Commit 3c80f6f8 authored by Hugues Fruchet's avatar Hugues Fruchet Committed by Mauro Carvalho Chehab
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media: stm32-dcmi: add support of BT656 bus 



Add support of BT656 embedded synchronization bus.
This mode allows to save hardware synchro lines hsync & vsync by replacing
them with synchro codes embedded in data stream.
This bus type is only compatible with 8 bits width data bus.
Due to reserved values 0x00 & 0xff used for synchro codes, valid data vary
from 0x1 to 0xfe, this is up to sensor to clip accordingly pixel data. As
a consequence of this clipping, JPEG is not supported with this bus type.
DCMI crop feature is also not available with this bus type.

Signed-off-by: default avatarHugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent e2881c64

drivers/media/platform/stm32/stm32-dcmi.c

+35 −2
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ struct stm32_dcmi { 
	struct vb2_queue		queue;



	struct v4l2_fwnode_bus_parallel	bus;

	enum v4l2_mbus_type		bus_type;

	struct completion		complete;

	struct clk			*mclk;

	enum state			state;
@@ -777,6 +778,23 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count) 
	if (dcmi->bus.flags & V4L2_MBUS_PCLK_SAMPLE_RISING)

		val |= CR_PCKPOL;



	/*

	 * BT656 embedded synchronisation bus mode.

	 *

	 * Default SAV/EAV mode is supported here with default codes

	 * SAV=0xff000080 & EAV=0xff00009d.

	 * With DCMI this means LSC=SAV=0x80 & LEC=EAV=0x9d.

	 */

	if (dcmi->bus_type == V4L2_MBUS_BT656) {

		val |= CR_ESS;



		/* Unmask all codes */

		reg_write(dcmi->regs, DCMI_ESUR, 0xffffffff);/* FEC:LEC:LSC:FSC */



		/* Trig on LSC=0x80 & LEC=0x9d codes, ignore FSC and FEC */

		reg_write(dcmi->regs, DCMI_ESCR, 0xff9d80ff);/* FEC:LEC:LSC:FSC */

	}



	reg_write(dcmi->regs, DCMI_CR, val);



	/* Set crop */
@@ -1067,8 +1085,9 @@ static int dcmi_set_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f) 
	if (ret)

		return ret;



	/* Disable crop if JPEG is requested */

	if (pix->pixelformat == V4L2_PIX_FMT_JPEG)

	/* Disable crop if JPEG is requested or BT656 bus is selected */

	if (pix->pixelformat == V4L2_PIX_FMT_JPEG &&

	    dcmi->bus_type != V4L2_MBUS_BT656)

		dcmi->do_crop = false;



	/* pix to mbus format */
@@ -1608,6 +1627,11 @@ static int dcmi_formats_init(struct stm32_dcmi *dcmi) 
			if (dcmi_formats[i].mbus_code != mbus_code.code)

				continue;



			/* Exclude JPEG if BT656 bus is selected */

			if (dcmi_formats[i].fourcc == V4L2_PIX_FMT_JPEG &&

			    dcmi->bus_type == V4L2_MBUS_BT656)

				continue;



			/* Code supported, have we got this fourcc yet? */

			for (j = 0; j < num_fmts; j++)

				if (sd_fmts[j]->fourcc ==
@@ -1891,9 +1915,18 @@ static int dcmi_probe(struct platform_device *pdev) 
		dev_err(&pdev->dev, "CSI bus not supported\n");

		return -ENODEV;

	}



	if (ep.bus_type == V4L2_MBUS_BT656 &&

	    ep.bus.parallel.bus_width != 8) {

		dev_err(&pdev->dev, "BT656 bus conflicts with %u bits bus width (8 bits required)\n",

			ep.bus.parallel.bus_width);

		return -ENODEV;

	}



	dcmi->bus.flags = ep.bus.parallel.flags;

	dcmi->bus.bus_width = ep.bus.parallel.bus_width;

	dcmi->bus.data_shift = ep.bus.parallel.data_shift;

	dcmi->bus_type = ep.bus_type;



	irq = platform_get_irq(pdev, 0);

	if (irq <= 0)