# \[PATCH\] atmel\_lcdfb: wiring BGR to RGB color mode - List: linux-fbdev - 3 messages, 2 authors - Page: https://ratatoskr.run/linux-fbdev/2008/03/1072867/t ## \[PATCH\] atmel\_lcdfb: wiring BGR to RGB color mode - From: Nicolas Ferre \ - Date: 2008-03-10 14:26:41 - Message: https://ratatoskr.run/linux-fbdev/2008/03/1072867.md ```text 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(-) --- linux-2.6.x-rc.orig/drivers/video/atmel_lcdfb.c +++ linux-2.6.x-rc/drivers/video/atmel_lcdfb.c @@ -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; --- linux-2.6.x-rc.orig/include/video/atmel_lcdc.h +++ linux-2.6.x-rc/include/video/atmel_lcdc.h @@ -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); ``` ## Re: \[Linux-fbdev-devel\] \[PATCH\] atmel\_lcdfb: wiring BGR to RGB colormode - From: Nicolas Ferre \ - Date: 2008-03-10 16:29:07 - Message: https://ratatoskr.run/linux-fbdev/2008/03/1072914.md ```text Nicolas Ferre : > 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). Forgotten line : Signed-off-by: Nicolas Ferre > --- > drivers/video/atmel_lcdfb.c | 27 ++++++++++++++++++++++----- > include/video/atmel_lcdc.h | 10 ++++++++++ > 2 files changed, 32 insertions(+), 5 deletions(-) -- Nicolas Ferre ``` ## Re: \[PATCH\] atmel\_lcdfb: wiring BGR to RGB color mode - From: Haavard Skinnemoen \ - Date: 2008-03-13 15:36:16 - Message: https://ratatoskr.run/linux-fbdev/2008/03/1074364.md ```text On Mon, 10 Mar 2008 15:26:18 +0100 Nicolas Ferre [ref] wrote: > 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) > - 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; > + } Does RGB:565 always imply RGB:888 and vice versa? If not, I think it would be better with separate flags for the possible wirings: * 18-bit BGR-555.1 / 24-bit BGR-888 * 16-bit RGB-565 * 24-bit RGB-888 Or maybe I misunderstand something? Haavard ```