On Friday, December 13, 2013, Dinh Nguyen wrote: > From: Dinh Nguyen <dinguyen@xxxxxxxxxx> > > All implementations of the Synopsys DW SD/MMC IP have settings to control > the phase shift of the CIU clk. These phase shift settings are necessary for > the SD/MMC to correctly clock the card. All variants of the dw_mmc will need > these settings, but how they are implemented can vastly vary. > > This patch enables the setting for the SDR and/or DDR settings through the > common clock framework. > > Depends on the patch "mmc: dw_mmc: Enable the hold reg for certain speed modes", > that is already reading the "samsung,dw-mshc-sdr-timing" and > "samsung,dw-mshc-ddr-timing" bindings, this patch saves those values into a > u32 bitmask that can be passed to the clock framework to use. I didn't understand this patch. As you mentioned, clock implementation can be different each SOC. And what is the difference with existing ciu clock? > > Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxx> > --- > v6: Add this patch > v5: none > v4: none > v3: none > v2: none > --- > drivers/mmc/host/dw_mmc.c | 23 +++++++++++++++++++++++ > include/linux/mmc/dw_mmc.h | 6 ++++++ > 2 files changed, 29 insertions(+) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 480dafe..1fb5cff 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -2431,6 +2431,8 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host) > if ((sdr_timing[1] == 0) || (ddr_timing[1] == 0)) > pdata->cclk_in_drv = 0; > > + pdata->sdr_timing = (sdr_timing[1] | (sdr_timing[0] << 4)); > + pdata->ddr_timing = (ddr_timing[1] | (ddr_timing[0] << 4)); Can you explain what it is for? Thanks, Seungwon > return pdata; > } > > @@ -2478,6 +2480,27 @@ int dw_mci_probe(struct dw_mci *host) > dev_dbg(host->dev, "ciu clock not available\n"); > host->bus_hz = host->pdata->bus_hz; > } else { > + /* If the CIU clk is available, we check for SDR and DDR > + * timing phase shift settings. But not all platforms > + * may have populated these settings, the driver will not fail > + * if these settings are not specified. > + */ > + if (host->pdata->sdr_timing) { > + host->sdr_clk = devm_clk_get(host->dev, "sdr_mmc_clk"); > + if (IS_ERR(host->sdr_clk)) > + dev_dbg(host->dev, "sdr_mmc clock not available\n"); > + else > + clk_set_rate(host->sdr_clk, host->pdata->sdr_timing); > + } > + > + if (host->pdata->ddr_timing) { > + host->ddr_clk = devm_clk_get(host->dev, "ddr_mmc_clk"); > + if (IS_ERR(host->ddr_clk)) > + dev_dbg(host->dev, "ddr_mmc clock not available\n"); > + else > + clk_set_rate(host->ddr_clk, host->pdata->ddr_timing); > + } > + > ret = clk_prepare_enable(host->ciu_clk); > if (ret) { > dev_err(host->dev, "failed to enable ciu clock\n"); > diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h > index 2b5b8bf..ad90ad1 100644 > --- a/include/linux/mmc/dw_mmc.h > +++ b/include/linux/mmc/dw_mmc.h > @@ -83,6 +83,8 @@ struct mmc_data; > * @priv: Implementation defined private data. > * @biu_clk: Pointer to bus interface unit clock instance. > * @ciu_clk: Pointer to card interface unit clock instance. > + * @sdr_clk: Pointer to the SDR clock instance. > + * @ddr_clk: Pointer to the DDR clock instance. > * @slot: Slots sharing this MMC controller. > * @fifo_depth: depth of FIFO. > * @data_shift: log2 of FIFO item size. > @@ -170,6 +172,8 @@ struct dw_mci { > void *priv; > struct clk *biu_clk; > struct clk *ciu_clk; > + struct clk *sdr_clk; > + struct clk *ddr_clk; > struct dw_mci_slot *slot[MAX_MCI_SLOTS]; > > /* FIFO push and pull */ > @@ -241,6 +245,8 @@ struct dw_mci_board { > u32 caps2; /* More capabilities */ > u32 pm_caps; /* PM capabilities */ > u32 cclk_in_drv; /*cclk_in_drv phase shift */ > + u32 sdr_timing; /* Single data rate timing setting. */ > + u32 ddr_timing; /* Double data rate timing setting. */ > /* > * Override fifo depth. If 0, autodetect it from the FIFOTH register, > * but note that this may not be reliable after a bootloader has used > -- > 1.7.9.5 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html