i2c/chips: Remove deprecated pcf8574 driver
The pcf8574 driver in drivers/i2c/chips which just exports its register to sysfs is superseded by drivers/gpio/pcf857x.c which properly uses the gpiolib. As this driver has been deprecated for more than a year, finally remove it. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Cc: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Wolfram Sang
Jean Delvare
parent
732d481127
commit
e7c5c49ecd
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@ -1,65 +0,0 @@
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Kernel driver pcf8574
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=====================
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Supported chips:
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* Philips PCF8574
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Prefix: 'pcf8574'
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Addresses scanned: none
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Datasheet: Publicly available at the Philips Semiconductors website
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http://www.semiconductors.philips.com/pip/PCF8574P.html
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* Philips PCF8574A
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Prefix: 'pcf8574a'
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Addresses scanned: none
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Datasheet: Publicly available at the Philips Semiconductors website
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http://www.semiconductors.philips.com/pip/PCF8574P.html
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Authors:
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Frodo Looijaard <frodol@dds.nl>,
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Philip Edelbrock <phil@netroedge.com>,
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Dan Eaton <dan.eaton@rocketlogix.com>,
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Aurelien Jarno <aurelien@aurel32.net>,
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Jean Delvare <khali@linux-fr.org>,
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Description
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-----------
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The PCF8574(A) is an 8-bit I/O expander for the I2C bus produced by Philips
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Semiconductors. It is designed to provide a byte I2C interface to up to 16
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separate devices (8 x PCF8574 and 8 x PCF8574A).
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This device consists of a quasi-bidirectional port. Each of the eight I/Os
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can be independently used as an input or output. To setup an I/O as an
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input, you have to write a 1 to the corresponding output.
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For more informations see the datasheet.
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Accessing PCF8574(A) via /sys interface
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-------------------------------------
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The PCF8574(A) is plainly impossible to detect ! Stupid chip.
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So, you have to pass the I2C bus and address of the installed PCF857A
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and PCF8574A devices explicitly to the driver at load time via the
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force=... parameter.
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On detection (i.e. insmod, modprobe et al.), directories are being
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created for each detected PCF8574(A):
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/sys/bus/i2c/devices/<0>-<1>/
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where <0> is the bus the chip was detected on (e. g. i2c-0)
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and <1> the chip address ([20..27] or [38..3f]):
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(example: /sys/bus/i2c/devices/1-0020/)
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Inside these directories, there are two files each:
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read and write (and one file with chip name).
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The read file is read-only. Reading gives you the current I/O input
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if the corresponding output is set as 1, otherwise the current output
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value, that is to say 0.
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The write file is read/write. Writing a value outputs it on the I/O
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port. Reading returns the last written value. As it is not possible
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to read this value from the chip, you need to write at least once to
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this file before you can read back from it.
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@ -16,23 +16,6 @@ config DS1682
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This driver can also be built as a module. If so, the module
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will be called ds1682.
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config SENSORS_PCF8574
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tristate "Philips PCF8574 and PCF8574A (DEPRECATED)"
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depends on EXPERIMENTAL && GPIO_PCF857X = "n"
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default n
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help
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If you say yes here you get support for Philips PCF8574 and
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PCF8574A chips. These chips are 8-bit I/O expanders for the I2C bus.
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This driver can also be built as a module. If so, the module
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will be called pcf8574.
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This driver is deprecated and will be dropped soon. Use
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drivers/gpio/pcf857x.c instead.
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These devices are hard to detect and rarely found on mainstream
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hardware. If unsure, say N.
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config SENSORS_TSL2550
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tristate "Taos TSL2550 ambient light sensor"
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depends on EXPERIMENTAL
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@ -11,7 +11,6 @@
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#
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obj-$(CONFIG_DS1682) += ds1682.o
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obj-$(CONFIG_SENSORS_PCF8574) += pcf8574.o
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obj-$(CONFIG_SENSORS_TSL2550) += tsl2550.o
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ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
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@ -1,215 +0,0 @@
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/*
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Copyright (c) 2000 Frodo Looijaard <frodol@dds.nl>,
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Philip Edelbrock <phil@netroedge.com>,
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Dan Eaton <dan.eaton@rocketlogix.com>
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Ported to Linux 2.6 by Aurelien Jarno <aurel32@debian.org> with
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the help of Jean Delvare <khali@linux-fr.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/* A few notes about the PCF8574:
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* The PCF8574 is an 8-bit I/O expander for the I2C bus produced by
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Philips Semiconductors. It is designed to provide a byte I2C
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interface to up to 8 separate devices.
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* The PCF8574 appears as a very simple SMBus device which can be
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read from or written to with SMBUS byte read/write accesses.
