Currently, each screen update triggers an I2C transfer of all screen data, up to 1 KiB of data for a 128x64 display, which takes at least 20 ms in Fast mode.
Reduce the amount of transferred data by only updating the rectangle that changed. Remove the call to ssd1307fb_set_address_range() during initialization, as ssd1307fb_update_rect() now takes care of that.
Note that for now the optimized operation is only used for fillrect, copyarea, and imageblit, which are used by fbcon.
Signed-off-by: Geert Uytterhoeven geert@linux-m68k.org --- drivers/video/fbdev/ssd1307fb.c | 43 ++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 17 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index cfa27ea0feab4f01..8e3d4be74723b9bf 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -184,16 +184,18 @@ static int ssd1307fb_set_address_range(struct ssd1307fb_par *par, u8 col_start, return ssd1307fb_write_cmd(par->client, page_end); }
-static int ssd1307fb_update_display(struct ssd1307fb_par *par) +static int ssd1307fb_update_rect(struct ssd1307fb_par *par, unsigned int x, + unsigned int y, unsigned int width, + unsigned int height) { struct ssd1307fb_array *array; u8 *vmem = par->info->screen_buffer; unsigned int line_length = par->info->fix.line_length; - unsigned int pages = DIV_ROUND_UP(par->height, 8); + unsigned int pages = DIV_ROUND_UP(height + y % 8, 8); u32 array_idx = 0; int ret, i, j, k;
- array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA); + array = ssd1307fb_alloc_array(width * pages, SSD1307FB_DATA); if (!array) return -ENOMEM;
@@ -226,13 +228,18 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par) * (5) A4 B4 C4 D4 E4 F4 G4 H4 */
- for (i = 0; i < pages; i++) { + ret = ssd1307fb_set_address_range(par, par->col_offset + x, width, + par->page_offset + y / 8, pages); + if (ret < 0) + goto out_free; + + for (i = y / 8; i < y / 8 + pages; i++) { int m = 8;
/* Last page may be partial */ - if (i + 1 == pages && par->height % 8) + if (8 * (i + 1) > par->height) m = par->height % 8; - for (j = 0; j < par->width; j++) { + for (j = x; j < x + width; j++) { u8 data = 0;
for (k = 0; k < m; k++) { @@ -245,11 +252,17 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par) } }
- ret = ssd1307fb_write_array(par->client, array, par->width * pages); + ret = ssd1307fb_write_array(par->client, array, width * pages); + +out_free: kfree(array); return ret; }
+static int ssd1307fb_update_display(struct ssd1307fb_par *par) +{ + return ssd1307fb_update_rect(par, 0, 0, par->width, par->height); +}
static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf, size_t count, loff_t *ppos) @@ -299,21 +312,24 @@ static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *r { struct ssd1307fb_par *par = info->par; sys_fillrect(info, rect); - ssd1307fb_update_display(par); + ssd1307fb_update_rect(par, rect->dx, rect->dy, rect->width, + rect->height); }
static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area) { struct ssd1307fb_par *par = info->par; sys_copyarea(info, area); - ssd1307fb_update_display(par); + ssd1307fb_update_rect(par, area->dx, area->dy, area->width, + area->height); }
static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image) { struct ssd1307fb_par *par = info->par; sys_imageblit(info, image); - ssd1307fb_update_display(par); + ssd1307fb_update_rect(par, image->dx, image->dy, image->width, + image->height); }
static const struct fb_ops ssd1307fb_ops = { @@ -493,13 +509,6 @@ static int ssd1307fb_init(struct ssd1307fb_par *par) if (ret < 0) return ret;
- /* Set column and page range */ - ret = ssd1307fb_set_address_range(par, par->col_offset, par->width, - par->page_offset, - DIV_ROUND_UP(par->height, 8)); - if (ret < 0) - return ret; - /* Clear the screen */ ret = ssd1307fb_update_display(par); if (ret < 0)