| /* |
| comedi/drivers/comedi_bond.c |
| A Comedi driver to 'bond' or merge multiple drivers and devices as one. |
| |
| COMEDI - Linux Control and Measurement Device Interface |
| Copyright (C) 2000 David A. Schleef <ds@schleef.org> |
| Copyright (C) 2005 Calin A. Culianu <calin@ajvar.org> |
| |
| 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. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| |
| */ |
| /* |
| Driver: comedi_bond |
| Description: A driver to 'bond' (merge) multiple subdevices from multiple |
| devices together as one. |
| Devices: |
| Author: ds |
| Updated: Mon, 10 Oct 00:18:25 -0500 |
| Status: works |
| |
| This driver allows you to 'bond' (merge) multiple comedi subdevices |
| (coming from possibly difference boards and/or drivers) together. For |
| example, if you had a board with 2 different DIO subdevices, and |
| another with 1 DIO subdevice, you could 'bond' them with this driver |
| so that they look like one big fat DIO subdevice. This makes writing |
| applications slightly easier as you don't have to worry about managing |
| different subdevices in the application -- you just worry about |
| indexing one linear array of channel id's. |
| |
| Right now only DIO subdevices are supported as that's the personal itch |
| I am scratching with this driver. If you want to add support for AI and AO |
| subdevs, go right on ahead and do so! |
| |
| Commands aren't supported -- although it would be cool if they were. |
| |
| Configuration Options: |
| List of comedi-minors to bond. All subdevices of the same type |
| within each minor will be concatenated together in the order given here. |
| */ |
| |
| #include <linux/string.h> |
| #include <linux/slab.h> |
| #include "../comedi.h" |
| #include "../comedilib.h" |
| #include "../comedidev.h" |
| |
| /* The maxiumum number of channels per subdevice. */ |
| #define MAX_CHANS 256 |
| |
| struct BondedDevice { |
| struct comedi_device *dev; |
| unsigned minor; |
| unsigned subdev; |
| unsigned subdev_type; |
| unsigned nchans; |
| unsigned chanid_offset; /* The offset into our unified linear |
| channel-id's of chanid 0 on this |
| subdevice. */ |
| }; |
| |
| /* this structure is for data unique to this hardware driver. If |
| several hardware drivers keep similar information in this structure, |
| feel free to suggest moving the variable to the struct comedi_device struct. */ |
| struct comedi_bond_private { |
| # define MAX_BOARD_NAME 256 |
| char name[MAX_BOARD_NAME]; |
| struct BondedDevice **devs; |
| unsigned ndevs; |
| struct BondedDevice *chanIdDevMap[MAX_CHANS]; |
| unsigned nchans; |
| }; |
| |
| /* DIO devices are slightly special. Although it is possible to |
| * implement the insn_read/insn_write interface, it is much more |
| * useful to applications if you implement the insn_bits interface. |
| * This allows packed reading/writing of the DIO channels. The |
| * comedi core can convert between insn_bits and insn_read/write */ |
| static int bonding_dio_insn_bits(struct comedi_device *dev, |
| struct comedi_subdevice *s, |
| struct comedi_insn *insn, unsigned int *data) |
| { |
| struct comedi_bond_private *devpriv = dev->private; |
| #define LSAMPL_BITS (sizeof(unsigned int)*8) |
| unsigned nchans = LSAMPL_BITS, num_done = 0, i; |
| |
| if (devpriv->nchans < nchans) |
| nchans = devpriv->nchans; |
| |
| /* The insn data is a mask in data[0] and the new data |
| * in data[1], each channel cooresponding to a bit. */ |
| for (i = 0; num_done < nchans && i < devpriv->ndevs; ++i) { |
| struct BondedDevice *bdev = devpriv->devs[i]; |
| /* Grab the channel mask and data of only the bits corresponding |
| to this subdevice.. need to shift them to zero position of |
| course. */ |
| /* Bits corresponding to this subdev. */ |
