From 7026ea4b52cf23a76507b5bddc92f394603c689e Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Tue, 18 Aug 2009 18:06:24 +0100 Subject: [PATCH] Staging: IIO: Add generic ring buffer support to the IIO core This provides a unified interface for hardware and software ring buffers. Changes since V2: * Moved to a more consistent structure. Now the ring buffer has an associated struct device which is a child of the relevant iio_dev. This in turn has two children, one for the event interface and one for the access interface. These two interfaces are now managed via cdev structures. * Numerous minor cleanups Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/staging/iio/Kconfig | 6 + drivers/staging/iio/Makefile | 1 + drivers/staging/iio/industrialio-ring.c | 568 ++++++++++++++++++++++++++++++++ drivers/staging/iio/ring_generic.h | 283 ++++++++++++++++ 4 files changed, 858 insertions(+) create mode 100644 drivers/staging/iio/industrialio-ring.c create mode 100644 drivers/staging/iio/ring_generic.h diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig index 309eb38..e554a9e 100644 --- a/drivers/staging/iio/Kconfig +++ b/drivers/staging/iio/Kconfig @@ -11,6 +11,12 @@ menuconfig IIO Documentation/industrialio for more information. if IIO +config IIO_RING_BUFFER + bool "Enable ring buffer support within IIO" + help + Provide core support for various ring buffer based data + acquisition methods. + source "drivers/staging/iio/accel/Kconfig" source "drivers/staging/iio/adc/Kconfig" source "drivers/staging/iio/light/Kconfig" diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile index 14c661b..670b8f3 100644 --- a/drivers/staging/iio/Makefile +++ b/drivers/staging/iio/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_IIO) += industrialio.o industrialio-y := industrialio-core.o +industrialio-$(CONFIG_IIO_RING_BUFFER) += industrialio-ring.o obj-y += accel/ obj-y += adc/ diff --git a/drivers/staging/iio/industrialio-ring.c b/drivers/staging/iio/industrialio-ring.c new file mode 100644 index 0000000..ebe5ccc --- /dev/null +++ b/drivers/staging/iio/industrialio-ring.c @@ -0,0 +1,568 @@ +/* The industrial I/O core + * + * 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. + * + * Handling of ring allocation / resizing. + * + * + * Things to look at here. + * - Better memory allocation techniques? + * - Alternative access techniques? + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#include "iio.h" +#include "ring_generic.h" + +/* IDR for ring buffer identifier */ +static DEFINE_IDR(iio_ring_idr); +/* IDR for ring event identifier */ +static DEFINE_IDR(iio_ring_event_idr); +/* IDR for ring access identifier */ +static DEFINE_IDR(iio_ring_access_idr); + +int iio_push_ring_event(struct iio_ring_buffer *ring_buf, + int event_code, + s64 timestamp) +{ + return __iio_push_event(&ring_buf->ev_int, + event_code, + timestamp, + &ring_buf->shared_ev_pointer); +} +EXPORT_SYMBOL(iio_push_ring_event); + +int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf, + int event_code, + s64 timestamp) +{ + if (ring_buf->shared_ev_pointer.ev_p) + __iio_change_event(ring_buf->shared_ev_pointer.ev_p, + event_code, + timestamp); + else + return iio_push_ring_event(ring_buf, + event_code, + timestamp); + return 0; +} +EXPORT_SYMBOL(iio_push_or_escallate_ring_event); + +/** + * iio_ring_open() chrdev file open for ring buffer access + * + * This function relies on all ring buffer implementations having an + * iio_ring_buffer as their first element. + **/ +int iio_ring_open(struct inode *inode, struct file *filp) +{ + struct iio_handler *hand + = container_of(inode->i_cdev, struct iio_handler, chrdev); + struct iio_ring_buffer *rb = hand->private; + + filp->private_data = hand->private; + if (rb->access.mark_in_use) + rb->access.mark_in_use(rb); + + return 0; +} + +/** + * iio_ring_release() -chrdev file close ring buffer access + * + * This function relies on all ring buffer implementations having an + * iio_ring_buffer as their first element. + **/ +int iio_ring_release(struct inode *inode, struct file *filp) +{ + struct cdev *cd = inode->i_cdev; + struct iio_handler *hand = iio_cdev_to_handler(cd); + struct iio_ring_buffer *rb = hand->private; + + clear_bit(IIO_BUSY_BIT_POS, &rb->access_handler.flags); + if (rb->access.unmark_in_use) + rb->access.unmark_in_use(rb); + + return 0; +} + +/** + * iio_ring_rip_outer() chrdev read for ring buffer access + * + * This function relies on all ring buffer implementations having an + * iio_ring _bufer as their first element. + **/ +ssize_t iio_ring_rip_outer(struct file *filp, + char *buf, + size_t count, + loff_t *f_ps) +{ + struct iio_ring_buffer *rb = filp->private_data; + int ret, dead_offset, copied; + u8 *data; + /* rip lots must exist. */ + if (!rb->access.rip_lots) + return -EINVAL; + copied = rb->access.rip_lots(rb, count, &data, &dead_offset); + + if (copied < 0) { + ret = copied; + goto error_ret; + } + if (copy_to_user(buf, data + dead_offset, copied)) { + ret = -EFAULT; + goto error_free_data_cpy; + } + /* In clever ring buffer designs this may not need to be freed. + * When such a design exists I'll add this to ring access funcs. + */ + kfree(data); + + return copied; + +error_free_data_cpy: + kfree(data); +error_ret: + return ret; +} + +static const struct file_operations iio_ring_fileops = { + .read = iio_ring_rip_outer, + .release = iio_ring_release, + .open = iio_ring_open, + .owner = THIS_MODULE, +}; + +/** + * __iio_request_ring_buffer_event_chrdev() allocate ring event chrdev + * @buf: ring buffer whose event chrdev we are allocating + * @owner: the module who owns the ring buffer (for ref counting) + * @dev: device with which the chrdev is associated + **/ +static inline int +__iio_request_ring_buffer_event_chrdev(struct iio_ring_buffer *buf, + int id, + struct module *owner, + struct device *dev) +{ + int ret; + ret = iio_get_new_idr_val(&iio_ring_event_idr); + if (ret < 0) + goto error_ret; + else + buf->ev_int.id = ret; + + snprintf(buf->ev_int._name, 20, + "ring_event_line%d", + buf->ev_int.id); + ret = iio_setup_ev_int(&(buf->ev_int), + buf->ev_int._name, + owner, + dev); + if (ret) + goto error_free_id; + return 0; + +error_free_id: + iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id); +error_ret: + return ret; +} + +static inline void +__iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf) +{ + iio_free_ev_int(&(buf->ev_int)); + iio_free_idr_val(&iio_ring_event_idr, buf->ev_int.id); +} + +static void iio_ring_access_release(struct device *dev) +{ + struct iio_ring_buffer *buf + = access_dev_to_iio_ring_buffer(dev); + cdev_del(&buf->access_handler.chrdev); + iio_device_free_chrdev_minor(MINOR(dev->devt)); +} + +static struct device_type iio_ring_access_type = { + .release = iio_ring_access_release, +}; + +static inline int +__iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf, + int id, + struct module *owner) +{ + int ret, minor; + + buf->access_handler.flags = 0; + + buf->access_dev.parent = &buf->dev; + buf->access_dev.class = &iio_class; + buf->access_dev.type = &iio_ring_access_type; + device_initialize(&buf->access_dev); + + minor = iio_device_get_chrdev_minor(); + if (minor < 0) { + ret = minor; + goto error_device_put; + } + buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor); + + ret = iio_get_new_idr_val(&iio_ring_access_idr); + if (ret < 0) + goto error_device_put; + else + buf->access_id = ret; + dev_set_name(&buf->access_dev, "ring_access%d", buf->access_id); + ret = device_add(&buf->access_dev); + if (ret < 0) { + printk(KERN_ERR "failed to add the ring access dev\n"); + goto error_free_idr; + } + + cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops); + buf->access_handler.chrdev.owner = owner; + + ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1); + if (ret) { + printk(KERN_ERR "failed to allocate ring access chrdev\n"); + goto error_device_unregister; + } + return 0; +error_device_unregister: + device_unregister(&buf->access_dev); +error_free_idr: + iio_free_idr_val(&iio_ring_access_idr, buf->access_id); +error_device_put: + put_device(&buf->access_dev); + + return ret; +} + +static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf) +{ + iio_free_idr_val(&iio_ring_access_idr, buf->access_id); + device_unregister(&buf->access_dev); +} + +void iio_ring_buffer_init(struct iio_ring_buffer *ring, + struct iio_dev *dev_info) +{ + if (ring->access.mark_param_change) + ring->access.mark_param_change(ring); + ring->indio_dev = dev_info; + ring->ev_int.private = ring; + ring->access_handler.private = ring; +} +EXPORT_SYMBOL(iio_ring_buffer_init); + +int iio_ring_buffer_register(struct iio_ring_buffer *ring) +{ + int ret; + ret = iio_get_new_idr_val(&iio_ring_idr); + if (ret < 0) + goto error_ret; + else + ring->id = ret; + + dev_set_name(&ring->dev, "ring_buffer%d", ring->id); + ret = device_add(&ring->dev); + if (ret) + goto error_free_id; + + ret = __iio_request_ring_buffer_event_chrdev(ring, + 0, + ring->owner, + &ring->dev); + if (ret) + goto error_remove_device; + + ret = __iio_request_ring_buffer_access_chrdev(ring, + 0, + ring->owner); + + if (ret) + goto error_free_ring_buffer_event_chrdev; + + return ret; +error_free_ring_buffer_event_chrdev: + __iio_free_ring_buffer_event_chrdev(ring); +error_remove_device: + device_del(&ring->dev); +error_free_id: + iio_free_idr_val(&iio_ring_idr, ring->id); +error_ret: + return ret; +} +EXPORT_SYMBOL(iio_ring_buffer_register); + +void iio_ring_buffer_unregister(struct iio_ring_buffer *ring) +{ + __iio_free_ring_buffer_access_chrdev(ring); + __iio_free_ring_buffer_event_chrdev(ring); + device_del(&ring->dev); + iio_free_idr_val(&iio_ring_idr, ring->id); +} +EXPORT_SYMBOL(iio_ring_buffer_unregister); + +ssize_t iio_read_ring_length(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int len = 0; + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + + if (ring->access.get_length) + len = sprintf(buf, "%d\n", + ring->access.get_length(ring)); + + return len; +} +EXPORT_SYMBOL(iio_read_ring_length); + + ssize_t iio_write_ring_length(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + int ret; + ulong val; + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + ret = strict_strtoul(buf, 10, &val); + if (ret) + return ret; + + if (ring->access.get_length) + if (val == ring->access.get_length(ring)) + return len; + + if (ring->access.set_length) { + ring->access.set_length(ring, val); + if (ring->access.mark_param_change) + ring->access.mark_param_change(ring); + } + + return len; +} +EXPORT_SYMBOL(iio_write_ring_length); + +ssize_t iio_read_ring_bps(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int len = 0; + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + + if (ring->access.get_bpd) + len = sprintf(buf, "%d\n", + ring->access.get_bpd(ring)); + + return len; +} +EXPORT_SYMBOL(iio_read_ring_bps); + +ssize_t iio_store_ring_enable(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + int ret; + bool requested_state, current_state; + int previous_mode; + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + struct iio_dev *dev_info = ring->indio_dev; + + mutex_lock(&dev_info->mlock); + previous_mode = dev_info->currentmode; + requested_state = !(buf[0] == '0'); + current_state = !!(previous_mode & INDIO_ALL_RING_MODES); + if (current_state == requested_state) { + printk(KERN_INFO "iio-ring, current state requested again\n"); + goto done; + } + if (requested_state) { + if (ring->preenable) { + ret = ring->preenable(dev_info); + if (ret) { + printk(KERN_ERR + "Buffer not started:" + "ring preenable failed\n"); + goto error_ret; + } + } + if (ring->access.request_update) { + ret = ring->access.request_update(ring); + if (ret) { + printk(KERN_INFO + "Buffer not started:" + "ring parameter update failed\n"); + goto error_ret; + } + } + if (ring->access.mark_in_use) + ring->access.mark_in_use(ring); + /* Definitely possible for devices to support both of these.*/ + if (dev_info->modes & INDIO_RING_TRIGGERED) { + if (!dev_info->trig) { + printk(KERN_INFO + "Buffer not started: no trigger\n"); + ret = -EINVAL; + if (ring->access.unmark_in_use) + ring->access.unmark_in_use(ring); + goto error_ret; + } + dev_info->currentmode = INDIO_RING_TRIGGERED; + } else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER) + dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER; + else { /* should never be reached */ + ret = -EINVAL; + goto error_ret; + } + + if (ring->postenable) { + + ret = ring->postenable(dev_info); + if (ret) { + printk(KERN_INFO + "Buffer not started:" + "postenable failed\n"); + if (ring->access.unmark_in_use) + ring->access.unmark_in_use(ring); + dev_info->currentmode = previous_mode; + if (ring->postdisable) + ring->postdisable(dev_info); + goto error_ret; + } + } + } else { + if (ring->predisable) { + ret = ring->predisable(dev_info); + if (ret) + goto error_ret; + } + if (ring->access.unmark_in_use) + ring->access.unmark_in_use(ring); + dev_info->currentmode = INDIO_DIRECT_MODE; + if (ring->postdisable) { + ret = ring->postdisable(dev_info); + if (ret) + goto error_ret; + } + } +done: + mutex_unlock(&dev_info->mlock); + return len; + +error_ret: + mutex_unlock(&dev_info->mlock); + return ret; +} +EXPORT_SYMBOL(iio_store_ring_enable); +ssize_t iio_show_ring_enable(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_ring_buffer *ring = dev_get_drvdata(dev); + return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode + & INDIO_ALL_RING_MODES)); +} +EXPORT_SYMBOL(iio_show_ring_enable); + +ssize_t iio_scan_el_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int ret; + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct iio_scan_el *this_el = to_iio_scan_el(attr); + + ret = iio_scan_mask_query(indio_dev, this_el->number); + if (ret < 0) + return ret; + return sprintf(buf, "%d\n", ret); +} +EXPORT_SYMBOL(iio_scan_el_show); + +ssize_t iio_scan_el_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + int ret = 0; + bool state; + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct iio_scan_el *this_el = to_iio_scan_el(attr); + + state = !(buf[0] == '0'); + mutex_lock(&indio_dev->mlock); + if (indio_dev->currentmode == INDIO_RING_TRIGGERED) { + ret = -EBUSY; + goto error_ret; + } + ret = iio_scan_mask_query(indio_dev, this_el->number); + if (ret < 0) + goto error_ret; + if (!state && ret) { + ret = iio_scan_mask_clear(indio_dev, this_el->number); + if (ret) + goto error_ret; + indio_dev->scan_count--; + } else if (state && !ret) { + ret = iio_scan_mask_set(indio_dev, this_el->number); + if (ret) + goto error_ret; + indio_dev->scan_count++; + } + if (this_el->set_state) + ret = this_el->set_state(this_el, indio_dev, state); +error_ret: + mutex_unlock(&indio_dev->mlock); + + return ret ? ret : len; + +} +EXPORT_SYMBOL(iio_scan_el_store); + +ssize_t iio_scan_el_ts_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + return sprintf(buf, "%d\n", indio_dev->scan_timestamp); +} +EXPORT_SYMBOL(iio_scan_el_ts_show); + +ssize_t iio_scan_el_ts_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + int ret = 0; + struct iio_dev *indio_dev = dev_get_drvdata(dev); + bool state; + state = !(buf[0] == '0'); + mutex_lock(&indio_dev->mlock); + if (indio_dev->currentmode == INDIO_RING_TRIGGERED) { + ret = -EBUSY; + goto error_ret; + } + indio_dev->scan_timestamp = state; +error_ret: + mutex_unlock(&indio_dev->mlock); + + return ret ? ret : len; +} +EXPORT_SYMBOL(iio_scan_el_ts_store); + diff --git a/drivers/staging/iio/ring_generic.h b/drivers/staging/iio/ring_generic.h new file mode 100644 index 0000000..d926189 --- /dev/null +++ b/drivers/staging/iio/ring_generic.h @@ -0,0 +1,283 @@ +/* The industrial I/O core - generic ring buffer interfaces. + * + * 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. + */ + +#ifndef _IIO_RING_GENERIC_H_ +#define _IIO_RING_GENERIC_H_ +#include "iio.h" + +struct iio_handler; +struct iio_ring_buffer; +struct iio_dev; + +/** + * iio_push_ring_event() - ring buffer specific push to event chrdev + * @ring_buf: ring buffer that is the event source + * @event_code: event indentification code + * @timestamp: time of event + **/ +int iio_push_ring_event(struct iio_ring_buffer *ring_buf, + int event_code, + s64 timestamp); +/** + * iio_push_or_escallate_ring_event() - escallate or add as appropriate + * + * Typical usecase is to escallate a 50% ring full to 75% full if noone has yet + * read the first event. Clearly the 50% full is no longer of interest in + * typical use case. + **/ +int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf, + int event_code, + s64 timestamp); + +/** + * struct iio_ring_access_funcs - access functions for ring buffers. + * @create: perform allocation + * @init: get ring buffer ready for use + * @_exit: reverse steps in init + * @_free: deallocate ring buffer + * @mark_in_use: reference counting, typically to