Message-ID: <549095CA.7090505@broadcom.com>
Date: Tue, 16 Dec 2014 12:27:54 -0800
From: Ray Jui <rjui@broadcom.com>
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To: Arnd Bergmann <arnd@arndb.de>, <linux-arm-kernel@lists.infradead.org>
CC: Arun Ramamurthy <arun.ramamurthy@broadcom.com>, <mark.rutland@arm.com>,
        <a.zummo@towertech.it>, <sbranden@broadcom.com>, <pawel.moll@arm.com>,
        <devicetree@vger.kernel.org>, <ijc+devicetree@hellion.org.uk>,
        "Arun Ramamurthy" <arunrama@broadcom.com>,
        <linux-kernel@vger.kernel.org>, <grant.likely@linaro.org>,
        <robh+dt@kernel.org>, <bcm-kernel-feedback-list@broadcom.com>,
        <galak@codeaurora.org>, <rtc-linux@googlegroups.com>
Subject: Re: [PATCHv1] rtc: bcm-iproc: Add support for Broadcom iproc rtc
References: <1418757750-3628-1-git-send-email-arun.ramamurthy@broadcom.com> <7947905.aK8KkUx4sY@wuerfel> <54909074.2070804@broadcom.com> <1418783023.hzNZBNCmFc@wuerfel>
In-Reply-To: <1418783023.hzNZBNCmFc@wuerfel>
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On 12/16/2014 12:19 PM, Arnd Bergmann wrote:
> On Tuesday 16 December 2014 12:05:08 Arun Ramamurthy wrote:
>> On 14-12-16 11:42 AM, Arnd Bergmann wrote:
>>> On Tuesday 16 December 2014 11:22:30 arun.ramamurthy@broadcom.com wrote:
>>>> +       rtc: iproc_rtc@0x03026000 {
>>>> +               compatible = "brcm,iproc-rtc";
>>>> +               reg =   spru_bbl:               <0x03026000 0xC>,
>>>> +                       crmu_pwr_good_status:   <0x0301C02C 0x14>,
>>>> +                       crmu_bbl_auth:          <0x03024C74 0x8>;
>>>> +               interrupts = spru_rtc_periodic: <GIC_SPI 142 IRQ_TYPE_LEVEL_HIGH>,
>>>> +                            spru_alarm:        <GIC_SPI 133 IRQ_TYPE_LEVEL_HIGH>;
>>>
>>> The reg properties look really random, could it be that the registers
>>> are really part of some other device that contains multiple functions?
>>>
>> This RTC block is on a battery backed logic island and is accessed
>> indirectly using the spru_bbl registers. The CRMU registers are required
>> to read the power status and write to some authentication registers.
>> Without writing to these authentication
>> registers, we cannot access any of the spru_bbl registers. In conclusion
>> I don't think the CRMU register accesses can be considered as another
>> device access. Do you agree Arnd?
>
> It sounds like CRMU is some other unit aside from the RTC. Could this
> be something like a generic system controller? I think it should
> either have its own driver or use the syscon logic if that is what
> this is.
>
Giving that CRMU has scattered, miscellaneous control logic for multiple 
different peripherals, it probably makes more sense to use the syscon 
logic here.

>>> Also, what do you use the labels for?
>>>
>> The labels are purely to improve readability of the device tree entry
>
> Please remove them then, they don't help at all.
>
> 	Arnd
>
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