Cache the column and page ranges, to avoid doing unneeded I2C transfers when the values haven't changed.
Signed-off-by: Geert Uytterhoeven geert@linux-m68k.org --- drivers/video/fbdev/ssd1307fb.c | 52 +++++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 16 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 8e3d4be74723b9bf..23b43ce479898813 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -82,6 +82,11 @@ struct ssd1307fb_par { struct regulator *vbat_reg; u32 vcomh; u32 width; + /* Cached address ranges */ + u8 col_start; + u8 col_end; + u8 page_start; + u8 page_end; };
struct ssd1307fb_array { @@ -160,28 +165,43 @@ static int ssd1307fb_set_address_range(struct ssd1307fb_par *par, u8 col_start, int ret;
/* Set column range */ - ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE); - if (ret < 0) - return ret; + if (col_start != par->col_start || col_end != par->col_end) { + ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE); + if (ret < 0) + return ret;
- ret = ssd1307fb_write_cmd(par->client, col_start); - if (ret < 0) - return ret; + ret = ssd1307fb_write_cmd(par->client, col_start); + if (ret < 0) + return ret;
- ret = ssd1307fb_write_cmd(par->client, col_end); - if (ret < 0) - return ret; + ret = ssd1307fb_write_cmd(par->client, col_end); + if (ret < 0) + return ret; + + par->col_start = col_start; + par->col_end = col_end; + }
/* Set page range */ - ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE); - if (ret < 0) - return ret; + if (page_start != par->page_start || page_end != par->page_end) { + ret = ssd1307fb_write_cmd(par->client, + SSD1307FB_SET_PAGE_RANGE); + if (ret < 0) + return ret;
- ret = ssd1307fb_write_cmd(par->client, page_start); - if (ret < 0) - return ret; + ret = ssd1307fb_write_cmd(par->client, page_start); + if (ret < 0) + return ret; + + ret = ssd1307fb_write_cmd(par->client, page_end); + if (ret < 0) + return ret;
- return ssd1307fb_write_cmd(par->client, page_end); + par->page_start = page_start; + par->page_end = page_end; + } + + return 0; }
static int ssd1307fb_update_rect(struct ssd1307fb_par *par, unsigned int x,