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--Dan
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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/* Addresses to scan: none, device can't be detected */
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static const unsigned short normal_i2c[] = { I2C_CLIENT_END };
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/* Insmod parameters */
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I2C_CLIENT_INSMOD_2(pcf8574, pcf8574a);
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/* Each client has this additional data */
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struct pcf8574_data {
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int write; /* Remember last written value */
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};
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static void pcf8574_init_client(struct i2c_client *client);
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/* following are the sysfs callback functions */
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static ssize_t show_read(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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return sprintf(buf, "%u\n", i2c_smbus_read_byte(client));
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}
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static DEVICE_ATTR(read, S_IRUGO, show_read, NULL);
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static ssize_t show_write(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct pcf8574_data *data = i2c_get_clientdata(to_i2c_client(dev));
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if (data->write < 0)
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return data->write;
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return sprintf(buf, "%d\n", data->write);
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}
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static ssize_t set_write(struct device *dev, struct device_attribute *attr, const char *buf,
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size_t count)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct pcf8574_data *data = i2c_get_clientdata(client);
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unsigned long val = simple_strtoul(buf, NULL, 10);
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if (val > 0xff)
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return -EINVAL;
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data->write = val;
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i2c_smbus_write_byte(client, data->write);
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return count;
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}
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static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write);
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static struct attribute *pcf8574_attributes[] = {
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&dev_attr_read.attr,
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&dev_attr_write.attr,
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NULL
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};
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static const struct attribute_group pcf8574_attr_group = {
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.attrs = pcf8574_attributes,
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};
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/*
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* Real code
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*/
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/* Return 0 if detection is successful, -ENODEV otherwise */
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static int pcf8574_detect(struct i2c_client *client, int kind,
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struct i2c_board_info *info)
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{
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struct i2c_adapter *adapter = client->adapter;
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const char *client_name;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
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return -ENODEV;
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/* Now, we would do the remaining detection. But the PCF8574 is plainly
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impossible to detect! Stupid chip. */
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/* Determine the chip type */
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if (kind <= 0) {
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if (client->addr >= 0x38 && client->addr <= 0x3f)
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kind = pcf8574a;
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else
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kind = pcf8574;
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}
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if (kind == pcf8574a)
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client_name = "pcf8574a";
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else
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client_name = "pcf8574";
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strlcpy(info->type, client_name, I2C_NAME_SIZE);
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return 0;
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}
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static int pcf8574_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct pcf8574_data *data;
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int err;
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data = kzalloc(sizeof(struct pcf8574_data), GFP_KERNEL);
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if (!data) {
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err = -ENOMEM;
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goto exit;
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}
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i2c_set_clientdata(client, data);
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/* Initialize the PCF8574 chip */
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pcf8574_init_client(client);
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/* Register sysfs hooks */
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err = sysfs_create_group(&client->dev.kobj, &pcf8574_attr_group);
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if (err)
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goto exit_free;
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return 0;
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exit_free:
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kfree(data);
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exit:
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return err;
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}
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static int pcf8574_remove(struct i2c_client *client)
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{
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sysfs_remove_group(&client->dev.kobj, &pcf8574_attr_group);
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kfree(i2c_get_clientdata(client));
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return 0;
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}
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/* Called when we have found a new PCF8574. */
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static void pcf8574_init_client(struct i2c_client *client)
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{
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struct pcf8574_data *data = i2c_get_clientdata(client);
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data->write = -EAGAIN;
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}
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static const struct i2c_device_id pcf8574_id[] = {
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{ "pcf8574", 0 },
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{ "pcf8574a", 0 },
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{ }
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};
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static struct i2c_driver pcf8574_driver = {
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.driver = {
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.name = "pcf8574",
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},
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.probe = pcf8574_probe,
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.remove = pcf8574_remove,
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.id_table = pcf8574_id,
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.detect = pcf8574_detect,
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.address_data = &addr_data,
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};
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static int __init pcf8574_init(void)
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{
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return i2c_add_driver(&pcf8574_driver);
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}
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static void __exit pcf8574_exit(void)
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{
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i2c_del_driver(&pcf8574_driver);
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}
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MODULE_AUTHOR
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("Frodo Looijaard <frodol@dds.nl>, "
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"Philip Edelbrock <phil@netroedge.com>, "
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"Dan Eaton <dan.eaton@rocketlogix.com> "
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"and Aurelien Jarno <aurelien@aurel32.net>");
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MODULE_DESCRIPTION("PCF8574 driver");
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MODULE_LICENSE("GPL");
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module_init(pcf8574_init);
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module_exit(pcf8574_exit);
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