+++ /dev/null
-About the PCF8575 chip and the pcf8575 kernel driver
-====================================================
-
-The PCF8575 chip is produced by the following manufacturers:
-
- * Philips NXP
- http://www.nxp.com/#/pip/cb=[type=product,path=50807/41735/41850,final=PCF8575_3]|pip=[pip=PCF8575_3][0]
-
- * Texas Instruments
- http://focus.ti.com/docs/prod/folders/print/pcf8575.html
-
-
-Some vendors sell small PCB's with the PCF8575 mounted on it. You can connect
-such a board to a Linux host via e.g. an USB to I2C interface. Examples of
-PCB boards with a PCF8575:
-
- * SFE Breakout Board for PCF8575 I2C Expander by RobotShop
- http://www.robotshop.ca/home/products/robot-parts/electronics/adapters-converters/sfe-pcf8575-i2c-expander-board.html
-
- * Breakout Board for PCF8575 I2C Expander by Spark Fun Electronics
- http://www.sparkfun.com/commerce/product_info.php?products_id=8130
-
-
-Description
------------
-The PCF8575 chip is a 16-bit I/O expander for the I2C bus. Up to eight of
-these chips can be connected to the same I2C bus. You can find this
-chip on some custom designed hardware, but you won't find it on PC
-motherboards.
-
-The PCF8575 chip consists of a 16-bit quasi-bidirectional port and an I2C-bus
-interface. Each of the sixteen I/O's can be independently used as an input or
-an output. To set up an I/O pin as an input, you have to write a 1 to the
-corresponding output.
-
-For more information please see the datasheet.
-
-
-Detection
----------
-
-There is no method known to detect whether a chip on a given I2C address is
-a PCF8575 or whether it is any other I2C device, so you have to pass the I2C
-bus and address of the installed PCF8575 devices explicitly to the driver at
-load time via the force=... parameter.
-
-/sys interface
---------------
-
-For each address on which a PCF8575 chip was found or forced the following
-files will be created under /sys:
-* /sys/bus/i2c/devices/<bus>-<address>/read
-* /sys/bus/i2c/devices/<bus>-<address>/write
-where bus is the I2C bus number (0, 1, ...) and address is the four-digit
-hexadecimal representation of the 7-bit I2C address of the PCF8575
-(0020 .. 0027).
-
-The read file is read-only. Reading it will trigger an I2C read and will hence
-report the current input state for the pins configured as inputs, and the
-current output value for the pins configured as outputs.
-
-The write file is read-write. Writing a value to it will configure all pins
-as output for which the corresponding bit is zero. Reading the write file will
-return the value last written, or -EAGAIN if no value has yet been written to
-the write file.
-
-On module initialization the configuration of the chip is not changed -- the
-chip is left in the state it was already configured in through either power-up
-or through previous I2C write actions.
+++ /dev/null
-/*
- pcf8575.c
-
- About the PCF8575 chip: the PCF8575 is a 16-bit I/O expander for the I2C bus
- produced by a.o. Philips Semiconductors.
-
- Copyright (C) 2006 Michael Hennerich, Analog Devices Inc.
- <hennerich@blackfin.uclinux.org>
- Based on pcf8574.c.
-
- Copyright (c) 2007 Bart Van Assche <bart.vanassche@gmail.com>.
- Ported this driver from ucLinux to the mainstream Linux kernel.
-
- 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.
