/* module/drivers.c functions for manipulating drivers COMEDI - Linux Control and Measurement Device Interface Copyright (C) 1997-2000 David A. Schleef Copyright (C) 2002 Frank Mori Hess This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include /* for SuSE brokenness */ #include #include #include #include #include #include #include "comedidev.h" #include "comedi_internal.h" struct comedi_driver *comedi_drivers; /* protects access to comedi_drivers */ DEFINE_MUTEX(comedi_drivers_list_lock); int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev) { if (hw_dev == dev->hw_dev) return 0; if (dev->hw_dev) return -EEXIST; dev->hw_dev = get_device(hw_dev); return 0; } EXPORT_SYMBOL_GPL(comedi_set_hw_dev); static void comedi_clear_hw_dev(struct comedi_device *dev) { put_device(dev->hw_dev); dev->hw_dev = NULL; } /** * comedi_alloc_devpriv() - Allocate memory for the device private data. * @dev: comedi_device struct * @size: size of the memory to allocate */ void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size) { dev->private = kzalloc(size, GFP_KERNEL); return dev->private; } EXPORT_SYMBOL_GPL(comedi_alloc_devpriv); int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices) { struct comedi_subdevice *s; int i; if (num_subdevices < 1) return -EINVAL; s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; dev->subdevices = s; dev->n_subdevices = num_subdevices; for (i = 0; i < num_subdevices; ++i) { s = &dev->subdevices[i]; s->device = dev; s->index = i; s->async_dma_dir = DMA_NONE; spin_lock_init(&s->spin_lock); s->minor = -1; } return 0; } EXPORT_SYMBOL_GPL(comedi_alloc_subdevices); /** * comedi_alloc_subdev_readback() - Allocate memory for the subdevice readback. * @s: comedi_subdevice struct */ int comedi_alloc_subdev_readback(struct comedi_subdevice *s) { if (!s->n_chan) return -EINVAL; s->readback = kcalloc(s->n_chan, sizeof(*s->readback), GFP_KERNEL); if (!s->readback) return -ENOMEM; if (!s->insn_read) s->insn_read = comedi_readback_insn_read; return 0; } EXPORT_SYMBOL_GPL(comedi_alloc_subdev_readback); static void comedi_device_detach_cleanup(struct comedi_device *dev) { int i; struct comedi_subdevice *s; if (dev->subdevices) { for (i = 0; i < dev->n_subdevices; i++) { s = &dev->subdevices[i]; if (s->runflags & COMEDI_SRF_FREE_SPRIV) kfree(s->private); comedi_free_subdevice_minor(s); if (s->async) { comedi_buf_alloc(dev, s, 0); kfree(s->async); } kfree(s->readback); } kfree(dev->subdevices); dev->subdevices = NULL; dev->n_subdevices = 0; } kfree(dev->private); kfree(dev->pacer); dev->private = NULL; dev->pacer = NULL; dev->driver = NULL; dev->board_name = NULL; dev->board_ptr = NULL; dev->mmio = NULL; dev->iobase = 0; dev->iolen = 0; dev->ioenabled = false; dev->irq = 0; dev->read_subdev = NULL; dev->write_subdev = NULL; dev->open = NULL; dev->close = NULL; comedi_clear_hw_dev(dev); } void comedi_device_detach(struct comedi_device *dev) { comedi_device_cancel_all(dev); down_write(&dev->attach_lock); dev->attached = false; dev->detach_count++; if (dev->driver) dev->driver->detach(dev); comedi_device_detach_cleanup(dev); up_write(&dev->attach_lock); } static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s) { return -EINVAL; } int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { return -EINVAL; } /** * comedi_readback_insn_read() - A generic (*insn_read) for subdevice readback. * @dev: comedi_device struct * @s: comedi_subdevice struct * @insn: comedi_insn struct * @data: pointer to return the readback data */ int comedi_readback_insn_read(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { unsigned int chan = CR_CHAN(insn->chanspec); int i; if (!s->readback) return -EINVAL; for (i = 0; i < insn->n; i++) data[i] = s->readback[chan]; return