From: Aapo Vienamo <avienamo@nvidia.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Mikko Perttunen <mperttunen@nvidia.com>
Cc: <linux-mmc@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Aapo Vienamo <avienamo@nvidia.com>
Subject: [PATCH 03/10] mmc: tegra: Power on the calibration pad
Date: Tue, 24 Jul 2018 17:34:19 +0300 [thread overview]
Message-ID: <1532442865-6391-2-git-send-email-avienamo@nvidia.com> (raw)
In-Reply-To: <1532442865-6391-1-git-send-email-avienamo@nvidia.com>
Automatic pad drive strength calibration is performed on a separate pad
identical to the ones used for driving the actual bus. Power on the
calibration pad during the calibration procedure and power it off
afterwards to save power.
Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
---
drivers/mmc/host/sdhci-tegra.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index 6008e2f..61067b7 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -209,11 +209,30 @@ static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask)
tegra_host->ddr_signaling = false;
}
+static void tegra_sdhci_configure_cal_pad(struct sdhci_host *host, bool enable)
+{
+ u32 reg;
+
+ /*
+ * Enable or disable the additional I/O pad used by the drive strength
+ * calibration process.
+ */
+ reg = sdhci_readl(host, SDHCI_TEGRA_SDMEM_COMP_PADCTRL);
+ if (enable)
+ reg |= SDHCI_TEGRA_PAD_E_INPUT_OR_E_PWRD;
+ else
+ reg &= ~SDHCI_TEGRA_PAD_E_INPUT_OR_E_PWRD;
+ sdhci_writel(host, reg, SDHCI_TEGRA_SDMEM_COMP_PADCTRL);
+ udelay(1);
+}
+
static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)
{
unsigned timeout = 10;
u32 reg;
+ tegra_sdhci_configure_cal_pad(host, true);
+
reg = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
reg |= SDHCI_AUTO_CAL_ENABLE | SDHCI_AUTO_CAL_START;
sdhci_writel(host, reg, SDHCI_TEGRA_AUTO_CAL_CONFIG);
@@ -227,6 +246,8 @@ static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)
timeout--;
} while (timeout);
+ tegra_sdhci_configure_cal_pad(host, false);
+
if (timeout == 0)
dev_err(mmc_dev(host->mmc), "Pad autocal timed out\n");
}
--
2.7.4
next prev parent reply other threads:[~2018-07-24 14:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-24 14:29 [PATCH 00/10] Update the pad autocal procedure Aapo Vienamo
2018-07-24 14:29 ` [PATCH 01/10] mmc: tegra: Poll for calibration completion Aapo Vienamo
2018-07-25 7:04 ` Mikko Perttunen
2018-07-24 14:34 ` [PATCH 02/10] mmc: tegra: Set calibration pad voltage reference Aapo Vienamo
2018-07-24 14:34 ` Aapo Vienamo [this message]
2018-07-25 7:11 ` [PATCH 03/10] mmc: tegra: Power on the calibration pad Mikko Perttunen
2018-07-24 14:34 ` [PATCH 04/10] mmc: tegra: Disable card clock during pad calibration Aapo Vienamo
2018-07-25 7:14 ` Mikko Perttunen
2018-07-24 14:34 ` [PATCH 05/10] dt-bindings: Add Tegra SDHCI pad pdpu offset bindings Aapo Vienamo
2018-07-25 7:16 ` Mikko Perttunen
2018-07-24 14:34 ` [PATCH 06/10] mmc: tegra: Program pad autocal offsets from dt Aapo Vienamo
2018-07-25 7:24 ` Mikko Perttunen
2018-07-24 14:34 ` [PATCH 07/10] arm64: dts: tegra186: Add sdmmc pad auto calibration offsets Aapo Vienamo
2018-07-24 14:34 ` [PATCH 08/10] arm64: dts: tegra210: " Aapo Vienamo
2018-07-24 14:34 ` [PATCH 09/10] mmc: tegra: Perform pad calibration after voltage switch Aapo Vienamo
2018-07-25 7:25 ` Mikko Perttunen
2018-07-25 10:43 ` Aapo Vienamo
2018-07-25 7:08 ` [PATCH 02/10] mmc: tegra: Set calibration pad voltage reference Mikko Perttunen
2018-07-25 10:00 ` Aapo Vienamo
2018-07-25 12:06 ` [PATCH 00/10] Update the pad autocal procedure Peter Geis
2018-07-25 14:28 ` Aapo Vienamo
2018-07-25 14:27 ` [PATCH 10/10] mmc: tegra: Enable pad calibration on Tegra210 and Tegra186 Aapo Vienamo
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