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authorSimon Glass <sjg@chromium.org>2015-04-14 21:03:21 -0600
committerTom Warren <twarren@nvidia.com>2015-05-13 09:24:06 -0700
commit12e671142daa5d4dce5961e6f573a8b740b16f88 (patch)
tree30eafbb47ee45d9de1683074067fd573163a0c20 /include/fdtdec.h
parent962f5caf600c54f4103bfa6b31fa2fb4e8aaacb9 (diff)
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fdt: Add binding decode function for display-timings
This is useful for display parameters. Add a simple decode function to read from this device tree node. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Tom Warren <twarren@nvidia.com>
Diffstat (limited to 'include/fdtdec.h')
-rw-r--r--include/fdtdec.h77
1 files changed, 77 insertions, 0 deletions
diff --git a/include/fdtdec.h b/include/fdtdec.h
index f11475b..f304199 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -802,6 +802,83 @@ int fdtdec_decode_memory_region(const void *blob, int node,
const char *mem_type, const char *suffix,
fdt_addr_t *basep, fdt_size_t *sizep);
+/* Display timings from linux include/video/display_timing.h */
+enum display_flags {
+ DISPLAY_FLAGS_HSYNC_LOW = 1 << 0,
+ DISPLAY_FLAGS_HSYNC_HIGH = 1 << 1,
+ DISPLAY_FLAGS_VSYNC_LOW = 1 << 2,
+ DISPLAY_FLAGS_VSYNC_HIGH = 1 << 3,
+
+ /* data enable flag */
+ DISPLAY_FLAGS_DE_LOW = 1 << 4,
+ DISPLAY_FLAGS_DE_HIGH = 1 << 5,
+ /* drive data on pos. edge */
+ DISPLAY_FLAGS_PIXDATA_POSEDGE = 1 << 6,
+ /* drive data on neg. edge */
+ DISPLAY_FLAGS_PIXDATA_NEGEDGE = 1 << 7,
+ DISPLAY_FLAGS_INTERLACED = 1 << 8,
+ DISPLAY_FLAGS_DOUBLESCAN = 1 << 9,
+ DISPLAY_FLAGS_DOUBLECLK = 1 << 10,
+};
+
+/*
+ * A single signal can be specified via a range of minimal and maximal values
+ * with a typical value, that lies somewhere inbetween.
+ */
+struct timing_entry {
+ u32 min;
+ u32 typ;
+ u32 max;
+};
+
+/*
+ * Single "mode" entry. This describes one set of signal timings a display can
+ * have in one setting. This struct can later be converted to struct videomode
+ * (see include/video/videomode.h). As each timing_entry can be defined as a
+ * range, one struct display_timing may become multiple struct videomodes.
+ *
+ * Example: hsync active high, vsync active low
+ *
+ * Active Video
+ * Video ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
+ * |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
+ * | | porch | | porch |
+ *
+ * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
+ *
+ * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
+ */
+struct display_timing {
+ struct timing_entry pixelclock;
+
+ struct timing_entry hactive; /* hor. active video */
+ struct timing_entry hfront_porch; /* hor. front porch */
+ struct timing_entry hback_porch; /* hor. back porch */
+ struct timing_entry hsync_len; /* hor. sync len */
+
+ struct timing_entry vactive; /* ver. active video */
+ struct timing_entry vfront_porch; /* ver. front porch */
+ struct timing_entry vback_porch; /* ver. back porch */
+ struct timing_entry vsync_len; /* ver. sync len */
+
+ enum display_flags flags; /* display flags */
+};
+
+/**
+ * fdtdec_decode_display_timing() - decode display timings
+ *
+ * Decode display timings from the supplied 'display-timings' node.
+ * See doc/device-tree-bindings/video/display-timing.txt for binding
+ * information.
+ *
+ * @param blob FDT blob
+ * @param node 'display-timing' node containing the timing subnodes
+ * @param index Index number to read (0=first timing subnode)
+ * @param config Place to put timings
+ * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
+ */
+int fdtdec_decode_display_timing(const void *blob, int node, int index,
+ struct display_timing *config);
/**
* Set up the device tree ready for use
*/