insn->n; } EXPORT_SYMBOL_GPL(comedi_readback_insn_read); /** * comedi_timeout() - busy-wait for a driver condition to occur. * @dev: comedi_device struct * @s: comedi_subdevice struct * @insn: comedi_insn struct * @cb: callback to check for the condition * @context: private context from the driver */ int comedi_timeout(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, int (*cb)(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned long context), unsigned long context) { unsigned long timeout = jiffies + msecs_to_jiffies(COMEDI_TIMEOUT_MS); int ret; while (time_before(jiffies, timeout)) { ret = cb(dev, s, insn, context); if (ret != -EBUSY) return ret; /* success (0) or non EBUSY errno */ cpu_relax(); } return -ETIMEDOUT; } EXPORT_SYMBOL_GPL(comedi_timeout); /** * comedi_dio_insn_config() - boilerplate (*insn_config) for DIO subdevices. * @dev: comedi_device struct * @s: comedi_subdevice struct * @insn: comedi_insn struct * @data: parameters for the @insn * @mask: io_bits mask for grouped channels */ int comedi_dio_insn_config(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data, unsigned int mask) { unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec); if (!mask) mask = chan_mask; switch (data[0]) { case INSN_CONFIG_DIO_INPUT: s->io_bits &= ~mask; break; case INSN_CONFIG_DIO_OUTPUT: s->io_bits |= mask; break; case INSN_CONFIG_DIO_QUERY: data[1] = (s->io_bits & mask) ? COMEDI_OUTPUT : COMEDI_INPUT; return insn->n; default: return -EINVAL; } return 0; } EXPORT_SYMBOL_GPL(comedi_dio_insn_config); /** * comedi_dio_update_state() - update the internal state of DIO subdevices. * @s: comedi_subdevice struct * @data: the channel mask and bits to update */ unsigned int comedi_dio_update_state(struct comedi_subdevice *s, unsigned int *data) { unsigned int chanmask = (s->n_chan < 32) ? ((1 << s->n_chan) - 1) : 0xffffffff; unsigned int mask = data[0] & chanmask; unsigned int bits = data[1]; if (mask) { s->state &= ~mask; s->state |= (bits & mask); } return mask; } EXPORT_SYMBOL_GPL(comedi_dio_update_state); /** * comedi_bytes_per_scan - get length of asynchronous command "scan" in bytes * @s: comedi_subdevice struct * * Determines the overall scan length according to the subdevice type and the * number of channels in the scan. * * For digital input, output or input/output subdevices, samples for multiple * channels are assumed to be packed into one or more unsigned short or * unsigned int values according to the subdevice's SDF_LSAMPL flag. For other * types of subdevice, samples are assumed to occupy a whole unsigned short or * unsigned int according to the SDF_LSAMPL flag. * * Returns the overall scan length in bytes. */ unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s) { struct comedi_cmd *cmd = &s->async->cmd; unsigned int num_samples; unsigned int bits_per_sample; switch (s->type) { case COMEDI_SUBD_DI: case COMEDI_SUBD_DO: case COMEDI_SUBD_DIO: bits_per_sample = 8 * comedi_bytes_per_sample(s); num_samples = DIV_ROUND_UP(cmd->scan_end_arg, bits_per_sample); break; default: num_samples = cmd->scan_end_arg; break; } return comedi_samples_to_bytes(s, num_samples); } EXPORT_SYMBOL_GPL(comedi_bytes_per_scan); /** * comedi_nscans_left - return the number of scans left in the command * @s: comedi_subdevice struct * @nscans: the expected number of scans * * If nscans is 0, the number of scans available in the async buffer will be * used. Otherwise the expected number of scans will be used. * * If the async command has a stop_src of TRIG_COUNT, the nscans will be * checked against the number of scans left in the command. * * The return value will then be either the expected number of scans or the * number of scans remaining in the command. */ unsigned int