drm/mcde: Support DPI output

This implements support for DPI output using the port node
in the device tree to connect a DPI LCD display to the
MCDE. The block also supports TV-out but we leave that
for another day when we have a hardware using it.

We implement parsing and handling of the "port" node,
and follow that to the DPI endpoint.

The clock divider used by the MCDE to divide down the
"lcdclk" (this has been designed for TV-like frequencies)
is represented by an ordinary clock provider internally
in the MCDE. This idea was inspired by the PL111 solution
by Eric Anholt: the divider also works very similar to
the Pl111 clock divider.

We take care to clear up some errors regarding the number
of available formatters and their type. We have 6 DSI
formatters and 2 DPI formatters.

Tested on the Samsung GT-I9070 Janice mobile phone.

Signed-off-by: Linus Walleij <[e-mail]>
Acked-by: Sam Ravnborg <[e-mail]>
Cc: Stephan Gerhold <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/mcde/Kconfig

···
 	depends on CMA
 	depends on ARM || COMPILE_TEST
 	depends on OF
+	depends on COMMON_CLK
 	select MFD_SYSCON
 	select DRM_MIPI_DSI
 	select DRM_BRIDGE

drivers/gpu/drm/mcde/Makefile

···
-mcde_drm-y +=	mcde_drv.o mcde_dsi.o mcde_display.o
+mcde_drm-y +=	mcde_drv.o mcde_dsi.o mcde_clk_div.o mcde_display.o
 
