^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) ===============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) Industrial IIO configfs support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) ===============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) 1. Overview
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) ===========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) Configfs is a filesystem-based manager of kernel objects. IIO uses some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) objects that could be easily configured using configfs (e.g.: devices,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) triggers).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) See Documentation/filesystems/configfs.rst for more information
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) about how configfs works.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 2. Usage
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) ========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) In order to use configfs support in IIO we need to select it at compile
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) time via CONFIG_IIO_CONFIGFS config option.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) Then, mount the configfs filesystem (usually under /config directory)::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) $ mkdir /config
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) $ mount -t configfs none /config
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) At this point, all default IIO groups will be created and can be accessed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) under /config/iio. Next chapters will describe available IIO configuration
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) objects.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 3. Software triggers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) ====================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) One of the IIO default configfs groups is the "triggers" group. It is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) automagically accessible when the configfs is mounted and can be found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) under /config/iio/triggers.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) IIO software triggers implementation offers support for creating multiple
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) trigger types. A new trigger type is usually implemented as a separate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) kernel module following the interface in include/linux/iio/sw_trigger.h::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * drivers/iio/trigger/iio-trig-sample.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * sample kernel module implementing a new trigger type
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) #include <linux/iio/sw_trigger.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) static struct iio_sw_trigger *iio_trig_sample_probe(const char *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * This allocates and registers an IIO trigger plus other
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * trigger type specific initialization.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) static int iio_trig_sample_remove(struct iio_sw_trigger *swt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * This undoes the actions in iio_trig_sample_probe
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) static const struct iio_sw_trigger_ops iio_trig_sample_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) .probe = iio_trig_sample_probe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) .remove = iio_trig_sample_remove,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) static struct iio_sw_trigger_type iio_trig_sample = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) .name = "trig-sample",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) .owner = THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) .ops = &iio_trig_sample_ops,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) module_iio_sw_trigger_driver(iio_trig_sample);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) Each trigger type has its own directory under /config/iio/triggers. Loading
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) iio-trig-sample module will create 'trig-sample' trigger type directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) /config/iio/triggers/trig-sample.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) We support the following interrupt sources (trigger types):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) * hrtimer, uses high resolution timers as interrupt source
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) 3.1 Hrtimer triggers creation and destruction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) ---------------------------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) Loading iio-trig-hrtimer module will register hrtimer trigger types allowing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) users to create hrtimer triggers under /config/iio/triggers/hrtimer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) e.g::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) $ mkdir /config/iio/triggers/hrtimer/instance1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) $ rmdir /config/iio/triggers/hrtimer/instance1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) Each trigger can have one or more attributes specific to the trigger type.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) 3.2 "hrtimer" trigger types attributes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) --------------------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) "hrtimer" trigger type doesn't have any configurable attribute from /config dir.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) It does introduce the sampling_frequency attribute to trigger directory.
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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