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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Maxime Ripard <mripard@kernel.org>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>
Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH 5/5] video: fbdev: ssd1307fb: Cache address ranges
Date: Tue, 18 May 2021 10:28:09 +0200	[thread overview]
Message-ID: <20210518082809.1467549-6-geert@linux-m68k.org> (raw)
In-Reply-To: <20210518082809.1467549-1-geert@linux-m68k.org>

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


      parent reply	other threads:[~2021-05-18  9:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-18  8:28 [PATCH 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Geert Uytterhoeven
2021-05-18  8:28 ` [PATCH 1/5] video: fbdev: ssd1307fb: Propagate errors via ssd1307fb_update_display() Geert Uytterhoeven
2021-05-18  8:28 ` [PATCH 2/5] video: fbdev: ssd1307fb: Simplify ssd1307fb_update_display() Geert Uytterhoeven
2021-05-18  8:28 ` [PATCH 3/5] video: fbdev: ssd1307fb: Extract ssd1307fb_set_address_range() Geert Uytterhoeven
2021-05-18  8:28 ` [PATCH 4/5] video: fbdev: ssd1307fb: Optimize screen updates Geert Uytterhoeven
2021-05-18  8:28 ` Geert Uytterhoeven [this message]

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