Skip to content

Commit

Permalink
mmc: sdhci: Add regulator support for vccq (voltage regualor)
Browse files Browse the repository at this point in the history 
On some systems the host controller does not support vccq
signaling.  This is supplied by a dedicated regulator (vqmmc).
Add support for this regulator.

Signed-off-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
  • Loading branch information
Philip Rakity authored and Chris Ball committed Sep 4, 2012
1 parent 137ccd4 commit 6231f3d
Show file tree
Hide file tree
Showing 2 changed files with 118 additions and 66 deletions.
181 changes: 116 additions & 65 deletions drivers/mmc/host/sdhci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1597,57 +1597,65 @@ static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)
spin_unlock_irqrestore(&host->lock, flags);
}

static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,
struct mmc_ios *ios)
static int sdhci_do_3_3v_signal_voltage_switch(struct sdhci_host *host,
u16 ctrl)
{
u8 pwr;
u16 clk, ctrl;
u32 present_state;
int ret;

/*
* Signal Voltage Switching is only applicable for Host Controllers
* v3.00 and above.
*/
if (host->version < SDHCI_SPEC_300)
return 0;
/* Set 1.8V Signal Enable in the Host Control2 register to 0 */
ctrl &= ~SDHCI_CTRL_VDD_180;
sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);

/*
* We first check whether the request is to set signalling voltage
* to 3.3V. If so, we change the voltage to 3.3V and return quickly.
*/
if (host->vqmmc) {
ret = regulator_set_voltage(host->vqmmc, 3300000, 3300000);
if (ret) {
pr_warning("%s: Switching to 3.3V signalling voltage "
" failed\n", mmc_hostname(host->mmc));
return -EIO;
}
}
/* Wait for 5ms */
usleep_range(5000, 5500);

/* 3.3V regulator output should be stable within 5 ms */
ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
/* Set 1.8V Signal Enable in the Host Control2 register to 0 */
ctrl &= ~SDHCI_CTRL_VDD_180;
sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
if (!(ctrl & SDHCI_CTRL_VDD_180))
return 0;

/* Wait for 5ms */
usleep_range(5000, 5500);
pr_warning("%s: 3.3V regulator output did not became stable\n",
mmc_hostname(host->mmc));

/* 3.3V regulator output should be stable within 5 ms */
ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
if (!(ctrl & SDHCI_CTRL_VDD_180))
return 0;
else {
pr_info(DRIVER_NAME ": Switching to 3.3V "
"signalling voltage failed\n");
return -EIO;
}
} else if (!(ctrl & SDHCI_CTRL_VDD_180) &&
(ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180)) {
/* Stop SDCLK */
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
clk &= ~SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
return -EIO;
}

/* Check whether DAT[3:0] is 0000 */
present_state = sdhci_readl(host, SDHCI_PRESENT_STATE);
if (!((present_state & SDHCI_DATA_LVL_MASK) >>
SDHCI_DATA_LVL_SHIFT)) {
/*
* Enable 1.8V Signal Enable in the Host Control2
* register
*/
static int sdhci_do_1_8v_signal_voltage_switch(struct sdhci_host *host,
u16 ctrl)
{
u8 pwr;
u16 clk;
u32 present_state;
int ret;

/* Stop SDCLK */
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
clk &= ~SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);

/* Check whether DAT[3:0] is 0000 */
present_state = sdhci_readl(host, SDHCI_PRESENT_STATE);
if (!((present_state & SDHCI_DATA_LVL_MASK) >>
SDHCI_DATA_LVL_SHIFT)) {
/*
* Enable 1.8V Signal Enable in the Host Control2
* register
*/
if (host->vqmmc)
ret = regulator_set_voltage(host->vqmmc,
1800000, 1800000);
else
ret = 0;

if (!ret) {
ctrl |= SDHCI_CTRL_VDD_180;
sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);

Expand All @@ -1656,7 +1664,7 @@ static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,

ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
if (ctrl & SDHCI_CTRL_VDD_180) {
/* Provide SDCLK again and wait for 1ms*/
/* Provide SDCLK again and wait for 1ms */
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
clk |= SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
Expand All @@ -1673,29 +1681,55 @@ static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,
return 0;
}
}
}

/*
* If we are here, that means the switch to 1.8V signaling
* failed. We power cycle the card, and retry initialization
* sequence by setting S18R to 0.
*/
pwr = sdhci_readb(host, SDHCI_POWER_CONTROL);
pwr &= ~SDHCI_POWER_ON;
sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
if (host->vmmc)
regulator_disable(host->vmmc);
/*
* If we are here, that means the switch to 1.8V signaling
* failed. We power cycle the card, and retry initialization
* sequence by setting S18R to 0.
*/
pwr = sdhci_readb(host, SDHCI_POWER_CONTROL);
pwr &= ~SDHCI_POWER_ON;
sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
if (host->vmmc)
regulator_disable(host->vmmc);

/* Wait for 1ms as per the spec */
usleep_range(1000, 1500);
pwr |= SDHCI_POWER_ON;
sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
if (host->vmmc)
regulator_enable(host->vmmc);
/* Wait for 1ms as per the spec */
usleep_range(1000, 1500);
pwr |= SDHCI_POWER_ON;
sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
if (host->vmmc)
regulator_enable(host->vmmc);

pr_info(DRIVER_NAME ": Switching to 1.8V signalling "
"voltage failed, retrying with S18R set to 0\n");
return -EAGAIN;
} else
pr_warning("%s: Switching to 1.8V signalling voltage failed, "
"retrying with S18R set to 0\n", mmc_hostname(host->mmc));

return -EAGAIN;
}

static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,
struct mmc_ios *ios)
{
u16 ctrl;

/*
* Signal Voltage Switching is only applicable for Host Controllers
* v3.00 and above.
*/
if (host->version < SDHCI_SPEC_300)
return 0;

/*
* We first check whether the request is to set signalling voltage
* to 3.3V. If so, we change the voltage to 3.3V and return quickly.
*/
ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330)
return sdhci_do_3_3v_signal_voltage_switch(host, ctrl);
else if (!(ctrl & SDHCI_CTRL_VDD_180) &&
(ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180))
return sdhci_do_1_8v_signal_voltage_switch(host, ctrl);
else
/* No signal voltage switch required */
return 0;
}
Expand Down Expand Up @@ -2802,6 +2836,18 @@ int sdhci_add_host(struct sdhci_host *host)
!(host->mmc->caps & MMC_CAP_NONREMOVABLE))
mmc->caps |= MMC_CAP_NEEDS_POLL;

/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
if (IS_ERR(host->vqmmc)) {
pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
host->vqmmc = NULL;
}
else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
regulator_enable(host->vqmmc);
else
caps[1] &= ~(SDHCI_SUPPORT_SDR104 | SDHCI_SUPPORT_SDR50 |
SDHCI_SUPPORT_DDR50);

/* Any UHS-I mode in caps implies SDR12 and SDR25 support. */
if (caps[1] & (SDHCI_SUPPORT_SDR104 | SDHCI_SUPPORT_SDR50 |
SDHCI_SUPPORT_DDR50))
Expand Down Expand Up @@ -3122,6 +3168,11 @@ void sdhci_remove_host(struct sdhci_host *host, int dead)
if (host->vmmc)
regulator_put(host->vmmc);

if (host->vqmmc) {
regulator_disable(host->vqmmc);
regulator_put(host->vqmmc);
}

kfree(host->adma_desc);
kfree(host->align_buffer);

Expand Down
3 changes: 2 additions & 1 deletion include/linux/mmc/sdhci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,8 @@ struct sdhci_host {

const struct sdhci_ops *ops; /* Low level hw interface */

struct regulator *vmmc; /* Power regulator */
struct regulator *vmmc; /* Power regulator (vmmc) */
struct regulator *vqmmc; /* Signaling regulator (vccq) */

/* Internal data */
struct mmc_host *mmc; /* MMC structure */
Expand Down

0 comments on commit 6231f3d

Please sign in to comment.