508 lines
12 KiB
C
508 lines
12 KiB
C
/*
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module/drivers.c
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functions for manipulating drivers
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COMEDI - Linux Control and Measurement Device Interface
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Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/kconfig.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/fcntl.h>
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#include <linux/delay.h>
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#include <linux/ioport.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/highmem.h> /* for SuSE brokenness */
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#include <linux/vmalloc.h>
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#include <linux/cdev.h>
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#include <linux/dma-mapping.h>
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#include <linux/io.h>
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#include "comedidev.h"
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#include "comedi_internal.h"
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struct comedi_driver *comedi_drivers;
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int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)
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{
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if (hw_dev == dev->hw_dev)
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return 0;
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if (dev->hw_dev != NULL)
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return -EEXIST;
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dev->hw_dev = get_device(hw_dev);
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return 0;
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}
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EXPORT_SYMBOL_GPL(comedi_set_hw_dev);
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static void comedi_clear_hw_dev(struct comedi_device *dev)
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{
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put_device(dev->hw_dev);
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dev->hw_dev = NULL;
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}
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int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
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{
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struct comedi_subdevice *s;
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int i;
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if (num_subdevices < 1)
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return -EINVAL;
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s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
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if (!s)
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return -ENOMEM;
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dev->subdevices = s;
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dev->n_subdevices = num_subdevices;
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for (i = 0; i < num_subdevices; ++i) {
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s = &dev->subdevices[i];
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s->device = dev;
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s->index = i;
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s->async_dma_dir = DMA_NONE;
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spin_lock_init(&s->spin_lock);
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s->minor = -1;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
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static void cleanup_device(struct comedi_device *dev)
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{
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int i;
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struct comedi_subdevice *s;
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if (dev->subdevices) {
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for (i = 0; i < dev->n_subdevices; i++) {
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s = &dev->subdevices[i];
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comedi_free_subdevice_minor(s);
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if (s->async) {
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comedi_buf_alloc(dev, s, 0);
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kfree(s->async);
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}
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}
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kfree(dev->subdevices);
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dev->subdevices = NULL;
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dev->n_subdevices = 0;
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}
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kfree(dev->private);
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dev->private = NULL;
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dev->driver = NULL;
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dev->board_name = NULL;
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dev->board_ptr = NULL;
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dev->iobase = 0;
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dev->irq = 0;
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dev->read_subdev = NULL;
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dev->write_subdev = NULL;
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dev->open = NULL;
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dev->close = NULL;
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comedi_clear_hw_dev(dev);
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}
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static void __comedi_device_detach(struct comedi_device *dev)
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{
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dev->attached = 0;
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if (dev->driver)
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dev->driver->detach(dev);
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else
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dev_warn(dev->class_dev,
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"BUG: dev->driver=NULL in comedi_device_detach()\n");
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cleanup_device(dev);
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}
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void comedi_device_detach(struct comedi_device *dev)
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{
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if (!dev->attached)
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return;
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__comedi_device_detach(dev);
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}
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static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
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{
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return -EINVAL;
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}
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int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
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struct comedi_insn *insn, unsigned int *data)
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{
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return -EINVAL;
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}
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static int insn_rw_emulate_bits(struct comedi_device *dev,
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struct comedi_subdevice *s,
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struct comedi_insn *insn, unsigned int *data)
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{
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struct comedi_insn new_insn;
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int ret;
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static const unsigned channels_per_bitfield = 32;
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unsigned chan = CR_CHAN(insn->chanspec);
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const unsigned base_bitfield_channel =
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(chan < channels_per_bitfield) ? 0 : chan;
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unsigned int new_data[2];
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memset(new_data, 0, sizeof(new_data));
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memset(&new_insn, 0, sizeof(new_insn));
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new_insn.insn = INSN_BITS;
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new_insn.chanspec = base_bitfield_channel;
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new_insn.n = 2;
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new_insn.subdev = insn->subdev;
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if (insn->insn == INSN_WRITE) {
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if (!(s->subdev_flags & SDF_WRITABLE))
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return -EINVAL;
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new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
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new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
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: 0; /* bits */
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}
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ret = s->insn_bits(dev, s, &new_insn, new_data);
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if (ret < 0)
