IIO: Move the core files to drivers/iio

Take the core support + the kfifo buffer implentation out of
staging.  Whilst we are far from done in improving this subsystem
it is now at a stage where the userspae interfaces (provided by
the core) can be considered stable.

Drivers will follow over a longer time scale.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 509 insertions, 0 deletions

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
new file mode 100644
index 000000000000..03fee2e097ca
--- /dev/null
+++ b/drivers/iio/industrialio-trigger.c
@@ -0,0 +1,509 @@
+/* The industrial I/O core, trigger handling functions
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/trigger_consumer.h>
+
+/* RFC - Question of approach
+ * Make the common case (single sensor single trigger)
+ * simple by starting trigger capture from when first sensors
+ * is added.
+ *
+ * Complex simultaneous start requires use of 'hold' functionality
+ * of the trigger. (not implemented)
+ *
+ * Any other suggestions?
+ */
+
+static DEFINE_IDA(iio_trigger_ida);
+
+/* Single list of all available triggers */
+static LIST_HEAD(iio_trigger_list);
+static DEFINE_MUTEX(iio_trigger_list_lock);
+
+/**
+ * iio_trigger_read_name() - retrieve useful identifying name
+ **/
+static ssize_t iio_trigger_read_name(struct device *dev,
+                                     struct device_attribute *attr,
+                                     char *buf)
+{
+        struct iio_trigger *trig = dev_get_drvdata(dev);
+        return sprintf(buf, "%s\n", trig->name);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
+
+/**
+ * iio_trigger_register_sysfs() - create a device for this trigger
+ * @trig_info:  the trigger
+ *
+ * Also adds any control attribute registered by the trigger driver
+ **/
+static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
+{
+        return sysfs_add_file_to_group(&trig_info->dev.kobj,
+                                       &dev_attr_name.attr,
+                                       NULL);
+}
+
+static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
+{
+        sysfs_remove_file_from_group(&trig_info->dev.kobj,
+                                           &dev_attr_name.attr,
+                                           NULL);
+}
+
+int iio_trigger_register(struct iio_trigger *trig_info)
+{
+        int ret;
+
+        trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
+        if (trig_info->id < 0) {
+                ret = trig_info->id;
+                goto error_ret;
+        }
+        /* Set the name used for the sysfs directory etc */
+        dev_set_name(&trig_info->dev, "trigger%ld",
+                     (unsigned long) trig_info->id);
+
+        ret = device_add(&trig_info->dev);
+        if (ret)
+                goto error_unregister_id;
+
+        ret = iio_trigger_register_sysfs(trig_info);
+        if (ret)
+                goto error_device_del;
+
+        /* Add to list of available triggers held by the IIO core */
+        mutex_lock(&iio_trigger_list_lock);
+        list_add_tail(&trig_info->list, &iio_trigger_list);
+        mutex_unlock(&iio_trigger_list_lock);
+
+        return 0;
+
+error_device_del:
+        device_del(&trig_info->dev);
+error_unregister_id:
+        ida_simple_remove(&iio_trigger_ida, trig_info->id);
+error_ret:
+        return ret;
+}
+EXPORT_SYMBOL(iio_trigger_register);
+
+void iio_trigger_unregister(struct iio_trigger *trig_info)
+{
+        mutex_lock(&iio_trigger_list_lock);
+        list_del(&trig_info->list);
+        mutex_unlock(&iio_trigger_list_lock);
+
+        iio_trigger_unregister_sysfs(trig_info);
+        ida_simple_remove(&iio_trigger_ida, trig_info->id);
+        /* Possible issue in here */
+        device_unregister(&trig_info->dev);
+}
+EXPORT_SYMBOL(iio_trigger_unregister);
+
+static struct iio_trigger *iio_trigger_find_by_name(const char *name,
+                                                    size_t len)
+{
+        struct iio_trigger *trig = NULL, *iter;
+
+        mutex_lock(&iio_trigger_list_lock);
+        list_for_each_entry(iter, &iio_trigger_list, list)
+                if (sysfs_streq(iter->name, name)) {
+                        trig = iter;
+                        break;
+                }
+        mutex_unlock(&iio_trigger_list_lock);
+
+        return trig;
+}
+
+void iio_trigger_poll(struct iio_trigger *trig, s64 time)
+{
+        int i;
+        if (!trig->use_count)
+                for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
+                        if (trig->subirqs[i].enabled) {
+                                trig->use_count++;
+                                generic_handle_irq(trig->subirq_base + i);
+                        }
+}
+EXPORT_SYMBOL(iio_trigger_poll);
+
+irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
+{
+        iio_trigger_poll(private, iio_get_time_ns());
+        return IRQ_HANDLED;
+}
+EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
+
+void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
+{
+        int i;
+        if (!trig->use_count)
+                for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
+                        if (trig->subirqs[i].enabled) {
+                                trig->use_count++;
+                                handle_nested_irq(trig->subirq_base + i);
+                        }
+}
+EXPORT_SYMBOL(iio_trigger_poll_chained);
+
+void iio_trigger_notify_done(struct iio_trigger *trig)
+{
+        trig->use_count--;
+        if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
+                if (trig->ops->try_reenable(trig))
+                        /* Missed and interrupt so launch new poll now */
+                        iio_trigger_poll(trig, 0);
+}
+EXPORT_SYMBOL(iio_trigger_notify_done);
+
+/* Trigger Consumer related functions */
+static int iio_trigger_get_irq(struct iio_trigger *trig)
+{
+        int ret;
+        mutex_lock(&trig->pool_lock);
+        ret = bitmap_find_free_region(trig->pool,
+                                      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+                                      ilog2(1));
+        mutex_unlock(&trig->pool_lock);
+        if (ret >= 0)
+                ret += trig->subirq_base;
+
+        return ret;
+}
+
+static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
+{
+        mutex_lock(&trig->pool_lock);
+        clear_bit(irq - trig->subirq_base, trig->pool);
+        mutex_unlock(&trig->pool_lock);
+}
+
+/* Complexity in here.  With certain triggers (datardy) an acknowledgement
+ * may be needed if the pollfuncs do not include the data read for the
+ * triggering device.
