Re: [RFC 17/18] mfd: max14577: Do not enforce (incorrect) interrupt trigger type

From: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	devicetree@vger.kernel.org, linux-rtc@vger.kernel.org,
	linux-samsung-soc@vger.kernel.org,
	Rob Herring <robh+dt@kernel.org>,
	linux-clk@vger.kernel.org,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Alessandro Zummo <a.zummo@towertech.it>,
	linux-kernel@vger.kernel.org, Sebastian Reichel <sre@kernel.org>,
	Matheus Castello <matheus@castello.eng.br>,
	Stephen Boyd <sboyd@kernel.org>,
	Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>,
	Iskren Chernev <iskren.chernev@gmail.com>,
	Andy Gross <agross@kernel.org>,
	linux-arm-msm@vger.kernel.org,
	Hans de Goede <hdegoede@redhat.com>,
	Mark Brown <broonie@kernel.org>, Lee Jones <lee.jones@linaro.org>,
	Angus Ainslie <angus@akkea.ca>,
	Michael Turquette <mturquette@baylibre.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	linux-pm@vger.kernel.org, Liam Girdwood <lgirdwood@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 17/18] mfd: max14577: Do not enforce (incorrect) interrupt trigger type
Date: Mon, 21 Dec 2020 11:47:07 -0700	[thread overview]
Message-ID: <20201221184707.GA344409@robh.at.kernel.org> (raw)
In-Reply-To: <20201210212534.216197-17-krzk@kernel.org>

On Thu, 10 Dec 2020 22:25:33 +0100, Krzysztof Kozlowski wrote:
> Interrupt line can be configured on different hardware in different way,
> even inverted.  Therefore driver should not enforce specific trigger
> type - edge falling - but instead rely on Devicetree to configure it.
> 
> The Maxim 14577/77836 datasheets describe the interrupt line as active
> low with a requirement of acknowledge from the CPU therefore the edge
> falling is not correct.
> 
> The interrupt line is shared between PMIC and charger driver, so using
> level sensitive interrupt is here especially important to avoid races.
> With an edge configuration in case if first PMIC signals interrupt
> followed shortly after by the RTC, the interrupt might not be yet
> cleared/acked thus the second one would not be noticed.
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> 
> ---
> 
> This patch should wait till DTS changes are merged, as it relies on
> proper Devicetree.
> ---
>  Documentation/devicetree/bindings/mfd/max14577.txt | 4 ++--
>  drivers/mfd/max14577.c                             | 6 +++---
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 

Acked-by: Rob Herring <robh@kernel.org>