atmel_lcdfb: wiring BGR to RGB color mode

Adds different wiring mode for the LCD screen.

The legacy atmel LCDC IP uses a non standard color mode,
"BGR-555.1" instead "RGB-565". The major part of graphic stacks for embedded systems uses only "RGB-565". It is possible to swap LCD IOs instead of doing this bit swapping by software (See application note AT91SAM9 LCD Controller
http://www.atmel.com/dyn/resources/prod_documents/doc6300.pdf)

This wire swapping is done on the at91sam9rl-ek board (board code using this patch will come later).
---

drivers/video/atmel_lcdfb.c |   27 ++++++++++++++++++++++-----
include/video/atmel_lcdc.h  |   10 ++++++++++
2 files changed, 32 insertions(+), 5 deletions(-)

@@ -338,19 +338,35 @@ static int atmel_lcdfb_check_var(struct 

		break;
	case 15:
	case 16:

- var->red.offset = 0;
+ if (sinfo->lcd_wiring_mode == ATMEL_LCDC_WIRING_RGB) {
+ /* RGB:565 mode */
+ var->red.offset = 11;
+ var->blue.offset = 0;
+ var->green.length = 6;
+ } else {
+ /* BGR:555 mode */
+ var->red.offset = 0;
+ var->blue.offset = 10;
+ var->green.length = 5;
+ }

		var->green.offset = 5;
-		var->blue.offset = 10;
-		var->red.length = var->green.length = var->blue.length = 5;
+		var->red.length = var->blue.length = 5;
		break;
	case 32:
		var->transp.offset = 24;
		var->transp.length = 8;
		/* fall through */
	case 24:

- var->red.offset = 0;
+ if (sinfo->lcd_wiring_mode == ATMEL_LCDC_WIRING_RGB) {
+ /* RGB:888 mode */
+ var->red.offset = 16;
+ var->blue.offset = 0;
+ } else {
+ /* BGR:888 mode */
+ var->red.offset = 0;
+ var->blue.offset = 16;
+ }

		var->green.offset = 8;
-		var->blue.offset = 16;
		var->red.length = var->green.length = var->blue.length = 8;
		break;
	default:
@@ -697,6 +713,7 @@ static int __init atmel_lcdfb_probe(stru
		sinfo->atmel_lcdfb_power_control = pdata_sinfo->atmel_lcdfb_power_control;
		sinfo->guard_time = pdata_sinfo->guard_time;
		sinfo->lcdcon_is_backlight = pdata_sinfo->lcdcon_is_backlight;
+		sinfo->lcd_wiring_mode = pdata_sinfo->lcd_wiring_mode;
	} else {
		dev_err(dev, "cannot get default configuration\n");
		goto free_info;

@@ -22,6 +22,15 @@

#ifndef __ATMEL_LCDC_H__
#define __ATMEL_LCDC_H__

+
+/* Way LCD wires are connected to the chip:
+ * Some Atmel chips use BGR color mode (instead of standard RGB)
+ * A swapped wiring onboard can bring to RGB mode.
+ */
+#define ATMEL_LCDC_WIRING_BGR 0
+#define ATMEL_LCDC_WIRING_RGB 1
+
+
/* LCD Controller info data structure, stored in device platform_data */

struct atmel_lcdfb_info {
	spinlock_t		lock;
@@ -42,6 +51,7 @@ struct atmel_lcdfb_info {
	u8			saved_lcdcon;

	u8			default_bpp;
+	u8			lcd_wiring_mode;
	unsigned int		default_lcdcon2;
	unsigned int		default_dmacon;
	void (*atmel_lcdfb_power_control)(int on);

Nicolas Ferre :

Forgotten line :

Nicolas Ferre