We can use horizontal and vertical flipping via the MIPI DCS address
mode to rotate the display by 180° using the device tree "rotation"
property. Since the tl050hdv35 panel has been defined as rotated,
we have to invert the bits there.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/gpu/drm/panel/panel-ilitek-ili9881c.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
index 084c37fa7348..b4565ff1a0de 100644
--- a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
+++ b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
@@ -42,6 +42,7 @@ struct ili9881c_desc {
 	const size_t init_length;
 	const struct drm_display_mode *mode;
 	const unsigned long mode_flags;
+	u8 default_address_mode;
 };
 
 struct ili9881c {
@@ -53,6 +54,7 @@ struct ili9881c {
 	struct gpio_desc	*reset;
 
 	enum drm_panel_orientation	orientation;
+	u8 address_mode;
 };
 
 #define ILI9881C_SWITCH_PAGE_INSTR(_page)	\
@@ -815,8 +817,6 @@ static const struct ili9881c_instr tl050hdv35_init[] = {
 	ILI9881C_COMMAND_INSTR(0xd1, 0x4b),
 	ILI9881C_COMMAND_INSTR(0xd2, 0x60),
 	ILI9881C_COMMAND_INSTR(0xd3, 0x39),
-	ILI9881C_SWITCH_PAGE_INSTR(0),
-	ILI9881C_COMMAND_INSTR(0x36, 0x03),
 };
 
 static const struct ili9881c_instr w552946ab_init[] = {
@@ -1299,6 +1299,14 @@ static int ili9881c_prepare(struct drm_panel *panel)
 	if (ret)
 		return ret;
 
+	if (ctx->address_mode) {
+		ret = mipi_dsi_dcs_write(ctx->dsi, MIPI_DCS_SET_ADDRESS_MODE,
+					 &ctx->address_mode,
+					 sizeof(ctx->address_mode));
+		if (ret < 0)
+			return ret;
+	}
+
 	ret = mipi_dsi_dcs_set_tear_on(ctx->dsi, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
 	if (ret)
 		return ret;
@@ -1521,6 +1529,12 @@ static int ili9881c_dsi_probe(struct mipi_dsi_device *dsi)
 		return ret;
 	}
 
+	ctx->address_mode = ctx->desc->default_address_mode;
+	if (ctx->orientation == DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP) {
+		ctx->address_mode ^= 0x03;
+		ctx->orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
+	}
+
 	ctx->panel.prepare_prev_first = true;
 
 	ret = drm_panel_of_backlight(&ctx->panel);
@@ -1572,6 +1586,7 @@ static const struct ili9881c_desc tl050hdv35_desc = {
 	.mode = &tl050hdv35_default_mode,
 	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
 		      MIPI_DSI_MODE_LPM,
+	.default_address_mode = 0x03,
 };
 
 static const struct ili9881c_desc w552946aba_desc = {

-- 
2.39.2

On Mi, 2024-06-26 at 16:40 +0200, Philipp Zabel wrote:
> We can use horizontal and vertical flipping via the MIPI DCS address
> mode to rotate the display by 180° using the device tree "rotation"
> property. Since the tl050hdv35 panel has been defined as rotated,
> we have to invert the bits there.
> 
> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Gentle ping, this still cleanly applies on drm-misc-next.

> ---
>  drivers/gpu/drm/panel/panel-ilitek-ili9881c.c | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
> index 084c37fa7348..b4565ff1a0de 100644
> --- a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
> @@ -42,6 +42,7 @@ struct ili9881c_desc {
>  	const size_t init_length;
>  	const struct drm_display_mode *mode;
>  	const unsigned long mode_flags;
> +	u8 default_address_mode;
>  };
>  
>  struct ili9881c {
> @@ -53,6 +54,7 @@ struct ili9881c {
>  	struct gpio_desc	*reset;
>  
>  	enum drm_panel_orientation	orientation;
> +	u8 address_mode;
>  };
>  
>  #define ILI9881C_SWITCH_PAGE_INSTR(_page)	\
> @@ -815,8 +817,6 @@ static const struct ili9881c_instr tl050hdv35_init[] = {
>  	ILI9881C_COMMAND_INSTR(0xd1, 0x4b),
>  	ILI9881C_COMMAND_INSTR(0xd2, 0x60),
>  	ILI9881C_COMMAND_INSTR(0xd3, 0x39),
> -	ILI9881C_SWITCH_PAGE_INSTR(0),
> -	ILI9881C_COMMAND_INSTR(0x36, 0x03),
>  };
>  
>  static const struct ili9881c_instr w552946ab_init[] = {
> @@ -1299,6 +1299,14 @@ static int ili9881c_prepare(struct drm_panel *panel)
>  	if (ret)
>  		return ret;
>  
> +	if (ctx->address_mode) {
> +		ret = mipi_dsi_dcs_write(ctx->dsi, MIPI_DCS_SET_ADDRESS_MODE,
> +					 &ctx->address_mode,
> +					 sizeof(ctx->address_mode));
> +		if (ret < 0)
> +			return ret;
> +	}
> +
>  	ret = mipi_dsi_dcs_set_tear_on(ctx->dsi, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
>  	if (ret)
>  		return ret;
> @@ -1521,6 +1529,12 @@ static int ili9881c_dsi_probe(struct mipi_dsi_device *dsi)
>  		return ret;
>  	}
>  
> +	ctx->address_mode = ctx->desc->default_address_mode;
> +	if (ctx->orientation == DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP) {
> +		ctx->address_mode ^= 0x03;
> +		ctx->orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
> +	}
> +

Is there anything wrong with the panel driver eating the bottom-up
panel orientation property by flipping scanout in the panel?

regards
Philipp

>  	ctx->panel.prepare_prev_first = true;
>  
>  	ret = drm_panel_of_backlight(&ctx->panel);
> @@ -1572,6 +1586,7 @@ static const struct ili9881c_desc tl050hdv35_desc = {
>  	.mode = &tl050hdv35_default_mode,
>  	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
>  		      MIPI_DSI_MODE_LPM,
> +	.default_address_mode = 0x03,
>  };
>  
>  static const struct ili9881c_desc w552946aba_desc = {
>