| Message ID | 20210112040923.2613711-1-gwendal@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v5] iio: hrtimer: Allow sub Hz granularity | expand |
On Tue, Jan 12, 2021 at 6:09 AM Gwendal Grignou <gwendal@chromium.org> wrote: > > Allow setting frequency below 1Hz or sub 1Hz precision. > Useful for slow sensors like ALS. > > Test frequency is set properly: > modprobe iio-trig-hrtimer && \ > mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && \ This && seems strange... > cd /sys/bus/iio/devices/triggerX ; ...because if the above fails, the below becomes a total train wreck. > for i in 1 .1 .01 .001 ; do > echo $i > sampling_frequency > cat sampling_frequency > done Something like this perhaps (note {} and also I dropped unneeded ; and whitespace) modprobe iio-trig-hrtimer && \ mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && { \ cd /sys/bus/iio/devices/triggerX for i in 1 .1 .01 .001; do echo $i > sampling_frequency cat sampling_frequency done } ... > + if (!val || val > NSEC_PER_SEC * 1000) > return -EINVAL; > + info->period = NSEC_PER_SEC * 1000; I didn't get these * 1000 parts, why not define and use PSEC_PER_SEC? I'll send a patch soon. You may include it in your series as prerequisite.
On Tue, Jan 12, 2021 at 6:22 AM Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > > On Tue, Jan 12, 2021 at 6:09 AM Gwendal Grignou <gwendal@chromium.org> wrote: > > > > Allow setting frequency below 1Hz or sub 1Hz precision. > > Useful for slow sensors like ALS. > > > > Test frequency is set properly: > > modprobe iio-trig-hrtimer && \ > > mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && \ > > This && seems strange... > > > cd /sys/bus/iio/devices/triggerX ; This is just for testing. X in triggerX should be replaced with the newly created trigger. > > ...because if the above fails, the below becomes a total train wreck. > > > for i in 1 .1 .01 .001 ; do > > echo $i > sampling_frequency > > cat sampling_frequency > > done > > Something like this perhaps (note {} and also I dropped unneeded ; and > whitespace) > modprobe iio-trig-hrtimer && \ > mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && { \ > cd /sys/bus/iio/devices/triggerX > for i in 1 .1 .01 .001; do > echo $i > sampling_frequency > cat sampling_frequency > done > } > > ... > > > + if (!val || val > NSEC_PER_SEC * 1000) > > return -EINVAL; > > > + info->period = NSEC_PER_SEC * 1000; > > I didn't get these * 1000 parts, why not define and use PSEC_PER_SEC? Indeed only Nano and Femto SEC_PER_SEC are defined. > > I'll send a patch soon. You may include it in your series as prerequisite. Thanks, Gwendal. > > -- > With Best Regards, > Andy Shevchenko
diff --git a/Documentation/iio/iio_configfs.rst b/Documentation/iio/iio_configfs.rst index ecbfdb3afef7e..807589ef2bea0 100644 --- a/Documentation/iio/iio_configfs.rst +++ b/Documentation/iio/iio_configfs.rst @@ -99,3 +99,4 @@ Each trigger can have one or more attributes specific to the trigger type. "hrtimer" trigger type doesn't have any configurable attribute from /config dir. It does introduce the sampling_frequency attribute to trigger directory. +That attribute sets the polling frequency in Hz, with mHz precision. diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c index 58c1c30d5612b..1effab04e00a8 100644 --- a/drivers/iio/trigger/iio-trig-hrtimer.c +++ b/drivers/iio/trigger/iio-trig-hrtimer.c @@ -22,7 +22,7 @@ struct iio_hrtimer_info { struct iio_sw_trigger swt; struct hrtimer timer; - unsigned long sampling_frequency; + int sampling_frequency[2]; ktime_t period; }; @@ -38,7 +38,9 @@ ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev, struct iio_trigger *trig = to_iio_trigger(dev); struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig); - return snprintf(buf, PAGE_SIZE, "%lu\n", info->sampling_frequency); + return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO, + ARRAY_SIZE(info->sampling_frequency), + info->sampling_frequency); } static @@ -48,18 +50,22 @@ ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev, { struct iio_trigger *trig = to_iio_trigger(dev); struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig); - unsigned long val; - int ret; + unsigned long long val; + int integer, fract, ret; - ret = kstrtoul(buf, 10, &val); + ret = iio_str_to_fixpoint(buf, 100, &integer, &fract); if (ret) return ret; - if (!val || val > NSEC_PER_SEC) + val = fract + 1000 * integer; + + if (!val || val > NSEC_PER_SEC * 1000) return -EINVAL; - info->sampling_frequency = val; - info->period = NSEC_PER_SEC / val; + info->sampling_frequency[0] = integer; + info->sampling_frequency[1] = fract * 1000; + info->period = NSEC_PER_SEC * 1000; + do_div(info->period, val); return len; } @@ -135,8 +141,8 @@ static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); trig_info->timer.function = iio_hrtimer_trig_handler; - trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY; - trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency; + trig_info->sampling_frequency[0] = HRTIMER_DEFAULT_SAMPLING_FREQUENCY; + trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency[0]; ret = iio_trigger_register(trig_info->swt.trigger); if (ret)
Allow setting frequency below 1Hz or sub 1Hz precision. Useful for slow sensors like ALS. Test frequency is set properly: modprobe iio-trig-hrtimer && \ mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && \ cd /sys/bus/iio/devices/triggerX ; for i in 1 .1 .01 .001 ; do echo $i > sampling_frequency cat sampling_frequency done Signed-off-by: Gwendal Grignou <gwendal@chromium.org> --- Changes since v4: - Use do_div() properly. Changes since v3: - Fix rebasing issue. Changes since v2: - Add do_div to allow divide by a u64 on 32bit machines. Changes since v1: - Added documentation. Documentation/iio/iio_configfs.rst | 1 + drivers/iio/trigger/iio-trig-hrtimer.c | 26 ++++++++++++++++---------- 2 files changed, 17 insertions(+), 10 deletions(-)