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return ret;
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if (insn->insn == INSN_READ)
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data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
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return 1;
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}
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static int __comedi_device_postconfig_async(struct comedi_device *dev,
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struct comedi_subdevice *s)
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{
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struct comedi_async *async;
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unsigned int buf_size;
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int ret;
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if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
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dev_warn(dev->class_dev,
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"async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
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return -EINVAL;
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}
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if (!s->do_cmdtest) {
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dev_warn(dev->class_dev,
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"async subdevices must have a do_cmdtest() function\n");
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return -EINVAL;
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}
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async = kzalloc(sizeof(*async), GFP_KERNEL);
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if (!async)
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return -ENOMEM;
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init_waitqueue_head(&async->wait_head);
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async->subdevice = s;
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s->async = async;
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async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;
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buf_size = comedi_default_buf_size_kb * 1024;
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if (buf_size > async->max_bufsize)
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buf_size = async->max_bufsize;
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if (comedi_buf_alloc(dev, s, buf_size) < 0) {
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dev_warn(dev->class_dev, "Buffer allocation failed\n");
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return -ENOMEM;
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}
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if (s->buf_change) {
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ret = s->buf_change(dev, s, buf_size);
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if (ret < 0)
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return ret;
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}
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comedi_alloc_subdevice_minor(s);
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return 0;
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}
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static int __comedi_device_postconfig(struct comedi_device *dev)
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{
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struct comedi_subdevice *s;
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int ret;
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int i;
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for (i = 0; i < dev->n_subdevices; i++) {
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s = &dev->subdevices[i];
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if (s->type == COMEDI_SUBD_UNUSED)
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continue;
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if (s->len_chanlist == 0)
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s->len_chanlist = 1;
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if (s->do_cmd) {
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ret = __comedi_device_postconfig_async(dev, s);
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if (ret)
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return ret;
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}
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if (!s->range_table && !s->range_table_list)
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s->range_table = &range_unknown;
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if (!s->insn_read && s->insn_bits)
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s->insn_read = insn_rw_emulate_bits;
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if (!s->insn_write && s->insn_bits)
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s->insn_write = insn_rw_emulate_bits;
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if (!s->insn_read)
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s->insn_read = insn_inval;
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if (!s->insn_write)
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s->insn_write = insn_inval;
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if (!s->insn_bits)
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s->insn_bits = insn_inval;
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if (!s->insn_config)
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s->insn_config = insn_inval;
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if (!s->poll)
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s->poll = poll_invalid;
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}
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return 0;
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}
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/* do a little post-config cleanup */
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/* called with module refcount incremented, decrements it */
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static int comedi_device_postconfig(struct comedi_device *dev)
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{
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int ret = __comedi_device_postconfig(dev);
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module_put(dev->driver->module);
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if (ret < 0) {
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__comedi_device_detach(dev);
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return ret;
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}
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if (!dev->board_name) {
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dev_warn(dev->class_dev, "BUG: dev->board_name=NULL\n");
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dev->board_name = "BUG";
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}
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smp_wmb();
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dev->attached = 1;
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return 0;
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}
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/*
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* Generic recognize function for drivers that register their supported
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* board names.
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*
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* 'driv->board_name' points to a 'const char *' member within the
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* zeroth element of an array of some private board information
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* structure, say 'struct foo_board' containing a member 'const char
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* *board_name' that is initialized to point to a board name string that
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* is one of the candidates matched against this function's 'name'
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* parameter.
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*
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* 'driv->offset' is the size of the private board information
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* structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
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* the length of the array of private board information structures.
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*
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* If one of the board names in the array of private board information
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* structures matches the name supplied to this function, the function
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* returns a pointer to the pointer to the board name, otherwise it
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* returns NULL. The return value ends up in the 'board_ptr' member of
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* a 'struct comedi_device' that the low-level comedi driver's
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* 'attach()' hook can convert to a point to a particular element of its
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* array of private board information structures by subtracting the
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* offset of the member that points to the board name. (No subtraction
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* is required if the board name pointer is the first member of the
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* private board information structure, which is generally the case.)
