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From: Arnd Bergmann <arnd@arndb.de>
To: Lars Persson <lars.persson@axis.com>
Cc: Lars Persson <larper@axis.com>,
	linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
	g.liakhovetski@gmx.de, ulf.hansson@linaro.org,
	robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com,
	ijc+devicetree@hellion.org.uk, galak@codeaurora.org
Subject: Re: [PATCH v3 2/3] mmc: usdhi6rol0: add support for UHS modes
Date: Thu, 21 Apr 2016 09:53:42 +0200	[thread overview]
Message-ID: <4129305.Ka9B8YpEaI@wuerfel> (raw)
In-Reply-To: <57187D74.8090601@axis.com>

On Thursday 21 April 2016 09:12:52 Lars Persson wrote:
> On 04/20/2016 04:53 PM, Lars Persson wrote:
> > Add a start_signal_voltage_switch() operation to support enabling of
> > UHS modes.
> >
> > Signed-off-by: Lars Persson <larper@axis.com>
> > ---
> >   drivers/mmc/host/usdhi6rol0.c | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/mmc/host/usdhi6rol0.c b/drivers/mmc/host/usdhi6rol0.c
> > index 807c06e..2585ea4 100644
> > --- a/drivers/mmc/host/usdhi6rol0.c
> > +++ b/drivers/mmc/host/usdhi6rol0.c
> > @@ -1147,12 +1147,25 @@ static void usdhi6_enable_sdio_irq(struct mmc_host *mmc, int enable)
> >       }
> >   }
> >
> > +static int usdhi6_sig_volt_switch(struct mmc_host *mmc, struct mmc_ios *ios)
> > +{
> > +     int ret;
> > +
> 
> To support boards without regulator we need to put a 
> IS_ERR_OR_NULL(mmc->supply.vqmmc) check here and bail out with return 0. 
> Missing vqmmc is OK according to our binding document, but treated as an 
> error by mmc_regulator_set_vqmmc().

mmc_regulator_set_vqmmc() should already take care of handling
all the those cases. In general, it's almost always a bug to use
IS_ERR_OR_NULL(): if you ever feel the need to use it, you should
either fix the code that made the pointer ambiguous or you have
misunderstood the interface.

	Arnd

  reply	other threads:[~2016-04-21  7:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-20 14:53 [PATCH v3 0/3] mmc: usdhi6rol0: UHS support Lars Persson
2016-04-20 14:53 ` [PATCH v3 1/3] mmc: dt: usdhi6rol0: add optional pinctrl binding Lars Persson
2016-04-20 14:53 ` [PATCH v3 2/3] mmc: usdhi6rol0: add support for UHS modes Lars Persson
2016-04-21  7:12   ` Lars Persson
2016-04-21  7:53     ` Arnd Bergmann [this message]
2016-04-21  8:26       ` Lars Persson
2016-04-21  9:52         ` Arnd Bergmann
2016-04-21 13:47           ` Lars Persson
2016-04-20 14:53 ` [PATCH v3 3/3] mmc: usdhi6rol0: add pinctrl to set pin drive strength Lars Persson

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