| unsigned int subdevMask = ((1 << bdev->nchans) - 1); |
| unsigned int writeMask, dataBits; |
| |
| /* Argh, we have >= LSAMPL_BITS chans.. take all bits */ |
| if (bdev->nchans >= LSAMPL_BITS) |
| subdevMask = (unsigned int)(-1); |
| |
| writeMask = (data[0] >> num_done) & subdevMask; |
| dataBits = (data[1] >> num_done) & subdevMask; |
| |
| /* Read/Write the new digital lines */ |
| if (comedi_dio_bitfield(bdev->dev, bdev->subdev, writeMask, |
| &dataBits) != 2) |
| return -EINVAL; |
| |
| /* Make room for the new bits in data[1], the return value */ |
| data[1] &= ~(subdevMask << num_done); |
| /* Put the bits in the return value */ |
| data[1] |= (dataBits & subdevMask) << num_done; |
| /* Save the new bits to the saved state.. */ |
| s->state = data[1]; |
| |
| num_done += bdev->nchans; |
| } |
| |
| return insn->n; |
| } |
| |
| static int bonding_dio_insn_config(struct comedi_device *dev, |
| struct comedi_subdevice *s, |
| struct comedi_insn *insn, unsigned int *data) |
| { |
| struct comedi_bond_private *devpriv = dev->private; |
| int chan = CR_CHAN(insn->chanspec), ret, io_bits = s->io_bits; |
| unsigned int io; |
| struct BondedDevice *bdev; |
| |
| if (chan < 0 || chan >= devpriv->nchans) |
| return -EINVAL; |
| bdev = devpriv->chanIdDevMap[chan]; |
| |
| /* The input or output configuration of each digital line is |
| * configured by a special insn_config instruction. chanspec |
| * contains the channel to be changed, and data[0] contains the |
| * value COMEDI_INPUT or COMEDI_OUTPUT. */ |
| switch (data[0]) { |
| case INSN_CONFIG_DIO_OUTPUT: |
| io = COMEDI_OUTPUT; /* is this really necessary? */ |
| io_bits |= 1 << chan; |
| break; |
| case INSN_CONFIG_DIO_INPUT: |
| io = COMEDI_INPUT; /* is this really necessary? */ |
| io_bits &= ~(1 << chan); |
| break; |
| case INSN_CONFIG_DIO_QUERY: |
| data[1] = |
| (io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT; |
| return insn->n; |
| break; |
| default: |
| return -EINVAL; |
| break; |
| } |
| /* 'real' channel id for this subdev.. */ |
| chan -= bdev->chanid_offset; |
| ret = comedi_dio_config(bdev->dev, bdev->subdev, chan, io); |
| if (ret != 1) |
| return -EINVAL; |
| /* Finally, save the new io_bits values since we didn't get |
| an error above. */ |
| s->io_bits = io_bits; |
| return insn->n; |
| } |
| |
| static void *Realloc(const void *oldmem, size_t newlen, size_t oldlen) |
| { |
| void *newmem = kmalloc(newlen, GFP_KERNEL); |
| |
| if (newmem && oldmem) |
| memcpy(newmem, oldmem, min(oldlen, newlen)); |
| kfree(oldmem); |
| return newmem; |
| } |
| |
| static int doDevConfig(struct comedi_device *dev, struct comedi_devconfig *it) |
| { |
| struct comedi_bond_private *devpriv = dev->private; |
| int i; |
| struct comedi_device *devs_opened[COMEDI_NUM_BOARD_MINORS]; |
| |
| memset(devs_opened, 0, sizeof(devs_opened)); |
| devpriv->name[0] = 0; |
| /* Loop through all comedi devices specified on the command-line, |
| building our device list */ |
| for (i = 0; i < COMEDI_NDEVCONFOPTS && (!i || it->options[i]); ++i) { |
| char file[] = "/dev/comediXXXXXX"; |
| int minor = it->options[i]; |
| struct comedi_device *d; |
| int sdev = -1, nchans, tmp; |
| struct BondedDevice *bdev = NULL; |
| |
| if (minor < 0 || minor >= COMEDI_NUM_BOARD_MINORS) { |
| dev_err(dev->class_dev, |
| "Minor %d is invalid!\n", minor); |
| return 0; |
| } |
| if (minor == dev->minor) { |
| dev_err(dev->class_dev, |
| "Cannot bond this driver to itself!\n"); |
| return 0; |
| } |
| if (devs_opened[minor]) { |
| dev_err(dev->class_dev, |
| "Minor %d specified more than once!\n", minor); |
| return 0; |
| } |
| |
| snprintf(file, sizeof(file), "/dev/comedi%u", minor); |
| file[sizeof(file) - 1] = 0; |
| |
| d = devs_opened[minor] = comedi_open(file); |
| |
| if (!d) { |
| dev_err(dev->class_dev, |
