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cmd: add new command to read edid

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Add a new command to read EDID info from connected display.

When applicable EDID can also be retrieved by commands such as:

  i2c dev x
  i2c edid 0x50

but the new read_edid function relies on the implementation of the
read_edid callback from DISPLAY driver.

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
This commit is contained in:
Julien Stephan
2025-06-30 12:08:16 +02:00
committed by Tom Rini
parent 5b2ee2c4a2
commit 5e9b0b56ad
5 changed files with 56 additions and 1 deletions
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6
cmd/Kconfig
View File

@@ -1608,6 +1608,12 @@ config CMD_READ
help
Provides low-level access to the data in a partition.
config CMD_READ_EDID
bool "read_edid - Read display EDID"
depends on DISPLAY
help
Read and parse edid from connected display device.
config CMD_REMOTEPROC
bool "remoteproc"
depends on REMOTEPROC

1
cmd/Makefile
View File

@@ -154,6 +154,7 @@ obj-$(CONFIG_CMD_WOL) += wol.o
obj-$(CONFIG_CMD_QFW) += qfw.o
obj-$(CONFIG_CMD_READ) += read.o
obj-$(CONFIG_CMD_WRITE) += read.o
obj-$(CONFIG_CMD_READ_EDID) += read_edid.o
obj-$(CONFIG_CMD_REGINFO) += reginfo.o
obj-$(CONFIG_CMD_REMOTEPROC) += remoteproc.o
obj-$(CONFIG_CMD_RNG) += rng.o

38
cmd/read_edid.c Normal file
View File

@@ -0,0 +1,38 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2025 BayLibre, SAS
*/
#include <command.h>
#include <dm.h>
#include <display.h>
#include <edid.h>
static int do_read_edid(struct cmd_tbl *cmdtp, int flag, int argc, char * const argv[])
{
struct udevice *dev;
int ret;
u8 edid[EDID_EXT_SIZE];
/* Get the first display device (UCLASS_DISPLAY) */
ret = uclass_first_device_err(UCLASS_DISPLAY, &dev);
if (ret) {
printf("Cannot get display device: %d\n", ret);
return CMD_RET_FAILURE;
}
ret = display_read_edid(dev, edid, EDID_EXT_SIZE);
if (ret) {
printf("Cannot read edid: %d\n", ret);
return CMD_RET_FAILURE;
}
edid_print_info((struct edid1_info *)edid);
return CMD_RET_SUCCESS;
}
U_BOOT_CMD(read_edid, 1, 0, do_read_edid,
"Read and print EDID from display",
""
);

2
drivers/video/display-uclass.c
View File

@@ -10,7 +10,7 @@
#include <edid.h>
#include <errno.h>
static int display_read_edid(struct udevice *dev, u8 *buf, int buf_size)
int display_read_edid(struct udevice *dev, u8 *buf, int buf_size)
{
struct dm_display_ops *ops = display_get_ops(dev);

10
include/display.h
View File

@@ -25,6 +25,16 @@ struct display_plat {
bool in_use;
};
/**
* display_read_edid() - Read edid from display
*
* @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_read_edid(struct udevice *dev, u8 *buf, int buf_size);
/**
* display_read_timing() - Read timing information
*