fdt_support: support adding EDID property to FDT display nodes

Boards can pass display timing info for drivers using EDID
block. Provide common function to add board specific EDID
data to the device tree. Subsequent patch makes use of this
functionality.

Detailed timing descriptor data from EDID is used for
programming the display controller. This is currently
implemented on the Linux side by the fsl-diu-fb frame
buffer driver and it is documented there in
Documentation/powerpc/dts-bindings/fsl/diu.txt.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
Cc: Gerald Van Baren <vanbaren@cideas.com>

common/fdt_support.c

@@ -1189,3 +1189,32 @@ int fdt_alloc_phandle(void *blob)
 
 	return phandle + 1;
 }
+
+#if defined(CONFIG_VIDEO)
+int fdt_add_edid(void *blob, const char *compat, unsigned char *edid_buf)
+{
+	int noff;
+	int ret;
+
+	noff = fdt_node_offset_by_compatible(blob, -1, compat);
+	if (noff != -FDT_ERR_NOTFOUND) {
+		debug("%s: %s\n", fdt_get_name(blob, noff, 0), compat);
+add_edid:
+		ret = fdt_setprop(blob, noff, "edid", edid_buf, 128);
+		if (ret == -FDT_ERR_NOSPACE) {
+			ret = fdt_increase_size(blob, 512);
+			if (!ret)
+				goto add_edid;
+			else
+				goto err_size;
+		} else if (ret < 0) {
+			printf("Can't add property: %s\n", fdt_strerror(ret));
+			return ret;
+		}
+	}
+	return 0;
+err_size:
+	printf("Can't increase blob size: %s\n", fdt_strerror(ret));
+	return ret;
+}
+#endif

include/fdt_support.h

@@ -87,6 +87,7 @@ u64 fdt_translate_address(void *blob, int node_offset, const u32 *in_addr);
 int fdt_node_offset_by_compat_reg(void *blob, const char *compat,
 					phys_addr_t compat_off);
 int fdt_alloc_phandle(void *blob);
+int fdt_add_edid(void *blob, const char *compat, unsigned char *buf);
 
 #endif /* ifdef CONFIG_OF_LIBFDT */
 #endif /* ifndef __FDT_SUPPORT_H */