Re: [PATCH 4/4] firmware sysfs node

[Rafi Rubin <rafi@seas.upenn.edu>]

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On 08/27/10 12:34, Dmitry Torokhov wrote:
> On Fri, Aug 27, 2010 at 02:09:05PM +0200, Henrik Rydberg wrote:
>> On 08/26/2010 06:54 AM, Rafi Rubin wrote:
>>
>>> Signed-off-by: Rafi Rubin <rafi@seas.upenn.edu>
>>> ---
>>>  drivers/hid/hid-ntrig.c |   21 +++++++++++++++++++++
>>>  1 files changed, 21 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
>>> index ab0ca7f..e341e88 100644
>>> --- a/drivers/hid/hid-ntrig.c
>>> +++ b/drivers/hid/hid-ntrig.c
>>> @@ -375,6 +375,26 @@ static ssize_t set_deactivate_slack(struct device *dev,
>>>  static DEVICE_ATTR(deactivate_slack, S_IWUSR | S_IRUGO, show_deactivate_slack,
>>>  		   set_deactivate_slack);
>>>  
>>> +static ssize_t show_firmware(struct device *dev,
>>> +			       struct device_attribute *attr,
>>> +			       char *buf)
>>> +{
>>> +	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
>>> +	struct ntrig_data *nd = hid_get_drvdata(hdev);
>>> +
>>> +	if (!(nd->firmware_version[0] || nd->firmware_version[1] ||
>>> +	      nd->firmware_version[2] || nd->firmware_version[3]))
>>> +		return sprintf(buf, "Firmware version unavailable");
>>
>>
>> If this sysfs node should really be added (see EVIO), it is probably better if
>> it returns the same format for all devices. If all numbers are zero, that is
>> understandable also by someone reading the node.
>>
> 
> Yes, I think we should stick it into input_id and be done with it. Note
> that input_id is not only available via EVIOCGID ioctl but also already
> exported in sysfs.

The version in input_id is only 16 bits, whereas the ntrig version codes seem to
be 32 bits.  Actually I've only mapped 21 bits out of 64, but I figure the first
and last 8 are not actually part of the version, but that's still more than 16.

So, would you prefer that I increase the size of that field, or keep the
firmware version code separate?


Also does it make sense to have a provide a pretty printer in the kernel, or
should that be left to userspace?  The hardware returns a raw version code in
the form:
	1a08 a521

In the ntrig utilities and documentation the where firmware version is mentioned
it looks more like this:
	4.6.17.13.5

My intent was to make that second form more accessible to keep things simple for
users, who if they are checking that probably already have enough troubling them :)

Rafi
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