prevent module removal + * @unmark_in_use: reduce reference count when no longer using ring buffer + * @store_to: actually store stuff to the ring buffer + * @read_last: get the last element stored + * @rip_lots: try to get a specified number of elements (must exist) + * @mark_param_change: notify ring that some relevant parameter has changed + * Often this means the underlying storage may need to + * change. + * @request_update: if a parameter change has been marked, update underlying + * storage. + * @get_bpd: get current bytes per datum + * @set_bpd: set number of bytes per datum + * @get_length: get number of datums in ring + * @set_length: set number of datums in ring + * @is_enabled: query if ring is currently being used + * @enable: enable the ring + * + * The purpose of this structure is to make the ring buffer element + * modular as event for a given driver, different usecases may require + * different ring designs (space efficiency vs speed for example. + * + * It is worth noting that a given ring implementation may only support a small + * proportion of these functions. The core code 'should' cope fine with any of + * them not existing. + **/ +struct iio_ring_access_funcs { + void (*mark_in_use)(struct iio_ring_buffer *ring); + void (*unmark_in_use)(struct iio_ring_buffer *ring); + + int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp); + int (*read_last)(struct iio_ring_buffer *ring, u8 *data); + int (*rip_lots)(struct iio_ring_buffer *ring, + size_t count, + u8 **data, + int *dead_offset); + + int (*mark_param_change)(struct iio_ring_buffer *ring); + int (*request_update)(struct iio_ring_buffer *ring); + + int (*get_bpd)(struct iio_ring_buffer *ring); + int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd); + int (*get_length)(struct iio_ring_buffer *ring); + int (*set_length)(struct iio_ring_buffer *ring, int length); + + int (*is_enabled)(struct iio_ring_buffer *ring); + int (*enable)(struct iio_ring_buffer *ring); +}; + +/** + * struct iio_ring_buffer - general ring buffer structure + * @length: [DEVICE]number of datums in ring + * @bpd: [DEVICE]size of individual datum including timestamp + * @loopcount: [INTERN]number of times the ring has looped + * @access_minor_name: [INTERN]store of name of the access chrdev minor number + * sysfs attribute + * @access_handler: [INTERN]chrdev access handling + * @event_minor_name: [INTERN]store of name of the event chrdev minor number + * sysfs attribute + * @ev_int: [INTERN]chrdev interface for the event chrdev + * @shared_ev_pointer: [INTERN]the shared event pointer to allow escalation of + * events + * @ring_access: [DRIVER]ring access functions associated with the + * implementation. + * @ring_prenable: [DRIVER] function to run prior to marking ring enabled + * @ring_postenable: [DRIVER] function to run after marking ring enabled + * @ring_predisable: [DRIVER] function to run prior to marking ring disabled + * @ring_postdisable: [DRIVER] function to run after marking ring disabled + **/ +struct iio_ring_buffer { + struct device dev; + struct device access_dev; + struct iio_dev *indio_dev; + struct module *owner; + int id; + int access_id; + int length; + int bpd; + int loopcount; + struct iio_handler access_handler; + struct iio_event_interface ev_int; + struct iio_shared_ev_pointer shared_ev_pointer; + struct iio_ring_access_funcs access; + int (*preenable)(struct iio_dev *); + int (*postenable)(struct iio_dev *); + int (*predisable)(struct iio_dev *); + int (*postdisable)(struct iio_dev *); + +}; +void iio_ring_buffer_init(struct iio_ring_buffer *ring, + struct iio_dev *dev_info); + +/** + * __iio_init_ring_buffer() - initialize common elements of ring buffers. + **/ +static inline void __iio_init_ring_buffer(struct iio_ring_buffer *ring, + int bytes_per_datum, int length) +{ + ring->bpd = bytes_per_datum; + ring->length = length; + ring->loopcount = 0; + ring->shared_ev_pointer.ev_p = 0; + ring->shared_ev_pointer.lock = + __SPIN_LOCK_UNLOCKED(ring->shared_ev_pointer->loc); +} + +/** + * struct iio_scan_el - an individual element of a scan + * @dev_attr: control attribute (if directly controllable) + * @number: unique identifier of element (used for bit mask) + * @bit_count: number of bits in scan element + * @label: useful data for the scan el (often reg address) + * @set_state: for some devices datardy signals are generated + * for any enabled lines. This allows unwanted lines + * to be disabled and hence not get in the way. + **/ +struct iio_scan_el { + struct device_attribute dev_attr; + unsigned int number; + int bit_count; + unsigned int label; + + int (*set_state)(struct iio_scan_el *scanel, + struct iio_dev *dev_info, + bool state); +}; + +#define to_iio_scan_el(_dev_attr) \ + container_of(_dev_attr, struct iio_scan_el, dev_attr); + +/** + * iio_scan_el_store() - sysfs scan element selection interface. + * + * A generic function used to enable various scan elements. In some + * devices explicit read commands for each channel mean this is merely + * a software switch. In others this must actively disable the channel. + * Complexities occur when this interacts with data ready type triggers + * which may not reset unless every channel that is enabled is explicitly + * read. + **/ +ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len); +/** + * iio_scal_el_show() - sysfs interface to query whether a scan element is + * is enabled or not. + **/ +ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr, + char *buf); +/** + * IIO_SCAN_EL: - declare and initialize a scan element without control func + * @_name: identifying name. Resulting struct is iio_scan_el_##_name, + * sysfs element, scan_en_##_name. + * @_number: unique id number for the scan element. + * @_bits: number of bits in the scan element result (used in mixed bit + * length devices). + * @_label: indentification variable used by drivers. Often a reg address. + **/ +#define IIO_SCAN_EL(_name, _number, _bits, _label) \ + struct iio_scan_el iio_scan_el_##_name = { \ + .dev_attr = __ATTR(scan_en_##_name, \ + S_IRUGO | S_IWUSR, \ + iio_scan_el_show, \ + iio_scan_el_store), \ + .mask = (1 << _number), \ + .bit_count = _bits, \ + .label = _label, \ + } + +ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len); + +ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr, + char *buf); +/** + * IIO_SCAN_EL_C: - declare and initialize a scan element with a control func + * + * @_controlfunc: function used to notify hardware of whether state changes + **/ +#define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \ + struct iio_scan_el iio_scan_el_##_name = { \ + .dev_attr = __ATTR(scan_en_##_name, \ + S_IRUGO | S_IWUSR, \ + iio_scan_el_show, \ + iio_scan_el_store), \ + .number = _number, \ + .bit_count = _bits, \ + .label = _label, \ + .set_state = _controlfunc, \ + } +/** + * IIO_SCAN_EL_TIMESTAMP: - declare a special scan element for timestamps + * + * Odd one out. Handled slightly differently from other scan elements. + **/ +#define IIO_SCAN_EL_TIMESTAMP \ + struct iio_scan_el iio_scan_el_timestamp = { \ + .dev_attr = __ATTR(scan_en_timestamp, \ + S_IRUGO | S_IWUSR, \ + iio_scan_el_ts_show, \ + iio_scan_el_ts_store), \ + } + +static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring) +{ + put_device(&ring->dev); +}; + +#define to_iio_ring_buffer(d) \ + container_of(d, struct iio_ring_buffer, dev) +#define access_dev_to_iio_ring_buffer(d) \ + container_of(d, struct iio_ring_buffer, access_dev) +int iio_ring_buffer_register(struct iio_ring_buffer *ring); +void iio_ring_buffer_unregister(struct iio_ring_buffer *ring); + +ssize_t iio_read_ring_length(struct device *dev, + struct device_attribute *attr, + char *buf); +ssize_t iio_write_ring_length(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len); +ssize_t iio_read_ring_bps(struct device *dev, + struct device_attribute *attr, + char *buf); +ssize_t iio_store_ring_enable(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len); +ssize_t iio_show_ring_enable(struct device *dev, + struct device_attribute *attr, + char *buf); +#define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \ + iio_read_ring_length, \ + iio_write_ring_length) +#define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \ + iio_read_ring_bps, NULL) +#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \ + iio_show_ring_enable, \ + iio_store_ring_enable) + +#endif /* _IIO_RING_GENERIC_H_ */ -- 2.7.4