[PATCH] atmel_lcdfb: wiring BGR to RGB color mode - Kernel

This is a discussion on [PATCH] atmel_lcdfb: wiring BGR to RGB color mode - Kernel ; 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 ...

+ Reply to Thread
Results 1 to 3 of 3

Thread: [PATCH] atmel_lcdfb: wiring BGR to RGB color mode

  1. [PATCH] 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/p...ts/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);

    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  2. Re: [Linux-fbdev-devel] [PATCH] atmel_lcdfb: wiring BGR to RGB colormode

    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/p...ts/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
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  3. Re: [PATCH] atmel_lcdfb: wiring BGR to RGB color mode

    On Mon, 10 Mar 2008 15:26:18 +0100
    Nicolas Ferre 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/p...ts/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
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

+ Reply to Thread