 obj-$(CONFIG_DRM_MCDE) += mcde_drm.o

drivers/gpu/drm/mcde/mcde_clk_div.c

···
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/clk-provider.h>
+#include <linux/regulator/consumer.h>
+
+#include "mcde_drm.h"
+#include "mcde_display_regs.h"
+
+/* The MCDE internal clock dividers for FIFO A and B */
+struct mcde_clk_div {
+	struct clk_hw hw;
+	struct mcde *mcde;
+	u32 cr;
+	u32 cr_div;
+};
+
+static int mcde_clk_div_enable(struct clk_hw *hw)
+{
+	struct mcde_clk_div *cdiv = container_of(hw, struct mcde_clk_div, hw);
+	struct mcde *mcde = cdiv->mcde;
+	u32 val;
+
+	spin_lock(&mcde->fifo_crx1_lock);
+	val = readl(mcde->regs + cdiv->cr);
+	/*
+	 * Select the PLL72 (LCD) clock as parent
+	 * FIXME: implement other parents.
+	 */
+	val &= ~MCDE_CRX1_CLKSEL_MASK;
+	val |= MCDE_CRX1_CLKSEL_CLKPLL72 << MCDE_CRX1_CLKSEL_SHIFT;
+	/* Internal clock */
+	val |= MCDE_CRA1_CLKTYPE_TVXCLKSEL1;
+
+	/* Clear then set the divider */
+	val &= ~(MCDE_CRX1_BCD | MCDE_CRX1_PCD_MASK);
+	val |= cdiv->cr_div;
+
+	writel(val, mcde->regs + cdiv->cr);
+	spin_unlock(&mcde->fifo_crx1_lock);
+
+	return 0;
+}
+
+static int mcde_clk_div_choose_div(struct clk_hw *hw, unsigned long rate,
+				   unsigned long *prate, bool set_parent)
+{
+	int best_div = 1, div;
+	struct clk_hw *parent = clk_hw_get_parent(hw);
+	unsigned long best_prate = 0;
+	unsigned long best_diff = ~0ul;
+	int max_div = (1 << MCDE_CRX1_PCD_BITS) - 1;
+
+	for (div = 1; div < max_div; div++) {
+		unsigned long this_prate, div_rate, diff;
+
+		if (set_parent)
+			this_prate = clk_hw_round_rate(parent, rate * div);
+		else
+			this_prate = *prate;
+		div_rate = DIV_ROUND_UP_ULL(this_prate, div);
+		diff = abs(rate - div_rate);
+
+		if (diff < best_diff) {
+			best_div = div;
+			best_diff = diff;
+			best_prate = this_prate;
+		}
+	}
+
+	*prate = best_prate;
+	return best_div;
+}
+
+static long mcde_clk_div_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *prate)
+{
+	int div = mcde_clk_div_choose_div(hw, rate, prate, true);
+
+	return DIV_ROUND_UP_ULL(*prate, div);
+}
+
+static unsigned long mcde_clk_div_recalc_rate(struct clk_hw *hw,
+					       unsigned long prate)
+{
+	struct mcde_clk_div *cdiv = container_of(hw, struct mcde_clk_div, hw);
+	struct mcde *mcde = cdiv->mcde;
+	u32 cr;
+	int div;
+
+	/*
+	 * If the MCDE is not powered we can't access registers.
+	 * It will come up with 0 in the divider register bits, which
+	 * means "divide by 2".
+	 */
+	if (!regulator_is_enabled(mcde->epod))
+		return DIV_ROUND_UP_ULL(prate, 2);
+
+	cr = readl(mcde->regs + cdiv->cr);
+	if (cr & MCDE_CRX1_BCD)
+		return prate;
+
+	/* 0 in the PCD means "divide by 2", 1 means "divide by 3" etc */
+	div = cr & MCDE_CRX1_PCD_MASK;
+	div += 2;
+
+	return DIV_ROUND_UP_ULL(prate, div);
+}
+
+static int mcde_clk_div_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long prate)
+{
+	struct mcde_clk_div *cdiv = container_of(hw, struct mcde_clk_div, hw);
+	int div = mcde_clk_div_choose_div(hw, rate, &prate, false);
+	u32 cr = 0;
+
+	/*
+	 * We cache the CR bits to set the divide in the state so that
+	 * we can call this before we can even write to the hardware.
+	 */
+	if (div == 1) {
+		/* Bypass clock divider */
+		cr |= MCDE_CRX1_BCD;
+	} else {
+		div -= 2;
+		cr |= div & MCDE_CRX1_PCD_MASK;
+	}
+	cdiv->cr_div = cr;
+
+	return 0;
+}
+
+static const struct clk_ops mcde_clk_div_ops = {
+	.enable = mcde_clk_div_enable,
+	.recalc_rate = mcde_clk_div_recalc_rate,
+	.round_rate = mcde_clk_div_round_rate,
+	.set_rate = mcde_clk_div_set_rate,
+};
+
+int mcde_init_clock_divider(struct mcde *mcde)
+{
+	struct device *dev = mcde->dev;
+	struct mcde_clk_div *fifoa;
+	struct mcde_clk_div *fifob;
+	const char *parent_name;
+	struct clk_init_data fifoa_init = {
+		.name = "fifoa",
+		.ops = &mcde_clk_div_ops,
+		.parent_names = &parent_name,
+		.num_parents = 1,
+		.flags = CLK_SET_RATE_PARENT,
+	};
+	struct clk_init_data fifob_init = {
+		.name = "fifob",
+		.ops = &mcde_clk_div_ops,
+		.parent_names = &parent_name,
+		.num_parents = 1,
+		.flags = CLK_SET_RATE_PARENT,
+	};
+	int ret;
+
+	spin_lock_init(&mcde->fifo_crx1_lock);
+	parent_name = __clk_get_name(mcde->lcd_clk);
+
+	/* Allocate 2 clocks */
+	fifoa = devm_kzalloc(dev, sizeof(*fifoa), GFP_KERNEL);
+	if (!fifoa)
+		return -ENOMEM;
+	fifob = devm_kzalloc(dev, sizeof(*fifob), GFP_KERNEL);
+	if (!fifob)
+		return -ENOMEM;
+
+	fifoa->mcde = mcde;
+	fifoa->cr = MCDE_CRA1;
+	fifoa->hw.init = &fifoa_init;
+	ret = devm_clk_hw_register(dev, &fifoa->hw);
+	if (ret) {
+		dev_err(dev, "error registering FIFO A clock divider\n");
+		return ret;
+	}
+	mcde->fifoa_clk = fifoa->hw.clk;
+
+	fifob->mcde = mcde;
+	fifob->cr = MCDE_CRB1;
+	fifob->hw.init = &fifob_init;
+	ret = devm_clk_hw_register(dev, &fifob->hw);
+	if (ret) {
+		dev_err(dev, "error registering FIFO B clock divider\n");
+		return ret;
+	}
+	mcde->fifob_clk = fifob->hw.clk;
+
+	return 0;
+}

drivers/gpu/drm/mcde/mcde_display.c

···
 #include <linux/delay.h>
 #include <linux/dma-buf.h>
 #include <linux/regulator/consumer.h>
+#include <linux/media-bus-format.h>
 
 #include <drm/drm_device.h>
 #include <drm/drm_fb_cma_helper.h>
···
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_simple_kms_helper.h>
+#include <drm/drm_bridge.h>
 #include <drm/drm_vblank.h>
 #include <video/mipi_display.h>
 
···
 	MCDE_OVERLAY_5,
 };
 
