From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aapo Vienamo Subject: [PATCH 03/10] mmc: tegra: Power on the calibration pad Date: Tue, 24 Jul 2018 17:34:19 +0300 Message-ID: <1532442865-6391-2-git-send-email-avienamo@nvidia.com> References: <1532442591-5640-1-git-send-email-avienamo@nvidia.com> <1532442865-6391-1-git-send-email-avienamo@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1532442865-6391-1-git-send-email-avienamo@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Ulf Hansson , Rob Herring , Mark Rutland , Thierry Reding , Jonathan Hunter , Adrian Hunter , Mikko Perttunen Cc: linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, Aapo Vienamo List-Id: devicetree@vger.kernel.org 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 --- 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