Jacek
On 7/31/19 3:44 PM, Jacek Anaszewski wrote:
Dan,
[...]
+ for (i = 0; i < mcled_cdev->num_leds; i++) {
+ ret = sscanf(buf + offset, "%i%n", &value[i], &nrchars);
+ if (ret != 1)
+ break;
+
+ offset += nrchars;
+ }
+
+ if (i != mcled_cdev->num_leds) {
Shouldn't we return error if i != mcled_cdev->num_leds - 1 ?
How can we know which color the value will be for if there is less
values passed than the total number of colors in the cluster?
Ok so during my testing if I had the monochrome array as <R G B>
When I wrote only <R G> and no blue I was getting random values in the
array for the
remaining indexes and the blue LED would randomly turn on/off at
different levels.
So if the user passes in less then expected only ids with data will be
written and the other colors will be turned off by the for loop below.
From what I see it will lead to wrong mapping of given color to the
value array element in the following case:
echo "<green> <blue>" > color_mix
Then green intensity will be assigned to value[0] (expects red) and blue
to value[1] (expects green). Unless I don't get something.
Your ABI documentation doesn't mention any way to redefine the color_id
returned by <color>/color_id file. And that is good.
This is exactly the issue I had previously brought up. The user would
need to
write all leading colors with a value, even if 0, to correctly set the
target LEDs.
We can protect against the trailing colors but not leading colors.
The expectation is that the user space would read the color_id from the
file and align
the array accordingly. This is also why I exposed the intensity under
the color so if the
user wanted to not use color_mix file they can update the intensity per
LED color.
+ for (; i < LED_COLOR_ID_MAX; i++)
+ value[i] = 0;
What use case is it for?
See above but this should be
for (; i < mcled_cdev->num_leds; i++)
I might be able to eliminate this loop by initializing the array to 0.
+ }
+
+ list_for_each_entry(priv, &data->color_list, list) {
+ if (data->cluster_brightness) {
+ adj_brightness =
calculate_brightness(data->cluster_brightness,
+ value[priv->color_index],
+ priv->max_intensity);
+ ret = ops->set_color_brightness(priv->mcled_cdev,
+ priv->color_id,
+ adj_brightness);
+ if (ret < 0)
+ goto done;
+ }
+
+ priv->intensity = value[priv->color_index];
+ }
Here we could use just brightness_set op as a single call. We should
always write all colors as a result of write to color_mix anyway.
I guess what is gained by just passing the array down to the device
driver and having it
parse the array and do the peripheral call?
Those array values would not be directly written to the device,
but used for calculating the actual iout intensities. Driver
will just have to call calculate_brightness() (sticking to the naming
from this patch) and write the results calculated basing on brightness
and max_brightness.
I would expect that we would do the same behavior for the color_mix file
then.
[...]
+
+ priv->new_intensity = value;
+
+ if (data->cluster_brightness) {
+ adj_value = calculate_brightness(data->cluster_brightness,
+ priv->new_intensity,
+ priv->max_intensity);
+ ret = ops->set_color_brightness(priv->mcled_cdev,
+ priv->color_id, adj_value);
+ if (ret < 0) {
+ priv->new_intensity = priv->intensity;
This is unnecessary complication. Just write the calculated iout
intensity.
Not sure what complication you are referring to.
The whole need for new_intensity and cluster_brightness, and then
bringing back old intensity value on set_color_brightness() failure.
OK
We need to highlight it in the documentation that exact requested color
intensity values are written to the hardware only when
brightness == max_brightness.
But that is not a true statement. Thats not really how it was designed.
But it probably should be. It would simplify the design.
So my idea is like I previously described the way I had first understood
this design:
The colors set under colors directory don't reflect the iout
intensities, but are only used for calculating them, basing on the
brightness and max_intensity values.
Effectively, after changing the colors/<color>/intensity the global
(legacy monochrome) brightness value will be still valid, since iout
color will be recalculated basing on it and the new color intensity.
OK. This this would remove the ops from the driver as it is no longer
needed.
The color_mix file will work the same way.
What is the trigger then to update the LEDs?
We cannot write the same brightness value to trigger as the class blocks
calling down
to the driver if brightness_in == brightness_current.
Dan
