The callback functions for line conversion are almost identical for
some format. The generic READ_LINE macro generate all the required
boilerplate to process a line.

Two overrides of this macro have been added to avoid duplication of
the same arguments every time.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_formats.c | 163 +++++++++++++-----------------------
 1 file changed, 58 insertions(+), 105 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index f9841b8000c4..8f1bcca38148 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -292,6 +292,58 @@ VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1,
 }
 EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
 
+/**
+ * READ_LINE() - Generic generator for a read_line function which can be used for format with one
+ * plane and a block_h == block_w == 1.
+ *
+ * @function_name: Function name to generate
+ * @pixel_name: temporary pixel name used in the @__VA_ARGS__ parameters
+ * @pixel_type: Used to specify the type you want to cast the pixel pointer
+ * @callback: Callback to call for each pixels. This fonction should take @__VA_ARGS__ as parameter
+ *            and return a pixel_argb_u16
+ * @__VA_ARGS__: Argument to pass inside the callback. You can use @pixel_name to access current
+ *  pixel.
+ */
+#define READ_LINE(function_name, pixel_name, pixel_type, callback, ...)				\
+static void function_name(const struct vkms_plane_state *plane, int x_start,			\
+			      int y_start, enum pixel_read_direction direction, int count,	\
+			      struct pixel_argb_u16 out_pixel[])				\
+{												\
+	struct pixel_argb_u16 *end = out_pixel + count;						\
+	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);			\
+	u8 *src_pixels;										\
+												\
+	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);		\
+												\
+	while (out_pixel < end) {								\
+		pixel_type *(pixel_name) = (pixel_type *)src_pixels;				\
+		*out_pixel = (callback)(__VA_ARGS__);						\
+		out_pixel += 1;									\
+		src_pixels += step;								\
+	}											\
+}
+
+/**
+ * READ_LINE_ARGB8888() - Generic generator for ARGB8888 formats.
+ * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
+ *
+ * @function_name: Function name to generate
+ * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
+ * @a, @r, @g, @b: value of each channel
+ */
+#define READ_LINE_ARGB8888(function_name, pixel_name, a, r, g, b) \
+	READ_LINE(function_name, pixel_name, u8, argb_u16_from_u8888, a, r, g, b)
+/**
+ * READ_LINE_ARGB16161616() - Generic generator for ARGB16161616 formats.
+ * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
+ *
+ * @function_name: Function name to generate
+ * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
+ * @a, @r, @g, @b: value of each channel
+ */
+#define READ_LINE_16161616(function_name, pixel_name, a, r, g, b) \
+	READ_LINE(function_name, pixel_name, u16, argb_u16_from_u16161616, a, r, g, b)
+
 /*
  * The following functions are read_line function for each pixel format supported by VKMS.
  *
@@ -378,118 +430,19 @@ static void R4_read_line(const struct vkms_plane_state *plane, int x_start,
 	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel);
 }
 
-static void R8_read_line(const struct vkms_plane_state *plane, int x_start,
-			 int y_start, enum pixel_read_direction direction, int count,
-			 struct pixel_argb_u16 out_pixel[])
-{
-	struct pixel_argb_u16 *end = out_pixel + count;
-	u8 *src_pixels;
-	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
-
-	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
-
-	while (out_pixel < end) {
-		*out_pixel = argb_u16_from_gray8(*src_pixels);
-		src_pixels += step;
-		out_pixel += 1;
-	}
-}
-
-static void ARGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
-			       enum pixel_read_direction direction, int count,
-			       struct pixel_argb_u16 out_pixel[])
-{
-	struct pixel_argb_u16 *end = out_pixel + count;
-	u8 *src_pixels;
-
-	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
-
-	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
-
-	while (out_pixel < end) {
-		u8 *px = (u8 *)src_pixels;
-		*out_pixel = argb_u16_from_u8888(px[3], px[2], px[1], px[0]);
-		out_pixel += 1;
-		src_pixels += step;
-	}
-}
-
-static void XRGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
-			       enum pixel_read_direction direction, int count,
-			       struct pixel_argb_u16 out_pixel[])
-{
-	struct pixel_argb_u16 *end = out_pixel + count;
-	u8 *src_pixels;
-
-	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
-
-	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
-
-	while (out_pixel < end) {
-		u8 *px = (u8 *)src_pixels;
-		*out_pixel = argb_u16_from_u8888(255, px[2], px[1], px[0]);
-		out_pixel += 1;
-		src_pixels += step;
-	}
-}
-
-static void ARGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
-				   int y_start, enum pixel_read_direction direction, int count,
-				   struct pixel_argb_u16 out_pixel[])
-{
-	struct pixel_argb_u16 *end = out_pixel + count;
-	u8 *src_pixels;
-
-	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
-
-	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
-
-	while (out_pixel < end) {
-		u16 *px = (u16 *)src_pixels;
-		*out_pixel = argb_u16_from_u16161616(px[3], px[2], px[1], px[0]);
-		out_pixel += 1;
-		src_pixels += step;
-	}
-}
-
-static void XRGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
-				   int y_start, enum pixel_read_direction direction, int count,
-				   struct pixel_argb_u16 out_pixel[])
-{
-	struct pixel_argb_u16 *end = out_pixel + count;
-	u8 *src_pixels;
-
-	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
 
