diff options
| author | Aapo Vienamo <avienamo@nvidia.com> | 2018-08-30 18:06:15 +0300 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2018-10-08 12:40:43 +0300 |
| commit | 212b0cf14178663576ea3c01f25abe2f83d23565 (patch) | |
| tree | 2567d1d679e31377c02003d2acb90fdc28599066 | |
| parent | 9d548f118f57900449743709e8ba492efbe54be0 (diff) | |
| download | linux-212b0cf14178663576ea3c01f25abe2f83d23565.tar.xz | |
mmc: tegra: Power on the calibration pad
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>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
| -rw-r--r-- | drivers/mmc/host/sdhci-tegra.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c index 01a21e0af6d7..e63cd6b2fc9f 100644 --- a/drivers/mmc/host/sdhci-tegra.c +++ b/drivers/mmc/host/sdhci-tegra.c @@ -54,6 +54,7 @@ #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) @@ -238,11 +239,34 @@ 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 val; + + /* + * Enable or disable the additional I/O pad used by the drive strength + * calibration process. + */ + val = sdhci_readl(host, SDHCI_TEGRA_SDMEM_COMP_PADCTRL); + + if (enable) + val |= SDHCI_TEGRA_SDMEM_COMP_PADCTRL_E_INPUT_E_PWRD; + else + val &= ~SDHCI_TEGRA_SDMEM_COMP_PADCTRL_E_INPUT_E_PWRD; + + sdhci_writel(host, val, SDHCI_TEGRA_SDMEM_COMP_PADCTRL); + + if (enable) + usleep_range(1, 2); +} + 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); @@ -253,6 +277,8 @@ static void tegra_sdhci_pad_autocalib(struct sdhci_host *host) reg, !(reg & SDHCI_TEGRA_AUTO_CAL_ACTIVE), 1000, 10000); + tegra_sdhci_configure_cal_pad(host, false); + if (ret) dev_err(mmc_dev(host->mmc), "Pad autocal timed out\n"); } |