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.
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));
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
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