linux-kernel - Re: [PATCH v5 2/2] PCI: brcmstb: Use reset/rearm instead of deassert/assert

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Message-ID: <71903454-c20c-31f7-aaee-0d05eb22db7f@gmail.com>
Date:   Mon, 29 Mar 2021 09:50:13 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Jim Quinlan <jim2101024@...il.com>
Cc:     Bjorn Helgaas <helgaas@...nel.org>, linux-pci@...r.kernel.org,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        bcm-kernel-feedback-list@...adcom.com, james.quinlan@...adcom.com,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Jim Quinlan <jquinlan@...adcom.com>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-rpi-kernel@...ts.infradead.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 2/2] PCI: brcmstb: Use reset/rearm instead of
 deassert/assert

On 3/29/21 9:10 AM, Lorenzo Pieralisi wrote:
> On Fri, Mar 12, 2021 at 03:45:55PM -0500, Jim Quinlan wrote:
>> The Broadcom STB PCIe RC uses a reset control "rescal" for certain chips.
>> The "rescal" implements a "pulse reset" so using assert/deassert is wrong
>> for this device.  Instead, we use reset/rearm.  We need to use rearm so
>> that we can reset it after a suspend/resume cycle; w/o using "rearm", the
>> "rescal" device will only ever fire once.
>>
>> Of course for suspend/resume to work we also need to put the reset/rearm
>> calls in the suspend and resume routines.
> 
> Actually - I am sorry but it looks like you will have to split the patch
> in two since this is two logical changes.

I do not believe this can be easily split, since there is currently a
misused of the reset controller API and this patch fixes all call sites
at once. It would not really make sense to fix probe/remove and then
leave suspend/resume broken in the same manner.
-- 
Florian