-enum mcde_dsi_formatter {
+enum mcde_formatter {
 	MCDE_DSI_FORMATTER_0 = 0,
 	MCDE_DSI_FORMATTER_1,
 	MCDE_DSI_FORMATTER_2,
+	MCDE_DSI_FORMATTER_3,
+	MCDE_DSI_FORMATTER_4,
+	MCDE_DSI_FORMATTER_5,
+	MCDE_DPI_FORMATTER_0,
+	MCDE_DPI_FORMATTER_1,
 };
 
 void mcde_display_irq(struct mcde *mcde)
···
 	 *
 	 * TODO: Currently only one DSI link is supported.
 	 */
-	if (mcde_dsi_irq(mcde->mdsi)) {
+	if (!mcde->dpi_output && mcde_dsi_irq(mcde->mdsi)) {
 		u32 val;
 
 		/*
···
 			<< MCDE_CHNLXSYNCHMOD_OUT_SYNCH_SRC_SHIFT;
 		break;
 	case MCDE_VIDEO_FORMATTER_FLOW:
+	case MCDE_DPI_FORMATTER_FLOW:
 		val = MCDE_CHNLXSYNCHMOD_SRC_SYNCH_HARDWARE
 			<< MCDE_CHNLXSYNCHMOD_SRC_SYNCH_SHIFT;
 		val |= MCDE_CHNLXSYNCHMOD_OUT_SYNCH_SRC_FORMATTER
···
 		       mcde->regs + mux);
 		break;
 	}
+
+	/*
+	 * If using DPI configure the sync event.
+	 * TODO: this is for LCD only, it does not cover TV out.
+	 */
+	if (mcde->dpi_output) {
+		u32 stripwidth;
+
+		stripwidth = 0xF000 / (mode->vdisplay * 4);
+		dev_info(mcde->dev, "stripwidth: %d\n", stripwidth);
+
+		val = MCDE_SYNCHCONF_HWREQVEVENT_ACTIVE_VIDEO |
+			(mode->hdisplay - 1 - stripwidth) << MCDE_SYNCHCONF_HWREQVCNT_SHIFT |
+			MCDE_SYNCHCONF_SWINTVEVENT_ACTIVE_VIDEO |
+			(mode->hdisplay - 1 - stripwidth) << MCDE_SYNCHCONF_SWINTVCNT_SHIFT;
+
+		switch (fifo) {
+		case MCDE_FIFO_A:
+			writel(val, mcde->regs + MCDE_SYNCHCONFA);
+			break;
+		case MCDE_FIFO_B:
+			writel(val, mcde->regs + MCDE_SYNCHCONFB);
+			break;
+		}
+	}
 }
 
 static void mcde_configure_fifo(struct mcde *mcde, enum mcde_fifo fifo,
-				enum mcde_dsi_formatter fmt,
+				enum mcde_formatter fmt,
 				int fifo_wtrmrk)
 {
 	u32 val;
···
 	}
 
 	val = fifo_wtrmrk << MCDE_CTRLX_FIFOWTRMRK_SHIFT;
-	/* We only support DSI formatting for now */
-	val |= MCDE_CTRLX_FORMTYPE_DSI <<
-		MCDE_CTRLX_FORMTYPE_SHIFT;
 
-	/* Select the formatter to use for this FIFO */
-	val |= fmt << MCDE_CTRLX_FORMID_SHIFT;
+	/*
+	 * Select the formatter to use for this FIFO
+	 *
+	 * The register definitions imply that different IDs should be used
+	 * by the DSI formatters depending on if they are in VID or CMD
+	 * mode, and the manual says they are dedicated but identical.
+	 * The vendor code uses them as it seems fit.
+	 */
+	switch (fmt) {
+	case MCDE_DSI_FORMATTER_0:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI0VID << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_1:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI0CMD << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_2:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI1VID << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_3:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI1CMD << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_4:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI2VID << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DSI_FORMATTER_5:
+		val |= MCDE_CTRLX_FORMTYPE_DSI << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DSI2CMD << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DPI_FORMATTER_0:
+		val |= MCDE_CTRLX_FORMTYPE_DPITV << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DPIA << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	case MCDE_DPI_FORMATTER_1:
+		val |= MCDE_CTRLX_FORMTYPE_DPITV << MCDE_CTRLX_FORMTYPE_SHIFT;
+		val |= MCDE_CTRLX_FORMID_DPIB << MCDE_CTRLX_FORMID_SHIFT;
+		break;
+	}
 	writel(val, mcde->regs + ctrl);
 
 	/* Blend source with Alpha 0xff on FIFO */
···
 		0xff << MCDE_CRX0_ALPHABLEND_SHIFT;
 	writel(val, mcde->regs + cr0);
 
-	/* Set-up from mcde_fmtr_dsi.c, fmtr_dsi_enable_video() */
+	spin_lock(&mcde->fifo_crx1_lock);
+	val = readl(mcde->regs + cr1);
+	/*
+	 * Set-up from mcde_fmtr_dsi.c, fmtr_dsi_enable_video()
+	 * FIXME: a different clock needs to be selected for TV out.
+	 */
+	if (mcde->dpi_output) {
+		struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);
+		u32 bus_format;
 