-	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
+READ_LINE_ARGB8888(XRGB8888_read_line, px, 255, px[2], px[1], px[0])
 
-	while (out_pixel < end) {
-		__le16 *px = (__le16 *)src_pixels;
-		*out_pixel = argb_u16_from_le16161616(cpu_to_le16(0xFFFF), px[2], px[1], px[0]);
-		out_pixel += 1;
-		src_pixels += step;
-	}
-}
+READ_LINE_ARGB8888(ARGB8888_read_line, px, px[3], px[2], px[1], px[0])
 
-static void RGB565_read_line(const struct vkms_plane_state *plane, int x_start,
-			     int y_start, enum pixel_read_direction direction, int count,
-			     struct pixel_argb_u16 out_pixel[])
-{
-	struct pixel_argb_u16 *end = out_pixel + count;
-	u8 *src_pixels;
 
-	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
+READ_LINE_16161616(ARGB16161616_read_line, px, px[3], px[2], px[1], px[0]);
+READ_LINE_16161616(XRGB16161616_read_line, px, 0xFFFF, px[2], px[1], px[0]);
 
-	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
+READ_LINE(RGB565_read_line, px, __le16, argb_u16_from_RGB565, px)
 
-	while (out_pixel < end) {
-		__le16 *px = (__le16 *)src_pixels;
+READ_LINE(R8_read_line, px, u8, argb_u16_from_gray8, *px)
 
-		*out_pixel = argb_u16_from_RGB565(px);
-		out_pixel += 1;
-		src_pixels += step;
-	}
-}
 
