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mmc: sdhci-of-esdhc: add support for signal voltage switch 

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@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
yangbo lu 2017-04-20 16:14:41 +08:00 committed by Ulf Hansson
parent 19c3a0ef65
commit ea35645a3c
2 changed files with 75 additions and 0 deletions
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1
drivers/mmc/host/sdhci-esdhc.h
View File

@ -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)

74
drivers/mmc/host/sdhci-of-esdhc.c
View File

@ -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>
@ -560,6 +561,76 @@ 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);
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)
@ -717,6 +788,9 @@ 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);