-	/* Use the MCDE clock for this FIFO */
-	val = MCDE_CRX1_CLKSEL_MCDECLK << MCDE_CRX1_CLKSEL_SHIFT;
+		/* Assume RGB888 24 bit if we have no further info */
+		if (!connector->display_info.num_bus_formats) {
+			dev_info(mcde->dev, "panel does not specify bus format, assume RGB888\n");
+			bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+		} else {
+			bus_format = connector->display_info.bus_formats[0];
+		}
 
-	/* TODO: when adding DPI support add OUTBPP etc here */
+		/*
+		 * Set up the CDWIN and OUTBPP for the LCD
+		 *
+		 * FIXME: fill this in if you know the correspondance between the MIPI
+		 * DPI specification and the media bus formats.
+		 */
+		val &= ~MCDE_CRX1_CDWIN_MASK;
+		val &= ~MCDE_CRX1_OUTBPP_MASK;
+		switch (bus_format) {
+		case MEDIA_BUS_FMT_RGB888_1X24:
+			val |= MCDE_CRX1_CDWIN_24BPP << MCDE_CRX1_CDWIN_SHIFT;
+			val |= MCDE_CRX1_OUTBPP_24BPP << MCDE_CRX1_OUTBPP_SHIFT;
+			break;
+		default:
+			dev_err(mcde->dev, "unknown bus format, assume RGB888\n");
+			val |= MCDE_CRX1_CDWIN_24BPP << MCDE_CRX1_CDWIN_SHIFT;
+			val |= MCDE_CRX1_OUTBPP_24BPP << MCDE_CRX1_OUTBPP_SHIFT;
+			break;
+		}
+	} else {
+		/* Use the MCDE clock for DSI */
+		val &= ~MCDE_CRX1_CLKSEL_MASK;
+		val = MCDE_CRX1_CLKSEL_MCDECLK << MCDE_CRX1_CLKSEL_SHIFT;
+	}
 	writel(val, mcde->regs + cr1);
+	spin_unlock(&mcde->fifo_crx1_lock);
 };
 
 static void mcde_configure_dsi_formatter(struct mcde *mcde,
-					 enum mcde_dsi_formatter fmt,
+					 enum mcde_formatter fmt,
 					 u32 formatter_frame,
 					 int pkt_size)
 {
···
 		delay0 = MCDE_DSIVID2DELAY0;
 		delay1 = MCDE_DSIVID2DELAY1;
 		break;
+	default:
+		dev_err(mcde->dev, "tried to configure a non-DSI formatter as DSI\n");
+		return;
 	}
 