comedi_nscans_left(struct comedi_subdevice *s, unsigned int nscans) { struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; if (nscans == 0) { unsigned int nbytes = comedi_buf_read_n_available(s); nscans = nbytes / comedi_bytes_per_scan(s); } if (cmd->stop_src == TRIG_COUNT) { unsigned int scans_left = 0; if (async->scans_done < cmd->stop_arg) scans_left = cmd->stop_arg - async->scans_done; if (nscans > scans_left) nscans = scans_left; } return nscans; } EXPORT_SYMBOL_GPL(comedi_nscans_left); /** * comedi_nsamples_left - return the number of samples left in the command * @s: comedi_subdevice struct * @nsamples: the expected number of samples * * Returns the expected number of samples of the number of samples remaining * in the command. */ unsigned int comedi_nsamples_left(struct comedi_subdevice *s, unsigned int nsamples) { struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; if (cmd->stop_src == TRIG_COUNT) { /* +1 to force comedi_nscans_left() to return the scans left */ unsigned int nscans = (nsamples / cmd->scan_end_arg) + 1; unsigned int scans_left = comedi_nscans_left(s, nscans); unsigned int scan_pos = comedi_bytes_to_samples(s, async->scan_progress); unsigned long long samples_left = 0; if (scans_left) { samples_left = ((unsigned long long)scans_left * cmd->scan_end_arg) - scan_pos; } if (samples_left < nsamples) nsamples = samples_left; } return nsamples; } EXPORT_SYMBOL_GPL(comedi_nsamples_left); /** * comedi_inc_scan_progress - update scan progress in asynchronous command * @s: comedi_subdevice struct * @num_bytes: amount of data in bytes to increment scan progress * * Increments the scan progress by the number of bytes specified by num_bytes. * If the scan progress reaches or exceeds the scan length in bytes, reduce * it modulo the scan length in bytes and set the "end of scan" asynchronous * event flag to be processed later. */ void comedi_inc_scan_progress(struct comedi_subdevice *s, unsigned int num_bytes) { struct comedi_async *async = s->async; struct comedi_cmd *cmd = &async->cmd; unsigned int scan_length = comedi_bytes_per_scan(s); /* track the 'cur_chan' for non-SDF_PACKED subdevices */ if (!(s->subdev_flags & SDF_PACKED)) { async->cur_chan += comedi_bytes_to_samples(s, num_bytes); async->cur_chan %= cmd->chanlist_len; } async->scan_progress += num_bytes; if (async->scan_progress >= scan_length) { unsigned int nscans = async->scan_progress / scan_length; if (async->scans_done < (UINT_MAX - nscans)) async->scans_done += nscans; else async->scans_done = UINT_MAX; async->scan_progress %= scan_length; async->events |= COMEDI_CB_EOS; } } EXPORT_SYMBOL_GPL(comedi_inc_scan_progress); /** * comedi_handle_events - handle events and possibly stop acquisition * @dev: comedi_device struct * @s: comedi_subdevice struct * * Handles outstanding asynchronous acquisition event flags associated * with the subdevice. Call the subdevice's "->cancel()" handler if the * "end of acquisition", "error" or "overflow" event flags are set in order * to stop the acquisition at the driver level. * * Calls comedi_event() to further process the event flags, which may mark * the asynchronous command as no longer running, possibly terminated with * an error, and may wake up tasks. * * Return a bit-mask of the handled events. */ unsigned int comedi_handle_events(struct comedi_device *dev, struct comedi_subdevice *s) { unsigned int events = s->async->events; if (events == 0) return events; if (events & COMEDI_CB_CANCEL_MASK) s->cancel(dev, s); comedi_event(dev, s); return events; } EXPORT_SYMBOL_GPL(comedi_handle_events); static int insn_rw_emulate_bits(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { struct comedi_insn new_insn; int ret; static const unsigned channels_per_bitfield = 32; unsigned chan = CR_CHAN(insn->chanspec); const unsigned base_bitfield_channel = (chan < channels_per_bitfield) ? 