[PATCH v2 RFC 09/10] drm/fourcc: Add DRM_FORMAT_R[124]

[Geert Uytterhoeven <geert@linux-m68k.org>]

Introduce fourcc codes for single-channel light-on-dark frame buffer
formats with two, four, and sixteen intensity levels.

As the number of bits per pixel is less than eight, these rely on proper
block handling for the calculation of bits per pixel and pitch.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
RFC, as I have no immediate need for these formats.

v2:
  - Improve pixel descriptions.
---
 drivers/gpu/drm/drm_fourcc.c  |  6 ++++++
 include/uapi/drm/drm_fourcc.h | 11 ++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index 29f4fe199c4ddcf0..05e65e9ab0c69c6a 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -154,6 +154,12 @@ const struct drm_format_info *__drm_format_info(u32 format)
 		{ .format = DRM_FORMAT_C4,		.depth = 4,  .num_planes = 1,
 		  .char_per_block = { 1, }, .block_w = { 2, }, .block_h = { 1, }, .hsub = 1, .vsub = 1, .is_color_indexed = true },
 		{ .format = DRM_FORMAT_C8,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1, .is_color_indexed = true },
+		{ .format = DRM_FORMAT_R1,		.depth = 1,  .num_planes = 1,
+		  .char_per_block = { 1, }, .block_w = { 8, }, .block_h = { 1, }, .hsub = 1, .vsub = 1 },
+		{ .format = DRM_FORMAT_R2,		.depth = 2,  .num_planes = 1,
+		  .char_per_block = { 1, }, .block_w = { 4, }, .block_h = { 1, }, .hsub = 1, .vsub = 1 },
+		{ .format = DRM_FORMAT_R4,		.depth = 4,  .num_planes = 1,
+		  .char_per_block = { 1, }, .block_w = { 2, }, .block_h = { 1, }, .hsub = 1, .vsub = 1 },
 		{ .format = DRM_FORMAT_R8,		.depth = 8,  .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 },
 		{ .format = DRM_FORMAT_R10,		.depth = 10, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
 		{ .format = DRM_FORMAT_R12,		.depth = 12, .num_planes = 1, .cpp = { 2, 0, 0 }, .hsub = 1, .vsub = 1 },
diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index f0187cf20e4619d2..def0a73620dc86d2 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -104,8 +104,17 @@ extern "C" {
 #define DRM_FORMAT_C4		fourcc_code('C', '4', ' ', ' ') /* [7:0] C0:C1 4:4 two pixels/byte */
 #define DRM_FORMAT_C8		fourcc_code('C', '8', ' ', ' ') /* [7:0] C 8 one pixel/byte */
 
+/* 1 bpp Red (or monochrome light-on-dark) */
+#define DRM_FORMAT_R1		fourcc_code('R', '1', ' ', ' ') /* [7:0] R0:R1:R2:R3:R4:R5:R6:R7 1:1:1:1:1:1:1:1 eight pixels/byte */
+
+/* 2 bpp Red (or generic light-on-dark) */
+#define DRM_FORMAT_R2		fourcc_code('R', '2', ' ', ' ') /* [7:0] R0:R1:R2:R3 2:2:2:2 four pixels/byte */
+
+/* 4 bpp Red (or generic light-on-dark) */
+#define DRM_FORMAT_R4		fourcc_code('R', '4', ' ', ' ') /* [7:0] R0:R1 4:4 two pixels/byte */
+
 /* 8 bpp Red (or generic light-on-dark) */
-#define DRM_FORMAT_R8		fourcc_code('R', '8', ' ', ' ') /* [7:0] R */
+#define DRM_FORMAT_R8		fourcc_code('R', '8', ' ', ' ') /* [7:0] R 8 one pixel/byte */
 
 /* 10 bpp Red (or generic light-on-dark) */
 #define DRM_FORMAT_R10		fourcc_code('R', '1', '0', ' ') /* [15:0] x:R 6:10 little endian */
-- 
2.25.1