Re: [PATCH v2 7/7] wil6210: add support for device led configuration

[merez@codeaurora.org]

On 2016-04-25 21:56, Kalle Valo wrote:
> Maya Erez <qca_merez@qca.qualcomm.com> writes:
> 
>> Add the ability to configure the device led to be used for notifying
>> the AP activity (60G device supports leds 0-2).
>> The host can also configure the blinking frequency of the led in
>> three states.
> 
> [...]
> 
>> +/* led_blink_time, write:
>> + * "<blink_on_slow> <blink_off_slow> <blink_on_med> <blink_off_med>
> <blink_on_fast> <blink_off_fast>
>> + */
>> +static ssize_t wil_write_led_blink_time(struct file *file,
>> +					const char __user *buf,
>> +					size_t len, loff_t *ppos)
>> +{
>> +	int rc;
>> +	char *kbuf = kmalloc(len + 1, GFP_KERNEL);
>> +
>> +	if (!kbuf)
>> +		return -ENOMEM;
>> +
>> +	rc = simple_write_to_buffer(kbuf, len, ppos, buf, len);
>> +	if (rc != len) {
>> +		kfree(kbuf);
>> +		return rc >= 0 ? -EIO : rc;
>> +	}
>> +
>> +	kbuf[len] = '\0';
>> +	rc = sscanf(kbuf, "%d %d %d %d %d %d",
>> +		    &led_blink_time[WIL_LED_TIME_SLOW].on_ms,
>> +		    &led_blink_time[WIL_LED_TIME_SLOW].off_ms,
>> +		    &led_blink_time[WIL_LED_TIME_MED].on_ms,
>> +		    &led_blink_time[WIL_LED_TIME_MED].off_ms,
>> +		    &led_blink_time[WIL_LED_TIME_FAST].on_ms,
>> +		    &led_blink_time[WIL_LED_TIME_FAST].off_ms);
>> +	kfree(kbuf);
>> +
>> +	if (rc < 0)
>> +		return rc;
>> +	if (rc < 6)
>> +		return -EINVAL;
>> +
>> +	return len;
>> +}
> 
> Don't we already have a proper framework for leds? At least
> include/linux/led.h and drivers/led/ makes me suspect that. I'm not
> really fond of the idea reinventing the wheel, unless there's a really
> good reason.

The kernel led framework provides the host the ability to toggle a 
defined led,
but in our case the led toggling is fully offloaded to the device.
The host only configures the device with the led to activate and its 
parameters.
I agree that reusing an existing framework should be enforced when 
possible,
but as the WIL6210 host needs to align to the device led configuration
we cannot reuse the led kernel framework.
-- 
Maya Erez
Qualcomm Israel, Inc. on behalf of Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project