drm: atmel-hlcdc: add DPI mode support for XLCDC

Add support for Display Pixel Interface (DPI) Compatible Mode
support in atmel-hlcdc driver for XLCDC IP along with legacy
pixel mapping. DPI mode BIT is configured in LCDC_CFG5 register.

Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
[durai.manickamkr@microchip.com: update DPI mode bit using is_xlcdc flag]
Signed-off-by: Durai Manickam KR <durai.manickamkr@microchip.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240424053351.589830-6-manikandan.m@microchip.com

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c

@@ -30,10 +30,12 @@
  *
  * @base: base CRTC state
  * @output_mode: RGBXXX output mode
+ * @dpi: output DPI mode
  */
 struct atmel_hlcdc_crtc_state {
 	struct drm_crtc_state base;
 	unsigned int output_mode;
+	u8 dpi;
 };
 
 static inline struct atmel_hlcdc_crtc_state *
@@ -170,14 +172,18 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
 
 		if (adj->flags & DRM_MODE_FLAG_NHSYNC)
 			cfg |= ATMEL_HLCDC_HSPOL;
+	} else {
+		cfg |= state->dpi << 11;
 	}
 
 	regmap_update_bits(regmap, ATMEL_HLCDC_CFG(5),
 			   ATMEL_HLCDC_HSPOL | ATMEL_HLCDC_VSPOL |
 			   ATMEL_HLCDC_VSPDLYS | ATMEL_HLCDC_VSPDLYE |
 			   ATMEL_HLCDC_DISPPOL | ATMEL_HLCDC_DISPDLY |
 			   ATMEL_HLCDC_VSPSU | ATMEL_HLCDC_VSPHO |
-			   ATMEL_HLCDC_GUARDTIME_MASK | ATMEL_HLCDC_MODE_MASK,
+			   ATMEL_HLCDC_GUARDTIME_MASK |
+			   (crtc->dc->desc->is_xlcdc ? ATMEL_XLCDC_MODE_MASK |
+			   ATMEL_XLCDC_DPI : ATMEL_HLCDC_MODE_MASK),
 			   cfg);
 
 	clk_disable_unprepare(crtc->dc->hlcdc->sys_clk);
@@ -380,7 +386,15 @@ static int atmel_hlcdc_crtc_select_output_mode(struct drm_crtc_state *state)
 
 	hstate = drm_crtc_state_to_atmel_hlcdc_crtc_state(state);
 	hstate->output_mode = fls(output_fmts) - 1;
-
+	if (crtc->dc->desc->is_xlcdc) {
+		/* check if MIPI DPI bit needs to be set */
+		if (fls(output_fmts) > 3) {
+			hstate->output_mode -= 4;
+			hstate->dpi = 1;
+		} else {
+			hstate->dpi = 0;
+		}
+	}
 	return 0;
 }
 
@@ -484,6 +498,7 @@ static struct drm_crtc_state *
 atmel_hlcdc_crtc_duplicate_state(struct drm_crtc *crtc)
 {
 	struct atmel_hlcdc_crtc_state *state, *cur;
+	struct atmel_hlcdc_crtc *c = drm_crtc_to_atmel_hlcdc_crtc(crtc);
 
 	if (WARN_ON(!crtc->state))
 		return NULL;
@@ -495,6 +510,8 @@ atmel_hlcdc_crtc_duplicate_state(struct drm_crtc *crtc)
 
 	cur = drm_crtc_state_to_atmel_hlcdc_crtc_state(crtc->state);
 	state->output_mode = cur->output_mode;
+	if (c->dc->desc->is_xlcdc)
+		state->dpi = cur->dpi;
 
 	return &state->base;
 }