Re: [RFC 4/7] mmc: tmio: Add UHS-I mode support

[Wolfram Sang <wsa@the-dreams.de>]

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On Thu, Mar 03, 2016 at 03:41:13PM +0100, Ulf Hansson wrote:
> On 19 February 2016 at 21:16, Wolfram Sang <wsa@the-dreams.de> wrote:
> > From: Ben Hutchings <ben.hutchings@codethink.co.uk>
> >
> > Based on work by Shinobu Uehara and Ben Dooks.  This adds the voltage
> > switch operation needed for all UHS-I modes, but not the tuning needed
> > for SDR-104 which will come later.
> >
> > The card_busy implementation is a bit of a guess, but works for me on
> > an R8A7790 chip.
> >
> > Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > ---
> >  drivers/mmc/host/tmio_mmc.h     |  3 +++
> >  drivers/mmc/host/tmio_mmc_pio.c | 31 +++++++++++++++++++++++++++++++
> >  2 files changed, 34 insertions(+)
> >
> > diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
> > index b44b5890290622..aabd36955e73fb 100644
> > --- a/drivers/mmc/host/tmio_mmc.h
> > +++ b/drivers/mmc/host/tmio_mmc.h
> > @@ -101,6 +101,9 @@ struct tmio_mmc_host {
> >         void (*clk_disable)(struct tmio_mmc_host *host);
> >         int (*multi_io_quirk)(struct mmc_card *card,
> >                               unsigned int direction, int blk_size);
> > +
> > +       int (*start_signal_voltage_switch)(struct tmio_mmc_host *host,
> > +                                          unsigned char signal_voltage);
> 
> Do you really need to add a new tmio specific callback for this?
> 
> Why can't you instead have the tmio variant driver assign the
> ->start_signal_voltage_switch() callback into the struct mmc_host_ops
> instead?

Can do if you prefer that. I agree that it will save a bit of code; but
it also hides this feature, because all the other config is in struct
tmio_mmc_host. I like the better visibility a tad more.


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