Re: [PATCH v4 4/6] gpio: davinci: add OF support

[Grygorii Strashko]

On 11/05/2013 10:53 AM, Prabhakar Lad wrote:> Hi Grygorii,
>
> Thanks for the review.
>
> On Mon, Nov 4, 2013 at 11:58 PM, Grygorii Strashko
> <grygorii.strashko@xxxxxx> wrote:
>> Hi Prabhakar Lad,
>>
>>
>> On 11/02/2013 05:39 PM, Lad, Prabhakar wrote:
>>>
>>> From: KV Sujith <sujithkv@xxxxxx>
>>>
>>> This patch adds OF parser support for davinci gpio
>>> driver and also appropriate documentation in gpio-davinci.txt
>>> located at Documentation/devicetree/bindings/gpio/.
>>
>>
>> I worry, do we need to have gpio_chip.of_xlate() callback implemented?
>
> I looked for the other OF GPIO implementations with same "ngpio"
> property (marvel, msm) but I don’t see of_xlate() callback implemented.

The question: will below definitions in DT work or not after this series?
 Will of_get_gpio()/of_get_named_gpio() work?

Example1 - leds:
	leds {
		compatible = "gpio-leds";
		debug0 {
			label = "green:debug0";
			gpios = <&gpio 29 GPIO_ACTIVE_HIGH>;
		};
	};

Example2 - any dev:
devA {
	compatible = "devA";
	gpios = <&gpio 120 GPIO_ACTIVE_LOW>;
}


>
>> - From one side, Davinci GPIO controller in DT described by one entry
>> which defines number of supported GPIOs as "ti,ngpio = <144>;"
>>
>> - From other side, on Linux level more than one gpio_chip objects are
>> instantiated (one per each 32 GPIO).
>>
>> How the standard GPIO biding will work in this case? .. And will they?
>>
>> Linus, I'd very appreciate if you will be able to clarify this point.
>>
>>
>>>
>>> Signed-off-by: KV Sujith <sujithkv@xxxxxx>
>>> Signed-off-by: Philip Avinash <avinashphilip@xxxxxx>
>>> [prabhakar.csengg@xxxxxxxxx: simplified the OF code, removed
>>>                  unnecessary DT property and also simplified
>>>                  the commit message]
>>> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
>>> ---
>>>    .../devicetree/bindings/gpio/gpio-davinci.txt      |   32 
++++++++++++
>>>    drivers/gpio/gpio-davinci.c                        |   54
>>> ++++++++++++++++++--
>>>    2 files changed, 83 insertions(+), 3 deletions(-)
>>>    create mode 100644
>>> Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>>> b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>>> new file mode 100644
>>> index 0000000..55aae1c
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>>> @@ -0,0 +1,32 @@
>>> +Davinci GPIO controller bindings29
>>> +
>>> +Required Properties:
>>> +- compatible: should be "ti,dm6441-gpio"
>>> +
>>> +- reg: Physical base address of the controller and the size of memory
>>> mapped
>>> +       registers.
>>> +
>>> +- gpio-controller : Marks the device node as a gpio controller.
>>> +
>>> +- interrupts: Array of GPIO interrupt number.
>>
>>
>> May be meaning of <interrupts> property need to be extended, because,
>> as of now, only banked or unbanked IRQs are supported - and not both.
>>
>>
> OK
>
>>> +
>>> +- ti,ngpio: The number of GPIO pins supported.
>>> +
>>> +- ti,davinci-gpio-unbanked: The number of GPIOs that have an 
individual
>>> interrupt
>>> +                            line to processor.
>>
>>
>> Should interrupt-controller; specifier be added here?
>>
> No

So, it would be impossible to map GPIO IRQ to device through DT. Right?
Like:
	devX@0 {
		compatible = "devX";
		interrupt-parent = <&gpio>;
		interrupts = <50 IRQ_TYPE_EDGE_FALLING>; /* gpio line 50 */

	};


>
>>
>>> +
>>> +Example:
>>> +
>>> +gpio: gpio@1e26000 {
>>> +       compatible = "ti,dm6441-gpio";
>>> +       gpio-controller;
>>> +       reg = <0x226000 0x1000>;
>>> +       interrupts = <42 IRQ_TYPE_EDGE_BOTH 43 IRQ_TYPE_EDGE_BOTH
>>> +               44 IRQ_TYPE_EDGE_BOTH 45 IRQ_TYPE_EDGE_BOTH
>>> +               46 IRQ_TYPE_EDGE_BOTH 47 IRQ_TYPE_EDGE_BOTH
>>> +               48 IRQ_TYPE_EDGE_BOTH 49 IRQ_TYPE_EDGE_BOTH
>>> +               50 IRQ_TYPE_EDGE_BOTH>;
>>> +       ti,ngpio = <144>;
>>> +       ti,davinci-gpio-irq-base = <101>;
>>
>>
>>          ^^ Is it still needed?
>>
> OOps missed to remove that.
>
Regards,
-grygorii

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