RE: [PATCH v2 4/5] spi: tegra210-quad: add acpi support

[Krishna Yarlagadda <kyarlagadda@xxxxxxxxxx>]

> -----Original Message-----
> From: Mark Brown <broonie@xxxxxxxxxx>
> Sent: 23 February 2022 00:07
> To: Krishna Yarlagadda <kyarlagadda@xxxxxxxxxx>
> Cc: thierry.reding@xxxxxxxxx; Jonathan Hunter
> <jonathanh@xxxxxxxxxx>; linux-spi@xxxxxxxxxxxxxxx; linux-
> tegra@xxxxxxxxxxxxxxx; Sowjanya Komatineni
> <skomatineni@xxxxxxxxxx>; Laxman Dewangan
> <ldewangan@xxxxxxxxxx>; robh+dt@xxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> p.zabel@xxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 4/5] spi: tegra210-quad: add acpi support
> 
> On Tue, Feb 22, 2022 at 11:26:10PM +0530, Krishna Yarlagadda wrote:
> 
> > Add ACPI ID for Tegra QUAD SPI. Switch to common device property
> calls.
> > Skip clock calls that are not updated in ACPI boot.
> 
> > @@ -1377,6 +1400,8 @@ static int __maybe_unused
> tegra_qspi_runtime_suspend(struct device *dev)
> >  	struct spi_master *master = dev_get_drvdata(dev);
> >  	struct tegra_qspi *tqspi = spi_master_get_devdata(master);
> >
> > +	if (has_acpi_companion(tqspi->dev))
> > +		return 0;
> >  	/* flush all write which are in PPSB queue by reading back */
> >  	tegra_qspi_readl(tqspi, QSPI_COMMAND1);
> 
> As well as clock stuff this is also skipping flushing of pending writes
> - is that intentional?  It's not called out in the changelog and seems like
> something that could cause issues if someone runs on a system where
> the firmware does implement runtime suspend.
Runtime suspend is not enabled with ACPI firmware. Converted compiler flag in v1 to runtime check.
We must add more changes like setting DPM flags for runtime pm support with ACPI.
Can take this as part of a different series.