Hello Gwendal Grignou,
The patch dafcf4ed8392: "iio: hrtimer: Allow sub Hz granularity" from
Feb 25, 2021, leads to the following static checker warning:
drivers/iio/trigger/iio-trig-hrtimer.c:68 iio_hrtimer_store_sampling_frequency()
warn: assigned value is less than 'u32max'
drivers/iio/trigger/iio-trig-hrtimer.c
49 static
50 ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
51 struct device_attribute *attr,
52 const char *buf, size_t len)
53 {
54 struct iio_trigger *trig = to_iio_trigger(dev);
55 struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
56 unsigned long long val;
57 u64 period;
58 int integer, fract, ret;
59
60 ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
61 if (ret)
62 return ret;
63 if (integer < 0 || fract < 0)
64 return -ERANGE;
65
66 val = fract + 1000 * integer; /* mHz */
^^^^^^^^^^^^^^^^^^^^^^
"fract" and "integer" are integers so the arithmatic will wrap instead
of going above UINT_MAX
67
68 if (!val || val > UINT_MAX)
^^^^^^^^^^^^^^
Unpossible!
69 return -EINVAL;
70
71 info->sampling_frequency[0] = integer; /* Hz */
72 info->sampling_frequency[1] = fract * 1000; /* uHz */
73 period = PSEC_PER_SEC;
74 do_div(period, val);
75 info->period = period; /* nS */
76
77 return len;
78 }
regards,
dan carpenter
