[PATCH v2 1/4] driver core: Ignore 0 in dev_err_probe()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

In the similar way, ignore 0 error code (AKA "success") in
dev_err_probe(). This helps to simplify a code such as

  if (ret < 0)
    return dev_err_probe(int3472->dev, ret, err_msg);

  return ret;

to

  return dev_err_probe(int3472->dev, ret, err_msg);

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/base/core.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4bc8b88d697e..830a14084bf6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4987,13 +4987,14 @@ define_dev_printk_level(_dev_info, KERN_INFO);
  * This helper implements common pattern present in probe functions for error
  * checking: print debug or error message depending if the error value is
  * -EPROBE_DEFER and propagate error upwards.
+ *
  * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
  * checked later by reading devices_deferred debugfs attribute.
  * It replaces code sequence::
  *
  * 	if (err != -EPROBE_DEFER)
  * 		dev_err(dev, ...);
- * 	else
+ * 	else if (err)
  * 		dev_dbg(dev, ...);
  * 	return err;
  *
@@ -5003,12 +5004,16 @@ define_dev_printk_level(_dev_info, KERN_INFO);
  *
  * Using this helper in your probe function is totally fine even if @err is
  * known to never be -EPROBE_DEFER.
+ *
+ * NOTE: The message is not going to be printed or saved in cases when @err
+ * is equal to -ENOMEM or 0.
+ *
  * The benefit compared to a normal dev_err() is the standardized format
  * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
  * instead of "-35") and the fact that the error code is returned which allows
  * more compact error paths.
  *
- * Returns @err.
+ * Return: the value of @err.
  */
 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
 {
@@ -5032,6 +5037,10 @@ int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
 		 */
 		break;
 
+	case 0:
+		/* Success, no need to issue an error message */
+		break;
+
 	default:
 		dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
 		break;
-- 
2.43.0.rc1.1336.g36b5255a03ac