[PATCH 3.16 06/72] fbdev: ssd1307fb: return proper error code if write command fails

[Ben Hutchings]

3.16.79-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Prabhakar Lad <prabhakar.csengg@xxxxxxxxx>

commit 5b72ae9a901cbfbe632570f278486142b037fe51 upstream.

this patch fixes ssd1307fb_ssd1306_init() function to return
proper error codes in case of failures.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/video/fbdev/ssd1307fb.c | 67 ++++++++++++++++++++++++++-------
 1 file changed, 53 insertions(+), 14 deletions(-)

--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -320,7 +320,10 @@ static int ssd1307fb_ssd1306_init(struct
 
 	/* Set initial contrast */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x7f);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x7f);
 	if (ret < 0)
 		return ret;
 
@@ -336,63 +339,99 @@ static int ssd1307fb_ssd1306_init(struct
 
 	/* Set multiplex ratio value */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
-	ret = ret & ssd1307fb_write_cmd(par->client, par->height - 1);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
 	if (ret < 0)
 		return ret;
 
 	/* set display offset value */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
+	if (ret < 0)
+		return ret;
+
 	ret = ssd1307fb_write_cmd(par->client, 0x20);
 	if (ret < 0)
 		return ret;
 
 	/* Set clock frequency */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0xf0);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0xf0);
 	if (ret < 0)
 		return ret;
 
 	/* Set precharge period in number of ticks from the internal clock */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x22);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x22);
 	if (ret < 0)
 		return ret;
 
 	/* Set COM pins configuration */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x22);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x22);
 	if (ret < 0)
 		return ret;
 
 	/* Set VCOMH */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x49);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x49);
 	if (ret < 0)
 		return ret;
 
 	/* Turn on the DC-DC Charge Pump */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x14);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x14);
 	if (ret < 0)
 		return ret;
 
 	/* Switch to horizontal addressing mode */
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
-	ret = ret & ssd1307fb_write_cmd(par->client,
-					SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client,
+				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
 	if (ret < 0)
 		return ret;
 
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x0);
-	ret = ret & ssd1307fb_write_cmd(par->client, par->width - 1);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
 	if (ret < 0)
 		return ret;
 
 	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
-	ret = ret & ssd1307fb_write_cmd(par->client, 0x0);
-	ret = ret & ssd1307fb_write_cmd(par->client,
-					par->page_offset + (par->height / 8) - 1);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client,
+				  par->page_offset + (par->height / 8) - 1);
 	if (ret < 0)
 		return ret;