[PATCH v2 3/5] drm/mipi_dbi: Add support for display offsets

[Sam Ravnborg]

Hi Noralf.

If you could find time to review this patch it would be great.
I am reluctant to apply it until you have acked/reviewed it.

Thanks in advance,

	Sam

On Wed, Jan 15, 2020 at 01:45:46PM +0100, Geert Uytterhoeven wrote:
> If the resolution of the TFT display is smaller than the maximum
> resolution supported by the display controller, the display may be
> connected to the driver output arrays with a horizontal and/or vertical
> offset, leading to a shifted image.
> 
> Add support for specifying these offsets.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
> Reviewed-by: Sam Ravnborg <sam at ravnborg.org>
> ---
> v2:
>   - Add Reviewed-by.
> ---
>  drivers/gpu/drm/drm_mipi_dbi.c | 30 ++++++++++++++++++++----------
>  include/drm/drm_mipi_dbi.h     | 12 ++++++++++++
>  2 files changed, 32 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
> index 16bff1be4b8ac622..27fe81a53c88e338 100644
> --- a/drivers/gpu/drm/drm_mipi_dbi.c
> +++ b/drivers/gpu/drm/drm_mipi_dbi.c
> @@ -238,6 +238,23 @@ int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
>  }
>  EXPORT_SYMBOL(mipi_dbi_buf_copy);
>  
> +static void mipi_dbi_set_window_address(struct mipi_dbi_dev *dbidev,
> +					unsigned int xs, unsigned int xe,
> +					unsigned int ys, unsigned int ye)
> +{
> +	struct mipi_dbi *dbi = &dbidev->dbi;
> +
> +	xs += dbidev->left_offset;
> +	xe += dbidev->left_offset;
> +	ys += dbidev->top_offset;
> +	ye += dbidev->top_offset;
> +
> +	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS, (xs >> 8) & 0xff,
> +			 xs & 0xff, (xe >> 8) & 0xff, xe & 0xff);
> +	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS, (ys >> 8) & 0xff,
> +			 ys & 0xff, (ye >> 8) & 0xff, ye & 0xff);
> +}
> +
>  static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  {
>  	struct drm_gem_object *gem = drm_gem_fb_get_obj(fb, 0);
> @@ -271,12 +288,8 @@ static void mipi_dbi_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
>  		tr = cma_obj->vaddr;
>  	}
>  
> -	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
> -			 (rect->x1 >> 8) & 0xff, rect->x1 & 0xff,
> -			 ((rect->x2 - 1) >> 8) & 0xff, (rect->x2 - 1) & 0xff);
> -	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
> -			 (rect->y1 >> 8) & 0xff, rect->y1 & 0xff,
> -			 ((rect->y2 - 1) >> 8) & 0xff, (rect->y2 - 1) & 0xff);
> +	mipi_dbi_set_window_address(dbidev, rect->x1, rect->x2 - 1, rect->y1,
> +				    rect->y2 - 1);
>  
>  	ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START, tr,
>  				   width * height * 2);
> @@ -366,10 +379,7 @@ static void mipi_dbi_blank(struct mipi_dbi_dev *dbidev)
>  
>  	memset(dbidev->tx_buf, 0, len);
>  
> -	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS, 0, 0,
> -			 ((width - 1) >> 8) & 0xFF, (width - 1) & 0xFF);
> -	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS, 0, 0,
> -			 ((height - 1) >> 8) & 0xFF, (height - 1) & 0xFF);
> +	mipi_dbi_set_window_address(dbidev, 0, width - 1, 0, height - 1);
>  	mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
>  			     (u8 *)dbidev->tx_buf, len);
>  
> diff --git a/include/drm/drm_mipi_dbi.h b/include/drm/drm_mipi_dbi.h
> index 67c66f5ee591e80f..33f325f5af2b921f 100644
> --- a/include/drm/drm_mipi_dbi.h
> +++ b/include/drm/drm_mipi_dbi.h
> @@ -109,6 +109,18 @@ struct mipi_dbi_dev {
>  	 */
>  	unsigned int rotation;
>  
> +	/**
> +	 * @left_offset: Horizontal offset of the display relative to the
> +	 *               controller's driver array
> +	 */
> +	unsigned int left_offset;
> +
> +	/**
> +	 * @top_offset: Vertical offset of the display relative to the
> +	 *              controller's driver array
> +	 */
> +	unsigned int top_offset;
> +
>  	/**
>  	 * @backlight: backlight device (optional)
>  	 */
> -- 
> 2.17.1