diff options
Diffstat (limited to 'drivers/comedi/drivers/8255.c')
| -rw-r--r-- | drivers/comedi/drivers/8255.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/drivers/comedi/drivers/8255.c b/drivers/comedi/drivers/8255.c new file mode 100644 index 000000000..ced8ea09d --- /dev/null +++ b/drivers/comedi/drivers/8255.c @@ -0,0 +1,124 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * comedi/drivers/8255.c + * Driver for 8255 + * + * COMEDI - Linux Control and Measurement Device Interface + * Copyright (C) 1998 David A. Schleef <ds@schleef.org> + */ + +/* + * Driver: 8255 + * Description: generic 8255 support + * Devices: [standard] 8255 (8255) + * Author: ds + * Status: works + * Updated: Fri, 7 Jun 2002 12:56:45 -0700 + * + * The classic in digital I/O. The 8255 appears in Comedi as a single + * digital I/O subdevice with 24 channels. The channel 0 corresponds + * to the 8255's port A, bit 0; channel 23 corresponds to port C, bit + * 7. Direction configuration is done in blocks, with channels 0-7, + * 8-15, 16-19, and 20-23 making up the 4 blocks. The only 8255 mode + * supported is mode 0. + * + * You should enable compilation this driver if you plan to use a board + * that has an 8255 chip. For multifunction boards, the main driver will + * configure the 8255 subdevice automatically. + * + * This driver also works independently with ISA and PCI cards that + * directly map the 8255 registers to I/O ports, including cards with + * multiple 8255 chips. To configure the driver for such a card, the + * option list should be a list of the I/O port bases for each of the + * 8255 chips. For example, + * + * comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c + * + * Note that most PCI 8255 boards do NOT work with this driver, and + * need a separate driver as a wrapper. For those that do work, the + * I/O port base address can be found in the output of 'lspci -v'. + */ + +#include <linux/module.h> +#include <linux/comedi/comedidev.h> +#include <linux/comedi/comedi_8255.h> + +static int dev_8255_attach(struct comedi_device *dev, + struct comedi_devconfig *it) +{ + struct comedi_subdevice *s; + unsigned long iobase; + int ret; + int i; + + for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) { + iobase = it->options[i]; + if (!iobase) + break; + } + if (i == 0) { + dev_warn(dev->class_dev, "no devices specified\n"); + return -EINVAL; + } + + ret = comedi_alloc_subdevices(dev, i); + if (ret) + return ret; + + for (i = 0; i < dev->n_subdevices; i++) { + s = &dev->subdevices[i]; + iobase = it->options[i]; + + /* + * __comedi_request_region() does not set dev->iobase. + * + * For 8255 devices that are manually attached using + * comedi_config, the 'iobase' is the actual I/O port + * base address of the chip. + */ + ret = __comedi_request_region(dev, iobase, I8255_SIZE); + if (ret) { + s->type = COMEDI_SUBD_UNUSED; + } else { + ret = subdev_8255_init(dev, s, NULL, iobase); + if (ret) { + /* + * Release the I/O port region here, as the + * "detach" handler cannot find it. + */ + release_region(iobase, I8255_SIZE); + s->type = COMEDI_SUBD_UNUSED; + return ret; + } + } + } + + return 0; +} + +static void dev_8255_detach(struct comedi_device *dev) +{ + struct comedi_subdevice *s; + int i; + + for (i = 0; i < dev->n_subdevices; i++) { + s = &dev->subdevices[i]; + if (s->type != COMEDI_SUBD_UNUSED) { + unsigned long regbase = subdev_8255_regbase(s); + + release_region(regbase, I8255_SIZE); + } + } +} + +static struct comedi_driver dev_8255_driver = { + .driver_name = "8255", + .module = THIS_MODULE, + .attach = dev_8255_attach, + .detach = dev_8255_detach, +}; +module_comedi_driver(dev_8255_driver); + +MODULE_AUTHOR("Comedi https://www.comedi.org"); +MODULE_DESCRIPTION("Comedi driver for standalone 8255 devices"); +MODULE_LICENSE("GPL"); |