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Subject: Re: [PATCH v2 1/2] dt: bindings: lm3697: Add bindings for lm3697
 driver
To:     Jacek Anaszewski <jacek.anaszewski@gmail.com>,
        Pavel Machek <pavel@ucw.cz>
CC:     <robh+dt@kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-leds@vger.kernel.org>
References: <20180807160442.8937-1-dmurphy@ti.com>
 <20180808195903.GB20912@amd> <f6b3534b-2ee9-782e-35e5-e103c34528bc@ti.com>
 <20180808210215.GA15831@amd> <f18a5616-bb25-da0d-aec8-585e042b4919@ti.com>
 <53691469-4554-42a8-c182-762c1a3939b7@gmail.com>
From:   Dan Murphy <dmurphy@ti.com>
Message-ID: <01bbf05a-8e5e-d3ce-857a-ac5c6efb779c@ti.com>
Date:   Wed, 8 Aug 2018 16:45:06 -0500
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Jacek

On 08/08/2018 04:09 PM, Jacek Anaszewski wrote:
> Hi Dan,
> 
> On 08/08/2018 11:04 PM, Dan Murphy wrote:
>> On 08/08/2018 04:02 PM, Pavel Machek wrote:
>>> Hi!
>>>
>>>>>> +	- #size-cells : 0
>>>>>> +	- control-bank-cfg - : Indicates which sink is connected to which control bank
>>>>>> +		0 - All HVLED outputs are controlled by bank A
>>>>>> +		1 - HVLED1 is controlled bank B, HVLED2/3 are controlled by bank A
>>>>>> +		2 - HVLED2 is controlled bank B, HVLED1/3 are controlled by bank A
>>>>>> +		3 - HVLED1/2 are controlled by bank B, HVLED3 is controlled by bank A
>>>>>> +		4 - HVLED3 is controlled by bank B, HVLED1/2 are controlled by bank A
>>>>>> +		5 - HVLED1/3 is controlled by bank B, HVLED2 is controlled by bank A
>>>>>> +		6 - (default) HVLED1 is controlled by bank A, HVLED2/3 are controlled by bank B
>>>>>> +		7 - All HVLED outputs are controlled by bank B
>>>>>
>>>>> This is quite long way to describe a bitmask, no? Could we make
>>>>> it so that control-bank-cfg is not needed?
>>>>
>>>> The problem we have here is there is a potential to control
>>>> 3 different LED string but only 2 sinks.  So control bank A can control 2 LED strings and control
>>>> bank b can control 1 LED string.  
>>>>
>>>
>>> Can we forget about the LED strings, and just expose the sinks as
>>> Linux LED devices?
>>
>> 2 sinks 3 LED strings.  How do you know which LED string is which and what bank it belongs
>> to when setting the brightness.  Each Bank has a separate register for brightness control.
> 
> Just a blind shot, without going into details - could you please check
> if led-sources property documented in the common LED bindings couldn't
> help here?
> 

I could change the name to led-sources.  But this part does not really follow the 1 output to a
1 LED string topology.


-- 
------------------
Dan Murphy