kernel@lists.infradead.org |
| Cc: linux-stm32@st-md-mailman.stormreply.com |
| To: dri-devel@lists.freedesktop.org |
| Tested-by: Yannick Fertre <yannick.fertre@foss.st.com> |
| Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com> |
| Link: https://patchwork.freedesktop.org/patch/msgid/20210127110756.125570-1-marex@denx.de |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/gpu/drm/stm/ltdc.c | 33 +++++++++++++++++++++++++++++++-- |
| 1 file changed, 31 insertions(+), 2 deletions(-) |
| |
| diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c |
| index 3980677435cb..949511a0a24f 100644 |
| --- a/drivers/gpu/drm/stm/ltdc.c |
| +++ b/drivers/gpu/drm/stm/ltdc.c |
| @@ -525,13 +525,42 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc) |
| { |
| struct ltdc_device *ldev = crtc_to_ltdc(crtc); |
| struct drm_device *ddev = crtc->dev; |
| + struct drm_connector_list_iter iter; |
| + struct drm_connector *connector = NULL; |
| + struct drm_encoder *encoder = NULL; |
| + struct drm_bridge *bridge = NULL; |
| struct drm_display_mode *mode = &crtc->state->adjusted_mode; |
| struct videomode vm; |
| u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h; |
| u32 total_width, total_height; |
| + u32 bus_flags = 0; |
| u32 val; |
| int ret; |
| |
| + /* get encoder from crtc */ |
| + drm_for_each_encoder(encoder, ddev) |
| + if (encoder->crtc == crtc) |
| + break; |
| + |
| + if (encoder) { |
| + /* get bridge from encoder */ |
| + list_for_each_entry(bridge, &encoder->bridge_chain, chain_node) |
| + if (bridge->encoder == encoder) |
| + break; |
| + |
| + /* Get the connector from encoder */ |
| + drm_connector_list_iter_begin(ddev, &iter); |
| + drm_for_each_connector_iter(connector, &iter) |
| + if (connector->encoder == encoder) |
| + break; |
| + drm_connector_list_iter_end(&iter); |
| + } |
| + |
| + if (bridge && bridge->timings) |
| + bus_flags = bridge->timings->input_bus_flags; |
| + else if (connector) |
| + bus_flags = connector->display_info.bus_flags; |
| + |
| if (!pm_runtime_active(ddev->dev)) { |
| ret = pm_runtime_get_sync(ddev->dev); |
| if (ret) { |
| @@ -567,10 +596,10 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc) |
| if (vm.flags & DISPLAY_FLAGS_VSYNC_HIGH) |
| val |= GCR_VSPOL; |
| |
| - if (vm.flags & DISPLAY_FLAGS_DE_LOW) |
| + if (bus_flags & DRM_BUS_FLAG_DE_LOW) |
| val |= GCR_DEPOL; |
| |
| - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE) |
| + if (bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) |
| val |= GCR_PCPOL; |
| |
| reg_update_bits(ldev->regs, LTDC_GCR, |
| -- |
| 2.30.2 |
| |