mfd: Check for twl4030-madc NULL pointer

If the twl4030-madc device wasn't registered, and another device, such
as twl4030-madc-hwmon, calls twl4030_madc_conversion() a NULL pointer is
dereferenced.

Signed-off-by: Kyle Manna <kyle@kylemanna.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/mfd/twl4030-madc.c b/drivers/mfd/twl4030-madc.c
index cb44b53dee35..7cbf2aa9e64f 100644
--- a/drivers/mfd/twl4030-madc.c
+++ b/drivers/mfd/twl4030-madc.c
@@ -510,8 +510,9 @@ int twl4030_madc_conversion(struct twl4030_madc_request *req)
         u8 ch_msb, ch_lsb;
         int ret;
 
-        if (!req)
+        if (!req || !twl4030_madc)
                 return -EINVAL;
+
         mutex_lock(&twl4030_madc->lock);
         if (req->method < TWL4030_MADC_RT || req->method > TWL4030_MADC_SW2) {
                 ret = -EINVAL;