kernel/linux.git/drivers/gpu/drm/stm/ltdc.h, branch linux-7.0.y

drm/stm: ltdc: handle lvds pixel clock

2025-08-28T15:43:57+00:00

Handle LVDS pixel clock. The LTDC operates with multiple clock domains for register access, requiring all clocks to be provided during read/write operations. This imposes a dependency between the LVDS and LTDC to access correctly all LTDC registers. And because both IPs' pixel rates must be synchronized, the LTDC has to handle the LVDS clock. Signed-off-by: Yannick Fertre Acked-by: Yannick Fertre Acked-by: Philippe Cornu Link: https://lore.kernel.org/r/20250822-drm-misc-next-v5-8-9c825e28f733@foss.st.com Signed-off-by: Raphael Gallais-Pou

drm/stm: ltdc: support new hardware version for STM32MP25 SoC

2025-08-28T15:43:56+00:00

STM32MP25 SoC features a new version of the LTDC IP. Add its compatible to the list of device to probe and implement its quirks. This hardware supports a pad frequency of 150MHz and a peripheral bus clock. Signed-off-by: Yannick Fertre Acked-by: Yannick Fertre Acked-by: Philippe Cornu Link: https://lore.kernel.org/r/20250822-drm-misc-next-v5-7-9c825e28f733@foss.st.com Signed-off-by: Raphael Gallais-Pou

drm/stm: ltdc: update hardware error management

2022-06-27T14:01:50+00:00

The latest hardware version (0x40100) supports a hardware threshold register (aka FUTR) to trigger a fifo underrun interrupt. A software threshold has been implemented for other hardware versions. The threshold is set to 128 by default. Signed-off-by: Yannick Fertre Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20220603134654.594373-1-yannick.fertre@foss.st.com

drm/stm: ltdc: add support of horizontal & vertical mirroring

2022-06-27T14:01:40+00:00

Support of vertical & horizontal mirroring features thanks to the plane rotation property. Signed-off-by: Yannick Fertre Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20220603134547.593790-1-yannick.fertre@foss.st.com

drm/stm: ltdc: add support of the dynamic z-order

2022-06-27T14:01:17+00:00

Zpos property is immutable for all hardware versions except the last version (0x40100) which support the blending order feature (dynamic z-order). Signed-off-by: Yannick Fertre Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20220603134459.593379-1-yannick.fertre@foss.st.com

drm/stm: ltdc: add support for CRC hashing feature

2022-02-25T13:14:28+00:00

This patch adds the CRC hashing feature supported by some recent hardware versions of the LTDC. This is useful for test suite such as IGT-GPU-tools [1] where a CRTC output frame can be compared to a test reference frame thanks to their respective CRC hash. [1] https://cgit.freedesktop.org/drm/igt-gpu-tools Signed-off-by: Raphael Gallais-Pou Acked-by: Yannick Fertre Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20220211104620.421177-1-raphael.gallais-pou@foss.st.com

drm/stm: ltdc: add support of ycbcr pixel formats

2022-01-13T13:06:22+00:00

This patch adds the following YCbCr input pixel formats on the latest LTDC hardware version: 1 plane (co-planar) : YUYV, YVYU, UYVY, VYUY 2 planes (semi-planar): NV12, NV21 3 planes (full-planar): YU12=I420=DRM YUV420, YV12=DRM YVU420 Signed-off-by: Yannick Fertre Acked-by: Philippe Cornu Reviewed-by: Philippe Cornu Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20211215214843.20703-1-yannick.fertre@foss.st.com

drm/stm: ltdc: add support of flexible pixel formats

2022-01-13T13:06:22+00:00

This feature allows the generation of any RGB pixel format. The list of supported formats is no longer linked to the register LXPFCR_PF, that the reason why a list of drm formats is defined for each display controller version. Signed-off-by: Yannick Fertre Acked-by: Philippe Cornu Reviewed-by: Philippe Cornu Reviewed-by: Raphael Gallais-Pou Tested-by: Raphael Gallais-Pou Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20211215214835.20593-1-yannick.fertre@foss.st.com

drm/stm: ltdc: add per plane update support

2022-01-13T13:06:21+00:00

Recent ltdc hardware versions offer the ability to update a plane independently of others planes. This is could be useful especially if a plane is assigned to another OS. Signed-off-by: Yannick Fertre Acked-by: Philippe Cornu Reviewed-by: Philippe Cornu Reviewed-by: Raphael Gallais-Pou Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20211215214817.20310-1-yannick.fertre@foss.st.com

drm/stm: ltdc: add YCbCr 422 output support

2022-01-13T13:06:20+00:00

LTDC 40100 hw version supports the YCbCr 422 output, reducing the output pins from 24 to 16. This feature is useful for some external devices like HDMI bridges. Both ITU-R BT.601 & ITU-R BT.709 are supported. It is also possible to choose the chrominance order between * Cb is output first (Y0Cb, then Y1Cr, Y2Cb and so on). * Cr is output first (Y0Cr, then Y1Cb, Y2Cr and so on). Signed-off-by: Yannick Fertre Acked-by: Philippe Cornu Reviewed-by: Philippe Cornu Reviewed-by: Raphael Gallais-Pou Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20211215214750.20105-1-yannick.fertre@foss.st.com