This adds helper functions and support for ST7586 controllers. These
controllers have an unusual memory layout where 3 pixels are packed into
1 byte.
+-------+-----------------+
| bit | 7 6 5 4 3 2 1 0 |
+-------+-----------------+
| pixel | 0 0 0 1 1 1 2 2 |
+-------+-----------------+
So, there are a nuber of places in the tinydrm pipline where this format
needs to be taken into consideration.
Signed-off-by: David Lechner <da...@lechnology.com>
---
drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 148 +++++++++++++++++++++++++
drivers/gpu/drm/tinydrm/mipi-dbi.c | 96 ++++++++++++----
include/drm/tinydrm/tinydrm-helpers.h | 6 +
include/video/mipi_display.h | 2 +
4 files changed, 232 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
index d4cda33..4a36441 100644
--- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
@@ -181,6 +181,154 @@ void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
EXPORT_SYMBOL(tinydrm_xrgb8888_to_rgb565);
/**
+ * tinydrm_rgb565_to_st7586 - Convert RGB565 to ST7586 clip buffer
+ * @dst: ST7586 destination buffer
+ * @vaddr: RGB565 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ * @swap: Swap bytes
+ *
+ * The ST7586 controller has a non-standard pixel layout. It is 2-bit grayscale
+ * (or 1-bit monochrome) packed into 3 pixels per byte.
+ *
+ * Note: the @clip x values are modified! They are aligned to the 3 pixel
+ * boundtry and divied by 3 to get the starting and ending byte (+ 1) in the
+ * @dst buffer.
+ */
+void tinydrm_rgb565_to_st7586(u8 *dst, void *vaddr,
+ struct drm_framebuffer *fb,
+ struct drm_clip_rect *clip)
+{
+ size_t len;
+ unsigned int x, y;
+ u16 *src, *buf;
+ u8 val;
+
+ /* 3 pixels per byte, so align to dst byte */
+ clip->x1 -= clip->x1 % 3;
+ clip->x2 = (clip->x2 + 2) / 3 * 3;
+ len = (clip->x2 - clip->x1) * sizeof(u16);
+
+ buf = kmalloc(len, GFP_KERNEL);
+ if (!buf)
+ return;
+
+ for (y = clip->y1; y < clip->y2; y++) {
+ src = vaddr + (y * fb->pitches[0]);
+ src += clip->x1;
+ memcpy(buf, src, len);
+ src = buf;
+ for (x = clip->x1; x < clip->x2; x += 3) {
+ /*
+ * TODO: There is probably a better algorithm to get
+ * a better downsampling.
+ * If red or green is > 50%, set the high bit, which is
+ * bright gray. If blue is greater than 50%, set the
+ * low bit, which is dark gray.
+ */
+ val = ((*src & 0x8000) >> 8) |
+ ((*src & 0x0400) >> 3) |
+ ((*src & 0x0010) << 2);
+ if (val & 0xC0)
+ val |= 0x20;
+ src++;
+ val |= ((*src & 0x8000) >> 11) |
+ ((*src & 0x0400) >> 6) |
+ ((*src & 0x0010) >> 1);
+ if (val & 0x18)
+ val |= 0x04;
+ src++;
+ val |= ((*src & 0x8000) >> 14) |
+ ((*src & 0x0400) >> 9) |
+ ((*src & 0x0010) >> 4);
+ src++;
+ *dst++ = ~val;
+ }
+ }
+
+ /* now adjust the clip so it applies to dst */
+ clip->x1 /= 3;
+ clip->x2 /= 3;
+
+ kfree(buf);
+}
+EXPORT_SYMBOL(tinydrm_rgb565_to_st7586);
+
+/**
+ * tinydrm_xrgb8888_to_st7586 - Convert XRGB8888 to ST7586 clip buffer
+ * @dst: ST7586 destination buffer
+ * @vaddr: XRGB8888 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ * @swap: Swap bytes
+ *
+ * The ST7586 controller has a non-standard pixel layout. It is 2-bit grayscale
+ * (or 1-bit monochrome) packed into 3 pixels per byte.
+ *
+ * Note: the @clip x values are modified! They are aligned to the 3 pixel
+ * boundtry and divied by 3 to get the starting and ending byte (+ 1) in the
+ * @dst buffer.