 /*
  * This callback can be used for YUV formats where U and V values are

-- 
2.46.2

Hi Louis,

On 07/10/24 13:46, Louis Chauvet wrote:
> The callback functions for line conversion are almost identical for
> some format. The generic READ_LINE macro generate all the required
> boilerplate to process a line.
> 
> Two overrides of this macro have been added to avoid duplication of
> the same arguments every time.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>   drivers/gpu/drm/vkms/vkms_formats.c | 163 +++++++++++++-----------------------
>   1 file changed, 58 insertions(+), 105 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> index f9841b8000c4..8f1bcca38148 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.c
> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> @@ -292,6 +292,58 @@ VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1,
>   }
>   EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
>   
> +/**
> + * READ_LINE() - Generic generator for a read_line function which can be used for format with one
> + * plane and a block_h == block_w == 1.
> + *
> + * @function_name: Function name to generate
> + * @pixel_name: temporary pixel name used in the @__VA_ARGS__ parameters
> + * @pixel_type: Used to specify the type you want to cast the pixel pointer
> + * @callback: Callback to call for each pixels. This fonction should take @__VA_ARGS__ as parameter
> + *            and return a pixel_argb_u16
> + * @__VA_ARGS__: Argument to pass inside the callback. You can use @pixel_name to access current
> + *  pixel.
> + */
> +#define READ_LINE(function_name, pixel_name, pixel_type, callback, ...)				\
> +static void function_name(const struct vkms_plane_state *plane, int x_start,			\
> +			      int y_start, enum pixel_read_direction direction, int count,	\
> +			      struct pixel_argb_u16 out_pixel[])				\
> +{												\
> +	struct pixel_argb_u16 *end = out_pixel + count;						\
> +	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);			\
> +	u8 *src_pixels;										\
> +												\
> +	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);		\
> +												\
> +	while (out_pixel < end) {								\
> +		pixel_type *(pixel_name) = (pixel_type *)src_pixels;				\
> +		*out_pixel = (callback)(__VA_ARGS__);						\
> +		out_pixel += 1;									\
> +		src_pixels += step;								\
> +	}											\
> +}
> +
> +/**
> + * READ_LINE_ARGB8888() - Generic generator for ARGB8888 formats.
> + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> + *
> + * @function_name: Function name to generate
> + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> + * @a, @r, @g, @b: value of each channel
> + */
> +#define READ_LINE_ARGB8888(function_name, pixel_name, a, r, g, b) \
> +	READ_LINE(function_name, pixel_name, u8, argb_u16_from_u8888, a, r, g, b)
> +/**
> + * READ_LINE_ARGB16161616() - Generic generator for ARGB16161616 formats.
> + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> + *
> + * @function_name: Function name to generate
> + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> + * @a, @r, @g, @b: value of each channel
> + */
> +#define READ_LINE_16161616(function_name, pixel_name, a, r, g, b) \
> +	READ_LINE(function_name, pixel_name, u16, argb_u16_from_u16161616, a, r, g, b)
> +
>   /*
>    * The following functions are read_line function for each pixel format supported by VKMS.
>    *
> @@ -378,118 +430,19 @@ static void R4_read_line(const struct vkms_plane_state *plane, int x_start,
>   	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel);
>   }
>   
> -static void R8_read_line(const struct vkms_plane_state *plane, int x_start,
> -			 int y_start, enum pixel_read_direction direction, int count,
> -			 struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	while (out_pixel < end) {
> -		*out_pixel = argb_u16_from_gray8(*src_pixels);
> -		src_pixels += step;
> -		out_pixel += 1;
> -	}
> -}
> -
> -static void ARGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> -			       enum pixel_read_direction direction, int count,
> -			       struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	while (out_pixel < end) {
> -		u8 *px = (u8 *)src_pixels;
> -		*out_pixel = argb_u16_from_u8888(px[3], px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> -
> -static void XRGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> -			       enum pixel_read_direction direction, int count,
> -			       struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	while (out_pixel < end) {
> -		u8 *px = (u8 *)src_pixels;
> -		*out_pixel = argb_u16_from_u8888(255, px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> -
> -static void ARGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> -				   int y_start, enum pixel_read_direction direction, int count,
> -				   struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	while (out_pixel < end) {
> -		u16 *px = (u16 *)src_pixels;
> -		*out_pixel = argb_u16_from_u16161616(px[3], px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> -
> -static void XRGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> -				   int y_start, enum pixel_read_direction direction, int count,
> -				   struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
>   
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> +READ_LINE_ARGB8888(XRGB8888_read_line, px, 255, px[2], px[1], px[0])
>   
> -	while (out_pixel < end) {
> -		__le16 *px = (__le16 *)src_pixels;
> -		*out_pixel = argb_u16_from_le16161616(cpu_to_le16(0xFFFF), px[2], px[1], px[0]);

I just compile the whole series and I saw the warning:

drivers/gpu/drm/vkms/vkms_formats.c:226:30: warning: unused function 
'argb_u16_from_le16161616' [-Wunused-function]
   226 | static struct pixel_argb_u16 argb_u16_from_le16161616(__le16 a, 
__le16 r, __le16 g, __le16 b)
       |                              ^~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.

