Re: [PATCH v4 0/7] platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes

[Guenter Roeck <linux@roeck-us.net>]

On 8/21/20 1:21 AM, Enric Balletbo i Serra wrote:
> Hi Guenter et all,
> 
> On 6/8/20 17:33, Guenter Roeck wrote:
>> The EC reports a variety of error codes. Most of those, with the exception
>> of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
>> error code gets lost. In cros_ec_cmd_xfer_status(), convert all EC errors
>> to Linux error codes to report a more meaningful error to the caller to aid
>> debugging.
>>
>> To prepare for this change, handle error codes other than -EPROTO for all
>> callers of cros_ec_cmd_xfer_status(). Specifically, no longer assume that
>> -EPROTO reflects an error from the EC and all other error codes reflect a
>> transfer error.
>>
>> v2: Add patches 1/4 to 3/4 to handle callers of cros_ec_cmd_xfer_status()
>> v3: Add patches 4/6 and 5/6 to handle additional callers of
>> 	cros_ec_cmd_xfer_status()
>>     Use -ENOPROTOOPT for EC_RES_INVALID_VERSION
>>     Implement function to convert error codes
>> v4: Add coments describing the functionality of cros_ec_num_pwms().
>>     Add patch 7/7 to clean up cros_ec_num_pwms() after the new error code
>>     support has been implemented.
>>     Rebased series to v5.8.
>>
>> ----------------------------------------------------------------
>> Guenter Roeck (7):
>>       iio: cros_ec: Accept -EOPNOTSUPP as 'not supported' error code
>>       cros_ec_lightbar: Accept more error codes from cros_ec_cmd_xfer_status
>>       platform/chrome: cros_ec_sysfs: Report range of error codes from EC
>>       pwm: cros-ec: Accept more error codes from cros_ec_cmd_xfer_status
>>       platform/input: cros_ec: Replace -ENOTSUPP with -ENOPROTOOPT
>>       platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
>>       pwm: cros-ec: Simplify EC error handling
>>
>>  .../iio/common/cros_ec_sensors/cros_ec_sensors.c   |  2 +-
>>  drivers/input/keyboard/cros_ec_keyb.c              |  2 +-
>>  drivers/platform/chrome/cros_ec_lightbar.c         | 10 ++---
>>  drivers/platform/chrome/cros_ec_proto.c            | 52 +++++++++++++++++-----
>>  drivers/platform/chrome/cros_ec_sysfs.c            | 24 ++++------
>>  drivers/pwm/pwm-cros-ec.c                          | 37 +++++++--------
>>  6 files changed, 74 insertions(+), 53 deletions(-)
>>
> 
> The patches LGTM, and if the other maintainers are fine, I'd like to queue all
> these through the chrome-platform tree.
> 
> I noticed, thought, that KernelCI reported a regression on Kevin that I'll try
> to debug at the beginning of next week.
> 
> [    3.821203] cros-ec-spi spi2.0: Wrong size 1/3: 0 != 4
> [    3.827320] cros-ec-keyb ff200000.spi:ec@0:keyboard-controller: cannot
> register non-matrix inputs: -71
> [    3.838506] cros-ec-keyb: probe of ff200000.spi:ec@0:keyboard-controller
> failed with error -71
> [    3.853492] cros-ec-spi spi2.0: Chrome EC device registered
> 

Easy to debug. cros_ec_cmd_xfer_status() now returns 0 for success and < 0 for errors.
It needs to return the receive length if there is no error. I'll send v5 with a fix,
and sorry for the trouble.

Thanks,
Guenter