Re: [v3,1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper

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

On 06/17/2016 06:08 PM, Brian Norris wrote:
> On Fri, Jun 17, 2016 at 02:41:51PM -0700, Guenter Roeck wrote:
>> On Fri, Jun 17, 2016 at 12:58:12PM -0700, Brian Norris wrote:
>>> +int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
>>> +			    struct cros_ec_command *msg)
>>> +{
>>> +	int ret;
>>> +
>>> +	ret = cros_ec_cmd_xfer(ec_dev, msg);
>>> +	if (ret < 0)
>>> +		dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
>>> +	else if (msg->result != EC_RES_SUCCESS)
>>> +		return -EECRESULT - msg->result;
>>
>> I have been wondering about the error return codes here, and if they should be
>> converted to standard Linux error codes. For example, I just hit error -1003
>> with a driver I am working on. This translates to EC_RES_INVALID_PARAM, or,
>> in Linux terms, -EINVAL. I think it would be better to use standard error
>> codes, especially since some of the errors are logged.
>
> How do you propose we do that? Do all of the following become EINVAL?
>
>          EC_RES_INVALID_COMMAND

	-EOPNOTSUPP

>          EC_RES_INVALID_PARAM

	-EINVAL or -EBADMSG

>          EC_RES_INVALID_VERSION

	-EPROTO or -EBADR or -EBADE or -EBADRQC or -EPROTOOPT

>          EC_RES_INVALID_HEADER

	-EPROTO or -EBADR or -EBADE

Doesn't look that bad to me. Also, the raw error could still be logged,
for example with dev_dbg().

Guenter

>
> We lose a lot of information that way. And particularly, cros_ec_num_pwms()
> won't be able to count as accurately. But I can just go back to not using this
> API if that's what you'd like...
>
> Brian
>