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

Beniamin Bia
2020-01-07T13:14:53Z

From: Michael Hennerich <michael.hennerich@analog.com>

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@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
---
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