From 251e48a1db758ad7151e2dce146e63d9f4baf94b Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 27 Jul 2021 15:47:29 +0200 Subject: [PATCH] video: fbdev: ssd1307fb: Optimize screen updates 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 calls to ssd1307fb_set_col_range() and ssd1307fb_set_page_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 Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20210727134730.3765898-5-geert@linux-m68k.org --- drivers/video/fbdev/ssd1307fb.c | 50 ++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 21 deletions(-) diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 86eb9c9..9aed5ee 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -186,16 +186,18 @@ static int ssd1307fb_set_page_range(struct ssd1307fb_par *par, u8 page_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(y % 8 + height, 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; @@ -228,13 +230,21 @@ 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_col_range(par, par->col_offset + x, width); + if (ret < 0) + goto out_free; + + ret = ssd1307fb_set_page_range(par, 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++) { @@ -247,11 +257,17 @@ 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) @@ -301,21 +317,24 @@ 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 = { @@ -495,17 +514,6 @@ static int ssd1307fb_init(struct ssd1307fb_par *par) if (ret < 0) return ret; - /* Set column range */ - ret = ssd1307fb_set_col_range(par, par->col_offset, par->width); - if (ret < 0) - return ret; - - /* Set page range */ - ret = ssd1307fb_set_page_range(par, 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) -- 2.7.4