video: fbdev: ssd1307fb: Added support to Column offset

This patch provides support for displays like VGM128064B0W10,
which requires a column offset of 2, i.e., its segments starts
in SEG2 and ends in SEG129.
Signed-off-by: Rodrigo Alencar <455.rodrigo.alencar@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1595622138-3965-1-git-send-email-455.rodrigo.alencar@gmail.com

Documentation/devicetree/bindings/display/ssd1307fb.txt

@@ -19,6 +19,7 @@ Optional properties:
   - vbat-supply: The supply for VBAT
   - solomon,segment-no-remap: Display needs normal (non-inverted) data column
                               to segment mapping
+  - solomon,col-offset: Offset of columns (COL/SEG) that the screen is mapped to.
   - solomon,com-seq: Display uses sequential COM pin configuration
   - solomon,com-lrremap: Display uses left-right COM pin remap
   - solomon,com-invdir: Display uses inverted COM pin scan direction

drivers/video/fbdev/ssd1307fb.c

@@ -74,6 +74,7 @@ struct ssd1307fb_par {
 	struct fb_info *info;
 	u8 lookup_table[4];
 	u32 page_offset;
+	u32 col_offset;
 	u32 prechargep1;
 	u32 prechargep2;
 	struct pwm_device *pwm;
@@ -458,11 +459,11 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
 	if (ret < 0)
 		return ret;
 
-	ret = ssd1307fb_write_cmd(par->client, 0x0);
+	ret = ssd1307fb_write_cmd(par->client, par->col_offset);
 	if (ret < 0)
 		return ret;
 
-	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
+	ret = ssd1307fb_write_cmd(par->client, par->col_offset + par->width - 1);
 	if (ret < 0)
 		return ret;
 
@@ -626,6 +627,9 @@ static int ssd1307fb_probe(struct i2c_client *client)
 	if (device_property_read_u32(dev, "solomon,page-offset", &par->page_offset))
 		par->page_offset = 1;
 
+	if (device_property_read_u32(dev, "solomon,col-offset", &par->col_offset))
+		par->col_offset = 0;
+
 	if (device_property_read_u32(dev, "solomon,com-offset", &par->com_offset))
 		par->com_offset = 0;