atmel_lcdfb: fix 16-bpp modes on older SOCs

Fix regression introduced by commit 787f9fd23283 ("atmel_lcdfb: support
16bit BGR:565 mode, remove unsupported 15bit modes") which broke 16-bpp
modes for older SOCs which use IBGR:555 (msb is intensity) rather
than BGR:565.

Use SOC-type to determine the pixel layout.

Tested on at91sam9263 and at91sam9g45.

Cc: <stable@vger.kernel.org>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

drivers/video/atmel_lcdfb.c

@@ -422,17 +422,22 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
 			= var->bits_per_pixel;
 		break;
 	case 16:
+		/* Older SOCs use IBGR:555 rather than BGR:565. */
+		if (sinfo->have_intensity_bit)
+			var->green.length = 5;
+		else
+			var->green.length = 6;
+
 		if (sinfo->lcd_wiring_mode == ATMEL_LCDC_WIRING_RGB) {
-			/* RGB:565 mode */
-			var->red.offset = 11;
+			/* RGB:5X5 mode */
+			var->red.offset = var->green.length + 5;
 			var->blue.offset = 0;
 		} else {
-			/* BGR:565 mode */
+			/* BGR:5X5 mode */
 			var->red.offset = 0;
-			var->blue.offset = 11;
+			var->blue.offset = var->green.length + 5;
 		}
 		var->green.offset = 5;
-		var->green.length = 6;
 		var->red.length = var->blue.length = 5;
 		break;
 	case 32:
@@ -679,8 +684,7 @@ static int atmel_lcdfb_setcolreg(unsigned int regno, unsigned int red,
 
 	case FB_VISUAL_PSEUDOCOLOR:
 		if (regno < 256) {
-			if (cpu_is_at91sam9261() || cpu_is_at91sam9263()
-			    || cpu_is_at91sam9rl()) {
+			if (sinfo->have_intensity_bit) {
 				/* old style I+BGR:555 */
 				val  = ((red   >> 11) & 0x001f);
 				val |= ((green >>  6) & 0x03e0);
@@ -870,6 +874,10 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
 	}
 	sinfo->info = info;
 	sinfo->pdev = pdev;
+	if (cpu_is_at91sam9261() || cpu_is_at91sam9263() ||
+							cpu_is_at91sam9rl()) {
+		sinfo->have_intensity_bit = true;
+	}
 
 	strcpy(info->fix.id, sinfo->pdev->name);
 	info->flags = ATMEL_LCDFB_FBINFO_DEFAULT;

include/video/atmel_lcdc.h

@@ -62,6 +62,7 @@ struct atmel_lcdfb_info {
 	void (*atmel_lcdfb_power_control)(int on);
 	struct fb_monspecs	*default_monspecs;
 	u32			pseudo_palette[16];
+	bool			have_intensity_bit;
 };
 
 #define ATMEL_LCDC_DMABADDR1	0x00