Hi Andy,


On 09/01/2016 06:17 AM, Andy Shevchenko wrote:

On Tue, 2016-08-30 at 11:18 -0700, Sathyanarayanan Kuppuswamy wrote:

quoted

IMO, Main problem here is, In some scenarios get_platform_data
returns
NULL on error case and in some cases it return NULL for no platform
data
case.

We have possibility of the following scenarios:
1) fatal error (should return error code and fail booting)
2) non-fatal error (prevents certain device to be enumerated, pdata =
NULL)
3) no pdata for the device (not an error! pdata is optional to the
certain driver)
4) pdata != NULL (fully armed device driver)

According to above I doubt we will have many 1) cases. Otherwise pdata =
NULL is okay.

I agree with 2,3 and 4 scenarios. But I am not sure about the first 
case. Since these are peripheral devices, any failure in them should not 
stop the device boot. Do you have any examples for this case ?

Attached patch fixes the return value issues in get_platform_data code 
in device_libs directory. Please check and let me know your comments.

quoted

For example, in following function, returning NULL on gpio_base == -1
and when nr >= PCAL9555A_NUM is incorrect. I think in both these
scenarios valid behavior is to stop the device creation process.

Yes, but do _not_ stop processing and booting!

quoted

Creating an i2c device without validi irq number or gpio number is
incorrect.

So after investigating it bit more, I think its more appropriate to
fix
these error cases in device_libs dir. Let me know your comments.

I doubt that is a proper fix. It might be part of the fix in sfi.c where
you somehow distinguish fatal errors from non-fatal.

-- 
Sathyanarayanan Kuppuswamy
Android kernel developer