+ */
+void tinydrm_xrgb8888_to_st7586(u8 *dst, void *vaddr,
+ struct drm_framebuffer *fb,
+ struct drm_clip_rect *clip)
+{
+ size_t len;
+ unsigned int x, y;
+ u32 *src, *buf;
+ u8 val;
+
+ /* 3 pixels per byte, so align to dst byte */
+ clip->x1 -= clip->x1 % 3;
+ clip->x2 = (clip->x2 + 2) / 3 * 3;
+ len = (clip->x2 - clip->x1) * sizeof(u32);
+
+ buf = kmalloc(len, GFP_KERNEL);
+ if (!buf)
+ return;
+
+ for (y = clip->y1; y < clip->y2; y++) {
+ src = vaddr + (y * fb->pitches[0]);
+ src += clip->x1;
+ memcpy(buf, src, len);
+ src = buf;
+ for (x = clip->x1; x < clip->x2; x += 3) {
+ /*
+ * TODO: There is probably a better algorithm to get
+ * a better downsampling.
+ * If red or green is > 50%, set the high bit, which is
+ * bright gray. If blue is greater than 50%, set the
+ * low bit, which is dark gray.
+ */
+ val = ((*src & 0x00800000) >> 16) |
+ ((*src & 0x00008000) >> 8) |
+ ((*src & 0x00000080) >> 1);
+ if (val & 0xC0)
+ val |= 0x20;
+ src++;
+ val |= ((*src & 0x00800000) >> 19) |
+ ((*src & 0x00008000) >> 11) |
+ ((*src & 0x00000080) >> 4);
+ if (val & 0x18)
+ val |= 0x04;
+ src++;
+ val |= ((*src & 0x00800000) >> 22) |
+ ((*src & 0x00008000) >> 14) |
+ ((*src & 0x00000080) >> 7);
+ src++;
+ *dst++ = ~val;
+ }
+ }
+
+ /* now adjust the clip so it applies to dst */
+ clip->x1 /= 3;
+ clip->x2 /= 3;
+
+ kfree(buf);
+}
+EXPORT_SYMBOL(tinydrm_xrgb8888_to_st7586);
+
+/**
* tinydrm_of_find_backlight - Find backlight device in device-tree
* @dev: Device
*
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c
b/drivers/gpu/drm/tinydrm/mipi-dbi.c
index 7d49366..c8fb622 100644
--- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -154,7 +154,8 @@ int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8
*data, size_t len)
EXPORT_SYMBOL(mipi_dbi_command_buf);
static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
- struct drm_clip_rect *clip, bool swap)
+ struct drm_clip_rect *clip,
+ enum mipi_dcs_pixel_format pixel_fmt, bool swap)
{
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;
@@ -169,21 +170,45 @@ static int mipi_dbi_buf_copy(void *dst, struct
drm_framebuffer *fb,
return ret;
}
- switch (fb->format->format) {
- case DRM_FORMAT_RGB565:
- if (swap)
- tinydrm_swab16(dst, src, fb, clip);
- else
- tinydrm_memcpy(dst, src, fb, clip);
+ switch (pixel_fmt) {
+ case MIPI_DCS_PIXEL_FMT_16BIT:
+ switch (fb->format->format) {
+ case DRM_FORMAT_RGB565:
+ if (swap)
+ tinydrm_swab16(dst, src, fb, clip);
+ else
+ tinydrm_memcpy(dst, src, fb, clip);
+ break;
+ case DRM_FORMAT_XRGB8888:
+ tinydrm_xrgb8888_to_rgb565(dst, src, fb, clip, swap);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
break;
- case DRM_FORMAT_XRGB8888:
- tinydrm_xrgb8888_to_rgb565(dst, src, fb, clip, swap);
+ case MIPI_DCS_PIXEL_FMT_ST7586_332:
+ switch (fb->format->format) {
+ case DRM_FORMAT_RGB565:
+ tinydrm_rgb565_to_st7586(dst, src, fb, clip);
+ break;
+ case DRM_FORMAT_XRGB8888:
+ tinydrm_xrgb8888_to_st7586(dst, src, fb, clip);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
break;
default:
+ ret = -EINVAL;
+ break;
+ }
+ if (ret) {
dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
- drm_get_format_name(fb->format->format,
- &format_name));
- return -EINVAL;
+ drm_get_format_name(fb->format->format,
+ &format_name));
+ return ret;
}
if (import_attach)
@@ -204,8 +229,9 @@ static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,
bool swap = mipi->swap_bytes;
struct drm_clip_rect clip;
int ret = 0;
- bool full;
+ bool full, pixel_fmt_match;
void *tr;
+ size_t len;
mutex_lock(&tdev->dirty_lock);
@@ -218,20 +244,24 @@ static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,