-*/
-
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/i2c.h>
-#include <linux/slab.h> /* kzalloc() */
-#include <linux/sysfs.h> /* sysfs_create_group() */
-
-/* Addresses to scan: none, device can't be detected */
-static const unsigned short normal_i2c[] = { I2C_CLIENT_END };
-
-/* Insmod parameters */
-I2C_CLIENT_INSMOD;
-
-
-/* Each client has this additional data */
-struct pcf8575_data {
- int write; /* last written value, or error code */
-};
-
-/* following are the sysfs callback functions */
-static ssize_t show_read(struct device *dev, struct device_attribute *attr,
- char *buf)
-{
- struct i2c_client *client = to_i2c_client(dev);
- u16 val;
- u8 iopin_state[2];
-
- i2c_master_recv(client, iopin_state, 2);
-
- val = iopin_state[0];
- val |= iopin_state[1] << 8;
-
- return sprintf(buf, "%u\n", val);
-}
-
-static DEVICE_ATTR(read, S_IRUGO, show_read, NULL);
-
-static ssize_t show_write(struct device *dev, struct device_attribute *attr,
- char *buf)
-{
- struct pcf8575_data *data = dev_get_drvdata(dev);
- if (data->write < 0)
- return data->write;
- return sprintf(buf, "%d\n", data->write);
-}
-
-static ssize_t set_write(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct i2c_client *client = to_i2c_client(dev);
- struct pcf8575_data *data = i2c_get_clientdata(client);
- unsigned long val = simple_strtoul(buf, NULL, 10);
- u8 iopin_state[2];
-
- if (val > 0xffff)
- return -EINVAL;
-
- data->write = val;
-
- iopin_state[0] = val & 0xFF;
- iopin_state[1] = val >> 8;
-
- i2c_master_send(client, iopin_state, 2);
-
- return count;
-}
-
-static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write);
-
-static struct attribute *pcf8575_attributes[] = {
- &dev_attr_read.attr,
- &dev_attr_write.attr,
- NULL
-};
-
-static const struct attribute_group pcf8575_attr_group = {
- .attrs = pcf8575_attributes,
-};
-
-/*
- * Real code
- */
-
-/* Return 0 if detection is successful, -ENODEV otherwise */
-static int pcf8575_detect(struct i2c_client *client, int kind,
- struct i2c_board_info *info)
-{
- struct i2c_adapter *adapter = client->adapter;
-
- if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
- return -ENODEV;
-
- /* This is the place to detect whether the chip at the specified
- address really is a PCF8575 chip. However, there is no method known
- to detect whether an I2C chip is a PCF8575 or any other I2C chip. */
-
- strlcpy(info->type, "pcf8575", I2C_NAME_SIZE);
-
- return 0;
-}
-
-static int pcf8575_probe(struct i2c_client *client,
- const struct i2c_device_id *id)
-{
- struct pcf8575_data *data;
- int err;
-
- data = kzalloc(sizeof(struct pcf8575_data), GFP_KERNEL);
- if (!data) {
- err = -ENOMEM;
- goto exit;
- }
-
- i2c_set_clientdata(client, data);
- data->write = -EAGAIN;
-
- /* Register sysfs hooks */
- err = sysfs_create_group(&client->dev.kobj, &pcf8575_attr_group);
- if (err)
- goto exit_free;
-
- return 0;
-
-exit_free:
- kfree(data);
-exit:
- return err;
-}
-
-static int pcf8575_remove(struct i2c_client *client)
-{
- sysfs_remove_group(&client->dev.kobj, &pcf8575_attr_group);
- kfree(i2c_get_clientdata(client));
- return 0;
-}
-
-static const struct i2c_device_id pcf8575_id[] = {
- { "pcf8575", 0 },
- { }
-};
-
-static struct i2c_driver pcf8575_driver = {
- .driver = {
- .owner = THIS_MODULE,
- .name = "pcf8575",
- },
- .probe = pcf8575_probe,
- .remove = pcf8575_remove,
- .id_table = pcf8575_id,
-
- .detect = pcf8575_detect,
- .address_data = &addr_data,
-};
-
-static int __init pcf8575_init(void)
-{
- return i2c_add_driver(&pcf8575_driver);
-}
-
-static void __exit pcf8575_exit(void)
-{
- i2c_del_driver(&pcf8575_driver);
-}
-
-MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>, "
- "Bart Van Assche <bart.vanassche@gmail.com>");
-MODULE_DESCRIPTION("pcf8575 driver");
-MODULE_LICENSE("GPL");
-
-module_init(pcf8575_init);
-module_exit(pcf8575_exit);
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff