[U-Boot] [PATCH v4 2/3] mmc: dw_mmc: Support bypass mode with the get_mmc_clk() method

Marek Vasut
2015-08-12T08:55:03Z

On Wednesday, August 12, 2015 at 09:39:03 AM, Pantelis Antoniou wrote:
> Hi Simon,

Hi,

> > On Aug 7, 2015, at 05:16 , Simon Glass <sjg@chromium.org> wrote:
> >
> > Some SoCs want to adjust the input clock to the DWMMC block as a way of
> > controlling the MMC bus clock. Update the get_mmc_clk() method to support
> > this.
> >
> > Signed-off-by: Simon Glass <sjg@chromium.org>
> > ---
> >
> > Changes in v4:
> > - Update commit message to indicate this patch is for the dw_mmc driver
> >
> > drivers/mmc/dw_mmc.c | 2 +-
> > drivers/mmc/exynos_dw_mmc.c | 2 +-
> > include/dwmmc.h | 16 +++++++++++++++-
> > 3 files changed, 17 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> > index 8f28d7e..a034c3f 100644
> > --- a/drivers/mmc/dw_mmc.c
> > +++ b/drivers/mmc/dw_mmc.c
> > @@ -248,7 +248,7 @@ static int dwmci_setup_bus(struct dwmci_host *host,
> > u32 freq)
> >
> > * host->bus_hz should be set by user.
> > */
> >
> > if (host->get_mmc_clk)
> >
> > - sclk = host->get_mmc_clk(host);
> > + sclk = host->get_mmc_clk(host, freq);
> >
> > else if (host->bus_hz)
> >
> > sclk = host->bus_hz;
> >
> > else {
> >
> > diff --git a/drivers/mmc/exynos_dw_mmc.c b/drivers/mmc/exynos_dw_mmc.c
> > index e083745..3f702ba 100644
> > --- a/drivers/mmc/exynos_dw_mmc.c
> > +++ b/drivers/mmc/exynos_dw_mmc.c
> > @@ -39,7 +39,7 @@ static void exynos_dwmci_clksel(struct dwmci_host
> > *host)
> >
> > dwmci_writel(host, DWMCI_CLKSEL, priv->sdr_timing);
> >
> > }
> >
> > -unsigned int exynos_dwmci_get_clk(struct dwmci_host *host)
> > +unsigned int exynos_dwmci_get_clk(struct dwmci_host *host, uint freq)
> > {
> >
> > unsigned long sclk;
> > int8_t clk_div;
> >
> > diff --git a/include/dwmmc.h b/include/dwmmc.h
> > index 7a7555a..25cf42c 100644
> > --- a/include/dwmmc.h
> > +++ b/include/dwmmc.h
> > @@ -163,7 +163,21 @@ struct dwmci_host {
> >
> > void (*clksel)(struct dwmci_host *host);
> > void (*board_init)(struct dwmci_host *host);
> >
> > - unsigned int (*get_mmc_clk)(struct dwmci_host *host);
> > +
> > + /**
> > + * Get / set a particular MMC clock frequency
> > + *
> > + * This is used to request the current clock frequency of the clock
> > + * that drives the DWMMC peripheral. The caller will then use this
> > + * information to work out the divider it needs to achieve the
> > + * required MMC bus clock frequency. If you want to handle the
> > + * clock external to DWMMC, use @freq to select the frequency and
> > + * return that value too. Then DWMMC will put itself in bypass mode.
> > + *
> > + * @host: DWMMC host
> > + * @freq: Frequency the host is trying to achieve
> > + */
> > + unsigned int (*get_mmc_clk)(struct dwmci_host *host, uint freq);
> >
> > struct mmc_config cfg;
> >
> > };
>
> I?m applying this now. It makes sense. No, we don?t have a clock framework
> for now so this will do.

Please don't apply patches which still have open questions, besides I still
disagree with the patch.