Messages in this thread Patch in this message | | | From | Aapo Vienamo <> | Subject | [PATCH v2 03/10] mmc: tegra: Power on the calibration pad | Date | Thu, 26 Jul 2018 15:26:49 +0300 |
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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> Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com> --- drivers/mmc/host/sdhci-tegra.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)
diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c index 51eda20..363490e 100644 --- a/drivers/mmc/host/sdhci-tegra.c +++ b/drivers/mmc/host/sdhci-tegra.c @@ -53,6 +53,7 @@ #define SDHCI_TEGRA_SDMEM_COMP_PADCTRL 0x1e0 #define SDHCI_TEGRA_SDMEM_COMP_PADCTRL_VREF_SEL_MASK 0x0000000f #define SDHCI_TEGRA_SDMEM_COMP_PADCTRL_VREF_SEL_VAL 0x7 +#define SDHCI_TEGRA_SDMEM_COMP_PADCTRL_E_INPUT_E_PWRD BIT(31) #define SDHCI_TEGRA_AUTO_CAL_STATUS 0x1ec #define SDHCI_TEGRA_AUTO_CAL_ACTIVE BIT(31) @@ -241,11 +242,30 @@ 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_SDMEM_COMP_PADCTRL_E_INPUT_E_PWRD; + else + reg &= ~SDHCI_TEGRA_SDMEM_COMP_PADCTRL_E_INPUT_E_PWRD; + sdhci_writel(host, reg, SDHCI_TEGRA_SDMEM_COMP_PADCTRL); + udelay(1); +} + static void tegra_sdhci_pad_autocalib(struct sdhci_host *host) { u32 reg; int ret; + 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); @@ -255,6 +275,8 @@ static void tegra_sdhci_pad_autocalib(struct sdhci_host *host) reg, !(reg & SDHCI_TEGRA_AUTO_CAL_ACTIVE), 1, 10000); + tegra_sdhci_configure_cal_pad(host, false); + if (ret) dev_err(mmc_dev(host->mmc), "Pad autocal timed out\n"); } -- 2.7.4
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