 	/*
···
 	return 1;
 }
 
+static void mcde_setup_dpi(struct mcde *mcde, const struct drm_display_mode *mode,
+			   int *fifo_wtrmrk_lvl)
+{
+	struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);
+	u32 hsw, hfp, hbp;
+	u32 vsw, vfp, vbp;
+	u32 val;
+
+	/* FIXME: we only support LCD, implement TV out */
+	hsw = mode->hsync_end - mode->hsync_start;
+	hfp = mode->hsync_start - mode->hdisplay;
+	hbp = mode->htotal - mode->hsync_end;
+	vsw = mode->vsync_end - mode->vsync_start;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vbp = mode->vtotal - mode->vsync_end;
+
+	dev_info(mcde->dev, "output on DPI LCD from channel A\n");
+	/* Display actual values */
+	dev_info(mcde->dev, "HSW: %d, HFP: %d, HBP: %d, VSW: %d, VFP: %d, VBP: %d\n",
+		 hsw, hfp, hbp, vsw, vfp, vbp);
+
+	/*
+	 * The pixel fetcher is 128 64-bit words deep = 1024 bytes.
+	 * One overlay of 32bpp (4 cpp) assumed, fetch 160 pixels.
+	 * 160 * 4 = 640 bytes.
+	 */
+	*fifo_wtrmrk_lvl = 640;
+
+	/* Set up the main control, watermark level at 7 */
+	val = 7 << MCDE_CONF0_IFIFOCTRLWTRMRKLVL_SHIFT;
+
+	/*
+	 * This sets up the internal silicon muxing of the DPI
+	 * lines. This is how the silicon connects out to the
+	 * external pins, then the pins need to be further
+	 * configured into "alternate functions" using pin control
+	 * to actually get the signals out.
+	 *
+	 * FIXME: this is hardcoded to the only setting found in
+	 * the wild. If we need to use different settings for
+	 * different DPI displays, make this parameterizable from
+	 * the device tree.
+	 */
+	/* 24 bits DPI: connect Ch A LSB to D[0:7] */
+	val |= 0 << MCDE_CONF0_OUTMUX0_SHIFT;
+	/* 24 bits DPI: connect Ch A MID to D[8:15] */
+	val |= 1 << MCDE_CONF0_OUTMUX1_SHIFT;
+	/* Don't care about this muxing */
+	val |= 0 << MCDE_CONF0_OUTMUX2_SHIFT;
+	/* Don't care about this muxing */
+	val |= 0 << MCDE_CONF0_OUTMUX3_SHIFT;
+	/* 24 bits DPI: connect Ch A MSB to D[32:39] */
+	val |= 2 << MCDE_CONF0_OUTMUX4_SHIFT;
+	/* Syncmux bits zero: DPI channel A */
+	writel(val, mcde->regs + MCDE_CONF0);
+
+	/* This hammers us into LCD mode */
+	writel(0, mcde->regs + MCDE_TVCRA);
+
+	/* Front porch and sync width */
+	val = (vsw << MCDE_TVBL1_BEL1_SHIFT);
+	val |= (vfp << MCDE_TVBL1_BSL1_SHIFT);
+	writel(val, mcde->regs + MCDE_TVBL1A);
+	/* The vendor driver sets the same value into TVBL2A */
+	writel(val, mcde->regs + MCDE_TVBL2A);
+
+	/* Vertical back porch */
+	val = (vbp << MCDE_TVDVO_DVO1_SHIFT);
+	/* The vendor drivers sets the same value into TVDVOA */
+	val |= (vbp << MCDE_TVDVO_DVO2_SHIFT);
+	writel(val, mcde->regs + MCDE_TVDVOA);
+
+	/* Horizontal back porch, as 0 = 1 cycle we need to subtract 1 */
+	writel((hbp - 1), mcde->regs + MCDE_TVTIM1A);
+
+	/* Horizongal sync width and horizonal front porch, 0 = 1 cycle */
+	val = ((hsw - 1) << MCDE_TVLBALW_LBW_SHIFT);
+	val |= ((hfp - 1) << MCDE_TVLBALW_ALW_SHIFT);
+	writel(val, mcde->regs + MCDE_TVLBALWA);
+
+	/* Blank some TV registers we don't use */
+	writel(0, mcde->regs + MCDE_TVISLA);
+	writel(0, mcde->regs + MCDE_TVBLUA);
+
+	/* Set up sync inversion etc */
+	val = 0;
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		val |= MCDE_LCDTIM1B_IHS;
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		val |= MCDE_LCDTIM1B_IVS;
+	if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
+		val |= MCDE_LCDTIM1B_IOE;
+	if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
+		val |= MCDE_LCDTIM1B_IPC;
+	writel(val, mcde->regs + MCDE_LCDTIM1A);
+}
+
 static void mcde_setup_dsi(struct mcde *mcde, const struct drm_display_mode *mode,
 			   int cpp, int *fifo_wtrmrk_lvl, int *dsi_formatter_frame,
 			   int *dsi_pkt_size)
···
 	writel(0, mcde->regs + MCDE_IMSCERR);
 	writel(0xFFFFFFFF, mcde->regs + MCDE_RISERR);
 
-	mcde_setup_dsi(mcde, mode, cpp, &fifo_wtrmrk,
-		       &dsi_formatter_frame, &dsi_pkt_size);
+	if (mcde->dpi_output)
+		mcde_setup_dpi(mcde, mode, &fifo_wtrmrk);
+	else
+		mcde_setup_dsi(mcde, mode, cpp, &fifo_wtrmrk,
+			       &dsi_formatter_frame, &dsi_pkt_size);
 
 	mcde->stride = mode->hdisplay * cpp;
 	dev_dbg(drm->dev, "Overlay line stride: %u bytes\n",
···
 	 */
 	mcde_configure_channel(mcde, MCDE_CHANNEL_0, MCDE_FIFO_A, mode);
 
-	/* Configure FIFO A to use DSI formatter 0 */
-	mcde_configure_fifo(mcde, MCDE_FIFO_A, MCDE_DSI_FORMATTER_0,
-			    fifo_wtrmrk);
+	if (mcde->dpi_output) {
+		unsigned long lcd_freq;
 
-	/*
-	 * This brings up the DSI bridge which is tightly connected
-	 * to the MCDE DSI formatter.
-	 *
-	 * FIXME: if we want to use another formatter, such as DPI,
-	 * we need to be more elaborate here and select the appropriate
-	 * bridge.
-	 */
-	mcde_dsi_enable(mcde->bridge);
+		/* Configure FIFO A to use DPI formatter 0 */
+		mcde_configure_fifo(mcde, MCDE_FIFO_A, MCDE_DPI_FORMATTER_0,
+				    fifo_wtrmrk);
 
