drivers: Add OSD uclass

Some devices offer a text-based OSD (on-screen display) that can be
programmatically controlled (i.e. text displayed on).

Add a uclass to support such devices.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>

1 files changed, 192 insertions, 0 deletions

diff --git a/include/video_osd.h b/include/video_osd.h
new file mode 100644
index 0000000000..01ac94b425
--- /dev/null
+++ b/include/video_osd.h
@@ -0,0 +1,192 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2017
+ * Mario Six,  Guntermann & Drunck GmbH, mario.six@gdsys.cc
+ */
+
+#ifndef _VIDEO_OSD_H_
+#define _VIDEO_OSD_H_
+
+struct video_osd_info {
+	/* The width of the OSD display in columns */
+	uint width;
+	/* The height of the OSD display in rows */
+	uint height;
+	/* The major version of the OSD device */
+	uint major_version;
+	/* The minor version of the OSD device */
+	uint minor_version;
+};
+
+/**
+ * struct video_osd_ops - driver operations for OSD uclass
+ *
+ * The OSD uclass implements support for text-oriented on-screen displays,
+ * which are taken to be devices that independently display a graphical
+ * text-based overlay over the video output of an associated display.
+ *
+ * The functions defined by the uclass support writing text to the display in
+ * either a generic form (by specifying a string, a driver-specific color value
+ * for the text, and screen coordinates in rows and columns) or a
+ * driver-specific form (by specifying "raw" driver-specific data to display at
+ * a given coordinate).
+ *
+ * Functions to read device information and set the size of the virtual OSD
+ * screen (in rows and columns) are also supported.
+ *
+ * Drivers should support these operations unless otherwise noted. These
+ * operations are intended to be used by uclass code, not directly from
+ * other code.
+ */
+struct video_osd_ops {
+	/**
+	 * get_info() - Get information about a OSD instance
+	 *
+	 * A OSD instance may keep some internal data about itself. This
+	 * function can be used to access this data.
+	 *
+	 * @dev:	OSD instance to query.
+	 * @info:	Pointer to a structure that takes the information read
+	 *		from the OSD instance.
+	 * @return 0 if OK, -ve on error.
+	 */
+	int (*get_info)(struct udevice *dev, struct video_osd_info *info);
+
+	/**
+	 * set_mem() - Write driver-specific text data to OSD screen
+	 *
+	 * The passed data are device-specific, and it's up to the driver how
+	 * to interpret them. How the count parameter is interpreted is also
+	 * driver-specific; most likely the given data will be written to the
+	 * OSD count times back-to-back, which is e.g. convenient for filling
+	 * areas of the OSD with a single character.
+	 *
+	 * For example a invocation of
+	 *
+	 * video_osd_set_mem(dev, 0, 0, "A", 1, 10);
+	 *
+	 * will write the device-specific text data "A" to the positions (0, 0)
+	 * to (9, 0) on the OSD.
+	 *
+	 * Device-specific text data may, e.g. be a special encoding of glyphs
+	 * to display and color values in binary format.
+	 *
+	 * @dev:	OSD instance to write to.
+	 * @col:	Horizontal character coordinate to write to.
+	 * @row		Vertical character coordinate to write to.
+	 * @buf:	Array containing device-specific data to write to the
+	 *		specified coordinate on the OSD screen.
+	 * @buflen:	Length of the data in the passed buffer (in byte).
+	 * @count:	Write count many repetitions of the given text data
+	 * @return 0 if OK, -ve on error.
+	 */
+	int (*set_mem)(struct udevice *dev, uint col, uint row, u8 *buf,
+		       size_t buflen, uint count);
+
+	/**
+	 * set_size() - Set the position and dimension of the OSD's
+	 *              writeable window
+	 *
+	 * @dev:	OSD instance to write to.
+	 * @col		The number of characters in the window's columns
+	 * @row		The number of characters in the window's rows
+	 * @return 0 if OK, -ve on error.
+	 */
+	int (*set_size)(struct udevice *dev, uint col, uint row);
+
+	/**
+	 * print() - Print a string in a given color to specified coordinates
+	 *	     on the OSD
+	 *
+	 * @dev:	OSD instance to write to.
+	 * @col		The x-coordinate of the position the string should be
+	 *		written to
+	 * @row		The y-coordinate of the position the string should be
+	 *		written to
+	 * @color:	The color in which the specified string should be
+	 *		printed; the interpretation of the value is
+	 *		driver-specific, and possible values should be defined
+	 *		e.g. in a driver include file.
+	 * @text:	The string data that should be printed on the OSD
+	 * @return 0 if OK, -ve on error.
+	 */
+	int (*print)(struct udevice *dev, uint col, uint row, ulong color,
+		     char *text);
+};
+
+#define video_osd_get_ops(dev)	((struct video_osd_ops *)(dev)->driver->ops)
+
+/**
+ * video_osd_get_info() - Get information about a OSD instance
+ *
+ * A OSD instance may keep some internal data about itself. This function can
+ * be used to access this data.
+ *
+ * @dev:	OSD instance to query.
+ * @info:	Pointer to a structure that takes the information read from the
+ *		OSD instance.
+ * @return 0 if OK, -ve on error.
+ */
+int video_osd_get_info(struct udevice *dev, struct video_osd_info *info);
+
+/**
+ * video_osd_set_mem() - Write text data to OSD memory
+ *
+ * The passed data are device-specific, and it's up to the driver how to
+ * interpret them. How the count parameter is interpreted is also
+ * driver-specific; most likely the given data will be written to the OSD count
+ * times back-to-back, which is e.g. convenient for filling areas of the OSD
+ * with a single character.
+ *
+ * For example a invocation of
+ *
+ * video_osd_set_mem(dev, 0, 0, "A", 1, 10);
+ *
+ * will write the device-specific text data "A" to the positions (0, 0) to (9,
+ * 0) on the OSD.
+ *
+ * Device-specific text data may, e.g. be a special encoding of glyphs to
+ * display and color values in binary format.
+ *
+ * @dev:	OSD instance to write to.
+ * @col:	Horizontal character coordinate to write to.
+ * @row		Vertical character coordinate to write to.
+ * @buf:	Array containing device-specific data to write to the specified
+ *		coordinate on the OSD screen.
+ * @buflen:	Length of the data in the passed buffer (in byte).
+ * @count:	Write count many repetitions of the given text data
+ * @return 0 if OK, -ve on error.
+ */
+int video_osd_set_mem(struct udevice *dev, uint col, uint row, u8 *buf,
+		      size_t buflen, uint count);
+
+/**
+ * video_osd_set_size() - Set the position and dimension of the OSD's
+ *              writeable window
+ *
+ * @dev:	OSD instance to write to.
+ * @col		The number of characters in the window's columns
+ * @row		The number of characters in the window's rows
+ * @return 0 if OK, -ve on error.
+ */
+int video_osd_set_size(struct udevice *dev, uint col, uint row);
+
+/**
+ * video_osd_print() - Print a string in a given color to specified coordinates
+ *		       on the OSD
+ *
+ * @dev:	OSD instance to write to.
+ * @col		The x-coordinate of the position the string should be written
+ *		to
+ * @row		The y-coordinate of the position the string should be written
+ *		to
+ * @color:	The color in which the specified string should be printed; the
+ *		interpretation of the value is driver-specific, and possible
+ *		values should be defined e.g. in a driver include file.
+ * @text:	The string data that should be printed on the OSD
+ * @return 0 if OK, -ve on error.
+ */
+int video_osd_print(struct udevice *dev, uint col, uint row, ulong color,
+		    char *text);
+
+#endif /* !_VIDEO_OSD_H_ */