+ * This is not currently handled.  Alternative of not enabling trigger unless
+ * the relevant function is in there may be the best option.
+ */
+/* Worth protecting against double additions?*/
+static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
+                                        struct iio_poll_func *pf)
+{
+        int ret = 0;
+        bool notinuse
+                = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+        /* Prevent the module being removed whilst attached to a trigger */
+        __module_get(pf->indio_dev->info->driver_module);
+        pf->irq = iio_trigger_get_irq(trig);
+        ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
+                                   pf->type, pf->name,
+                                   pf);
+        if (ret < 0) {
+                module_put(pf->indio_dev->info->driver_module);
+                return ret;
+        }
+
+        if (trig->ops && trig->ops->set_trigger_state && notinuse) {
+                ret = trig->ops->set_trigger_state(trig, true);
+                if (ret < 0)
+                        module_put(pf->indio_dev->info->driver_module);
+        }
+
+        return ret;
+}
+
+static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
+                                         struct iio_poll_func *pf)
+{
+        int ret = 0;
+        bool no_other_users
+                = (bitmap_weight(trig->pool,
+                                 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
+                   == 1);
+        if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
+                ret = trig->ops->set_trigger_state(trig, false);
+                if (ret)
+                        goto error_ret;
+        }
+        iio_trigger_put_irq(trig, pf->irq);
+        free_irq(pf->irq, pf);
+        module_put(pf->indio_dev->info->driver_module);
+
+error_ret:
+        return ret;
+}
+
+irqreturn_t iio_pollfunc_store_time(int irq, void *p)
+{
+        struct iio_poll_func *pf = p;
+        pf->timestamp = iio_get_time_ns();
+        return IRQ_WAKE_THREAD;
+}
+EXPORT_SYMBOL(iio_pollfunc_store_time);
+
+struct iio_poll_func
+*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
+                    irqreturn_t (*thread)(int irq, void *p),
+                    int type,
+                    struct iio_dev *indio_dev,
+                    const char *fmt,
+                    ...)
+{
+        va_list vargs;
+        struct iio_poll_func *pf;
+
+        pf = kmalloc(sizeof *pf, GFP_KERNEL);
+        if (pf == NULL)
+                return NULL;
+        va_start(vargs, fmt);
+        pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+        va_end(vargs);
+        if (pf->name == NULL) {
+                kfree(pf);
+                return NULL;
+        }
+        pf->h = h;
+        pf->thread = thread;
+        pf->type = type;
+        pf->indio_dev = indio_dev;
+
+        return pf;
+}
+EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
+
+void iio_dealloc_pollfunc(struct iio_poll_func *pf)
+{
+        kfree(pf->name);
+        kfree(pf);
+}
+EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
+
+/**
+ * iio_trigger_read_current() - trigger consumer sysfs query which trigger
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used by the device to be queried.
+ **/
+static ssize_t iio_trigger_read_current(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf)
+{
+        struct iio_dev *indio_dev = dev_get_drvdata(dev);
+
+        if (indio_dev->trig)
+                return sprintf(buf, "%s\n", indio_dev->trig->name);
+        return 0;
+}
+
+/**
+ * iio_trigger_write_current() trigger consumer sysfs set current trigger
+ *
+ * For trigger consumers the current_trigger interface allows the trigger
+ * used for this device to be specified at run time based on the triggers
+ * name.