Best Regards,
- Maíra

> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> +READ_LINE_ARGB8888(ARGB8888_read_line, px, px[3], px[2], px[1], px[0])
>   
> -static void RGB565_read_line(const struct vkms_plane_state *plane, int x_start,
> -			     int y_start, enum pixel_read_direction direction, int count,
> -			     struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
>   
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> +READ_LINE_16161616(ARGB16161616_read_line, px, px[3], px[2], px[1], px[0]);
> +READ_LINE_16161616(XRGB16161616_read_line, px, 0xFFFF, px[2], px[1], px[0]);
>   
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> +READ_LINE(RGB565_read_line, px, __le16, argb_u16_from_RGB565, px)
>   
> -	while (out_pixel < end) {
> -		__le16 *px = (__le16 *)src_pixels;
> +READ_LINE(R8_read_line, px, u8, argb_u16_from_gray8, *px)
>   
> -		*out_pixel = argb_u16_from_RGB565(px);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
>   
>   /*
>    * This callback can be used for YUV formats where U and V values are
> 

On 26/10/24 - 11:58, Maíra Canal wrote:
> Hi Louis,
> 
> On 07/10/24 13:46, Louis Chauvet wrote:
> > The callback functions for line conversion are almost identical for
> > some format. The generic READ_LINE macro generate all the required
> > boilerplate to process a line.
> > 
> > Two overrides of this macro have been added to avoid duplication of
> > the same arguments every time.
> > 
> > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > ---
> >   drivers/gpu/drm/vkms/vkms_formats.c | 163 +++++++++++++-----------------------
> >   1 file changed, 58 insertions(+), 105 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> > index f9841b8000c4..8f1bcca38148 100644
> > --- a/drivers/gpu/drm/vkms/vkms_formats.c
> > +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> > @@ -292,6 +292,58 @@ VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1,
> >   }
> >   EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
> > +/**
> > + * READ_LINE() - Generic generator for a read_line function which can be used for format with one
> > + * plane and a block_h == block_w == 1.
> > + *
> > + * @function_name: Function name to generate
> > + * @pixel_name: temporary pixel name used in the @__VA_ARGS__ parameters
> > + * @pixel_type: Used to specify the type you want to cast the pixel pointer
> > + * @callback: Callback to call for each pixels. This fonction should take @__VA_ARGS__ as parameter
> > + *            and return a pixel_argb_u16
> > + * @__VA_ARGS__: Argument to pass inside the callback. You can use @pixel_name to access current
> > + *  pixel.
> > + */
> > +#define READ_LINE(function_name, pixel_name, pixel_type, callback, ...)				\
> > +static void function_name(const struct vkms_plane_state *plane, int x_start,			\
> > +			      int y_start, enum pixel_read_direction direction, int count,	\
> > +			      struct pixel_argb_u16 out_pixel[])				\
> > +{												\
> > +	struct pixel_argb_u16 *end = out_pixel + count;						\
> > +	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);			\
> > +	u8 *src_pixels;										\
> > +												\
> > +	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);		\
> > +												\
> > +	while (out_pixel < end) {								\
> > +		pixel_type *(pixel_name) = (pixel_type *)src_pixels;				\
> > +		*out_pixel = (callback)(__VA_ARGS__);						\
> > +		out_pixel += 1;									\
> > +		src_pixels += step;								\
> > +	}											\
> > +}
> > +
> > +/**
> > + * READ_LINE_ARGB8888() - Generic generator for ARGB8888 formats.
> > + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> > + *
> > + * @function_name: Function name to generate
> > + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> > + * @a, @r, @g, @b: value of each channel
> > + */
> > +#define READ_LINE_ARGB8888(function_name, pixel_name, a, r, g, b) \
> > +	READ_LINE(function_name, pixel_name, u8, argb_u16_from_u8888, a, r, g, b)
> > +/**
> > + * READ_LINE_ARGB16161616() - Generic generator for ARGB16161616 formats.
> > + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> > + *
> > + * @function_name: Function name to generate
> > + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> > + * @a, @r, @g, @b: value of each channel
> > + */
> > +#define READ_LINE_16161616(function_name, pixel_name, a, r, g, b) \
> > +	READ_LINE(function_name, pixel_name, u16, argb_u16_from_u16161616, a, r, g, b)
> > +
> >   /*
> >    * The following functions are read_line function for each pixel format supported by VKMS.
> >    *
> > @@ -378,118 +430,19 @@ static void R4_read_line(const struct vkms_plane_state *plane, int x_start,
> >   	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel);
> >   }
> > -static void R8_read_line(const struct vkms_plane_state *plane, int x_start,
> > -			 int y_start, enum pixel_read_direction direction, int count,
> > -			 struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	while (out_pixel < end) {
> > -		*out_pixel = argb_u16_from_gray8(*src_pixels);
> > -		src_pixels += step;
> > -		out_pixel += 1;
> > -	}
> > -}
> > -
> > -static void ARGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> > -			       enum pixel_read_direction direction, int count,
> > -			       struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	while (out_pixel < end) {
> > -		u8 *px = (u8 *)src_pixels;
> > -		*out_pixel = argb_u16_from_u8888(px[3], px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > -
> > -static void XRGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> > -			       enum pixel_read_direction direction, int count,
> > -			       struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	while (out_pixel < end) {
> > -		u8 *px = (u8 *)src_pixels;
> > -		*out_pixel = argb_u16_from_u8888(255, px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > -
> > -static void ARGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> > -				   int y_start, enum pixel_read_direction direction, int count,
> > -				   struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	while (out_pixel < end) {
> > -		u16 *px = (u16 *)src_pixels;
> > -		*out_pixel = argb_u16_from_u16161616(px[3], px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > -
> > -static void XRGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> > -				   int y_start, enum pixel_read_direction direction, int count,
> > -				   struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > +READ_LINE_ARGB8888(XRGB8888_read_line, px, 255, px[2], px[1], px[0])
> > -	while (out_pixel < end) {
> > -		__le16 *px = (__le16 *)src_pixels;
> > -		*out_pixel = argb_u16_from_le16161616(cpu_to_le16(0xFFFF), px[2], px[1], px[0]);
> 
> I just compile the whole series and I saw the warning:
> 
> drivers/gpu/drm/vkms/vkms_formats.c:226:30: warning: unused function
> 'argb_u16_from_le16161616' [-Wunused-function]
>   226 | static struct pixel_argb_u16 argb_u16_from_le16161616(__le16 a,
> __le16 r, __le16 g, __le16 b)
>       |                              ^~~~~~~~~~~~~~~~~~~~~~~~
> 1 warning generated.

