dm: video: Add a uclass for display port

eDP (Embedded DisplayPort) is a standard widely used in laptops to drive
LCD panels. Add a uclass for this which supports a few simple operations.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Tom Warren <twarren@nvidia.com>

drivers/video/Kconfig

@@ -88,3 +88,10 @@ config VIDEO_LCD_SPI_MISO
 	hardware and LCD panel id retrieval (if the panel can report it). The
 	option takes a string in the format understood by 'name_to_gpio'
 	function, e.g. PH1 for pin 1 of port H.
+
+config DISPLAY_PORT
+	bool "Enable DisplayPort support"
+	help
+	   eDP (Embedded DisplayPort) is a standard widely used in laptops
+	   to drive LCD panels. This framework provides support for enabling
+	   these displays where supported by the video hardware.

drivers/video/Makefile

@@ -5,6 +5,10 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+ifdef CONFIG_DM
+obj-$(CONFIG_DISPLAY_PORT) += dp-uclass.o
+endif
+
 obj-$(CONFIG_ATI_RADEON_FB) += ati_radeon_fb.o videomodes.o
 obj-$(CONFIG_ATMEL_HLCD) += atmel_hlcdfb.o
 obj-$(CONFIG_ATMEL_LCD) += atmel_lcdfb.o

drivers/video/dp-uclass.c

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <displayport.h>
+#include <errno.h>
+
+int display_port_read_edid(struct udevice *dev, u8 *buf, int buf_size)
+{
+	struct dm_display_port_ops *ops = display_port_get_ops(dev);
+
+	if (!ops || !ops->read_edid)
+		return -ENOSYS;
+	return ops->read_edid(dev, buf, buf_size);
+}
+
+int display_port_enable(struct udevice *dev, int panel_bpp,
+			const struct display_timing *timing)
+{
+	struct dm_display_port_ops *ops = display_port_get_ops(dev);
+
+	if (!ops || !ops->enable)
+		return -ENOSYS;
+	return ops->enable(dev, panel_bpp, timing);
+}
+
+UCLASS_DRIVER(display_port) = {
+	.id		= UCLASS_DISPLAY_PORT,
+	.name		= "display_port",
+};

include/displayport.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef _DISPLAYPORT_H
+#define _DISPLAYPORT_H
+
+struct udevice;
+struct display_timing;
+
+/**
+ * display_port_read_edid() - Read information from EDID
+ *
+ * @dev:	Device to read from
+ * @buf:	Buffer to read into (should be EDID_SIZE bytes)
+ * @buf_size:	Buffer size (should be EDID_SIZE)
+ * @return number of bytes read, <=0 for error
+ */
+int display_port_read_edid(struct udevice *dev, u8 *buf, int buf_size);
+
+/**
+ * display_port_enable() - Enable a display port device
+ *
+ * @dev:	Device to enable
+ * @panel_bpp:	Number of bits per pixel for panel
+ * @timing:	Display timings
+ * @return 0 if OK, -ve on error
+ */
+int display_port_enable(struct udevice *dev, int panel_bpp,
+			const struct display_timing *timing);
+
+struct dm_display_port_ops {
+	/**
+	 * read_edid() - Read information from EDID
+	 *
+	 * @dev:	Device to read from
+	 * @buf:	Buffer to read into (should be EDID_SIZE bytes)
+	 * @buf_size:	Buffer size (should be EDID_SIZE)
+	 * @return number of bytes read, <=0 for error
+	 */
+	int (*read_edid)(struct udevice *dev, u8 *buf, int buf_size);
+
+	/**
+	 * enable() - Enable the display port device
+	 *
+	 * @dev:	Device to enable
+	 * @panel_bpp:	Number of bits per pixel for panel
+	 * @timing:	Display timings
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*enable)(struct udevice *dev, int panel_bpp,
+		      const struct display_timing *timing);
+};
+
+#define display_port_get_ops(dev)	\
+	((struct dm_display_port_ops *)(dev)->driver->ops)
+
+#endif

include/dm/uclass-id.h

@@ -27,6 +27,7 @@ enum uclass_id {
 	/* U-Boot uclasses start here - in alphabetical order */
 	UCLASS_CPU,		/* CPU, typically part of an SoC */
 	UCLASS_CROS_EC,		/* Chrome OS EC */
+	UCLASS_DISPLAY_PORT,	/* Display port video */
 	UCLASS_ETH,		/* Ethernet device */
 	UCLASS_GPIO,		/* Bank of general-purpose I/O pins */
 	UCLASS_I2C,		/* I2C bus */