| Message ID | 20220119172740.1856302-1-hugo@hugovil.com |
|---|---|
| State | Rejected |
| Headers | show |
| Series | rtc: pcf2127: add error message if writing to CLKOUT register fails | expand |
On 19/01/2022 12:27:39-0500, Hugo Villeneuve wrote: > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > If writing to CLKOUT register fails, the probe operation will be aborted > without a meaningful error message. > The current trend is to remove debug messages, please do not add more :) > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> > --- > drivers/rtc/rtc-pcf2127.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > index 3d1f57e54372..823abe2a7147 100644 > --- a/drivers/rtc/rtc-pcf2127.c > +++ b/drivers/rtc/rtc-pcf2127.c > @@ -717,8 +717,10 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > if (!(val & PCF2127_BIT_CLKOUT_OTPR)) { > ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT, > PCF2127_BIT_CLKOUT_OTPR); > - if (ret < 0) > + if (ret < 0) { > + dev_err(dev, "writing to CLKOUT register failed\n"); > return ret; > + } > > msleep(100); > } > -- > 2.30.2 >
On Wed, 19 Jan 2022 18:37:40 +0100 Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > On 19/01/2022 12:27:39-0500, Hugo Villeneuve wrote: > > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > > If writing to CLKOUT register fails, the probe operation will be aborted > > without a meaningful error message. > > > > The current trend is to remove debug messages, please do not add more :) Hi, If the read operation fails, the probe function will exit silently, and our RTC chip will not work. In that case, if we parse the dmesg logs, I think we should have an indication that something went wrong. I had a case where my dev board was not properly plugged-in, and before this patch, I didn't notice it because of the silent abort of the probe function. > > > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > --- > > drivers/rtc/rtc-pcf2127.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > > index 3d1f57e54372..823abe2a7147 100644 > > --- a/drivers/rtc/rtc-pcf2127.c > > +++ b/drivers/rtc/rtc-pcf2127.c > > @@ -717,8 +717,10 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > > if (!(val & PCF2127_BIT_CLKOUT_OTPR)) { > > ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT, > > PCF2127_BIT_CLKOUT_OTPR); > > - if (ret < 0) > > + if (ret < 0) { > > + dev_err(dev, "writing to CLKOUT register failed\n"); > > return ret; > > + } > > > > msleep(100); > > } > > -- > > 2.30.2 > > > > -- > Alexandre Belloni, co-owner and COO, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com >
On 19/01/2022 13:08:45-0500, Hugo Villeneuve wrote: > On Wed, 19 Jan 2022 18:37:40 +0100 > Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > > > On 19/01/2022 12:27:39-0500, Hugo Villeneuve wrote: > > > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > > > > If writing to CLKOUT register fails, the probe operation will be aborted > > > without a meaningful error message. > > > > > > > The current trend is to remove debug messages, please do not add more :) > > Hi, > If the read operation fails, the probe function will exit silently, and our RTC chip will not work. In that case, if we parse the dmesg logs, I think we should have an indication that something went wrong. > This is not true, it doesn't fail silently, you'd get: rtc-pcf2127: probe of 1-0051 failed with error -121 > I had a case where my dev board was not properly plugged-in, and before this patch, I didn't notice it because of the silent abort of the probe function. > Again, not silent. > > > > > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > --- > > > drivers/rtc/rtc-pcf2127.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > > > index 3d1f57e54372..823abe2a7147 100644 > > > --- a/drivers/rtc/rtc-pcf2127.c > > > +++ b/drivers/rtc/rtc-pcf2127.c > > > @@ -717,8 +717,10 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > > > if (!(val & PCF2127_BIT_CLKOUT_OTPR)) { > > > ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT, > > > PCF2127_BIT_CLKOUT_OTPR); > > > - if (ret < 0) > > > + if (ret < 0) { > > > + dev_err(dev, "writing to CLKOUT register failed\n"); > > > return ret; > > > + } > > > > > > msleep(100); > > > } > > > -- > > > 2.30.2 > > > > > > > -- > > Alexandre Belloni, co-owner and COO, Bootlin > > Embedded Linux and Kernel engineering > > https://bootlin.com > > > > > -- > Hugo Villeneuve <hugo@hugovil.com>
