linux-kernel - Re: omap5 fixing palmas IRQ_TYPE_NONE warning leads to gpadc timeouts

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Date:   Mon, 26 Nov 2018 11:49:54 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     Thierry Reding <treding@...dia.com>,
        Tony Lindgren <tony@...mide.com>
CC:     Jon Hunter <jonathanh@...dia.com>,
        Belisko Marek <marek.belisko@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        <linux-omap@...r.kernel.org>,
        "Dr. H. Nikolaus Schaller" <hns@...delico.com>,
        Laxman Dewangan <ldewangan@...dia.com>
Subject: Re: omap5 fixing palmas IRQ_TYPE_NONE warning leads to gpadc timeouts

Thierry,

On 11/26/18 11:36 AM, Thierry Reding wrote:
> On Fri, Nov 23, 2018 at 08:48:27AM -0800, Tony Lindgren wrote:
>> * Jon Hunter <jonathanh@...dia.com> [181120 11:14]:
>>> On 19/11/2018 17:14, Tony Lindgren wrote:
>>>> Well so commit 7e9d474954f4 ("ARM: tegra: Correct polarity for
>>>> Tegra114 PMIC interrupt") states that tegra114 inverts the
>>>> polarity of the PMIC interrupt. So adding Jon and Thierry to Cc.
>>>
>>> Yes Tegra can invert the polarity of the PMIC interrupt.
>>
>> So is there some IP on Tegra called "Tegra PMC" that is
>> inverting the interrupt? Or is the "Tegra PMC" that commit
>> 7e9d474954f4 mentions just the palmas configuration for
>> inverting the interrupt?
> 
> Yes, there's indeed an IP called PMC (Power-Management Controller) on
> Tegra. It has a special input that is usually wired up to the PMIC
> interrupt and a bit in the control register that configures the polarity
> of that interrupt. If the PMIC generates a low-active interrupt we
> usually set that bit to make sure it is properly sampled by the PMC.
> 
> The symptoms of this being incorrectly configured is usually an
> interrupt storm on the PMIC interrupt, which I think typically results
> in the system not booting at all, or taking a very long time to boot
> because of that storm.
> 
>> The problem I'm having is With omap5 where I can only get the
>> PMIC interrupts working with IRQ_TYPE_LEVEL_HIGH if
>> PALMAS_POLARITY_CTRL_INT_POLARITY is not set unlike for
>> Tegra.
> 
> Does somebody have access to the Palmas documentation? That should
> pretty clearly state what the default polarity is and what it changes to
> if you set the interrupt polarity bit.

The register map documentation I have states the following:
bit7 INT_POLARITY Select the polarity of the INT output line
0: Interrupt line (INT) is low when interrupt is pending (default) RW
1: Interrupt line (INT) is high when interrupt is pending

By default the Palmas irq is active low.

> From what you're saying it sounds like either the logic is the wrong way
> around in the Palmas MFD driver (and we correct it by switching it back
> to the correct polarity in the PMC) or that you'd need to find some way
> of inverting in on OMAP5.
> 
> Thierry
> 

- Peter

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