[PATCH 2/9] mmc: sdhci: add a callback for signal voltage switching

[Y.B. Lu]

> -----Original Message-----
> From: Adrian Hunter [mailto:adrian.hunter at intel.com]
> Sent: Thursday, March 02, 2017 10:19 PM
> To: Y.B. Lu; linux-mmc at vger.kernel.org; ulf.hansson at linaro.org; Rob
> Herring; Mark Rutland; Catalin Marinas; Will Deacon
> Cc: devicetree at vger.kernel.org; linux-arm-kernel at lists.infradead.org;
> Xiaobo Xie
> Subject: Re: [PATCH 2/9] mmc: sdhci: add a callback for signal voltage
> switching
> 
> On 02/03/17 11:47, Yangbo Lu wrote:
> > Add a callback for signal voltage switching to let host driver switch
> > signal voltage in its own way.
> 
> That is not how we do things now.  Please just replace the host operation
> instead e.g.
> 
> host->mmc_host_ops.start_signal_voltage_switch =
> 				esdhc_signal_voltage_switch;
> 

[Lu Yangbo-B47093] Hi Adrian, your method is great! I will use this in v2.
Thanks.

> 
> 
> >
> > Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
> > ---
> >  drivers/mmc/host/sdhci.c | 6 ++++++
> >  drivers/mmc/host/sdhci.h | 2 ++
> >  2 files changed, 8 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index
> > 6fdd7a7..3c9a924 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -1852,6 +1852,12 @@ static int
> sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
> >  	if (host->version < SDHCI_SPEC_300)
> >  		return 0;
> >
> > +	if (host->ops->start_signal_voltage_switch) {
> > +		ret = host->ops->start_signal_voltage_switch(
> > +					host, ios->signal_voltage);
> > +		return ret;
> > +	}
> > +
> >  	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> >
> >  	switch (ios->signal_voltage) {
> > diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index
> > edf3adf..04af687 100644
> > --- a/drivers/mmc/host/sdhci.h
> > +++ b/drivers/mmc/host/sdhci.h
> > @@ -566,6 +566,8 @@ struct sdhci_ops {
> >  					 struct mmc_card *card,
> >  					 unsigned int max_dtr, int host_drv,
> >  					 int card_drv, int *drv_type);
> > +	int	(*start_signal_voltage_switch)(struct sdhci_host *host,
> > +					       unsigned char signal_voltage);
> >  };
> >
> >  #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
> >