# \[PATCH\] fbdev: ssd1307fb: return proper error code if write command fails - Subsystems: FRAMEBUFFER LAYER, THE REST - Maintainers: Helge Deller, Linus Torvalds - List: linux-fbdev - 2 messages, 2 authors - Page: https://ratatoskr.run/linux-fbdev/2015/01/4409639/t ## \[PATCH\] fbdev: ssd1307fb: return proper error code if write command fails - From: Lad, Prabhakar \ - Date: 2015-01-14 08:24:57 - Message: https://ratatoskr.run/linux-fbdev/2015/01/4409639.md ```text this patch fixes ssd1307fb_ssd1306_init() function to return proper error codes in case of failures. Signed-off-by: Lad, Prabhakar --- drivers/video/fbdev/ssd1307fb.c | 54 ++++++++++++++++++++++++++++++----------- 1 file changed, 40 insertions(+), 14 deletions(-) diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index f4daa59..528ea16 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -320,7 +320,9 @@ 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 +338,87 @@ 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 ``` ## Re: \[PATCH\] fbdev: ssd1307fb: return proper error code if write command fails - From: Maxime Ripard \ - Date: 2015-01-14 11:10:06 - Message: https://ratatoskr.run/linux-fbdev/2015/01/4409725.md ```text Hi, Thanks for doing this, On Wed, Jan 14, 2015 at 08:24:49AM +0000, Lad, Prabhakar wrote: > this patch fixes ssd1307fb_ssd1306_init() function to return > proper error codes in case of failures. > > Signed-off-by: Lad, Prabhakar > --- > drivers/video/fbdev/ssd1307fb.c | 54 ++++++++++++++++++++++++++++++----------- > 1 file changed, 40 insertions(+), 14 deletions(-) > > diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c > index f4daa59..528ea16 100644 > --- a/drivers/video/fbdev/ssd1307fb.c > +++ b/drivers/video/fbdev/ssd1307fb.c > @@ -320,7 +320,9 @@ 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; A newline here (and to all the subsequent changes) would be great. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com ```