| "Minor %u could not be opened\n", minor); |
| return 0; |
| } |
| |
| /* Do DIO, as that's all we support now.. */ |
| while ((sdev = comedi_find_subdevice_by_type(d, COMEDI_SUBD_DIO, |
| sdev + 1)) > -1) { |
| nchans = comedi_get_n_channels(d, sdev); |
| if (nchans <= 0) { |
| dev_err(dev->class_dev, |
| "comedi_get_n_channels() returned %d on minor %u subdev %d!\n", |
| nchans, minor, sdev); |
| return 0; |
| } |
| bdev = kmalloc(sizeof(*bdev), GFP_KERNEL); |
| if (!bdev) |
| return 0; |
| |
| bdev->dev = d; |
| bdev->minor = minor; |
| bdev->subdev = sdev; |
| bdev->subdev_type = COMEDI_SUBD_DIO; |
| bdev->nchans = nchans; |
| bdev->chanid_offset = devpriv->nchans; |
| |
| /* map channel id's to BondedDevice * pointer.. */ |
| while (nchans--) |
| devpriv->chanIdDevMap[devpriv->nchans++] = bdev; |
| |
| /* Now put bdev pointer at end of devpriv->devs array |
| * list.. */ |
| |
| /* ergh.. ugly.. we need to realloc :( */ |
| tmp = devpriv->ndevs * sizeof(bdev); |
| devpriv->devs = |
| Realloc(devpriv->devs, |
| ++devpriv->ndevs * sizeof(bdev), tmp); |
| if (!devpriv->devs) { |
| dev_err(dev->class_dev, |
| "Could not allocate memory. Out of memory?\n"); |
| return 0; |
| } |
| |
| devpriv->devs[devpriv->ndevs - 1] = bdev; |
| { |
| /** Append dev:subdev to devpriv->name */ |
| char buf[20]; |
| int left = |
| MAX_BOARD_NAME - strlen(devpriv->name) - 1; |
| snprintf(buf, sizeof(buf), "%d:%d ", dev->minor, |
| bdev->subdev); |
| buf[sizeof(buf) - 1] = 0; |
| strncat(devpriv->name, buf, left); |
| } |
| |
| } |
| } |
| |
| if (!devpriv->nchans) { |
| dev_err(dev->class_dev, "No channels found!\n"); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static int bonding_attach(struct comedi_device *dev, |
| struct comedi_devconfig *it) |
| { |
| struct comedi_bond_private *devpriv; |
| struct comedi_subdevice *s; |
| int ret; |
| |
| devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL); |
| if (!devpriv) |
| return -ENOMEM; |
| dev->private = devpriv; |
| |
| /* |
| * Setup our bonding from config params.. sets up our private struct.. |
| */ |
| if (!doDevConfig(dev, it)) |
| return -EINVAL; |
| |
| dev->board_name = devpriv->name; |
| |
| ret = comedi_alloc_subdevices(dev, 1); |
| if (ret) |
| return ret; |
| |
| s = &dev->subdevices[0]; |
| s->type = COMEDI_SUBD_DIO; |
| s->subdev_flags = SDF_READABLE | SDF_WRITABLE; |
| s->n_chan = devpriv->nchans; |
| s->maxdata = 1; |
| s->range_table = &range_digital; |
| s->insn_bits = bonding_dio_insn_bits; |
| s->insn_config = bonding_dio_insn_config; |
| |
| dev_info(dev->class_dev, |
| "%s: %s attached, %u channels from %u devices\n", |
| dev->driver->driver_name, dev->board_name, |
| devpriv->nchans, devpriv->ndevs); |
| |
| return 1; |
| } |
| |
| static void bonding_detach(struct comedi_device *dev) |
| { |
| struct comedi_bond_private *devpriv = dev->private; |
| unsigned long devs_closed = 0; |
| |
| if (devpriv) { |
| while (devpriv->ndevs-- && devpriv->devs) { |
| struct BondedDevice *bdev; |
| |
| bdev = devpriv->devs[devpriv->ndevs]; |
| if (!bdev) |
| continue; |
| if (!(devs_closed & (0x1 << bdev->minor))) { |
| comedi_close(bdev->dev); |
| devs_closed |= (0x1 << bdev->minor); |
| } |
| kfree(bdev); |
| } |
| kfree(devpriv->devs); |
| devpriv->devs = NULL; |
| kfree(devpriv); |
| dev->private = NULL; |
| } |
| } |
| |
| static struct comedi_driver bonding_driver = { |
| .driver_name = "comedi_bond", |
| .module = THIS_MODULE, |
| .attach = bonding_attach, |
| .detach = bonding_detach, |
| }; |
| module_comedi_driver(bonding_driver); |
| |
| MODULE_AUTHOR("Calin A. Culianu"); |
| MODULE_DESCRIPTION("comedi_bond: A driver for COMEDI to bond multiple COMEDI " |
| "devices together as one. In the words of John Lennon: " |
| "'And the world will live as one...'"); |
| MODULE_LICENSE("GPL"); |