mmc: sdhci: Add regulator support for vccq (voltage regualor)

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>

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9a11dc39921c06ebdf67a3ed602fbba79cc38b89..828ac6c2990cac4e05fb28e0521bdd8414dbbaa3 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -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);
 
@@ -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);
@@ -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;
 }
@@ -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))
@@ -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);
 

diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index ac83b105bedd66d2fb051ead198d11297ab650c3..fa8529a859b8b7637a6b25e76e15ba7848cd9f79 100644 (file)
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -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 */