Thanks, I will fix it for the v2!

In addition I will also fix the missing le/be managment in the macro, 
thanks!

Thanks,
Louis Chauvet
 
> Best Regards,
> - Maíra
> 
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > +READ_LINE_ARGB8888(ARGB8888_read_line, px, px[3], px[2], px[1], px[0])
> > -static void RGB565_read_line(const struct vkms_plane_state *plane, int x_start,
> > -			     int y_start, enum pixel_read_direction direction, int count,
> > -			     struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > +READ_LINE_16161616(ARGB16161616_read_line, px, px[3], px[2], px[1], px[0]);
> > +READ_LINE_16161616(XRGB16161616_read_line, px, 0xFFFF, px[2], px[1], px[0]);
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > +READ_LINE(RGB565_read_line, px, __le16, argb_u16_from_RGB565, px)
> > -	while (out_pixel < end) {
> > -		__le16 *px = (__le16 *)src_pixels;
> > +READ_LINE(R8_read_line, px, u8, argb_u16_from_gray8, *px)
> > -		*out_pixel = argb_u16_from_RGB565(px);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> >   /*
> >    * This callback can be used for YUV formats where U and V values are
> > 

Hi Louis,

On 07/10/24 13:46, Louis Chauvet wrote:
> The callback functions for line conversion are almost identical for
> some format. The generic READ_LINE macro generate all the required
> boilerplate to process a line.
> 
> Two overrides of this macro have been added to avoid duplication of
> the same arguments every time.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>   drivers/gpu/drm/vkms/vkms_formats.c | 163 +++++++++++++-----------------------
>   1 file changed, 58 insertions(+), 105 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> index f9841b8000c4..8f1bcca38148 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.c
> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> @@ -292,6 +292,58 @@ VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1,
>   }
>   EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
>   
> +/**
> + * READ_LINE() - Generic generator for a read_line function which can be used for format with one
> + * plane and a block_h == block_w == 1.
> + *
> + * @function_name: Function name to generate > + * @pixel_name: temporary pixel name used in the @__VA_ARGS__ parameters

