ARM: tegra: video: Support basic color scheme

This patch contains:
1. Changes in fb.c to support the old color scheme for fbcon
2. Addition of color registration function in fb ops in fb.c

tegra_fb_setcolreg was removed by mistake in commit
f80e81610f4e2e3a9051b465a9176ac70f6913f1 (http://git-master/r/60201)
This patch contains a work around for the co-existence of both basic
and new color schemes.

Bug: 921567
Change-Id: I2b10d4956ce655511fc277d113e623d5d717ed5c
Signed-off-by: Shashank Sharma <shashanks@nvidia.com>
Reviewed-on: http://git-master/r/79397
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>

Rebase-Id: Rab127e79e8fdc17051b1de665ff1dd35f7ef9651

1 files changed, 60 insertions, 8 deletions

diff --git a/drivers/video/tegra/fb.c b/drivers/video/tegra/fb.c
index 68c328c90..e9bc1f78c 100644
--- a/drivers/video/tegra/fb.c
+++ b/drivers/video/tegra/fb.c
@@ -146,6 +146,33 @@ static int tegra_fb_set_par(struct fb_info *info)
         return 0;
 }
 
+static int tegra_fb_setcolreg(unsigned regno, unsigned red, unsigned green,
+        unsigned blue, unsigned transp, struct fb_info *info)
+{
+        struct fb_var_screeninfo *var = &info->var;
+
+        if (info->fix.visual == FB_VISUAL_TRUECOLOR ||
+            info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
+                u32 v;
+
+                if (regno >= 16)
+                        return -EINVAL;
+
+                red = (red >> (16 - info->var.red.length));
+                green = (green >> (16 - info->var.green.length));
+                blue = (blue >> (16 - info->var.blue.length));
+
+                v = (red << var->red.offset) |
+                        (green << var->green.offset) |
+                        (blue << var->blue.offset);
+
+                ((u32 *)info->pseudo_palette)[regno] = v;
+        }
+
+        return 0;
+}
+
+
 static int tegra_fb_setcmap(struct fb_cmap *cmap, struct fb_info *info)
 {
         struct tegra_fb_info *tegra_fb = info->par;
@@ -160,16 +187,41 @@ static int tegra_fb_setcmap(struct fb_cmap *cmap, struct fb_info *info)
                 return -EINVAL;
 
         if (info->fix.visual == FB_VISUAL_TRUECOLOR ||
-            info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
-                for (i = 0; i < cmap->len; i++) {
-                        dc->fb_lut.r[start+i] = *red++ >> 8;
-                        dc->fb_lut.g[start+i] = *green++ >> 8;
-                        dc->fb_lut.b[start+i] = *blue++ >> 8;
+                info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
+                /*
+                 * For now we are considering color schemes with
+                 * cmap->len <=16 as special case of basic color
+                 * scheme to support fbconsole.But for DirectColor
+                 * visuals(like the one we actually have, that include
+                 * a HW LUT),the way it's intended to work is that the
+                 * actual LUT HW is programmed to the intended values,
+                 * even for small color maps like those with 16 or fewer
+                 * entries. The pseudo_palette is then programmed to the
+                 * identity transform.
+                 */
+                if (cmap->len <= 16) {
+                        /* Low-color schemes like fbconsole*/
+                        u16 *transp = cmap->transp;
+                        u_int vtransp = 0xffff;
+
+                        for (i = 0; i < cmap->len; i++) {
+                                if (transp)
+                                        vtransp = *transp++;
+                                if (tegra_fb_setcolreg(start++, *red++,
+                                        *green++, *blue++,
+                                        vtransp, info))
+                                                return -EINVAL;
+                        }
+                } else {
+                        /* High-color schemes*/
+                        for (i = 0; i < cmap->len; i++) {
+                                dc->fb_lut.r[start+i] = *red++ >> 8;
+                                dc->fb_lut.g[start+i] = *green++ >> 8;
+                                dc->fb_lut.b[start+i] = *blue++ >> 8;
+                        }
+                        tegra_dc_update_lut(dc, -1, -1);
                 }
-
-                tegra_dc_update_lut(dc, -1, -1);
         }
-
         return 0;
 }