[PATCH] iio: frequency: adf4371: Fix divide by zero exception bug

[Beniamin Bia]

From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>

During initialization adf4371_pll_fract_n_get_rate() is called on all
output channels to determine if the device was setup. In this case
mod2 is zero which can cause a divide by zero exception.
Return before that can happen.

Fixes: 7f699bd149134 ("iio: frequency: adf4371: Add support for ADF4371 PLL")
Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
Signed-off-by: Beniamin Bia <beniamin.bia@xxxxxxxxxx>
---
 drivers/iio/frequency/adf4371.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
index e2a599b912e5..c21462238314 100644
--- a/drivers/iio/frequency/adf4371.c
+++ b/drivers/iio/frequency/adf4371.c
@@ -191,6 +191,9 @@ static unsigned long long adf4371_pll_fract_n_get_rate(struct adf4371_state *st,
 	unsigned long long val, tmp;
 	unsigned int ref_div_sel;
 
+	if (st->mod2 == 0)
+		return 0;
+
 	val = (((u64)st->integer * ADF4371_MODULUS1) + st->fract1) * st->fpfd;
 	tmp = (u64)st->fract2 * st->fpfd;
 	do_div(tmp, st->mod2);
-- 
2.17.1