s/temporary/Temporary

> + * @pixel_type: Used to specify the type you want to cast the pixel pointer
> + * @callback: Callback to call for each pixels. This fonction should take @__VA_ARGS__ as parameter
> + *            and return a pixel_argb_u16
> + * @__VA_ARGS__: Argument to pass inside the callback. You can use @pixel_name to access current
> + *  pixel.
> + */
> +#define READ_LINE(function_name, pixel_name, pixel_type, callback, ...)				\
> +static void function_name(const struct vkms_plane_state *plane, int x_start,			\
> +			      int y_start, enum pixel_read_direction direction, int count,	\
> +			      struct pixel_argb_u16 out_pixel[])				\
> +{												\
> +	struct pixel_argb_u16 *end = out_pixel + count;						\
> +	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);			\
> +	u8 *src_pixels;										\
> +												\
> +	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);		\
> +												\
> +	while (out_pixel < end) {								\
> +		pixel_type *(pixel_name) = (pixel_type *)src_pixels;				\
> +		*out_pixel = (callback)(__VA_ARGS__);						\
> +		out_pixel += 1;									\
> +		src_pixels += step;								\
> +	}											\
> +}
> +
> +/**
> + * READ_LINE_ARGB8888() - Generic generator for ARGB8888 formats.
> + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> + *
> + * @function_name: Function name to generate
> + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> + * @a, @r, @g, @b: value of each channel
> + */
> +#define READ_LINE_ARGB8888(function_name, pixel_name, a, r, g, b) \
> +	READ_LINE(function_name, pixel_name, u8, argb_u16_from_u8888, a, r, g, b)
> +/**
> + * READ_LINE_ARGB16161616() - Generic generator for ARGB16161616 formats.
> + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.

s/u8/u16

Best Regard,
- Maíra

> + *
> + * @function_name: Function name to generate
> + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> + * @a, @r, @g, @b: value of each channel
> + */
> +#define READ_LINE_16161616(function_name, pixel_name, a, r, g, b) \
> +	READ_LINE(function_name, pixel_name, u16, argb_u16_from_u16161616, a, r, g, b)
> +
>   /*
>    * The following functions are read_line function for each pixel format supported by VKMS.
>    *
> @@ -378,118 +430,19 @@ static void R4_read_line(const struct vkms_plane_state *plane, int x_start,
>   	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel);
>   }
>   
> -static void R8_read_line(const struct vkms_plane_state *plane, int x_start,
> -			 int y_start, enum pixel_read_direction direction, int count,
> -			 struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	while (out_pixel < end) {
> -		*out_pixel = argb_u16_from_gray8(*src_pixels);
> -		src_pixels += step;
> -		out_pixel += 1;
> -	}
> -}
> -
> -static void ARGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> -			       enum pixel_read_direction direction, int count,
> -			       struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	while (out_pixel < end) {
> -		u8 *px = (u8 *)src_pixels;
> -		*out_pixel = argb_u16_from_u8888(px[3], px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> -
> -static void XRGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> -			       enum pixel_read_direction direction, int count,
> -			       struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	while (out_pixel < end) {
> -		u8 *px = (u8 *)src_pixels;
> -		*out_pixel = argb_u16_from_u8888(255, px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> -
> -static void ARGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> -				   int y_start, enum pixel_read_direction direction, int count,
> -				   struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> -
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> -
> -	while (out_pixel < end) {
> -		u16 *px = (u16 *)src_pixels;
> -		*out_pixel = argb_u16_from_u16161616(px[3], px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> -
> -static void XRGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> -				   int y_start, enum pixel_read_direction direction, int count,
> -				   struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
> -
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
>   
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> +READ_LINE_ARGB8888(XRGB8888_read_line, px, 255, px[2], px[1], px[0])
>   
> -	while (out_pixel < end) {
> -		__le16 *px = (__le16 *)src_pixels;
> -		*out_pixel = argb_u16_from_le16161616(cpu_to_le16(0xFFFF), px[2], px[1], px[0]);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
> +READ_LINE_ARGB8888(ARGB8888_read_line, px, px[3], px[2], px[1], px[0])
>   
> -static void RGB565_read_line(const struct vkms_plane_state *plane, int x_start,
> -			     int y_start, enum pixel_read_direction direction, int count,
> -			     struct pixel_argb_u16 out_pixel[])
> -{
> -	struct pixel_argb_u16 *end = out_pixel + count;
> -	u8 *src_pixels;
>   
> -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> +READ_LINE_16161616(ARGB16161616_read_line, px, px[3], px[2], px[1], px[0]);
> +READ_LINE_16161616(XRGB16161616_read_line, px, 0xFFFF, px[2], px[1], px[0]);
>   
> -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> +READ_LINE(RGB565_read_line, px, __le16, argb_u16_from_RGB565, px)
>   
> -	while (out_pixel < end) {
> -		__le16 *px = (__le16 *)src_pixels;
> +READ_LINE(R8_read_line, px, u8, argb_u16_from_gray8, *px)
>   
> -		*out_pixel = argb_u16_from_RGB565(px);
> -		out_pixel += 1;
> -		src_pixels += step;
> -	}
> -}
>   
>   /*
>    * This callback can be used for YUV formats where U and V values are
> 

