linux-kernel - Re: [PATCH v2 2/2] mmc: sdhci-of-aspeed: add inversion sighttps://elixir.bootlin.com/linux/v4.6/ident/sdhci

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Date:   Thu, 14 Nov 2019 20:19:31 +0300
From:   Ivan Mikhaylov <i.mikhaylov@...ro.com>
To:     Adrian Hunter <adrian.hunter@...el.com>
CC:     Joel Stanley <joel@....id.au>, Andrew Jeffery <andrew@...id.au>,
        "Rob Herring" <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "Ulf Hansson" <ulf.hansson@...aro.org>,
        <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-aspeed@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
        <linux-mmc@...r.kernel.org>, <openbmc@...ts.ozlabs.org>
Subject: Re: [PATCH v2 2/2] mmc: sdhci-of-aspeed: add inversion
 sighttps://elixir.bootlin.com/linux/v4.6/ident/sdhci_opsnal presence

On Thu, 2019-11-14 at 15:10 +0200, Adrian Hunter wrote:
> On 14/11/19 2:54 PM, Ivan Mikhaylov wrote:
> > Change the default .get_cd callback. Add inverted signal card detection
> > check.
> > 
> > Signed-off-by: Ivan Mikhaylov <i.mikhaylov@...ro.com>
> > 
> > diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-
> > aspeed.c
> > index 8962f6664381..186559ee8fcc 100644
> > --- a/drivers/mmc/host/sdhci-of-aspeed.c
> > +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> > @@ -143,6 +143,19 @@ static inline int aspeed_sdhci_calculate_slot(struct
> > aspeed_sdhci *dev,
> >  	return (delta / 0x100) - 1;
> >  }
> >  
> > +static int aspeed_get_cd(struct mmc_host *mmc)
> > +{
> > +	struct sdhci_host *host = mmc_priv(mmc);
> > +
> > +	int present = !!(sdhci_readl(host, SDHCI_PRESENT_STATE)
> > +			 & SDHCI_CARD_PRESENT);
> > +
> > +	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> > +		present = !present;
> 
> Perhaps safer to flip the bit using CONFIG_MMC_SDHCI_IO_ACCESSORS and
> ->readl() callback
> 

Sorry, don't quite understand what you're saying. You want to instantiate
'.read_l' callback instead of '.get_cd' in sdhci_ops and substitute the real
value?

res = readl(base, reg);
if (reg == SDHCI_PRESENT_STATE)
	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
		return !res;
return res;

Something like this?

>  
> > +	host->mmc_host_ops.get_cd = aspeed_get_cd;
> > +	if (of_property_read_bool(pdev->dev.of_node, "cd-inverted"))
> > +		dev_info(&pdev->dev, "aspeed: sdhci: presence signal inversion
> > enabled\n");
> 
> Is this print really needed?
> 
I can remove it if you think it's redundant.

Thanks.