Re: [PATCH v3] DT: Add documentation for the mfd Maxim max77693

[Jacek Anaszewski <j.anaszewski@samsung.com>]

On 03/30/2015 01:57 PM, Mark Rutland wrote:
> On Mon, Mar 30, 2015 at 10:52:28AM +0100, Jacek Anaszewski wrote:
>> This patch adds device tree binding documentation for
>> the flash cell of the Maxim max77693 multifunctional device.
>>
>> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
>> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>> Cc: Lee Jones <lee.jones@linaro.org>
>> Cc: Chanwoo Choi <cw00.choi@samsung.com>
>> Cc: Bryan Wu <cooloney@gmail.com>
>> Cc: Richard Purdie <rpurdie@rpsys.net>
>> Cc: devicetree@vger.kernel.org
>> ---
>>   Documentation/devicetree/bindings/mfd/max77693.txt |   63 ++++++++++++++++++++
>>   1 file changed, 63 insertions(+)
>>
>> - added range to maxim,boost-mvout and maxim,mvsys-min description
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/max77693.txt b/Documentation/devicetree/bindings/mfd/max77693.txt
>> index 38e6440..3d2103a 100644
>> --- a/Documentation/devicetree/bindings/mfd/max77693.txt
>> +++ b/Documentation/devicetree/bindings/mfd/max77693.txt
>> @@ -76,7 +76,55 @@ Optional properties:
>>       Valid values: 4300000, 4700000, 4800000, 4900000
>>       Default: 4300000
>>
>> +- led : the LED submodule device node
>> +
>> +There are two LED outputs available - FLED1 and FLED2. Each of them can
>> +control a separate LED or they can be connected together to double
>> +the maximum current for a single connected LED. One LED is represented
>> +by one child node.
>> +
>> +Required properties:
>> +- compatible : Must be "maxim,max77693-led".
>> +
>> +Optional properties:
>> +- maxim,trigger-type : Flash trigger type.
>> +	Possible trigger types:
>> +		LEDS_TRIG_TYPE_EDGE (0) - Rising edge of the signal triggers
>> +			the flash,
>> +		LEDS_TRIG_TYPE_LEVEL (1) - Strobe pulse length controls duration
>> +			of the flash.
>
> Surely this is required? What should be assumed if this property isn't
> present?

LEDS_TRIG_TYPE_LEVEL allows for an ISP to do e.g. short flash blink
before the actual strobe - it is used for eliminating photographs with
closed eyes, or can serve for probing ambient light conditions.

With LEDS_TRIG_TYPE_EDGE flash strobe is triggered on rising edge
and lasts until programmed timeout expires.

This setting is tightly related to a camera sensor, which generates
the strobe signal. Effectively it depends on board configuration.


> Otherwise this looks OK, but I'm not that familiar with LED/flash
> bindings.
>
> Mark.
>
>> +- maxim,boost-mode :
>> +	In boost mode the device can produce up to 1.2A of total current
>> +	on both outputs. The maximum current on each output is reduced
>> +	to 625mA then. If not enabled explicitly, boost setting defaults to
>> +	LEDS_BOOST_FIXED in case both current sources are used.
>> +	Possible values:
>> +		LEDS_BOOST_OFF (0) - no boost,
>> +		LEDS_BOOST_ADAPTIVE (1) - adaptive mode,
>> +		LEDS_BOOST_FIXED (2) - fixed mode.
>> +- maxim,boost-mvout : Output voltage of the boost module in millivolts.
>> +		Range: 3300 - 5500
>> +- maxim,mvsys-min : Low input voltage level in millivolts. Flash is not fired
>> +	if chip estimates that system voltage could drop below this level due
>> +	to flash power consumption.
>> +		Range: 2400 - 3400
>> +
>> +Required properties of the LED child node:
>> +- led-sources : see Documentation/devicetree/bindings/leds/common.txt;
>> +		device current output identifiers: 0 - FLED1, 1 - FLED2
>> +
>> +Optional properties of the LED child node:
>> +- label : see Documentation/devicetree/bindings/leds/common.txt
>> +- max-microamp : see Documentation/devicetree/bindings/leds/common.txt
>> +		Range: 15625 - 250000
>> +- flash-max-microamp : see Documentation/devicetree/bindings/leds/common.txt
>> +		Range: 15625 - 1000000
>> +- flash-timeout-us : see Documentation/devicetree/bindings/leds/common.txt
>> +		Range: 62500 - 1000000
>> +
>>   Example:
>> +#include <dt-bindings/leds/common.h>
>> +
>>   	max77693@66 {
>>   		compatible = "maxim,max77693";
>>   		reg = <0x66>;
>> @@ -117,5 +165,20 @@ Example:
>>   			maxim,thermal-regulation-celsius = <75>;
>>   			maxim,battery-overcurrent-microamp = <3000000>;
>>   			maxim,charge-input-threshold-microvolt = <4300000>;
>> +
>> +		led {
>> +			compatible = "maxim,max77693-led";
>> +			maxim,trigger-type = <LEDS_TRIG_TYPE_LEVEL>;
>> +			maxim,boost-mode = <LEDS_BOOST_FIXED>;
>> +			maxim,boost-mvout = <5000>;
>> +			maxim,mvsys-min = <2400>;
>> +
>> +			camera_flash: flash-led {
>> +				label = "max77693-flash";
>> +				led-sources = <0>, <1>;
>> +				max-microamp = <500000>;
>> +				flash-max-microamp = <1250000>;
>> +				flash-timeout-us = <1000000>;
>> +			};
>>   		};
>>   	};
>> --
>> 1.7.9.5
>>
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-- 
Best Regards,
Jacek Anaszewski