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>

1 files changed, 116 insertions, 65 deletions

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9a11dc39921c..828ac6c2990c 100644
--- 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);