diff mbox series

[v2,5/5] drm/ssd130x: Remove hardcoded bits-per-pixel in ssd130x_buf_alloc()

Message ID 20230609170941.1150941-6-javierm@redhat.com
State New
Headers
Series drm/ssd130x: A few enhancements and cleanups |

Commit Message

Javier Martinez Canillas June 9, 2023, 5:09 p.m. UTC 
  The driver only supports OLED controllers that have a native DRM_FORMAT_C1
pixel format and that is why it has harcoded a division of the width by 8.

But the driver might be extended to support devices that have a different
pixel format. So it's better to use the struct drm_format_info helpers to
compute the size of the buffer, used to store the pixels in native format.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---

(no changes since v1)

 drivers/gpu/drm/solomon/ssd130x.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Comments

Geert Uytterhoeven July 12, 2023, 10:24 a.m. UTC | #1 
Hi Javier,

Thanks for your patch!

On Fri, Jun 9, 2023 at 7:09 PM Javier Martinez Canillas
<javierm@redhat.com> wrote:
> The driver only supports OLED controllers that have a native DRM_FORMAT_C1

DRM_FORMAT_R1 (colormap is fixed to white-on-black).

> pixel format and that is why it has harcoded a division of the width by 8.

hardcoded.

> But the driver might be extended to support devices that have a different
> pixel format. So it's better to use the struct drm_format_info helpers to
> compute the size of the buffer, used to store the pixels in native format.
>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

> --- a/drivers/gpu/drm/solomon/ssd130x.c
> +++ b/drivers/gpu/drm/solomon/ssd130x.c
> @@ -150,9 +150,16 @@ static int ssd130x_buf_alloc(struct ssd130x_device *ssd130x)
>  {
>         unsigned int page_height = ssd130x->device_info->page_height;
>         unsigned int pages = DIV_ROUND_UP(ssd130x->height, page_height);
> +       const struct drm_format_info *fi;
> +       unsigned int pitch;
>
> -       ssd130x->buffer = kcalloc(DIV_ROUND_UP(ssd130x->width, 8),
> -                                 ssd130x->height, GFP_KERNEL);
> +       fi = drm_format_info(DRM_FORMAT_C1);

DRM_FORMAT_R1.

> +       if (!fi)
> +               return -EINVAL;
> +
> +       pitch = drm_format_info_min_pitch(fi, 0, ssd130x->width);
> +
> +       ssd130x->buffer = kcalloc(pitch, ssd130x->height, GFP_KERNEL);
>         if (!ssd130x->buffer)
>                 return -ENOMEM;

Gr{oetje,eeting}s,

                        Geert
diff mbox series

Patch

diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index 0be3b476dc60..b3dc1ca9dc10 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -150,9 +150,16 @@  static int ssd130x_buf_alloc(struct ssd130x_device *ssd130x)
 {
 	unsigned int page_height = ssd130x->device_info->page_height;
 	unsigned int pages = DIV_ROUND_UP(ssd130x->height, page_height);
+	const struct drm_format_info *fi;
+	unsigned int pitch;
 
-	ssd130x->buffer = kcalloc(DIV_ROUND_UP(ssd130x->width, 8),
-				  ssd130x->height, GFP_KERNEL);
+	fi = drm_format_info(DRM_FORMAT_C1);
+	if (!fi)
+		return -EINVAL;
+
+	pitch = drm_format_info_min_pitch(fi, 0, ssd130x->width);
+
+	ssd130x->buffer = kcalloc(pitch, ssd130x->height, GFP_KERNEL);
 	if (!ssd130x->buffer)
 		return -ENOMEM;