lcd: add functions to set up simplefb device tree

simple-framebuffer is a new device tree binding that describes a pre-
configured frame-buffer memory region and its format. The Linux kernel
contains a driver that supports this binding. Implement functions to
create a DT node (or fill in an existing node) with parameters that
describe the framebuffer format that U-Boot is using.

This will be immediately used by the Raspberry Pi board in U-Boot, and
likely will be used by the Samsung ARM ChromeBook support soon too. It
could well be used by many other boards (e.g. Tegra boards with built-in
LCD panels, which aren't yet supported by the Linux kernel).

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/common/lcd.c b/common/lcd.c
index edae835fb0be1e6eb1fccdbf373b42dfc588ee31..3a60484eea615a4f20bd78109f738de26478c88f 100644 (file)
--- a/common/lcd.c
+++ b/common/lcd.c
@@ -57,6 +57,10 @@
 #include <atmel_lcdc.h>
 #endif
 
+#if defined(CONFIG_LCD_DT_SIMPLEFB)
+#include <libfdt.h>
+#endif
+
 /************************************************************************/
 /* ** FONT DATA                                                                */
 /************************************************************************/
@@ -1182,3 +1186,86 @@ int lcd_get_screen_columns(void)
 {
        return CONSOLE_COLS;
 }
+
+#if defined(CONFIG_LCD_DT_SIMPLEFB)
+static int lcd_dt_simplefb_configure_node(void *blob, int off)
+{
+       u32 stride;
+       fdt32_t cells[2];
+       int ret;
+       const char format[] =
+#if LCD_BPP == LCD_COLOR16
+               "r5g6b5";
+#else
+               "";
+#endif
+
+       if (!format[0])
+               return -1;
+
+       stride = panel_info.vl_col * 2;
+
+       cells[0] = cpu_to_fdt32(gd->fb_base);
+       cells[1] = cpu_to_fdt32(stride * panel_info.vl_row);
+       ret = fdt_setprop(blob, off, "reg", cells, sizeof(cells[0]) * 2);
+       if (ret < 0)
+               return -1;
+
+       cells[0] = cpu_to_fdt32(panel_info.vl_col);
+       ret = fdt_setprop(blob, off, "width", cells, sizeof(cells[0]));
+       if (ret < 0)
+               return -1;
+
+       cells[0] = cpu_to_fdt32(panel_info.vl_row);
+       ret = fdt_setprop(blob, off, "height", cells, sizeof(cells[0]));
+       if (ret < 0)
+               return -1;
+
+       cells[0] = cpu_to_fdt32(stride);
+       ret = fdt_setprop(blob, off, "stride", cells, sizeof(cells[0]));
+       if (ret < 0)
+               return -1;
+
+       ret = fdt_setprop(blob, off, "format", format, strlen(format) + 1);
+       if (ret < 0)
+               return -1;
+
+       ret = fdt_delprop(blob, off, "status");
+       if (ret < 0)
+               return -1;
+
+       return 0;
+}
+
+int lcd_dt_simplefb_add_node(void *blob)
+{
+       const char compat[] = "simple-framebuffer";
+       const char disabled[] = "disabled";
+       int off, ret;
+
+       off = fdt_add_subnode(blob, 0, "framebuffer");
+       if (off < 0)
+               return -1;
+
+       ret = fdt_setprop(blob, off, "status", disabled, sizeof(disabled));
+       if (ret < 0)
+               return -1;
+
+       ret = fdt_setprop(blob, off, "compatible", compat, sizeof(compat));
+       if (ret < 0)
+               return -1;
+
+       return lcd_dt_simplefb_configure_node(blob, off);
+}
+
+int lcd_dt_simplefb_enable_existing_node(void *blob)
+{
+       int off;
+
+       off = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer");
+       if (off < 0)
+               return -1;
+
+       return lcd_dt_simplefb_configure_node(blob, off);
+}
+#endif

diff --git a/doc/device-tree-bindings/video/simple-framebuffer.txt b/doc/device-tree-bindings/video/simple-framebuffer.txt
new file mode 100644 (file)
index 0000000..3ea4605
--- /dev/null
+++ b/doc/device-tree-bindings/video/simple-framebuffer.txt
@@ -0,0 +1,25 @@
+Simple Framebuffer
+
+A simple frame-buffer describes a raw memory region that may be rendered to,
+with the assumption that the display hardware has already been set up to scan
+out from that buffer.
+
+Required properties:
+- compatible: "simple-framebuffer"
+- reg: Should contain the location and size of the framebuffer memory.
+- width: The width of the framebuffer in pixels.
+- height: The height of the framebuffer in pixels.
+- stride: The number of bytes in each line of the framebuffer.
+- format: The format of the framebuffer surface. Valid values are:
+  - r5g6b5 (16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b).
+
+Example:
+
+       framebuffer {
+               compatible = "simple-framebuffer";
+               reg = <0x1d385000 (1600 * 1200 * 2)>;
+               width = <1600>;
+               height = <1200>;
+               stride = <(1600 * 2)>;
+               format = "r5g6b5";
+       };

diff --git a/include/lcd.h b/include/lcd.h
index c6e7fc5216330c6797e7c28a640a67322766a446..30225edf563fb1212db8e3868e4ef626921affaf 100644 (file)
--- a/include/lcd.h
+++ b/include/lcd.h
@@ -324,6 +324,9 @@ void lcd_show_board_info(void);
 /* Return the size of the LCD frame buffer, and the line length */
 int lcd_get_size(int *line_length);
 
+int lcd_dt_simplefb_add_node(void *blob);
+int lcd_dt_simplefb_enable_existing_node(void *blob);
+
 /************************************************************************/
 /* ** BITMAP DISPLAY SUPPORT                                           */
 /************************************************************************/