diff options
Diffstat (limited to 'drivers/staging/comedi/drivers/8255.c')
| -rw-r--r-- | drivers/staging/comedi/drivers/8255.c | 174 |
1 files changed, 101 insertions, 73 deletions
diff --git a/drivers/staging/comedi/drivers/8255.c b/drivers/staging/comedi/drivers/8255.c index 34d4d8b5f31e..c2f15de6a547 100644 --- a/drivers/staging/comedi/drivers/8255.c +++ b/drivers/staging/comedi/drivers/8255.c @@ -1,76 +1,51 @@ /* - comedi/drivers/8255.c - Driver for 8255 - - COMEDI - Linux Control and Measurement Device Interface - Copyright (C) 1998 David A. Schleef <ds@schleef.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. -*/ -/* -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'. - -*/ + * comedi/drivers/8255.c + * Driver for 8255 + * + * COMEDI - Linux Control and Measurement Device Interface + * Copyright (C) 1998 David A. Schleef <ds@schleef.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. + */ /* - This file contains an exported subdevice for driving an 8255. - - To use this subdevice as part of another driver, you need to - set up the subdevice in the attach function of the driver by - calling: - - subdev_8255_init(device, subdevice, io_function, iobase) - - device and subdevice are pointers to the device and subdevice - structures. io_function will be called to provide the - low-level input/output to the device, i.e., actual register - access. io_function will be called with the value of iobase - as the last parameter. If the 8255 device is mapped as 4 - consecutive I/O ports, you can use NULL for io_function - and the I/O port base for iobase, and an internal function will - handle the register access. - - In addition, if the main driver handles interrupts, you can - enable commands on the subdevice by calling subdev_8255_init_irq() - instead. Then, when you get an interrupt that is likely to be - from the 8255, you should call subdev_8255_interrupt(), which - will copy the latched value to a Comedi buffer. + * 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> @@ -218,6 +193,33 @@ static int __subdev_8255_init(struct comedi_device *dev, return 0; } +/** + * subdev_8255_init - initialize DIO subdevice for driving I/O mapped 8255 + * @dev: comedi device owning subdevice + * @s: comedi subdevice to initialize + * @io: (optional) register I/O call-back function + * @regbase: offset of 8255 registers from dev->iobase, or call-back context + * + * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. + * + * If the optional I/O call-back function is provided, its prototype is of + * the following form: + * + * int my_8255_callback(struct comedi_device *dev, + * struct comedi_subdevice *s, int dir, int port, + * int data, unsigned long regbase); + * + * where 'dev', 's', and 'regbase' match the values passed to this function, + * 'port' is the 8255 port number 0 to 3 (including the control port), 'dir' + * is the direction (0 for read, 1 for write) and 'data' is the value to be + * written. It should return 0 if writing or the value read if reading. + * + * If the optional I/O call-back function is not provided, an internal + * call-back function is used which uses consecutive I/O port addresses + * starting at dev->iobase + regbase. + * + * Return: -ENOMEM if failed to allocate memory, zero on success. + */ int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s, int (*io)(struct comedi_device *, int, int, int, unsigned long), @@ -227,6 +229,33 @@ int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s, } EXPORT_SYMBOL_GPL(subdev_8255_init); +/** + * subdev_8255_mm_init - initialize DIO subdevice for driving mmio-mapped 8255 + * @dev: comedi device owning subdevice + * @s: comedi subdevice to initialize + * @io: (optional) register I/O call-back function + * @regbase: offset of 8255 registers from dev->mmio, or call-back context + * + * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. + * + * If the optional I/O call-back function is provided, its prototype is of + * the following form: + * + * int my_8255_callback(struct comedi_device *dev, + * struct comedi_subdevice *s, int dir, int port, + * int data, unsigned long regbase); + * + * where 'dev', 's', and 'regbase' match the values passed to this function, + * 'port' is the 8255 port number 0 to 3 (including the control port), 'dir' + * is the direction (0 for read, 1 for write) and 'data' is the value to be + * written. It should return 0 if writing or the value read if reading. + * + * If the optional I/O call-back function is not provided, an internal + * call-back function is used which uses consecutive MMIO virtual addresses + * starting at dev->mmio + regbase. + * + * Return: -ENOMEM if failed to allocate memory, zero on success. + */ int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s, int (*io)(struct comedi_device *, int, int, int, unsigned long), @@ -235,10 +264,9 @@ int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s, return __subdev_8255_init(dev, s, io, regbase, true); } EXPORT_SYMBOL_GPL(subdev_8255_mm_init); -/* - - Start of the 8255 standalone device +/* + * Start of the 8255 standalone device */ static int dev_8255_attach(struct comedi_device *dev, |