-	/* Configure the DSI formatter 0 for the DSI panel output */
-	mcde_configure_dsi_formatter(mcde, MCDE_DSI_FORMATTER_0,
-				     dsi_formatter_frame, dsi_pkt_size);
+		/* Set up and enable the LCD clock */
+		lcd_freq = clk_round_rate(mcde->fifoa_clk, mode->clock * 1000);
+		ret = clk_set_rate(mcde->fifoa_clk, lcd_freq);
+		if (ret)
+			dev_err(mcde->dev, "failed to set LCD clock rate %lu Hz\n",
+				lcd_freq);
+		ret = clk_prepare_enable(mcde->fifoa_clk);
+		if (ret) {
+			dev_err(mcde->dev, "failed to enable FIFO A DPI clock\n");
+			return;
+		}
+		dev_info(mcde->dev, "LCD FIFO A clk rate %lu Hz\n",
+			 clk_get_rate(mcde->fifoa_clk));
+	} else {
+		/* Configure FIFO A to use DSI formatter 0 */
+		mcde_configure_fifo(mcde, MCDE_FIFO_A, MCDE_DSI_FORMATTER_0,
+				    fifo_wtrmrk);
+
+		/*
+		 * This brings up the DSI bridge which is tightly connected
+		 * to the MCDE DSI formatter.
+		 */
+		mcde_dsi_enable(mcde->bridge);
+
+		/* Configure the DSI formatter 0 for the DSI panel output */
+		mcde_configure_dsi_formatter(mcde, MCDE_DSI_FORMATTER_0,
+					     dsi_formatter_frame, dsi_pkt_size);
+	}
 
 	switch (mcde->flow_mode) {
 	case MCDE_COMMAND_TE_FLOW:
 	case MCDE_COMMAND_BTA_TE_FLOW:
 	case MCDE_VIDEO_TE_FLOW:
-		/* We are using TE in some comination */
+		/* We are using TE in some combination */
 		if (mode->flags & DRM_MODE_FLAG_NVSYNC)
 			val = MCDE_VSCRC_VSPOL;
 		else
···
 	/* Disable FIFO A flow */
 	mcde_disable_fifo(mcde, MCDE_FIFO_A, true);
 
-	/* This disables the DSI bridge */
-	mcde_dsi_disable(mcde->bridge);
+	if (mcde->dpi_output) {
+		clk_disable_unprepare(mcde->fifoa_clk);
+	} else {
+		/* This disables the DSI bridge */
+		mcde_dsi_disable(mcde->bridge);
+	}
 
 	event = crtc->state->event;
 	if (event) {
···
 		DRM_FORMAT_BGR565,
 		DRM_FORMAT_YUV422,
 	};
+
+	ret = mcde_init_clock_divider(mcde);
+	if (ret)
+		return ret;
 
 	ret = drm_simple_display_pipe_init(drm, &mcde->pipe,
 					   &mcde_display_funcs,

