imxfb: add 18 bit support

v2: As pointed out by Hans J. Koch we have to claim we can do 24bit to
    make software like X work. We are lucky on i.MX that 18bit support
    has the necessary gaps in the fields to do so.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 15 insertions, 4 deletions

diff --git a/drivers/video/imxfb.c b/drivers/video/imxfb.c
index 629d66f32300..5c61286d7ff5 100644
--- a/drivers/video/imxfb.c
+++ b/drivers/video/imxfb.c
@@ -14,7 +14,6 @@
  *      linux-arm-kernel@lists.arm.linux.org.uk
  */
 
-
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
@@ -159,6 +158,17 @@ struct imxfb_info {
 #define MIN_XRES        64
 #define MIN_YRES        64
 
+/* Actually this really is 18bit support, the lowest 2 bits of each colour
+ * are unused in hardware. We claim to have 24bit support to make software
+ * like X work, which does not support 18bit.
+ */
+static struct imxfb_rgb def_rgb_18 = {
+        .red    = {.offset = 16, .length = 8,},
+        .green  = {.offset = 8, .length = 8,},
+        .blue   = {.offset = 0, .length = 8,},
+        .transp = {.offset = 0, .length = 0,},
+};
+
 static struct imxfb_rgb def_rgb_16_tft = {
         .red    = {.offset = 11, .length = 5,},
         .green  = {.offset = 5, .length = 6,},
@@ -286,6 +296,9 @@ static int imxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 
         pr_debug("var->bits_per_pixel=%d\n", var->bits_per_pixel);
         switch (var->bits_per_pixel) {
+        case 32:
+                rgb = &def_rgb_18;
+                break;
         case 16:
         default:
                 if (readl(fbi->regs + LCDC_PCR) & PCR_TFT)
@@ -327,9 +340,7 @@ static int imxfb_set_par(struct fb_info *info)
         struct imxfb_info *fbi = info->par;
         struct fb_var_screeninfo *var = &info->var;
 
-        pr_debug("set_par\n");
-
-        if (var->bits_per_pixel == 16)
+        if (var->bits_per_pixel == 16 || var->bits_per_pixel == 32)
                 info->fix.visual = FB_VISUAL_TRUECOLOR;
         else if (!fbi->cmap_static)
                 info->fix.visual = FB_VISUAL_PSEUDOCOLOR;