i.MX Framebuffer: add TFT support

With TFTs we can do 5/6/5 instead of 4/4/4. Add a bitfield for this
and use it with TFTs.
Acked-by: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers/video/imxfb.c

@@ -116,16 +116,10 @@ struct imxfb_rgb {
 	struct fb_bitfield	transp;
 };
 
-#define RGB_16	(0)
-#define RGB_8	(1)
-#define NR_RGB	2
-
 struct imxfb_info {
 	struct platform_device  *pdev;
 	void __iomem		*regs;
 
-	struct imxfb_rgb	*rgb[NR_RGB];
-
 	u_int			max_bpp;
 	u_int			max_xres;
 	u_int			max_yres;
@@ -165,7 +159,14 @@ struct imxfb_info {
 #define MIN_XRES	64
 #define MIN_YRES	64
 
-static struct imxfb_rgb def_rgb_16 = {
+static struct imxfb_rgb def_rgb_16_tft = {
+	.red	= {.offset = 11, .length = 5,},
+	.green	= {.offset = 5, .length = 6,},
+	.blue	= {.offset = 0, .length = 5,},
+	.transp = {.offset = 0, .length = 0,},
+};
+
+static struct imxfb_rgb def_rgb_16_stn = {
 	.red	= {.offset = 8, .length = 4,},
 	.green	= {.offset = 4, .length = 4,},
 	.blue	= {.offset = 0, .length = 4,},
@@ -270,7 +271,7 @@ static int imxfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 static int imxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 {
 	struct imxfb_info *fbi = info->par;
-	int rgbidx;
+	struct imxfb_rgb *rgb;
 
 	if (var->xres < MIN_XRES)
 		var->xres = MIN_XRES;
@@ -286,23 +287,25 @@ 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 16:
-		rgbidx = RGB_16;
+	default:
+		if (readl(fbi->regs + LCDC_PCR) & PCR_TFT)
+			rgb = &def_rgb_16_tft;
+		else
+			rgb = &def_rgb_16_stn;
 		break;
 	case 8:
-		rgbidx = RGB_8;
+		rgb = &def_rgb_8;
 		break;
-	default:
-		rgbidx = RGB_16;
 	}
 
 	/*
 	 * Copy the RGB parameters for this display
 	 * from the machine specific parameters.
 	 */
-	var->red    = fbi->rgb[rgbidx]->red;
-	var->green  = fbi->rgb[rgbidx]->green;
-	var->blue   = fbi->rgb[rgbidx]->blue;
-	var->transp = fbi->rgb[rgbidx]->transp;
+	var->red    = rgb->red;
+	var->green  = rgb->green;
+	var->blue   = rgb->blue;
+	var->transp = rgb->transp;
 
 	pr_debug("RGBT length = %d:%d:%d:%d\n",
 		var->red.length, var->green.length, var->blue.length,
@@ -545,9 +548,6 @@ static int __init imxfb_init_fbinfo(struct platform_device *pdev)
 	info->flags			= FBINFO_FLAG_DEFAULT |
 					  FBINFO_READS_FAST;
 
-	fbi->rgb[RGB_16]		= &def_rgb_16;
-	fbi->rgb[RGB_8]			= &def_rgb_8;
-
 	fbi->max_xres			= pdata->xres;
 	info->var.xres			= pdata->xres;
 	info->var.xres_virtual		= pdata->xres;