drivers/gpu/drm/mcde/mcde_display_regs.h

···
 #define MCDE_OVLXCOMP_Z_SHIFT 27
 #define MCDE_OVLXCOMP_Z_MASK 0x78000000
 
+/* DPI/TV configuration registers, channel A and B */
+#define MCDE_TVCRA 0x00000838
+#define MCDE_TVCRB 0x00000A38
+#define MCDE_TVCR_MOD_TV BIT(0) /* 0 = LCD mode */
+#define MCDE_TVCR_INTEREN BIT(1)
+#define MCDE_TVCR_IFIELD BIT(2)
+#define MCDE_TVCR_TVMODE_SDTV_656P (0 << 3)
+#define MCDE_TVCR_TVMODE_SDTV_656P_LE (3 << 3)
+#define MCDE_TVCR_TVMODE_SDTV_656P_BE (4 << 3)
+#define MCDE_TVCR_SDTVMODE_Y0CBY1CR (0 << 6)
+#define MCDE_TVCR_SDTVMODE_CBY0CRY1 (1 << 6)
+#define MCDE_TVCR_AVRGEN BIT(8)
+#define MCDE_TVCR_CKINV BIT(9)
+
+/* TV blanking control register 1, channel A and B */
+#define MCDE_TVBL1A 0x0000083C
+#define MCDE_TVBL1B 0x00000A3C
+#define MCDE_TVBL1_BEL1_SHIFT 0 /* VFP vertical front porch 11 bits */
+#define MCDE_TVBL1_BSL1_SHIFT 16 /* VSW vertical sync pulse width 11 bits */
+
+/* Pixel processing TV start line, channel A and B */
+#define MCDE_TVISLA 0x00000840
+#define MCDE_TVISLB 0x00000A40
+#define MCDE_TVISL_FSL1_SHIFT 0 /* Field 1 identification start line 11 bits */
+#define MCDE_TVISL_FSL2_SHIFT 16 /* Field 2 identification start line 11 bits */
+
+/* Pixel processing TV DVO offset */
+#define MCDE_TVDVOA 0x00000844
+#define MCDE_TVDVOB 0x00000A44
+#define MCDE_TVDVO_DVO1_SHIFT 0 /* VBP vertical back porch 0 = 0 */
+#define MCDE_TVDVO_DVO2_SHIFT 16
+
+/*
+ * Pixel processing TV Timing 1
+ * HBP horizontal back porch 11 bits horizontal offset
+ * 0 = 1 pixel HBP, 255 = 256 pixels, so actual value - 1
+ */
+#define MCDE_TVTIM1A 0x0000084C
+#define MCDE_TVTIM1B 0x00000A4C
+
+/* Pixel processing TV LBALW */
+/* 0 = 1 clock cycle, 255 = 256 clock cycles */
+#define MCDE_TVLBALWA 0x00000850
+#define MCDE_TVLBALWB 0x00000A50
+#define MCDE_TVLBALW_LBW_SHIFT 0 /* HSW horizonal sync width, line blanking width 11 bits */
+#define MCDE_TVLBALW_ALW_SHIFT 16 /* HFP horizontal front porch, active line width 11 bits */
+
+/* TV blanking control register 1, channel A and B */
+#define MCDE_TVBL2A 0x00000854
+#define MCDE_TVBL2B 0x00000A54
+#define MCDE_TVBL2_BEL2_SHIFT 0 /* Field 2 blanking end line 11 bits */
+#define MCDE_TVBL2_BSL2_SHIFT 16 /* Field 2 blanking start line 11 bits */
+
+/* Pixel processing TV background */
+#define MCDE_TVBLUA 0x00000858
+#define MCDE_TVBLUB 0x00000A58
+#define MCDE_TVBLU_TVBLU_SHIFT 0 /* 8 bits luminance */
+#define MCDE_TVBLU_TVBCB_SHIFT 8 /* 8 bits Cb chrominance */
+#define MCDE_TVBLU_TVBCR_SHIFT 16 /* 8 bits Cr chrominance */
+
+/* Pixel processing LCD timing 1 */
+#define MCDE_LCDTIM1A 0x00000860
+#define MCDE_LCDTIM1B 0x00000A60
+/* inverted vertical sync pulse for HRTFT 0 = active low, 1 active high */
+#define MCDE_LCDTIM1B_IVP BIT(19)
+/* inverted vertical sync, 0 = active high (the normal), 1 = active low */
+#define MCDE_LCDTIM1B_IVS BIT(20)
+/* inverted horizontal sync, 0 = active high (the normal), 1 = active low */
+#define MCDE_LCDTIM1B_IHS BIT(21)
+/* inverted panel clock 0 = rising edge data out, 1 = falling edge data out */
+#define MCDE_LCDTIM1B_IPC BIT(22)
+/* invert output enable 0 = active high, 1 = active low */
+#define MCDE_LCDTIM1B_IOE BIT(23)
+
 #define MCDE_CRC 0x00000C00
 #define MCDE_CRC_C1EN BIT(2)
 #define MCDE_CRC_C2EN BIT(3)
···
 #define MCDE_CRB1 0x00000A04
 #define MCDE_CRX1_PCD_SHIFT 0
 #define MCDE_CRX1_PCD_MASK 0x000003FF
+#define MCDE_CRX1_PCD_BITS 10
 #define MCDE_CRX1_CLKSEL_SHIFT 10
 #define MCDE_CRX1_CLKSEL_MASK 0x00001C00
 #define MCDE_CRX1_CLKSEL_CLKPLL72 0
···
 #define MCDE_ROTACONF 0x0000087C
 #define MCDE_ROTBCONF 0x00000A7C
 
+/* Synchronization event configuration */
 #define MCDE_SYNCHCONFA 0x00000880
 #define MCDE_SYNCHCONFB 0x00000A80
+#define MCDE_SYNCHCONF_HWREQVEVENT_SHIFT 0
+#define MCDE_SYNCHCONF_HWREQVEVENT_VSYNC (0 << 0)
+#define MCDE_SYNCHCONF_HWREQVEVENT_BACK_PORCH (1 << 0)
+#define MCDE_SYNCHCONF_HWREQVEVENT_ACTIVE_VIDEO (2 << 0)
+#define MCDE_SYNCHCONF_HWREQVEVENT_FRONT_PORCH (3 << 0)
+#define MCDE_SYNCHCONF_HWREQVCNT_SHIFT 2 /* 14 bits */
+#define MCDE_SYNCHCONF_SWINTVEVENT_VSYNC (0 << 16)
+#define MCDE_SYNCHCONF_SWINTVEVENT_BACK_PORCH (1 << 16)
+#define MCDE_SYNCHCONF_SWINTVEVENT_ACTIVE_VIDEO (2 << 16)
+#define MCDE_SYNCHCONF_SWINTVEVENT_FRONT_PORCH (3 << 16)
+#define MCDE_SYNCHCONF_SWINTVCNT_SHIFT 18 /* 14 bits */
 