On 26/10/24 - 11:29, Maíra Canal wrote:
> Hi Louis,
> 
> On 07/10/24 13:46, Louis Chauvet wrote:
> > The callback functions for line conversion are almost identical for
> > some format. The generic READ_LINE macro generate all the required
> > boilerplate to process a line.
> > 
> > Two overrides of this macro have been added to avoid duplication of
> > the same arguments every time.
> > 
> > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > ---
> >   drivers/gpu/drm/vkms/vkms_formats.c | 163 +++++++++++++-----------------------
> >   1 file changed, 58 insertions(+), 105 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> > index f9841b8000c4..8f1bcca38148 100644
> > --- a/drivers/gpu/drm/vkms/vkms_formats.c
> > +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> > @@ -292,6 +292,58 @@ VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1,
> >   }
> >   EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
> > +/**
> > + * READ_LINE() - Generic generator for a read_line function which can be used for format with one
> > + * plane and a block_h == block_w == 1.
> > + *
> > + * @function_name: Function name to generate > + * @pixel_name: temporary pixel name used in the @__VA_ARGS__ parameters
> 
> s/temporary/Temporary
> 
> > + * @pixel_type: Used to specify the type you want to cast the pixel pointer
> > + * @callback: Callback to call for each pixels. This fonction should take @__VA_ARGS__ as parameter
> > + *            and return a pixel_argb_u16
> > + * @__VA_ARGS__: Argument to pass inside the callback. You can use @pixel_name to access current
> > + *  pixel.
> > + */
> > +#define READ_LINE(function_name, pixel_name, pixel_type, callback, ...)				\
> > +static void function_name(const struct vkms_plane_state *plane, int x_start,			\
> > +			      int y_start, enum pixel_read_direction direction, int count,	\
> > +			      struct pixel_argb_u16 out_pixel[])				\
> > +{												\
> > +	struct pixel_argb_u16 *end = out_pixel + count;						\
> > +	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);			\
> > +	u8 *src_pixels;										\
> > +												\
> > +	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);		\
> > +												\
> > +	while (out_pixel < end) {								\
> > +		pixel_type *(pixel_name) = (pixel_type *)src_pixels;				\
> > +		*out_pixel = (callback)(__VA_ARGS__);						\
> > +		out_pixel += 1;									\
> > +		src_pixels += step;								\
> > +	}											\
> > +}
> > +
> > +/**
> > + * READ_LINE_ARGB8888() - Generic generator for ARGB8888 formats.
> > + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> > + *
> > + * @function_name: Function name to generate
> > + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> > + * @a, @r, @g, @b: value of each channel
> > + */
> > +#define READ_LINE_ARGB8888(function_name, pixel_name, a, r, g, b) \
> > +	READ_LINE(function_name, pixel_name, u8, argb_u16_from_u8888, a, r, g, b)
> > +/**
> > + * READ_LINE_ARGB16161616() - Generic generator for ARGB16161616 formats.
> > + * The pixel type used is u8, so pixel_name[0]..pixel_name[n] are the n components of the pixel.
> 
> s/u8/u16

