[PATCH resend 5/5] video: fbdev: ssd1307fb: Cache address ranges

Geert Uytterhoeven
2021-07-14T14:58:18Z

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,
--
2.25.1