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*/
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static void *comedi_recognize(struct comedi_driver *driv, const char *name)
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{
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char **name_ptr = (char **)driv->board_name;
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int i;
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for (i = 0; i < driv->num_names; i++) {
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if (strcmp(*name_ptr, name) == 0)
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return name_ptr;
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name_ptr = (void *)name_ptr + driv->offset;
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}
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return NULL;
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}
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static void comedi_report_boards(struct comedi_driver *driv)
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{
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unsigned int i;
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const char *const *name_ptr;
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pr_info("comedi: valid board names for %s driver are:\n",
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driv->driver_name);
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name_ptr = driv->board_name;
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for (i = 0; i < driv->num_names; i++) {
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pr_info(" %s\n", *name_ptr);
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name_ptr = (const char **)((char *)name_ptr + driv->offset);
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}
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if (driv->num_names == 0)
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pr_info(" %s\n", driv->driver_name);
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}
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int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
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{
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struct comedi_driver *driv;
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int ret;
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if (dev->attached)
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return -EBUSY;
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for (driv = comedi_drivers; driv; driv = driv->next) {
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if (!try_module_get(driv->module))
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continue;
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if (driv->num_names) {
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dev->board_ptr = comedi_recognize(driv, it->board_name);
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if (dev->board_ptr)
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break;
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} else if (strcmp(driv->driver_name, it->board_name) == 0)
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break;
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module_put(driv->module);
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}
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if (driv == NULL) {
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/* recognize has failed if we get here */
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/* report valid board names before returning error */
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for (driv = comedi_drivers; driv; driv = driv->next) {
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if (!try_module_get(driv->module))
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continue;
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comedi_report_boards(driv);
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module_put(driv->module);
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}
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return -EIO;
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}
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if (driv->attach == NULL) {
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/* driver does not support manual configuration */
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dev_warn(dev->class_dev,
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"driver '%s' does not support attach using comedi_config\n",
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driv->driver_name);
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module_put(driv->module);
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return -ENOSYS;
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}
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/* initialize dev->driver here so
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* comedi_error() can be called from attach */
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dev->driver = driv;
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ret = driv->attach(dev, it);
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if (ret < 0) {
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module_put(dev->driver->module);
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__comedi_device_detach(dev);
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return ret;
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}
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return comedi_device_postconfig(dev);
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}
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int comedi_auto_config(struct device *hardware_device,
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struct comedi_driver *driver, unsigned long context)
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{
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int minor;
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struct comedi_device *comedi_dev;
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int ret;
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if (!driver->auto_attach) {
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dev_warn(hardware_device,
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"BUG! comedi driver '%s' has no auto_attach handler\n",
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driver->driver_name);
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return -EINVAL;
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}
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minor = comedi_alloc_board_minor(hardware_device);
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if (minor < 0)
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return minor;
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comedi_dev = comedi_dev_from_minor(minor);
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mutex_lock(&comedi_dev->mutex);
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if (comedi_dev->attached)
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ret = -EBUSY;
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else if (!try_module_get(driver->module))
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ret = -EIO;
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else {
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comedi_set_hw_dev(comedi_dev, hardware_device);
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comedi_dev->driver = driver;
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ret = driver->auto_attach(comedi_dev, context);
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if (ret < 0) {
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module_put(driver->module);
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__comedi_device_detach(comedi_dev);
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} else {
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ret = comedi_device_postconfig(comedi_dev);
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}
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}
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mutex_unlock(&comedi_dev->mutex);
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if (ret < 0)
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comedi_free_board_minor(minor);
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return ret;
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}
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EXPORT_SYMBOL_GPL(comedi_auto_config);
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void comedi_auto_unconfig(struct device *hardware_device)
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{
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int minor;
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if (hardware_device == NULL)
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return;
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minor = comedi_find_board_minor(hardware_device);
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if (minor < 0)
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return;
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comedi_free_board_minor(minor);
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}
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EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
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int comedi_driver_register(struct comedi_driver *driver)
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{
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driver->next = comedi_drivers;
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comedi_drivers = driver;
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return 0;
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}
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EXPORT_SYMBOL(comedi_driver_register);
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int comedi_driver_unregister(struct comedi_driver *driver)
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{
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struct comedi_driver *prev;
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int i;
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/* check for devices using this driver */
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for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
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struct comedi_device *dev = comedi_dev_from_minor(i);
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if (!dev)
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continue;
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mutex_lock(&dev->mutex);
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if (dev->attached && dev->driver == driver) {
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if (dev->use_count)
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dev_warn(dev->class_dev,
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"BUG! detaching device with use_count=%d\n",
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dev->use_count);
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comedi_device_detach(dev);
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}
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mutex_unlock(&dev->mutex);
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}
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if (comedi_drivers == driver) {
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comedi_drivers = driver->next;
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return 0;
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}
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for (prev = comedi_drivers; prev->next; prev = prev->next) {
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if (prev->next == driver) {
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prev->next = driver->next;
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return 0;
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}
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}
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return -EINVAL;
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}
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EXPORT_SYMBOL(comedi_driver_unregister);
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