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@xxxxxxxxxxxx> --- Changes since v8: - Define PSEC_PER_SEC locally to avoid dependency - Add units of expressions in comment. 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@xxxxxxxxxxxxxxx/ 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 | 33 ++++++++++++++++++-------- 2 files changed, 24 insertions(+), 10 deletions(-) diff --git a/Documentation/iio/iio_configfs.rst b/Documentation/iio/iio_configfs.rst index 3a5d76f9e2b97..09845fe525e84 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 410de837d0417..aa8cc7391a60d 100644 --- a/drivers/iio/trigger/iio-trig-hrtimer.c +++ b/drivers/iio/trigger/iio-trig-hrtimer.c @@ -16,13 +16,16 @@ #include <linux/iio/trigger.h> #include <linux/iio/sw_trigger.h> +/* Defined locally, not in time64.h yet. */ +#define PSEC_PER_SEC 1000000000000LL + /* default sampling frequency - 100Hz */ #define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100 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 +41,9 @@ 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 +53,26 @@ 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; /* mHz */ - 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; /* Hz */ + info->sampling_frequency[1] = fract * 1000; /* uHz */ + period = PSEC_PER_SEC; + do_div(period, val); + info->period = period; /* nS */ return len; } @@ -135,8 +148,8 @@ 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) -- 2.30.1.766.gb4fecdf3b7-goog
