From:   Krishna Yarlagadda <kyarlagadda@nvidia.com>
To:     Mark Brown <broonie@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>
CC:     Laxman Dewangan <ldewangan@nvidia.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Sowjanya Komatineni <skomatineni@nvidia.com>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        "linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 2/2] spi: tegra210-quad: add acpi support
Thread-Topic: [PATCH 2/2] spi: tegra210-quad: add acpi support
Thread-Index: AQHX4eK2PmZ2lQM7W06Rx2eVyKwOx6wUNK6AgAYJLMCAADdLAIAA4EUg
Date:   Tue, 30 Nov 2021 01:50:07 +0000
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References: <1637834152-32093-1-git-send-email-kyarlagadda@nvidia.com>
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> -----Original Message-----
> From: Mark Brown <broonie@kernel.org>
> Sent: 29 November 2021 17:57
> To: Krishna Yarlagadda <kyarlagadda@nvidia.com>; Philipp Zabel
> <p.zabel@pengutronix.de>
> Cc: Laxman Dewangan <ldewangan@nvidia.com>; Thierry Reding
> <thierry.reding@gmail.com>; Jonathan Hunter <jonathanh@nvidia.com>;
> Sowjanya Komatineni <skomatineni@nvidia.com>; linux-
> tegra@vger.kernel.org; linux-spi@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH 2/2] spi: tegra210-quad: add acpi support
>=20
> On Mon, Nov 29, 2021 at 09:09:30AM +0000, Krishna Yarlagadda wrote:
>=20
> > > > +#ifdef CONFIG_ACPI
> > > > +	if (ACPI_FAILURE(acpi_evaluate_object(ACPI_HANDLE(tqspi->dev),
> > > > +					      "_RST", NULL, NULL)))
> > > > +		dev_err(tqspi->dev, "failed to reset device\n"); #endif
>=20
> > > What happens when this runs on a DT system?
>=20
> > For a DT system reset handle would be present and this code will not
> > run
>=20
> This code is really unclearly structured, the early return doesn't match =
the
> normal kernel style and the ifdefs aren't helping with clarity.  Please
> restructure it so it's clear that *both* cases have checks for the correc=
t
> firmware type being present.
I will move each reset method into their own function for readability.
>=20
> That said frankly I'd expect this handling of ACPI reset to be pushed int=
o the
> reset code, it's obviously not good to be open coding this in drivers whe=
n this
> looks like it's completely generic to any ACPI object so shouldn't be bei=
ng
> open coded in individual driers especially with the ifdefery.  Shouldn't =
the
> reset API be able to figure out that an object with _RST has a reset cont=
rol
> and provide access to it through the reset API?
Common reset apis are not handling _RST. Each driver is implementing
_RST method in ACPI and calling from drivers.