Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1751166AbbFYFoz (ORCPT <rfc822;w@1wt.eu>);
	Thu, 25 Jun 2015 01:44:55 -0400
Received: from mail-pd0-f181.google.com ([209.85.192.181]:35266 "EHLO
	mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750810AbbFYFos (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 25 Jun 2015 01:44:48 -0400
Message-ID: <558B9549.5010705@linaro.org>
Date: Thu, 25 Jun 2015 11:14:41 +0530
From: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0
MIME-Version: 1.0
To: Krzysztof Kozlowski <k.kozlowski@samsung.com>
CC: linux-arm-kernel@lists.infradead.org, Zhao Ye <zhaoy@marvell.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        robh+dt@kernel.org, lee.jones@linaro.org
Subject: Re: [PATCH-v3 2/3] mfd: 88pm800: Allow configuration of interrupt
 clear method
References: <1435137673-1629-1-git-send-email-vaibhav.hiremath@linaro.org> <1435137673-1629-3-git-send-email-vaibhav.hiremath@linaro.org> <CAJKOXPdqTnkB6Lw4fsJ-=o4=QcYcAtZK0zgOM9aqgesTU=Dw+A@mail.gmail.com> <558B90F7.80700@linaro.org> <558B9272.6090100@samsung.com>
In-Reply-To: <558B9272.6090100@samsung.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2404
Lines: 72



On Thursday 25 June 2015 11:02 AM, Krzysztof Kozlowski wrote:
> On 25.06.2015 14:26, Vaibhav Hiremath wrote:
>>
>>
>> On Thursday 25 June 2015 05:33 AM, Krzysztof Kozlowski wrote:
>>> 2015-06-24 18:21 GMT+09:00 Vaibhav Hiremath
>>> <vaibhav.hiremath@linaro.org>:
>>>> As per the spec, bit 1 (INT_CLEAR_MODE) of reg addr 0xe
>>>> (page 0) controls the method of clearing interrupt
>>>> status of 88pm800 family of devices;
>>>>
>>>>     0: clear on read
>>>>     1: clear on write
>>>>
>>>> This patch allows to configure this field, through DT.
>>>>
>>>> Also, as suggested by "Lee Jones" renaming DT property and variable
>>>> field to appropriate name.
>>>>
>>>> Signed-off-by: Zhao Ye <zhaoy@marvell.com>
>>>> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
>>>
>>> It does not look like a property of the board. Instead it looks like a
>>> runtime configuration so it should not be part of DT bindings.
>>>
>>
>> Why do you say that?
>>
>> It is very well feature of 88PM860 device, where you can control irq
>> clear operation (either read/write).
>>
>>
>> Thanks,
>> Vaibhav
>>
>>> I understand that previously this was configured by platform data and
>>> now you want to move everything to DT. But this does not belong to
>>> DT...
>>>
>>
>> Thats not completely true.
>> I think DT is the right place for this configuration.
>
> DT and its bindings describe the specific board or device. Let me quote:
> <<The "Open Firmware Device Tree", or simply Device Tree (DT), is a data
> structure and language for describing hardware.  More specifically, it
> is a description of hardware that is readable by an operating system...>>
>
> Whether you clear interrupts by writing or reading is configured during
> runtime and it is completely independent to wiring. Each board with
> 88pm800 would allow both methods. So this is not a property of hardware
> in the terms of open firmware. This is a runtime configuration.
>

Yes,
Fair enough...

I see very little value in runtime configuration, why not just do it
only way (either read or write)?
I would prefer to just set it by default (during init), to clear irq on
write.


Thanks,
Vaibhav
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/