0 : chan; unsigned int new_data[2]; memset(new_data, 0, sizeof(new_data)); memset(&new_insn, 0, sizeof(new_insn)); new_insn.insn = INSN_BITS; new_insn.chanspec = base_bitfield_channel; new_insn.n = 2; new_insn.subdev = insn->subdev; if (insn->insn == INSN_WRITE) { if (!(s->subdev_flags & SDF_WRITABLE)) return -EINVAL; new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */ new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel)) : 0; /* bits */ } ret = s->insn_bits(dev, s, &new_insn, new_data); if (ret < 0) return ret; if (insn->insn == INSN_READ) data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1; return 1; } static int __comedi_device_postconfig_async(struct comedi_device *dev, struct comedi_subdevice *s) { struct comedi_async *async; unsigned int buf_size; int ret; if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) { dev_warn(dev->class_dev, "async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n"); return -EINVAL; } if (!s->do_cmdtest) { dev_warn(dev->class_dev, "async subdevices must have a do_cmdtest() function\n"); return -EINVAL; } async = kzalloc(sizeof(*async), GFP_KERNEL); if (!async) return -ENOMEM; init_waitqueue_head(&async->wait_head); s->async = async; async->max_bufsize = comedi_default_buf_maxsize_kb * 1024; buf_size = comedi_default_buf_size_kb * 1024; if (buf_size > async->max_bufsize) buf_size = async->max_bufsize; if (comedi_buf_alloc(dev, s, buf_size) < 0) { dev_warn(dev->class_dev, "Buffer allocation failed\n"); return -ENOMEM; } if (s->buf_change) { ret = s->buf_change(dev, s); if (ret < 0) return ret; } comedi_alloc_subdevice_minor(s); return 0; } static int __comedi_device_postconfig(struct comedi_device *dev) { struct comedi_subdevice *s; int ret; int i; for (i = 0; i < dev->n_subdevices; i++) { s = &dev->subdevices[i]; if (s->type == COMEDI_SUBD_UNUSED) continue; if (s->type == COMEDI_SUBD_DO) { if (s->n_chan < 32) s->io_bits = (1 << s->n_chan) - 1; else s->io_bits = 0xffffffff; } if (s->len_chanlist == 0) s->len_chanlist = 1; if (s->do_cmd) { ret = __comedi_device_postconfig_async(dev, s); if (ret) return ret; } if (!s->range_table && !s->range_table_list) s->range_table = &range_unknown; if (!s->insn_read && s->insn_bits) s->insn_read = insn_rw_emulate_bits; if (!s->insn_write && s->insn_bits) s->insn_write = insn_rw_emulate_bits; if (!s->insn_read) s->insn_read = insn_inval; if (!s->insn_write) s->insn_write = insn_inval; if (!s->insn_bits) s->insn_bits = insn_inval; if (!s->insn_config) s->insn_config = insn_inval; if (!s->poll) s->poll = poll_invalid; } return 0; } /* do a little post-config cleanup */ static int comedi_device_postconfig(struct comedi_device *dev) { int ret; ret = __comedi_device_postconfig(dev); if (ret < 0) return ret; down_write(&dev->attach_lock); dev->attached = true; up_write(&dev->attach_lock); return 0; } /* * Generic recognize function for drivers that register their supported * board names. * * 'driv->board_name' points to a 'const char *' member within the * zeroth element of an array of some private board information * structure, say 'struct foo_board' containing a member 'const char * *board_name' that is initialized to point to a board name string that * is one of the candidates matched against this function's 'name' * parameter. * * 'driv->offset' is the size of the private board information * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is * the length of the array of private board information structures. * * If one of the board names in the array of private board information * structures matches the name supplied to this function, the function * returns a