Re: [PATCH 3/3 v2] iio: add rtc-driver for HID sensors of type time

[Alexander Holler]

Am 10.12.2012 18:05, schrieb Lars-Peter Clausen:
> On 12/10/2012 03:51 PM, Alexander Holler wrote:

> The channel spec is semi unused. You use it to lookup the scan index and the
> name, but that could easily be implemented without the channel spec.
> Especially considering that the scan index lookup is only ever done for
> channel 0, which will always return CHANNEL_SCAN_INDEX_YEAR.

Thats what I had in mind for v3.

> Are the entries in info ordered in the same way as the addresses in
> hid_time_addresses? If yes you could just use a lookup-table like
>
> static const char * const hid_time_attrib_names[] = {
> 	"second",
> 	...
> };
>
> and just use 'i' to look them up.

Again, what I had in mind for v3. It would have been better I wouldn't 
have used one of the existing drivers as template and afterwards 
removing tons of stuff. ;)

> > +	init_completion(&time_state->comp_last_time);
>
> This needs to be INIT_COMPLETION. init_completion must be called exactly
> once on a completion, which should be from inside probe() in this case.

Ah, so I've misread http://lwn.net/Articles/23993/ . I've read it as 
init_completion() is usable multiple times (I had the impression 
INIT_COMPLETION got replaced by init_completion().

> > +	/* wait for all values (event) */
> > +	wait_for_completion_interruptible_timeout(&time_state->comp_last_time,
> > +							HZ*6);
>
> You should check the return value in case either a timeout happens or the
> sleep is interrupted.

Yes, I already wanted to do it, but it seems I've forgotten it.

> > +	struct hid_time_state *time_state =
> > +		kzalloc(sizeof(struct hid_time_state), GFP_KERNEL);
>
> You could use devm_kzalloc here. By doing so you don't have to take care of
> freeing it again since it will be auto-freed once the device is removed.

Thanks. I already searched such and wondered why such didn't exist. Just 
to clarify, if I use devm_kzalloc, I don't have to free time_state here

> > +error_free_drvdata:
> > +	platform_set_drvdata(pdev, NULL);
>
> Setting the platform data to NULL should not be necessary. Some drivers do
> this but it's kind of the result of cargo-cult-coding.
>
> > +	kfree(time_state);
> > +error_ret:
> > +	return ret;
> > +}
> > +
> > +static int __devinit hid_time_remove(struct platform_device *pdev)
> > +{
> > +	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
> > +	struct hid_time_state *time_state = platform_get_drvdata(pdev);
> > +
> > +	if (!IS_ERR(time_state->rtc))
> > +		rtc_device_unregister(time_state->rtc);
> > +	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
> > +	platform_set_drvdata(pdev, NULL);

and here?

> Same here.
>
> > +	kfree(time_state);
> > +
> > +	return 0;
> > +}
> > +
> [...]

Regards,

Alexander
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