| Message ID | 20210129230249.816268-1-gwendal@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v8] iio: hrtimer: Allow sub Hz granularity | expand |
On Sat, Jan 30, 2021 at 1:02 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 && \ > cd /sys/bus/iio/devices/triggerX ; > for i in 1 .1 .01 .001 ; do > echo $i > sampling_frequency > cat sampling_frequency > done I think it's good enough, though one hint below. After taking it into account Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Signed-off-by: Gwendal Grignou <gwendal@chromium.org> > --- > Changes since v7: > - Check for sign properly, only allow positive frequencies. > - Return proper error code when input frequency is negative. > > Changes since v6: > - Check for sign, only allow positive frequencies. > > Changes since v5: > - Properly support do_div on 32bit architecture: quotient must be u64, dividend > u32. > - Use PSEC_PER_SEC from > https://patchwork.kernel.org/project/linux-iio/patch/20210112153709.1074-1-andriy.shevchenko@linux.intel.com/ > > 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 | 30 +++++++++++++++++--------- > 2 files changed, 21 insertions(+), 10 deletions(-) > > 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 f59bf8d585866..69c2943583b36 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 +50,26 @@ 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; > + u64 period; > + int integer, fract, ret; > > - ret = kstrtoul(buf, 10, &val); > + ret = iio_str_to_fixpoint(buf, 100, &integer, &fract); > if (ret) > return ret; > + if (integer < 0 || fract < 0) > + return -ERANGE; > + > + val = fract + 1000 * integer; To avoid dependencies right now, define at the top of this file #define PSEC_PER_SEC 1000000000000LL #define NSEC_PER_PSEC 1000L And use them here and there. val = fract + PSEC_PER_NSEC * integer; > - if (!val || val > NSEC_PER_SEC) > + if (!val || val > UINT_MAX) > return -EINVAL; > > - info->sampling_frequency = val; > - info->period = NSEC_PER_SEC / val; > + info->sampling_frequency[0] = integer; > + info->sampling_frequency[1] = fract * 1000; Likewise. > + period = PSEC_PER_SEC; > + do_div(period, val); > + info->period = period; > > return len; > } > @@ -135,8 +145,8 @@ static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) > hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > 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) > -- > 2.30.0.365.g02bc693789-goog >
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 f59bf8d585866..69c2943583b36 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 +50,26 @@ 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; + u64 period; + int integer, fract, ret; - ret = kstrtoul(buf, 10, &val); + ret = iio_str_to_fixpoint(buf, 100, &integer, &fract); if (ret) return ret; + if (integer < 0 || fract < 0) + return -ERANGE; + + val = fract + 1000 * integer; - if (!val || val > NSEC_PER_SEC) + if (!val || val > UINT_MAX) return -EINVAL; - info->sampling_frequency = val; - info->period = NSEC_PER_SEC / val; + info->sampling_frequency[0] = integer; + info->sampling_frequency[1] = fract * 1000; + period = PSEC_PER_SEC; + do_div(period, val); + info->period = period; return len; } @@ -135,8 +145,8 @@ static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 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 v7: - Check for sign properly, only allow positive frequencies. - Return proper error code when input frequency is negative. Changes since v6: - Check for sign, only allow positive frequencies. Changes since v5: - Properly support do_div on 32bit architecture: quotient must be u64, dividend u32. - Use PSEC_PER_SEC from https://patchwork.kernel.org/project/linux-iio/patch/20210112153709.1074-1-andriy.shevchenko@linux.intel.com/ 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 | 30 +++++++++++++++++--------- 2 files changed, 21 insertions(+), 10 deletions(-)