+ **/
+static ssize_t iio_trigger_write_current(struct device *dev,
+                                         struct device_attribute *attr,
+                                         const char *buf,
+                                         size_t len)
+{
+        struct iio_dev *indio_dev = dev_get_drvdata(dev);
+        struct iio_trigger *oldtrig = indio_dev->trig;
+        struct iio_trigger *trig;
+        int ret;
+
+        mutex_lock(&indio_dev->mlock);
+        if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+                mutex_unlock(&indio_dev->mlock);
+                return -EBUSY;
+        }
+        mutex_unlock(&indio_dev->mlock);
+
+        trig = iio_trigger_find_by_name(buf, len);
+        if (oldtrig == trig)
+                return len;
+
+        if (trig && indio_dev->info->validate_trigger) {
+                ret = indio_dev->info->validate_trigger(indio_dev, trig);
+                if (ret)
+                        return ret;
+        }
+
+        if (trig && trig->ops && trig->ops->validate_device) {
+                ret = trig->ops->validate_device(trig, indio_dev);
+                if (ret)
+                        return ret;
+        }
+
+        indio_dev->trig = trig;
+
+        if (oldtrig && indio_dev->trig != oldtrig)
+                iio_put_trigger(oldtrig);
+        if (indio_dev->trig)
+                iio_get_trigger(indio_dev->trig);
+
+        return len;
+}
+
+static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
+                   iio_trigger_read_current,
+                   iio_trigger_write_current);
+
+static struct attribute *iio_trigger_consumer_attrs[] = {
+        &dev_attr_current_trigger.attr,
+        NULL,
+};
+
+static const struct attribute_group iio_trigger_consumer_attr_group = {
+        .name = "trigger",
+        .attrs = iio_trigger_consumer_attrs,
+};
+
+static void iio_trig_release(struct device *device)
+{
+        struct iio_trigger *trig = to_iio_trigger(device);
+        int i;
+
+        if (trig->subirq_base) {
+                for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+                        irq_modify_status(trig->subirq_base + i,
+                                          IRQ_NOAUTOEN,
+                                          IRQ_NOREQUEST | IRQ_NOPROBE);
+                        irq_set_chip(trig->subirq_base + i,
+                                     NULL);
+                        irq_set_handler(trig->subirq_base + i,
+                                        NULL);
+                }
+
+                irq_free_descs(trig->subirq_base,
+                               CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+        }
+        kfree(trig->name);
+        kfree(trig);
+}
+
+static struct device_type iio_trig_type = {
+        .release = iio_trig_release,
+};
+
+static void iio_trig_subirqmask(struct irq_data *d)
+{
+        struct irq_chip *chip = irq_data_get_irq_chip(d);
+        struct iio_trigger *trig
+                = container_of(chip,
+                               struct iio_trigger, subirq_chip);
+        trig->subirqs[d->irq - trig->subirq_base].enabled = false;
+}
+
+static void iio_trig_subirqunmask(struct irq_data *d)
+{
+        struct irq_chip *chip = irq_data_get_irq_chip(d);
+        struct iio_trigger *trig
+                = container_of(chip,
+                               struct iio_trigger, subirq_chip);
+        trig->subirqs[d->irq - trig->subirq_base].enabled = true;
+}
+
+struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
+{
+        va_list vargs;
+        struct iio_trigger *trig;
+        trig = kzalloc(sizeof *trig, GFP_KERNEL);
+        if (trig) {
+                int i;
+                trig->dev.type = &iio_trig_type;
+                trig->dev.bus = &iio_bus_type;
+                device_initialize(&trig->dev);
+                dev_set_drvdata(&trig->dev, (void *)trig);
+
+                mutex_init(&trig->pool_lock);
+                trig->subirq_base
+                        = irq_alloc_descs(-1, 0,
+                                          CONFIG_IIO_CONSUMERS_PER_TRIGGER,
+                                          0);
+                if (trig->subirq_base < 0) {
+                        kfree(trig);
+                        return NULL;
+                }
+                va_start(vargs, fmt);
+                trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
+                va_end(vargs);
+                if (trig->name == NULL) {
+                        irq_free_descs(trig->subirq_base,
+                                       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+                        kfree(trig);
+                        return NULL;
+                }
+                trig->subirq_chip.name = trig->name;
+                trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
+                trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
+                for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+                        irq_set_chip(trig->subirq_base + i,
+                                     &trig->subirq_chip);
+                        irq_set_handler(trig->subirq_base + i,
+                                        &handle_simple_irq);
+                        irq_modify_status(trig->subirq_base + i,
+                                          IRQ_NOREQUEST | IRQ_NOAUTOEN,
+                                          IRQ_NOPROBE);
+                }
+                get_device(&trig->dev);
+        }
+        return trig;
+}
+EXPORT_SYMBOL(iio_allocate_trigger);
+
+void iio_free_trigger(struct iio_trigger *trig)
+{
+        if (trig)
+                put_device(&trig->dev);
+}
+EXPORT_SYMBOL(iio_free_trigger);
+
+void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
+{
+        indio_dev->groups[indio_dev->groupcounter++] =
+                &iio_trigger_consumer_attr_group;
+}
+
+void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
+{
+        /* Clean up and associated but not attached triggers references */
+        if (indio_dev->trig)
+                iio_put_trigger(indio_dev->trig);
+}
+
+int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
+{
+        return iio_trigger_attach_poll_func(indio_dev->trig,
+                                            indio_dev->pollfunc);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_postenable);
+
+int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
+{
+        return iio_trigger_dettach_poll_func(indio_dev->trig,
+                                             indio_dev->pollfunc);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_predisable);