On Wed, 19 Jan 2022 20:10:20 +0100 Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > On 19/01/2022 13:08:45-0500, Hugo Villeneuve wrote: > > On Wed, 19 Jan 2022 18:37:40 +0100 > > Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > > > > > On 19/01/2022 12:27:39-0500, Hugo Villeneuve wrote: > > > > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > > > > > > If writing to CLKOUT register fails, the probe operation will be aborted > > > > without a meaningful error message. > > > > > > > > > > The current trend is to remove debug messages, please do not add more :) > > > > Hi, > > If the read operation fails, the probe function will exit silently, and our RTC chip will not work. In that case, if we parse the dmesg logs, I think we should have an indication that something went wrong. > > > > This is not true, it doesn't fail silently, you'd get: > rtc-pcf2127: probe of 1-0051 failed with error -121 Well this is certainly true for me because I am not seing the same error message as you :) Just for context, I have defined a dummy pcf2127 on I2C bus 0 in my device tree (no actual hardware is present). I also added some debug messages to investigate (rtc-pcf2127.c and dd.c files), and here is the dmesg log after issuing "modprobe rtc-pcf2127": [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: pcf2127_i2c_probe [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: pcf2127_probe [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: PORO disabling failed with error -6 [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: call_driver_probe probe error: -6 Error code -6 is -ENXIO, and looking at the call_driver_probe() function in dd.c, I now understand why I didn't see the error message (line 531): case -ENXIO: pr_debug("%s: probe of %s rejects match %d\n", drv->name, dev_name(dev), ret); So it seems that the return code is different than what you got? > > I had a case where my dev board was not properly plugged-in, and before this patch, I didn't notice it because of the silent abort of the probe function. > > > > Again, not silent. > > > > > > > > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > > --- > > > > drivers/rtc/rtc-pcf2127.c | 4 +++- > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > > > > index 3d1f57e54372..823abe2a7147 100644 > > > > --- a/drivers/rtc/rtc-pcf2127.c > > > > +++ b/drivers/rtc/rtc-pcf2127.c > > > > @@ -717,8 +717,10 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > > > > if (!(val & PCF2127_BIT_CLKOUT_OTPR)) { > > > > ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT, > > > > PCF2127_BIT_CLKOUT_OTPR); > > > > - if (ret < 0) > > > > + if (ret < 0) { > > > > + dev_err(dev, "writing to CLKOUT register failed\n"); > > > > return ret; > > > > + } > > > > > > > > msleep(100); > > > > } > > > > -- > > > > 2.30.2 > > > > > > > > > > -- > > > Alexandre Belloni, co-owner and COO, Bootlin > > > Embedded Linux and Kernel engineering > > > https://bootlin.com > > > > > > > > > -- > > Hugo Villeneuve <hugo@hugovil.com> > > -- > Alexandre Belloni, co-owner and COO, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com >
On 20/01/2022 18:35:48-0500, Hugo Villeneuve wrote: > On Wed, 19 Jan 2022 20:10:20 +0100 > Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > > > On 19/01/2022 13:08:45-0500, Hugo Villeneuve wrote: > > > On Wed, 19 Jan 2022 18:37:40 +0100 > > > Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > > > > > > > On 19/01/2022 12:27:39-0500, Hugo Villeneuve wrote: > > > > > From: Hugo Villeneuve <hvilleneuve@dimonoff.com> > > > > > > > > > > If writing to CLKOUT register fails, the probe operation will be aborted > > > > > without a meaningful error message. > > > > > > > > > > > > > The current trend is to remove debug messages, please do not add more :) > > > > > > Hi, > > > If the read operation fails, the probe function will exit silently, and our RTC chip will not work. In that case, if we parse the dmesg logs, I think we should have an indication that something went wrong. > > > > > > > This is not true, it doesn't fail silently, you'd get: > > rtc-pcf2127: probe of 1-0051 failed with error -121 > > Well this is certainly true for me because I am not seing the same error message as you :) > > Just for context, I have defined a dummy pcf2127 on I2C bus 0 in my device tree (no actual hardware is present). I also added some debug messages to investigate (rtc-pcf2127.c and dd.c files), and here is the dmesg log after issuing "modprobe rtc-pcf2127": > > [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: pcf2127_i2c_probe > [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: pcf2127_probe > [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: PORO disabling failed with error -6 > [Thu Jan 20 23:22:20 2022] rtc-pcf2127-i2c 0-0051: call_driver_probe probe error: -6 > > Error code -6 is -ENXIO, and looking at the call_driver_probe() function in dd.c, I now understand why I didn't see the error message (line 531): > > case -ENXIO: > pr_debug("%s: probe of %s rejects match %d\n", > drv->name, dev_name(dev), ret); > > So it seems that the return code is different than what you got? > Probably because we don't have the same i2c controller and the driver for mine is returning -EREMOTEIO when the device is not present.
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c index 3d1f57e54372..823abe2a7147 100644 --- a/drivers/rtc/rtc-pcf2127.c +++ b/drivers/rtc/rtc-pcf2127.c @@ -717,8 +717,10 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, if (!(val & PCF2127_BIT_CLKOUT_OTPR)) { ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT, PCF2127_BIT_CLKOUT_OTPR); - if (ret < 0) + if (ret < 0) { + dev_err(dev, "writing to CLKOUT register failed\n"); return ret; + } msleep(100); }