mmc: cavium: Prevent crash with incomplete DT

In case the DT specifies neither a regulator nor a gpio
for the shared power the driver will crash accessing the regulator.
Prevent the crash by checking the regulator before use.

Use mmc_regulator_get_supply() instead of open coding the same
logic.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/cavium.c b/drivers/mmc/host/cavium.c
index 58b51ba6aabd2de7773209d42aa758cb493c2500..b8aaf0fdb77cf52bf89cd3000a98b77536a6f5a4 100644 (file)
--- a/drivers/mmc/host/cavium.c
+++ b/drivers/mmc/host/cavium.c
@@ -839,14 +839,14 @@ static void cvm_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                cvm_mmc_reset_bus(slot);
                if (host->global_pwr_gpiod)
                        host->set_shared_power(host, 0);
-               else
+               else if (!IS_ERR(mmc->supply.vmmc))
                        mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
                break;
 
        case MMC_POWER_UP:
                if (host->global_pwr_gpiod)
                        host->set_shared_power(host, 1);
-               else
+               else if (!IS_ERR(mmc->supply.vmmc))
                        mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);
                break;
        }
@@ -968,20 +968,15 @@ static int cvm_mmc_of_parse(struct device *dev, struct cvm_mmc_slot *slot)
                return -EINVAL;
        }
 
-       mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
-       if (IS_ERR(mmc->supply.vmmc)) {
-               if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
-                       return -EPROBE_DEFER;
-               /*
-                * Legacy Octeon firmware has no regulator entry, fall-back to
-                * a hard-coded voltage to get a sane OCR.
-                */
+       ret = mmc_regulator_get_supply(mmc);
+       if (ret == -EPROBE_DEFER)
+               return ret;
+       /*
+        * Legacy Octeon firmware has no regulator entry, fall-back to
+        * a hard-coded voltage to get a sane OCR.
+        */
+       if (IS_ERR(mmc->supply.vmmc))
                mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
-       } else {
-               ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
-               if (ret > 0)
-                       mmc->ocr_avail = ret;
-       }
 
        /* Common MMC bindings */
        ret = mmc_of_parse(mmc);