 /* Channel A+B control registers */
 #define MCDE_CTRLA 0x00000884

drivers/gpu/drm/mcde/mcde_drm.h

···
 	MCDE_VIDEO_TE_FLOW,
 	/* Video mode with the formatter itself as sync source */
 	MCDE_VIDEO_FORMATTER_FLOW,
+	/* DPI video with the formatter itsels as sync source */
+	MCDE_DPI_FORMATTER_FLOW,
 };
 
 struct mcde {
···
 	struct drm_connector *connector;
 	struct drm_simple_display_pipe pipe;
 	struct mipi_dsi_device *mdsi;
+	bool dpi_output;
 	s16 stride;
 	enum mcde_flow_mode flow_mode;
 	unsigned int flow_active;
···
 	struct clk *mcde_clk;
 	struct clk *lcd_clk;
 	struct clk *hdmi_clk;
+	/* Handles to the clock dividers for FIFO A and B */
+	struct clk *fifoa_clk;
+	struct clk *fifob_clk;
+	/* Locks the MCDE FIFO control register A and B */
+	spinlock_t fifo_crx1_lock;
 
 	struct regulator *epod;
 	struct regulator *vana;
···
 void mcde_display_irq(struct mcde *mcde);
 void mcde_display_disable_irqs(struct mcde *mcde);
 int mcde_display_init(struct drm_device *drm);
+
+int mcde_init_clock_divider(struct mcde *mcde);
 
 #endif /* _MCDE_DRM_H_ */

drivers/gpu/drm/mcde/mcde_drv.c

···
  * The hardware has four display pipes, and the layout is a little
  * bit like this::
  *
- *   Memory     -> Overlay -> Channel -> FIFO -> 5 formatters -> DSI/DPI
- *   External      0..5       0..3       A,B,    3 x DSI         bridge
+ *   Memory     -> Overlay -> Channel -> FIFO -> 8 formatters -> DSI/DPI
+ *   External      0..5       0..3       A,B,    6 x DSI         bridge
  *   source 0..9                         C0,C1   2 x DPI
  *
  * FIFOs A and B are for LCD and HDMI while FIFO CO/C1 are for
  * panels with embedded buffer.
- * 3 of the formatters are for DSI.
+ * 6 of the formatters are for DSI, 3 pairs for VID/CMD respectively.
  * 2 of the formatters are for DPI.
  *
  * Behind the formatters are the DSI or DPI ports that route to
···
 	struct mcde *mcde = to_mcde(drm);
 	int ret;
 
+	/*
+	 * If no other bridge was found, check if we have a DPI panel or
+	 * any other bridge connected directly to the MCDE DPI output.
+	 * If a DSI bridge is found, DSI will take precedence.
+	 *
+	 * TODO: more elaborate bridge selection if we have more than one
+	 * thing attached to the system.
+	 */
 	if (!mcde->bridge) {
-		dev_err(drm->dev, "no display output bridge yet\n");
-		return -EPROBE_DEFER;
+		struct drm_panel *panel;
+		struct drm_bridge *bridge;
+
+		ret = drm_of_find_panel_or_bridge(drm->dev->of_node,
+						  0, 0, &panel, &bridge);
+		if (ret) {
+			dev_err(drm->dev,
+				"Could not locate any output bridge or panel\n");
+			return ret;
+		}
+		if (panel) {
+			bridge = drm_panel_bridge_add_typed(panel,
+					DRM_MODE_CONNECTOR_DPI);
+			if (IS_ERR(bridge)) {
+				dev_err(drm->dev,
+					"Could not connect panel bridge\n");
+				return PTR_ERR(bridge);
+			}
+		}
+		mcde->dpi_output = true;
+		mcde->bridge = bridge;
+		mcde->flow_mode = MCDE_DPI_FORMATTER_FLOW;
 	}
 
 	mode_config = &drm->mode_config;
···
 		return ret;
 	}
 
-	/*
-	 * Attach the DSI bridge
-	 *
-	 * TODO: when adding support for the DPI bridge or several DSI bridges,
-	 * we selectively connect the bridge(s) here instead of this simple
-	 * attachment.
-	 */
+	/* Attach the bridge. */
 	ret = drm_simple_display_pipe_attach_bridge(&mcde->pipe,
 						    mcde->bridge);
 	if (ret) {