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>

diff --git a/drivers/video/imxfb.c b/drivers/video/imxfb.c
index 629d66f..5c61286 100644 (file)
--- 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;