full = tinydrm_merge_clips(&clip, clips, num_clips, flags,
fb->width, fb->height);
+ pixel_fmt_match = !swap && fb->format->format == DRM_FORMAT_RGB565 &&
+ mipi->pixel_fmt == MIPI_DCS_PIXEL_FMT_16BIT;
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);
- if (!mipi->dc || !full || swap ||
- fb->format->format == DRM_FORMAT_XRGB8888) {
+ if (!mipi->dc || !full || !pixel_fmt_match) {
tr = mipi->tx_buf;
- ret = mipi_dbi_buf_copy(mipi->tx_buf, fb, &clip, swap);
+ ret = mipi_dbi_buf_copy(mipi->tx_buf, fb, &clip,
+ mipi->pixel_fmt, swap);
if (ret)
goto out_unlock;
} else {
tr = cma_obj->vaddr;
}
+ /* NB: mipi_dbi_buf_copy() may modify 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);
@@ -239,8 +269,16 @@ static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,
(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, tr,
- (clip.x2 - clip.x1) * (clip.y2 - clip.y1) * 2);
+ len = (clip.x2 - clip.x1) * (clip.y2 - clip.y1);
+ switch (mipi->pixel_fmt) {
+ case MIPI_DCS_PIXEL_FMT_16BIT:
+ len *= sizeof(u16);
+ break;
+ default:
+ break;
+ }
+
+ ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START, tr, len);
out_unlock:
mutex_unlock(&tdev->dirty_lock);
@@ -288,7 +326,20 @@ static void mipi_dbi_blank(struct mipi_dbi *mipi)
struct drm_device *drm = mipi->tinydrm.drm;
u16 height = drm->mode_config.min_height;
u16 width = drm->mode_config.min_width;
- size_t len = width * height * 2;
+ size_t len;
+
+ switch (mipi->pixel_fmt) {
+ case MIPI_DCS_PIXEL_FMT_16BIT:
+ len = width * height * sizeof(u16);
+ break;
+ case MIPI_DCS_PIXEL_FMT_ST7586_332:
+ width = (width + 2) / 3;
+ len = width * height;
+ break;
+ default:
+ /* unsupported pixel format */
+ return;
+ }
memset(mipi->tx_buf, 0, len);
@@ -367,6 +418,10 @@ int mipi_dbi_init(struct device *dev, struct mipi_dbi
*mipi,
case MIPI_DCS_PIXEL_FMT_16BIT:
bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
break;
+ case MIPI_DCS_PIXEL_FMT_ST7586_332:
+ /* 3 pixels per byte */
+ bufsize = (mode->vdisplay + 2) / 3 * mode->hdisplay;
+ break;
default:
DRM_ERROR("Pixel format is not supported\n");
return -EINVAL;
@@ -776,7 +831,8 @@ static int mipi_dbi_typec3_command(struct mipi_dbi *mipi,
u8 cmd,
if (ret || !num)
return ret;
- if (cmd == MIPI_DCS_WRITE_MEMORY_START && !mipi->swap_bytes)
+ if (cmd == MIPI_DCS_WRITE_MEMORY_START && !mipi->swap_bytes &&
+ mipi->pixel_fmt != MIPI_DCS_PIXEL_FMT_ST7586_332)
bpw = 16;
gpiod_set_value_cansleep(mipi->dc, 1);
diff --git a/include/drm/tinydrm/tinydrm-helpers.h
b/include/drm/tinydrm/tinydrm-helpers.h
index 9b9b6cf..94792fb 100644
--- a/include/drm/tinydrm/tinydrm-helpers.h
+++ b/include/drm/tinydrm/tinydrm-helpers.h
@@ -43,6 +43,12 @@ void tinydrm_swab16(u16 *dst, void *vaddr, struct
drm_framebuffer *fb,
void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
struct drm_framebuffer *fb,
struct drm_clip_rect *clip, bool swap);
+void tinydrm_rgb565_to_st7586(u8 *dst, void *vaddr,
+ struct drm_framebuffer *fb,
+ struct drm_clip_rect *clip);
+void tinydrm_xrgb8888_to_st7586(u8 *dst, void *vaddr,
+ struct drm_framebuffer *fb,
+ struct drm_clip_rect *clip);
struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
int tinydrm_enable_backlight(struct backlight_device *backlight);
diff --git a/include/video/mipi_display.h b/include/video/mipi_display.h
index 84b70cd..1c134c4 100644
--- a/include/video/mipi_display.h
+++ b/include/video/mipi_display.h
@@ -135,6 +135,8 @@ enum mipi_dcs_pixel_format {
MIPI_DCS_PIXEL_FMT_12BIT = 3,
MIPI_DCS_PIXEL_FMT_8BIT = 2,
MIPI_DCS_PIXEL_FMT_3BIT = 1,
+ /* non-standard format packing 1 or 2bpp in 3:3:2 bits */
+ MIPI_DCS_PIXEL_FMT_ST7586_332 = -1,
};
#endif
--
2.7.4
