[RFC PATCH v3.1 14/27] mmc: sdhci-uhs2: skip signal_voltage_switch()

AKASHI Takahiro
2020-11-06T02:28:45Z

For UHS2, the signal voltage is supplied by vdd2 which is already 1.8v,
so no voltage switch required.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
drivers/mmc/host/sdhci-uhs2.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
index 2bf78cc4e9ed..1eca89359351 100644
--- a/drivers/mmc/host/sdhci-uhs2.c
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -178,6 +178,29 @@ void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
}
EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);

+/*****************************************************************************\
+ * *
+ * MMC callbacks *
+ * *
+\*****************************************************************************/
+
+static int sdhci_uhs2_start_signal_voltage_switch(struct mmc_host *mmc,
+ struct mmc_ios *ios)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+
+ /*
+ * For UHS2, the signal voltage is supplied by vdd2 which is
+ * already 1.8v so no voltage switch required.
+ */
+ if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
+ host->version >= SDHCI_SPEC_400 &&
+ host->mmc->flags & MMC_UHS2_SUPPORT)
+ return 0;
+
+ return sdhci_start_signal_voltage_switch(mmc, ios);
+}
+
/*****************************************************************************\
* *
* Driver init/exit *
@@ -186,6 +209,9 @@ EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);

static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
{
+ host->mmc_host_ops.start_signal_voltage_switch =
+ sdhci_uhs2_start_signal_voltage_switch;
+
return 0;
}

--
2.28.0