Ask ESP-IDF for public DSI video-mode and clock-lane options (draft to post) #49

mipidsi.Display(non_burst=True, continuous_clock=True) (#48) reaches ESP-IDF's private esp_lcd_dsi_bus_t to set two things the public API doesn't offer, and is checked against v5.5.4 only. Once ESP-IDF has a public switch, that code can go. Below is a draft feature request for espressif/esp-idf, for a maintainer to post or edit; it isn't posted.

Title: esp_lcd DPI panel: option for non-burst video mode and a continuous clock lane

Is your feature request related to a problem?
esp_lcd_new_panel_dpi() always selects burst video mode (mipi_dsi_host_ll_dpi_set_video_burst_type(..., MIPI_DSI_LL_VIDEO_BURST_WITH_SYNC_PULSES) in esp_lcd_panel_dpi.c), and panel init sets the clock lane to MIPI_DSI_LL_CLOCK_LANE_STATE_AUTO. DSI-to-RGB bridges such as the Chipone ICN6211, used on many Raspberry Pi-style DSI displays, need non-burst video with sync pulses and a continuous HS clock. With burst mode they output nothing and the panel stays white. Linux drives these panels with MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE and no MIPI_DSI_CLOCK_NON_CONTINUOUS.

Describe the solution you'd like
Two fields in esp_lcd_dpi_panel_config_t (or its flags): the video burst type (burst / non-burst with sync pulses / non-burst with sync events), and whether the clock lane stays in HS. Defaults should be today's behaviour.

Describe alternatives you've considered
Setting both through hal/mipi_dsi_host_ll.h after esp_lcd_new_panel_dpi() and esp_lcd_panel_init() works on an ESP32-P4 with ESP-IDF v5.5.4, a Chipone ICN6211-based KeDei 5" panel shows correct images. But it means mirroring the private esp_lcd_dsi_bus_t from mipi_dsi_priv.h to reach the HAL context.

After posting, add the link here. When a release with the options lands, switch mod_mipidsi.c to them and drop the mirrored struct.