Den 05.08.2017 20.19, skrev Noralf Tr?nnes:

Den 04.08.2017 00.33, skrev David Lechner:

quoted

LEGO MINDSTORMS EV3 has an LCD with a ST7586 controller. This adds a new
module for the ST7586 controller with parameters for the LEGO MINDSTORMS
EV3 LCD display.

Signed-off-by: David Lechner <david@lechnology.com>
---

[...]

quoted

diff --git a/drivers/gpu/drm/tinydrm/st7586.c 

b/drivers/gpu/drm/tinydrm/st7586.c

[...]

quoted

+static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,

Could you put a comment somewhere explaining what grey332 means, that 
it's not
a 332 pixel format that I first thought, but that you store 3x 2-bit 
pixles in one byte.

quoted

+                       struct drm_framebuffer *fb,
+                       struct drm_clip_rect *clip)
+{
+    size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
+    unsigned int x, y;
+    u8 *src, *buf, val;
+
+    /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
+    clip->x1 = clip->x1 / 3 * 3;

Something wrong here: 3 * 3.

quoted

+    clip->x2 = (clip->x2 + 2) / 3 * 3;

You can use DIV_ROUND_UP().

Now I see what you're doing, can you use roundup() and rounddown()?

quoted

+
+    buf = kmalloc(len, GFP_KERNEL);
+    if (!buf)
+        return;
+
+    tinydrm_xrgb8888_to_gray8(buf, vaddr, fb, clip);
+    src = buf;
+
+    for (y = clip->y1; y < clip->y2; y++) {
+        for (x = clip->x1; x < clip->x2; x += 3) {
+            val = *src++ & 0xc0;
+            if (val & 0xc0)
+                val |= 0x20;
+            val |= (*src++ & 0xc0) >> 3;
+            if (val & 0x18)
+                val |= 0x04;
+            val |= *src++ >> 6;
+            *dst++ = ~val;

I don't understand how this pixel packing matches the one described in
the datasheet. Why do you flip the bits at the end?

quoted

+        }
+    }
+
+    /* now adjust the clip so it applies to dst */
+    clip->x1 /= 3;
+    clip->x2 /= 3;

I don't like this, you are changing the clip into a buffer length.
Better do the calculation before you call mipi_dbi_command_buf().

quoted

+
+    kfree(buf);
+}
+
+static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
+               struct drm_clip_rect *clip)
+{
+    struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
+    struct dma_buf_attachment *import_attach = 
cma_obj->base.import_attach;
+    struct drm_format_name_buf format_name;
+    void *src = cma_obj->vaddr;
+    int ret = 0;
+
+    if (import_attach) {
+        ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
+                           DMA_FROM_DEVICE);
+        if (ret)
+            return ret;
+    }
+
+    switch (fb->format->format) {
+    case DRM_FORMAT_XRGB8888:
+        st7586_xrgb8888_to_gray332(dst, src, fb, clip);
+        break;

I assume you will be adding monochrome and greyscale formats here soon.
Maybe you should have a function st7586_grey8_pack() or something, and do:

switch (fb->format->format) {
         case DRM_FORMAT_XRGB8888:
                 buf = kmalloc();
                 tinydrm_xrgb8888_to_gray8(buf, src, fb, clip);
                 st7586_grey8_to_packed8(dst, buf, clip);
                 kfree();
                 break;

And then later add:

         case DRM_FORMAT_Y8:
                 st7586_grey8_to_packed8(dst, src,...);
                 break;
         case DRM_FORMAT_Y1:
                 st7586_mono_to_packed8(dst, src,...);
                 break;

Just a suggestion, feel free to do what you want.

A patch adding greyscale came today:
https://lists.freedesktop.org/archives/dri-devel/2017-August/149445.html

quoted

+    default:
+        dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
+                 drm_get_format_name(fb->format->format,
+                         &format_name));
+        ret = -EINVAL;
+        break;

You don't need this default, because you can only get the ones in 
st7586_formats.

quoted

+    }
+
+    if (import_attach)
+        dma_buf_end_cpu_access(import_attach->dmabuf, DMA_FROM_DEVICE);

ret = dma_buf_end_cpu_access(...)

quoted

+
+    return ret;
+}
+
+static int st7586_fb_dirty(struct drm_framebuffer *fb,
+               struct drm_file *file_priv, unsigned int flags,
+               unsigned int color, struct drm_clip_rect *clips,
+               unsigned int num_clips)
+{
+    struct tinydrm_device *tdev = fb->dev->dev_private;
+    struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+    struct drm_clip_rect clip;
+    int ret = 0;
+
+    mutex_lock(&tdev->dirty_lock);
+
+    if (!mipi->enabled)
+        goto out_unlock;
+
+    /* fbdev can flush even when we're not interested */
+    if (tdev->pipe.plane.fb != fb)
+        goto out_unlock;
+
+    tinydrm_merge_clips(&clip, clips, num_clips, flags, fb->width,
+                fb->height);
+

I suggest you adjust the clip here since it applies to all formats:

     /* pixels are packed in threes */
     clip->x1 = rounddown(clip->x1, 3);
     clip->x2 = roundup(clip->x2, 3);

quoted

+    DRM_DEBUG("Flushing [FB:%d] x1=%u, x2=%u, y1=%u, y2=%u\n", 
fb->base.id,
+          clip.x1, clip.x2, clip.y1, clip.y2);
+
+    ret = st7586_buf_copy(mipi->tx_buf, fb, &clip);
+    if (ret)
+        goto out_unlock;
+
+    /* NB: st7586_buf_copy() modifies clip */
+
+    mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
+             (clip.x1 >> 8) & 0xFF, clip.x1 & 0xFF,
+             (clip.x2 >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
+    mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
+             (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
+             (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
+
+    ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
+                   (u8 *)mipi->tx_buf,
+                   (clip.x2 - clip.x1) * (clip.y2 - clip.y1));
+
+out_unlock:
+    mutex_unlock(&tdev->dirty_lock);
+
+    if (ret)
+        dev_err_once(fb->dev->dev, "Failed to update display %d\n",
+                 ret);
+
+    return ret;
+}
+