Thanks,
Louis Chauvet
 
> Best Regard,
> - Maíra
> 
> > + *
> > + * @function_name: Function name to generate
> > + * @pixel_name: temporary pixel to use in @a, @r, @g and @b parameters
> > + * @a, @r, @g, @b: value of each channel
> > + */
> > +#define READ_LINE_16161616(function_name, pixel_name, a, r, g, b) \
> > +	READ_LINE(function_name, pixel_name, u16, argb_u16_from_u16161616, a, r, g, b)
> > +
> >   /*
> >    * The following functions are read_line function for each pixel format supported by VKMS.
> >    *
> > @@ -378,118 +430,19 @@ static void R4_read_line(const struct vkms_plane_state *plane, int x_start,
> >   	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel);
> >   }
> > -static void R8_read_line(const struct vkms_plane_state *plane, int x_start,
> > -			 int y_start, enum pixel_read_direction direction, int count,
> > -			 struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	while (out_pixel < end) {
> > -		*out_pixel = argb_u16_from_gray8(*src_pixels);
> > -		src_pixels += step;
> > -		out_pixel += 1;
> > -	}
> > -}
> > -
> > -static void ARGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> > -			       enum pixel_read_direction direction, int count,
> > -			       struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	while (out_pixel < end) {
> > -		u8 *px = (u8 *)src_pixels;
> > -		*out_pixel = argb_u16_from_u8888(px[3], px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > -
> > -static void XRGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
> > -			       enum pixel_read_direction direction, int count,
> > -			       struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	while (out_pixel < end) {
> > -		u8 *px = (u8 *)src_pixels;
> > -		*out_pixel = argb_u16_from_u8888(255, px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > -
> > -static void ARGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> > -				   int y_start, enum pixel_read_direction direction, int count,
> > -				   struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > -
> > -	while (out_pixel < end) {
> > -		u16 *px = (u16 *)src_pixels;
> > -		*out_pixel = argb_u16_from_u16161616(px[3], px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > -
> > -static void XRGB16161616_read_line(const struct vkms_plane_state *plane, int x_start,
> > -				   int y_start, enum pixel_read_direction direction, int count,
> > -				   struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > +READ_LINE_ARGB8888(XRGB8888_read_line, px, 255, px[2], px[1], px[0])
> > -	while (out_pixel < end) {
> > -		__le16 *px = (__le16 *)src_pixels;
> > -		*out_pixel = argb_u16_from_le16161616(cpu_to_le16(0xFFFF), px[2], px[1], px[0]);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> > +READ_LINE_ARGB8888(ARGB8888_read_line, px, px[3], px[2], px[1], px[0])
> > -static void RGB565_read_line(const struct vkms_plane_state *plane, int x_start,
> > -			     int y_start, enum pixel_read_direction direction, int count,
> > -			     struct pixel_argb_u16 out_pixel[])
> > -{
> > -	struct pixel_argb_u16 *end = out_pixel + count;
> > -	u8 *src_pixels;
> > -	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
> > +READ_LINE_16161616(ARGB16161616_read_line, px, px[3], px[2], px[1], px[0]);
> > +READ_LINE_16161616(XRGB16161616_read_line, px, 0xFFFF, px[2], px[1], px[0]);
> > -	int step = get_block_step_bytes(plane->frame_info->fb, direction, 0);
> > +READ_LINE(RGB565_read_line, px, __le16, argb_u16_from_RGB565, px)
> > -	while (out_pixel < end) {
> > -		__le16 *px = (__le16 *)src_pixels;
> > +READ_LINE(R8_read_line, px, u8, argb_u16_from_gray8, *px)
> > -		*out_pixel = argb_u16_from_RGB565(px);
> > -		out_pixel += 1;
> > -		src_pixels += step;
> > -	}
> > -}
> >   /*
> >    * This callback can be used for YUV formats where U and V values are
> >