Le 27. 06. 16 à 10:33, Jacek Anaszewski a écrit : > On 06/27/2016 10:30 AM, Florian Vaussard wrote: >> Hi Jacek, >> >> Le 27. 06. 16 à 10:11, Jacek Anaszewski a écrit : >>> Hi Florian, >>> >>> On 06/27/2016 09:03 AM, Florian Vaussard wrote: >>>> Add device tree binding documentation for On Semiconductor NCP5623 I2C >>>> LED driver. The driver can independently control the PWM of the 3 >>>> channels with 32 levels of intensity. >>>> >>>> The current delivered by the current source can also be controlled. To >>>> do so, the led-max-microamp property is used by each LED sub-node. The >>>> maximum value is then found and used as a limit to compute the final >>>> intensity of the current source. If a LED happens to have a lower limit, >>>> the PWM is then used to limit the current to the requested value. >>>> >>>> In order to control the current source, it is also necessary to know >>>> the current on the Iref pin, hence the onnn,led-iref-microamp property. >>>> It is usually set using an external bias resistor, following >>>> Iref = Vref/Rbias with Vref=0.6V. >>>> >>>> Signed-off-by: Florian Vaussard <florian.vaussard@xxxxxxxxxx> >>>> --- >>>> .../devicetree/bindings/leds/leds-ncp5623.txt | 60 >>>> ++++++++++++++++++++++ >>>> 1 file changed, 60 insertions(+) >>>> create mode 100644 Documentation/devicetree/bindings/leds/leds-ncp5623.txt >>>> >>>> diff --git a/Documentation/devicetree/bindings/leds/leds-ncp5623.txt >>>> b/Documentation/devicetree/bindings/leds/leds-ncp5623.txt >>>> new file mode 100644 >>>> index 0000000..77dd7ad >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/leds/leds-ncp5623.txt >>>> @@ -0,0 +1,60 @@ >>>> +* ON Semiconductor - NCP5623 3-Channel LED Driver >>>> + >>>> +The NCP5623 is a 3-channel I2C LED driver. The brightness of each >>>> +channel can be independently set using 32 levels. Each LED is represented >>>> +as a sub-node of the device. >>>> + >>>> +Required properties: >>>> + - compatible: Should be "onnn,ncp5623" >>>> + - reg: I2C slave address (fixed to 0x38) >>>> + - #address-cells: must be 1 >>>> + - #size-cells: must be 0 >>>> + - onnn,led-iref-microamp: Current on the Iref pin in microampere. It depends >>>> + on the value of the external bias resistor Rbias, following >>>> + Iref = Vref / Rbias with Vref = 0.6V. This is used to set the intensity of >>>> + the current that can be provided by the internal current source, based on >>>> + the maximum current permitted by LED sub-nodes (see below), but no more >>>> than >>>> + Imax = 2400 * Iref. >>>> + >>>> +LED sub-nodes >>>> +============= >>>> + >>>> +Required properties: >>>> + - reg : LED channel number (0..2) >>>> + - led-max-microamp: Maximum allowable current inside the LED in microampere. >>>> + This property is used to limit the PWM ratio, based on the intensity of >>>> the >>>> + internal current source (see above). >>>> + >>>> +Optional properties: >>>> + - label: Used for naming LEDs >>> >>> Instead of the above description use same reference to common led >>> bindings as below. >>> >> >> Ok. >> >> BTW I saw the thread about the "default-state" property on the DT list and >> realized that it was not implemented in my driver. I wonder if standard LED >> properties (with label and default-trigger) should not be parsed by LED core >> (i.e. using a helper function) to avoid such mistake. This could also remove >> some boilerplate code in other LED drivers. > > Yes, generic DT parser is a nice-to-have feature for the LED subsystem. > Would you like to implement it? > Sure, if it can be useful. I will have a look in the coming days. Best, Florian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
