On Wed, 19 Sep 2012 09:28:04 -0600, Stephen Warren wrote:

On 09/18/2012 07:15 PM, Bo Shen wrote:

quoted

I add the debug info, and it give the following error without this patch.

--<8----------------------------------
adap->name = i2c-gpio-1
i2c-gpio i2c.2: using pins 30 (SDA) and 31 (SCL)
adap->name = i2c-gpio-1
i2c-gpio: probe of i2c.3 failed with error -16
-->8----------------------------------

With this patch, it successfully registered.
--<8----------------------------------
adap->name = i2c-gpio0
i2c-gpio i2c.2: using pins 30 (SDA) and 31 (SCL)
adap->name = i2c-gpio1
i2c-gpio i2c.3: using pins 90 (SDA) and 91 (SCL)
-->8----------------------------------

Yes, that explains why the registration fails, but not why this patch is
the correct solution to the problem.

The problematic code appears to be:

snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);

Instead, I think that should be something more like:

adap->name = dev_name(&pdev->dev);

strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name))

if anything, as adap->name is a buffer, not a pointer.

or perhaps:

if (pdev->dev.of_node)
  /* named will be based on DT node name */
  adap->name = dev_name(&pdev->dev);
else
  snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);

?

-- 
Jean Delvare