On 27/03/17 10:49, Yangbo Lu wrote:
> eSDHC supports signal voltage switch from 3.3v to 1.8v by
> eSDHC_PROCTL[VOLT_SEL] bit. This bit changes the value of output
> signal SDHC_VS, and there must be a control circuit out of eSDHC
> to change the signal voltage according to SDHC_VS output signal.
>
> Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx>
Apart from minor comment below:
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> Changes for v2:
> - Used Adrain's method to support voltage switching:
> host->mmc_host_ops.start_signal_voltage_switch =
> esdhc_signal_voltage_switch;
> Changes for v3:
> - Put .start_signal_voltage_switch assigning after IS_ERR(host) check.
> ---
> drivers/mmc/host/sdhci-esdhc.h | 1 +
> drivers/mmc/host/sdhci-of-esdhc.c | 74 +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 75 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc.h b/drivers/mmc/host/sdhci-esdhc.h
> index 5343fc0..6869567 100644
> --- a/drivers/mmc/host/sdhci-esdhc.h
> +++ b/drivers/mmc/host/sdhci-esdhc.h
> @@ -37,6 +37,7 @@
>
> /* Protocol Control Register */
> #define ESDHC_PROCTL 0x28
> +#define ESDHC_VOLT_SEL 0x00000400
> #define ESDHC_CTRL_4BITBUS (0x1 << 1)
> #define ESDHC_CTRL_8BITBUS (0x2 << 1)
> #define ESDHC_CTRL_BUSWIDTH_MASK (0x3 << 1)
> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
> index 7ce1caf..a70499a 100644
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -16,6 +16,7 @@
> #include <linux/err.h>
> #include <linux/io.h>
> #include <linux/of.h>
> +#include <linux/of_address.h>
> #include <linux/delay.h>
> #include <linux/module.h>
> #include <linux/sys_soc.h>
> @@ -559,6 +560,76 @@ static void esdhc_reset(struct sdhci_host *host, u8 mask)
> sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
> }
>
> +/* The SCFG, Supplemental Configuration Unit, provides SoC specific
> + * configuration and status registers for the device. There is a
> + * SDHC IO VSEL control register on SCFG for some platforms. It's
> + * used to support SDHC IO voltage switching.
> + */
> +static const struct of_device_id scfg_device_ids[] = {
> + { .compatible = "fsl,t1040-scfg", },
> + { .compatible = "fsl,ls1012a-scfg", },
> + { .compatible = "fsl,ls1046a-scfg", },
> + {}
> +};
> +
> +/* SDHC IO VSEL control register definition */
> +#define SCFG_SDHCIOVSELCR 0x408
> +#define SDHCIOVSELCR_TGLEN 0x80000000
> +#define SDHCIOVSELCR_VSELVAL 0x60000000
> +#define SDHCIOVSELCR_SDHC_VS 0x00000001
> +
> +static int esdhc_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct device_node *scfg_node;
> + void __iomem *scfg_base = NULL;
> + u32 sdhciovselcr;
> + u32 val;
> +
> + /*
> + * Signal Voltage Switching is only applicable for Host Controllers
> + * v3.00 and above.
> + */
> + if (host->version < SDHCI_SPEC_300)
> + return 0;
> +
> + val = sdhci_readl(host, ESDHC_PROCTL);
> +
> + switch (ios->signal_voltage) {
> + case MMC_SIGNAL_VOLTAGE_330:
> + val &= ~ESDHC_VOLT_SEL;
> + sdhci_writel(host, val, ESDHC_PROCTL);
> + return 0;
> + case MMC_SIGNAL_VOLTAGE_180:
> + scfg_node = of_find_matching_node(NULL, scfg_device_ids);
> + if (scfg_node)
> + scfg_base = of_iomap(scfg_node, 0);
> + if (scfg_base) {
> + sdhciovselcr = SDHCIOVSELCR_TGLEN |
> + SDHCIOVSELCR_VSELVAL;
> + iowrite32be(sdhciovselcr,
> + scfg_base + SCFG_SDHCIOVSELCR);
In other places there is support for little endian also, so why not here?
> +
> + val |= ESDHC_VOLT_SEL;
> + sdhci_writel(host, val, ESDHC_PROCTL);
> + mdelay(5);
> +
> + sdhciovselcr = SDHCIOVSELCR_TGLEN |
> + SDHCIOVSELCR_SDHC_VS;
> + iowrite32be(sdhciovselcr,
> + scfg_base + SCFG_SDHCIOVSELCR);
> + iounmap(scfg_base);
> + } else {
> + val |= ESDHC_VOLT_SEL;
> + sdhci_writel(host, val, ESDHC_PROCTL);
> + }
> + return 0;
> + default:
> + return 0;
> + }
> +}
> +
> #ifdef CONFIG_PM_SLEEP
> static u32 esdhc_proctl;
> static int esdhc_of_suspend(struct device *dev)
> @@ -714,6 +785,9 @@ static int sdhci_esdhc_probe(struct platform_device *pdev)
> if (IS_ERR(host))
> return PTR_ERR(host);
>
> + host->mmc_host_ops.start_signal_voltage_switch =
> + esdhc_signal_voltage_switch;
> +
> esdhc_init(pdev, host);
>
> sdhci_get_of_property(pdev);
>
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