pointer to the pointer to the board name, otherwise it * returns NULL. The return value ends up in the 'board_ptr' member of * a 'struct comedi_device' that the low-level comedi driver's * 'attach()' hook can convert to a point to a particular element of its * array of private board information structures by subtracting the * offset of the member that points to the board name. (No subtraction * is required if the board name pointer is the first member of the * private board information structure, which is generally the case.) */ static void *comedi_recognize(struct comedi_driver *driv, const char *name) { char **name_ptr = (char **)driv->board_name; int i; for (i = 0; i < driv->num_names; i++) { if (strcmp(*name_ptr, name) == 0) return name_ptr; name_ptr = (void *)name_ptr + driv->offset; } return NULL; } static void comedi_report_boards(struct comedi_driver *driv) { unsigned int i; const char *const *name_ptr; pr_info("comedi: valid board names for %s driver are:\n", driv->driver_name); name_ptr = driv->board_name; for (i = 0; i < driv->num_names; i++) { pr_info(" %s\n", *name_ptr); name_ptr = (const char **)((char *)name_ptr + driv->offset); } if (driv->num_names == 0) pr_info(" %s\n", driv->driver_name); } /** * comedi_load_firmware() - Request and load firmware for a device. * @dev: comedi_device struct * @hw_device: device struct for the comedi_device * @name: the name of the firmware image * @cb: callback to the upload the firmware image * @context: private context from the driver */ int comedi_load_firmware(struct comedi_device *dev, struct device *device, const char *name, int (*cb)(struct comedi_device *dev, const u8 *data, size_t size, unsigned long context), unsigned long context) { const struct firmware *fw; int ret; if (!cb) return -EINVAL; ret = request_firmware(&fw, name, device); if (ret == 0) { ret = cb(dev, fw->data, fw->size, context); release_firmware(fw); } return ret < 0 ? ret : 0; } EXPORT_SYMBOL_GPL(comedi_load_firmware); /** * __comedi_request_region() - Request an I/O reqion for a legacy driver. * @dev: comedi_device struct * @start: base address of the I/O reqion * @len: length of the I/O region */ int __comedi_request_region(struct comedi_device *dev, unsigned long start, unsigned long len) { if (!start) { dev_warn(dev->class_dev, "%s: a I/O base address must be specified\n", dev->board_name); return -EINVAL; } if (!request_region(start, len, dev->board_name)) { dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n", dev->board_name, start, len); return -EIO; } return 0; } EXPORT_SYMBOL_GPL(__comedi_request_region); /** * comedi_request_region() - Request an I/O reqion for a legacy driver. * @dev: comedi_device struct * @start: base address of the I/O reqion * @len: length of the I/O region */ int comedi_request_region(struct comedi_device *dev, unsigned long start, unsigned long len) { int ret; ret = __comedi_request_region(dev, start, len); if (ret == 0) { dev->iobase = start; dev->iolen = len; } return ret; } EXPORT_SYMBOL_GPL(comedi_request_region); /** * comedi_legacy_detach() - A generic (*detach) function for legacy drivers. * @dev: comedi_device struct */ void comedi_legacy_detach(struct comedi_device *dev) { if (dev->irq) { free_irq(dev->irq, dev); dev->irq = 0; } if (dev->iobase && dev->iolen) { release_region(dev->iobase, dev->iolen); dev->iobase = 0; dev->iolen = 0; } } EXPORT_SYMBOL_GPL(comedi_legacy_detach); int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it) { struct comedi_driver *driv; int ret; if (dev->attached) return -EBUSY; mutex_lock(&comedi_drivers_list_lock); for (driv = comedi_drivers; driv; driv = driv->next) { if (!try_module_get(driv->module)) continue; if (driv->num_names) { dev->board_ptr = comedi_recognize(driv, it->board_name); if (dev->board_ptr) break; } else if (strcmp(driv->driver_name, it->board_name) == 0) { break; } module_put(driv->module); } if (!driv) { /* recognize has failed if we get here */ /* report valid board names before returning error */ for (driv = comedi_drivers; driv; driv = driv->next) { if (!try_module_get(driv->module)) continue; comedi_report_boards(driv); module_put(driv->module); } ret = -EIO; goto out; } if (!driv->attach) { /* driver does not support manual configuration */ dev_warn(dev->class_dev, "driver '%s' does not support attach using comedi_config\n", driv->driver_name); module_put(driv->module); ret = -ENOSYS; goto out; } dev->driver = driv; dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr : dev->driver->driver_name; ret = driv->attach(dev, it); if (ret >= 0) ret = comedi_device_postconfig(dev); if (ret < 0) { comedi_device_detach(dev); module_put(driv->module); } /* On success, the driver module count has been incremented. */ out: mutex_unlock(&comedi_drivers_list_lock); return ret; } int comedi_auto_config(struct device *hardware_device, struct comedi_driver *driver, unsigned long context) { struct comedi_device *dev; int ret; if (!hardware_device) { pr_warn("BUG! comedi_auto_config called with NULL hardware_device\n"); return -EINVAL; } if (!driver) { dev_warn(hardware_device, "BUG! comedi_auto_config called with NULL comedi driver\n"); return -EINVAL; } if (!driver->auto_attach) { dev_warn(hardware_device, "BUG! comedi driver '%s' has no auto_attach handler\n", driver->driver_name); return -EINVAL; } dev = comedi_alloc_board_minor(hardware_device); if (IS_ERR(dev)) { dev_warn(hardware_device, "driver '%s' could not create device.\n", driver->driver_name); return PTR_ERR(dev); } /* Note: comedi_alloc_board_minor() locked dev->mutex. */ dev->driver = driver; dev->board_name = dev->driver->driver_name; ret = driver->auto_attach(dev, context); if (ret >= 0) ret = comedi_device_postconfig(dev); mutex_unlock(&dev->mutex); if (ret < 0) { dev_warn(hardware_device, "driver '%s' failed to auto-configure device.\n", driver->driver_name); comedi_release_hardware_device(hardware_device); } else { /* * class_dev should be set properly here * after a successful auto config */ dev_info(dev->class_dev, "driver '%s' has successfully auto-configured '%s'.\n", driver->driver_name, dev->board_name); } return ret; } EXPORT_SYMBOL_GPL(comedi_auto_config); void comedi_auto_unconfig(struct device *hardware_device) { if (!hardware_device) return; comedi_release_hardware_device(hardware_device); } EXPORT_SYMBOL_GPL(comedi_auto_unconfig); int comedi_driver_register(struct comedi_driver *driver) { mutex_lock(&comedi_drivers_list_lock); driver->next = comedi_drivers; comedi_drivers = driver; mutex_unlock(&comedi_drivers_list_lock); return 0; } EXPORT_SYMBOL_GPL(comedi_driver_register); void comedi_driver_unregister(struct comedi_driver *driver) { struct comedi_driver *prev; int i; /* unlink the driver */ mutex_lock(&comedi_drivers_list_lock); if (comedi_drivers == driver) { comedi_drivers = driver->next; } else { for (prev = comedi_drivers; prev->next; prev = prev->next) { if (prev->next == driver) { prev->next = driver->next; break; } } } mutex_unlock(&comedi_drivers_list_lock); /* check for devices using this driver */ for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) { struct comedi_device *dev = comedi_dev_get_from_minor(i); if (!dev) continue; mutex_lock(&dev->mutex); if (dev->attached && dev->driver == driver) { if (dev->use_count) dev_warn(dev->class_dev, "BUG! detaching device with use_count=%d\n", dev->use_count); comedi_device_detach(dev); } mutex_unlock(&dev->mutex); comedi_dev_put(dev); } } EXPORT_SYMBOL_GPL(comedi_driver_unregister);