linux-kernel - Re: [PATCH 1/2] devicetree: Add UCS1002 USB Port Power Controller binding

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Date:	Fri, 29 Jan 2016 07:33:52 +0100
From:	Enric Balletbo Serra <eballetbo@...il.com>
To:	Rob Herring <robh@...nel.org>
Cc:	Enric Balletbo i Serra <enric.balletbo@...labora.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Sjoerd Simons <sjoerd.simons@...labora.co.uk>,
	Martyn Welch <martyn.welch@...labora.com>
Subject: Re: [PATCH 1/2] devicetree: Add UCS1002 USB Port Power Controller binding

Hi Rob,

Thanks for the review.

2016-01-29 3:35 GMT+01:00 Rob Herring <robh@...nel.org>:
> On Tue, Jan 26, 2016 at 10:12:20AM +0100, Enric Balletbo i Serra wrote:
>> The UCS1002-2 provides a USB port power switch for precise control of up
>> to 2.5 amperes continuous current.
>>
>> You can add support to your board with current binding.
>>
>> Example:
>>
>>     ucs1002: ucs1002@57 {
>>              compatible = "microchip,ucs1002";
>>              reg = <0x57>;
>>              microchip,pin-ignore;
>>     };
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>> ---
>>  .../devicetree/bindings/power/ucs1002.txt          | 47 ++++++++++++++++++++++
>>  1 file changed, 47 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/power/ucs1002.txt
>>
>> diff --git a/Documentation/devicetree/bindings/power/ucs1002.txt b/Documentation/devicetree/bindings/power/ucs1002.txt
>> new file mode 100644
>> index 0000000..1b89f0a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/power/ucs1002.txt
>> @@ -0,0 +1,47 @@
>> +UCS1002-2 Programmable USB Port Power Controller with Charger Emulation bindings
>> +
>> +Required properties:
>> +- compatible: "microchip,ucs1002"
>> +- reg: integer, the I2C address of the device.
>> +
>> +Required properties (if pin-ignore functionality is not set):
>> +- em-gpios: which GPIO to use for EM_EN pin.
>> +- pwr-gpios: which GPIO to use for PWR_EN pin.
>> +- m1-gpios: which GPIO to use for M1 pin.
>> +- m2-gpios: which GPIO to use for M2 pin.
>> +
>> +Optional properties:
>> +- interrupt-parent: the phandle of the interrupt controller that services
>> +    interrupts for this device.
>> +- interrupts: interrupt specifiers for two interrupt sources.
>> +    - First interrupt specifier is for A_DET interrupt.
>> +    - Second interrupt specifier is for ALERT interrupt.
>> +- microchip,current-limit: integer, maximum current in mA. Note that the default
>
> mA or ...
>
>> +    value is based on the resistor on the COMM_SEL/ILIM pin and this value cannot
>> +    be changed to be higher than hardware set value. Accepted values are: 500000,
>> +    900000, 1000000, 1200000, 1500000, 1800000, 2000000, 2500000 (uA)
>
> uA?
>
> Either way append units (-microamps)
>

Right, should be  microamps, will change in next version

>> +- microchip,pin-ignore: boolean, if present uses I2C for configuration, otherwise,
>> +    we must provide EM_EN, M1 and M2 gpio mapping.
>
> Wouldn't this be implied by absence of gpio properties?
>

Yes, would you prefer I get rid of this propriety and simply check if
gpio properties are absence or not in the driver ?

In such case I'll do in next version.

>> +
>> +Example (poll):
>> +
>> +     ucs1002: ucs1002@57 {
>> +             compatible = "microchip,ucs1002";
>> +             reg = <0x57>;
>> +             microchip,current-limit = <2000000>;
>> +             microchip,pin-ignore;
>> +     };
>> +
>> +Example (interrupts + pin control):
>> +
>> +     ucs1002: ucs1002@57 {
>> +             compatible = "microchip,ucs1002";
>> +             reg = <0x57>;
>> +             interrupt-parent = <&gpio0>;
>> +             interrupts = <30 0>, <31 0>;
>> +             microchip,current-limit = <2000000>;
>> +             em-gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
>> +             m1-gpios = <&gpio0 3 GPIO_ACTIVE_HIGH>;
>> +             m2-gpios = <&gpio1 17 GPIO_ACTIVE_HIGH>;
>> +             pwr-gpios = <&gpio1 19 0>;
>> +     };
>> --
>> 2.1.0
>>

Best regards,
Enric