Messages in this thread | | | Date | Wed, 10 Nov 2021 00:29:31 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH 1/2] leds: ktd20xx: Add the KTD20xx family of the RGB LEDs driver from Kinetic |
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hi!
> Introduce the KTD2061/58/59/60 RGB LEDs driver. The difference in these > parts are the address number on the I2C bus the device is listen on. > > All KT20xx device could control up to 12 LEDs. The chip can be operated > in two variants.
How are the variants selected?
> Variant 1: > The device has the ability to group LED outputs into two banks so that > the two LED banks can be controlled with the same color. This could not > be done via the LEDs 'sysfs' entry because of the limitation on the color > register count. The color of the two banks can be configured via device > 'sysfs' entry for all LEDs at once [current_color0|current_color1]. > Which color the LED is to be used can be set via the 'sysfs' of the > individual LEDs via the 'multi_intensity' file. Valid values for the > colors (RGB) are 0 | 1. The value 0 selects the color register 0 and the > value 1 selects the color register 1.
So... you can select two colors (current_color0, current_color1), and then then each of the 12 LEDs get one of those colors. What about intensities? Can brightness be set arbitrarily for each LED?
> Variant 2: > The device can also set the LED color independently. Since the chip only > has two color registers, but we want to control the 12 LEDs > independently via the 'led-class-multicolour' sysfs entry, > the full RGB color depth cannot be used. Due to this limitation, only 7 > colors and the color black (off) can be set. To use this mode the color > registers must be preset via the device tree or the device 'sysfs'. The > color registers 0 must be preset with 0x00 (Red=0x00 Green=0x00 Blue=0x00). > The color register1 should be preset all with the same value. This value > depends on which light intensity is to be used in the setup.
So now we have 7 colors we can select from. That sounds better than two colors. Why would we ever want to use variant 1?
Can we simply pretend this is 7 LED RGB driver?
> +/* Device attribute for color0 register > + * > + * The device attribute colour1 is intended to adjust the colour space.
Use color, not colour. Plus run this through checkpatch.
> + * The colour strength can be controlled via the current in 125uA steps.
I don't know what "colour strength" is.
> +/* > + * The chip also offers the option "Fade rate". > + */ > +static ssize_t faderate_show(struct device *dev, struct device_attribute *a, > + char *buf) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct ktd20xx *chip = i2c_get_clientdata(client); > + unsigned int value; > + > + mutex_lock(&chip->lock); > + regmap_field_read(chip->faderate, &value); > + mutex_unlock(&chip->lock); > + > + return sprintf(buf, "%d\n", value); > +}
That's way too hardware specific.
Best regards, Pavel -- http://www.livejournal.com/~pavelmachek [unhandled content-type:application/pgp-signature] | |