[PATCH v3 15/38] mmc: tegra: Disable card clock during pad calibration

Aapo Vienamo
2018-08-30T15:06:16Z

Disable the card clock during automatic pad drive strength calibration
and re-enable it afterwards.

Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
---
drivers/mmc/host/sdhci-tegra.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index e63cd6b2fc9f..ec07a3ce0247 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -260,11 +260,35 @@ static void tegra_sdhci_configure_cal_pad(struct sdhci_host *host, bool enable)
usleep_range(1, 2);
}

+static bool tegra_sdhci_configure_card_clk(struct sdhci_host *host, bool enable)
+{
+ bool status;
+ u32 reg;
+
+ reg = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+ status = !!(reg & SDHCI_CLOCK_CARD_EN);
+
+ if (status == enable)
+ return status;
+
+ if (enable)
+ reg |= SDHCI_CLOCK_CARD_EN;
+ else
+ reg &= ~SDHCI_CLOCK_CARD_EN;
+
+ sdhci_writew(host, reg, SDHCI_CLOCK_CONTROL);
+
+ return status;
+}
+
static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)
{
+ bool card_clk_enabled;
u32 reg;
int ret;

+ card_clk_enabled = tegra_sdhci_configure_card_clk(host, false);
+
tegra_sdhci_configure_cal_pad(host, true);

reg = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
@@ -279,6 +303,8 @@ static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)

tegra_sdhci_configure_cal_pad(host, false);

+ tegra_sdhci_configure_card_clk(host, card_clk_enabled);
+
if (ret)
dev_err(mmc_dev(host->mmc), "Pad autocal timed out\n");
}
--
2.18.0