[PATCH v2] fbdev: ssd1307fb: return proper error code if write command fails

Lad, Prabhakar
2015-01-15T19:05:45Z

From: Prabhakar Lad <prabhakar.csengg@gmail.com>

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

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
---
Changes for v2:
a: Added new line as per Maxime's suggestion.

drivers/video/fbdev/ssd1307fb.c | 67 ++++++++++++++++++++++++++++++++---------
1 file changed, 53 insertions(+), 14 deletions(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index f4daa59..0ea6345 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -320,7 +320,10 @@ static int ssd1307fb_ssd1306_init(struct ssd1307fb_par *par)

/* 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 ssd1307fb_par *par)

/* 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;

--
1.9.1