[PATCH v2] drm/i915/dsi: Fix swapping of MIPI_SEQ_DEASSERT_RESET / MIPI_SEQ_ASSERT_RESET

[Hans de Goede]

Looking at the ADF code from the Android kernel sources for a
cherrytrail tablet I noticed that it is calling the
MIPI_SEQ_ASSERT_RESET sequence from the panel prepare hook.

Until commit b1cb1bd29189 ("drm/i915/dsi: update reset and power sequences
in panel prepare/unprepare hooks") the mainline i915 code was doing the
same. That commits effectively swaps the calling of MIPI_SEQ_ASSERT_RESET /
MIPI_SEQ_DEASSERT_RESET.

Looking at the naming of the sequences that is the right thing to do,
but the problem is, that the old mainline code and the ADF code was
actually calling the right sequence (tested on a cube iwork8 air tablet),
and the swapping of the calling breaks things.

This breakage was likely not noticed in testing because on cherrytrail,
currently chv_exec_gpio ends up disabling the gpio pins rather then
setting them (this is fixed in the next patch in this patch-set).

This commit fixes the swapping by fixing MIPI_SEQ_ASSERT/DEASSERT_RESET's
places in the enum defining them, so that their (new) names match their
actual use.

Fixes: b1cb1bd29189 ("drm/i915/dsi: update reset and power sequences...")
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
Acked-by: Jani Nikula <jani.nikula at intel.com>
---
Changes in v2:
-Add a comment to the enum explaining that the assert/reassert names
 are swapped in the spec
---
 drivers/gpu/drm/i915/intel_bios.h          | 12 +++++++++---
 drivers/gpu/drm/i915/intel_dsi_panel_vbt.c |  4 ++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index 8405b5a..7e3545f 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -46,14 +46,20 @@ struct edp_power_seq {
 	u16 t11_t12;
 } __packed;
 
-/* MIPI Sequence Block definitions */
+/*
+ * MIPI Sequence Block definitions
+ *
+ * Note the VBT spec has AssertReset / DeassertReset swapped from their
+ * usual naming, we use the proper names here to avoid confusion when
+ * reading the code.
+ */
 enum mipi_seq {
 	MIPI_SEQ_END = 0,
-	MIPI_SEQ_ASSERT_RESET,
+	MIPI_SEQ_DEASSERT_RESET,	/* Spec says MipiAssertResetPin */
 	MIPI_SEQ_INIT_OTP,
 	MIPI_SEQ_DISPLAY_ON,
 	MIPI_SEQ_DISPLAY_OFF,
-	MIPI_SEQ_DEASSERT_RESET,
+	MIPI_SEQ_ASSERT_RESET,		/* Spec says MipiDeassertResetPin */
 	MIPI_SEQ_BACKLIGHT_ON,		/* sequence block v2+ */
 	MIPI_SEQ_BACKLIGHT_OFF,		/* sequence block v2+ */
 	MIPI_SEQ_TEAR_ON,		/* sequence block v2+ */
diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
index 0d8ff00..579d2f5 100644
--- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
@@ -376,11 +376,11 @@ static const fn_mipi_elem_exec exec_elem[] = {
  */
 
 static const char * const seq_name[] = {
-	[MIPI_SEQ_ASSERT_RESET] = "MIPI_SEQ_ASSERT_RESET",
+	[MIPI_SEQ_DEASSERT_RESET] = "MIPI_SEQ_DEASSERT_RESET",
 	[MIPI_SEQ_INIT_OTP] = "MIPI_SEQ_INIT_OTP",
 	[MIPI_SEQ_DISPLAY_ON] = "MIPI_SEQ_DISPLAY_ON",
 	[MIPI_SEQ_DISPLAY_OFF]  = "MIPI_SEQ_DISPLAY_OFF",
-	[MIPI_SEQ_DEASSERT_RESET] = "MIPI_SEQ_DEASSERT_RESET",
+	[MIPI_SEQ_ASSERT_RESET] = "MIPI_SEQ_ASSERT_RESET",
 	[MIPI_SEQ_BACKLIGHT_ON] = "MIPI_SEQ_BACKLIGHT_ON",
 	[MIPI_SEQ_BACKLIGHT_OFF] = "MIPI_SEQ_BACKLIGHT_OFF",
 	[MIPI_SEQ_TEAR_ON] = "MIPI_SEQ_TEAR_ON",
-- 
2.9.3