Re: [PATCH v29 03/16] leds: multicolor: Introduce a multicolor class definition

[Dan Murphy]

Pavel

Thanks for the review

On 7/11/20 10:57 AM, Pavel Machek wrote:
> Hi!
>
> > Introduce a multicolor class that groups colored LEDs
> > within a LED node.
> > +What:		/sys/class/leds/<led>/multi_intensity
> > +Date:		March 2020
> > +KernelVersion:	5.8
> > +Contact:	Dan Murphy <dmurphy@xxxxxx>
> > +Description:	read/write
> > +		Intensity level for the LED color within an array of integers.
> ? "This file contains array of integers".
OK
> > +		The intensities for each color must be entered based on the
> > +		multi_index array.
> This does not make sense to me. "Order of components is described by
> the multi_index array"?
>
> > The max_intensity should not exceed
> "max_intensity" -> "maximum intensity"?
OK
> > +		/sys/class/leds/<led>/max_brightness.
> > +Multicolor Class Brightness Control
> > +===================================
> > +The multicolor class framework will calculate each monochrome LEDs intensity.
> ?
This is redundant and will be removed.
> > +static ssize_t multi_intensity_store(struct device *dev,
> > +				struct device_attribute *intensity_attr,
> > +				const char *buf, size_t size)
> > +{
> > +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> > +	struct led_classdev_mc *mcled_cdev = lcdev_to_mccdev(led_cdev);
> > +	int nrchars, offset = 0;
> > +	int intensity_value[LED_COLOR_ID_MAX];
> > +	int i;
> > +	ssize_t ret;
> > +
> > +	mutex_lock(&led_cdev->led_access);
> > +
> > +	for (i = 0; i < mcled_cdev->num_colors; i++) {
> > +		ret = sscanf(buf + offset, "%i%n",
> > +			     &intensity_value[i], &nrchars);
> > +		if (ret != 1) {
> > +			dev_dbg(led_cdev->dev,
> > +				"Incorrect number of LEDs expected %i values intensity was not applied\n",
> > +				mcled_cdev->num_colors);
> > +			ret = -EINVAL;
> > +			goto err_out;
> > +		}
> > +		offset += nrchars;
> > +	}
> > +
> > +	/* account for the space at the end of the buffer */
> > +	offset++;
> space? I'd expect \n there. And it would be good to verify it is
> indeed \n, so that for example "0 0 0b" is not accepted.
It is a new line the comment is incorrect I can remove the comment or 
update the comment to account for the new line
> Please remove the dev_dbg()s that can be triggered by userspace. We
> don't want users spamming the logs.
Removed
> > +static ssize_t multi_intensity_show(struct device *dev,
> > +			      struct device_attribute *intensity_attr,
> > +			      char *buf)
> > +{
> > +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> > +	struct led_classdev_mc *mcled_cdev = lcdev_to_mccdev(led_cdev);
> > +	int len = 0;
> > +	int i;
> > +
> > +	for (i = 0; i < mcled_cdev->num_colors; i++) {
> > +		len += sprintf(buf + len, "%d",
> > +			       mcled_cdev->subled_info[i].intensity);
> > +		len += sprintf(buf + len, " ");
> We should not really put " " before newline.

OK I will fix that.


> > +static ssize_t multi_index_show(struct device *dev,
> > +			      struct device_attribute *multi_index_attr,
> > +			      char *buf)
> > +{
> > +	for (i = 0; i < mcled_cdev->num_colors; i++) {
> > +		index = mcled_cdev->subled_info[i].color_index;
> > +		len += sprintf(buf + len, "%s", led_colors[index]);
> > +		len += sprintf(buf + len, " ");
> > +	}
> We should not really put " " before newline.
>
> > +{
> > +	struct led_classdev *led_cdev;
> > +
> > +	if (!mcled_cdev)
> > +		return -EINVAL;
> > +
> > +	if (!mcled_cdev->num_colors)
> > +		return -EINVAL;
> It is plain int, so you may want to check for <= 0? Or maybe make it
> unsigned?

ok


> > +MODULE_LICENSE("GPL v2");
> If your legal department allows that, GPL v2+ would be preffered
> (globally).

OK


> > +struct mc_subled {
> > +	int color_index;
> > +	int brightness;
> > +	int intensity;
> > +	int channel;
> > +};
> > +
> > +struct led_classdev_mc {
> > +	/* led class device */
> > +	struct led_classdev led_cdev;
> > +	int num_colors;
> > +
> > +	struct mc_subled *subled_info;
> > +};
> Would some "unsigned"s make sense here to cut number of corner cases?

I made these unsigned.

Dan

> Best regards,
> 									Pavel