[PATCH resend 05/15] drm/i915/dsi: Document the panel enable / disable sequences from the spec

[Hans de Goede <hdegoede@redhat.com>]

Document the DSI panel enable / disable sequences from the spec,
for easy comparison between the code and the spec.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_dsi.c | 68 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 072f99b..8808f87 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -552,6 +552,74 @@ static void intel_dsi_prepare(struct intel_encoder *intel_encoder,
 			      struct intel_crtc_state *pipe_config);
 static void intel_dsi_unprepare(struct intel_encoder *encoder);
 
+/*
+ * Panel enable/disable sequences from the VBT spec.
+ *
+ * Note the spec has AssertReset / DeassertReset swapped from their
+ * usual naming. We use the normal names to avoid confusion (so below
+ * they are swapped compared to the spec).
+ *
+ * v2 sequence for video mode:
+ * - power on
+ * - wait t1+t2
+ * - MIPIDeassertResetPin
+ * - clk/data lines to lp-11
+ * - MIPISendInitialDcsCmds
+ * - turn on DPI
+ * - MIPIDisplayOn
+ * - wait t5
+ * - backlight on
+ * ...
+ * - backlight off
+ * - wait t6
+ * - MIPIDisplayOff
+ * - turn off DPI
+ * - clk/data lines to lp-00
+ * - MIPIAssertResetPin
+ * - wait t3
+ * - power off
+ * - wait t4
+ *
+ * v3 sequence for video mode:
+ * - MIPIPanelPowerOn
+ * - MIPIDeassertResetPin
+ * - set clk/data lines to lp-11
+ * - MIPISendInitialDcsCmds (LP)
+ * - turn on DPI
+ * - MIPITearOn (command mode only) + MIPIDisplayOn (LP and HS)
+ * - MIPIBacklightOn
+ * ...
+ * - MIPIBacklightOff
+ * - turn off DPI
+ * - MIPITearOff + MIPIDisplayOff (LP)
+ * - clk/data lines to lp-00
+ * - MIPIAssertResetPin
+ * - MIPIPanelPowerOff
+ *
+ * sequence for command mode:
+ * - power on
+ * - wait t1+t2
+ * - MIPIDeassertResetPin
+ * - clk/data lines to lp-11
+ * - MIPISendInitialDcsCmds
+ * - MIPITearOn
+ * - MIPIDisplayOn
+ * - set pipe to dsr mode
+ * - wait t5
+ * - backlight on
+ * ... issue write_mem_start/write_mem_continue commands ...
+ * - backlight off
+ * - wait t6
+ * - disable pipe dsr mode
+ * - MIPITearOff
+ * - MIPIDisplayOff
+ * - clk/data lines to lp-00
+ * - MIPIAssertResetPin
+ * - wait t3
+ * - power off
+ * - wait t4
+ */
+
 static void intel_dsi_pre_enable(struct intel_encoder *encoder,
 				 struct intel_crtc_state *pipe_config,
 				 struct drm_connector_state *conn_state)
-- 
2.9.3

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