Commit 69dd204b authored by bgardner@wabtec.com's avatar bgardner@wabtec.com Committed by Greg Kroah-Hartman

[PATCH] I2C: add new pca9539 driver

This is an i2c driver for the Philips PCA9539 (16 bit I/O port).
It uses the new i2c-sysfs interfaces.
The patch includes documentation.
It depends on the patch that renames "i2c-sysfs.h" to "hwmon-sysfs.h"
Signed-off-by: default avatarBen Gardner <bgardner@wabtec.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 10c08f81
Kernel driver pca9539
=====================
Supported chips:
* Philips PCA9539
Prefix: 'pca9539'
Addresses scanned: 0x74 - 0x77
Datasheet:
http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf
Author: Ben Gardner <bgardner@wabtec.com>
Description
-----------
The Philips PCA9539 is a 16 bit low power I/O device.
All 16 lines can be individually configured as an input or output.
The input sense can also be inverted.
The 16 lines are split between two bytes.
Sysfs entries
-------------
Each is a byte that maps to the 8 I/O bits.
A '0' suffix is for bits 0-7, while '1' is for bits 8-15.
input[01] - read the current value
output[01] - sets the output value
direction[01] - direction of each bit: 1=input, 0=output
invert[01] - toggle the input bit sense
input reads the actual state of the line and is always available.
The direction defaults to input for all channels.
General Remarks
---------------
Note that each output, direction, and invert entry controls 8 lines.
You should use the read, modify, write sequence.
For example. to set output bit 0 of 1.
val=$(cat output0)
val=$(( $val | 1 ))
echo $val > output0
......@@ -440,6 +440,16 @@ config SENSORS_PCF8574
This driver can also be built as a module. If so, the module
will be called pcf8574.
config SENSORS_PCA9539
tristate "Philips PCA9539 16-bit I/O port"
depends on I2C && EXPERIMENTAL
help
If you say yes here you get support for the Philips PCA9539
16-bit I/O port.
This driver can also be built as a module. If so, the module
will be called pca9539.
config SENSORS_PCF8591
tristate "Philips PCF8591"
depends on I2C && EXPERIMENTAL
......
......@@ -35,6 +35,7 @@ obj-$(CONFIG_SENSORS_MAX1619) += max1619.o
obj-$(CONFIG_SENSORS_MAX6875) += max6875.o
obj-$(CONFIG_SENSORS_M41T00) += m41t00.o
obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
obj-$(CONFIG_SENSORS_PCA9539) += pca9539.o
obj-$(CONFIG_SENSORS_PCF8574) += pcf8574.o
obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
obj-$(CONFIG_SENSORS_RTC8564) += rtc8564.o
......
/*
pca9539.c - 16-bit I/O port with interrupt and reset
Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
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; version 2 of the License.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon-sysfs.h>
#include <linux/i2c-sensor.h>
/* Addresses to scan */
static unsigned short normal_i2c[] = {0x74, 0x75, 0x76, 0x77, I2C_CLIENT_END};
static unsigned int normal_isa[] = {I2C_CLIENT_ISA_END};
/* Insmod parameters */
SENSORS_INSMOD_1(pca9539);
enum pca9539_cmd
{
PCA9539_INPUT_0 = 0,
PCA9539_INPUT_1 = 1,
PCA9539_OUTPUT_0 = 2,
PCA9539_OUTPUT_1 = 3,
PCA9539_INVERT_0 = 4,
PCA9539_INVERT_1 = 5,
PCA9539_DIRECTION_0 = 6,
PCA9539_DIRECTION_1 = 7,
};
static int pca9539_attach_adapter(struct i2c_adapter *adapter);
static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind);
static int pca9539_detach_client(struct i2c_client *client);
/* This is the driver that will be inserted */
static struct i2c_driver pca9539_driver = {
.owner = THIS_MODULE,
.name = "pca9539",
.flags = I2C_DF_NOTIFY,
.attach_adapter = pca9539_attach_adapter,
.detach_client = pca9539_detach_client,
};
struct pca9539_data {
struct i2c_client client;
};
/* following are the sysfs callback functions */
static ssize_t pca9539_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
struct i2c_client *client = to_i2c_client(dev);
return sprintf(buf, "%d\n", i2c_smbus_read_byte_data(client,
psa->index));
}
static ssize_t pca9539_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
struct i2c_client *client = to_i2c_client(dev);
unsigned long val = simple_strtoul(buf, NULL, 0);
if (val > 0xff)
return -EINVAL;
i2c_smbus_write_byte_data(client, psa->index, val);
return count;
}
/* Define the device attributes */
#define PCA9539_ENTRY_RO(name, cmd_idx) \
static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9539_show, NULL, cmd_idx)
#define PCA9539_ENTRY_RW(name, cmd_idx) \
static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, pca9539_show, \
pca9539_store, cmd_idx)
PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);
static struct attribute *pca9539_attributes[] = {
&sensor_dev_attr_input0.dev_attr.attr,
&sensor_dev_attr_input1.dev_attr.attr,
&sensor_dev_attr_output0.dev_attr.attr,
&sensor_dev_attr_output1.dev_attr.attr,
&sensor_dev_attr_invert0.dev_attr.attr,
&sensor_dev_attr_invert1.dev_attr.attr,
&sensor_dev_attr_direction0.dev_attr.attr,
&sensor_dev_attr_direction1.dev_attr.attr,
NULL
};
static struct attribute_group pca9539_defattr_group = {
.attrs = pca9539_attributes,
};
static int pca9539_attach_adapter(struct i2c_adapter *adapter)
{
return i2c_detect(adapter, &addr_data, pca9539_detect);
}
/* This function is called by i2c_detect */
static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct i2c_client *new_client;
struct pca9539_data *data;
int err = 0;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
goto exit;
/* OK. For now, we presume we have a valid client. We now create the
client structure, even though we cannot fill it completely yet. */
if (!(data = kmalloc(sizeof(struct pca9539_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
memset(data, 0, sizeof(struct pca9539_data));
new_client = &data->client;
i2c_set_clientdata(new_client, data);
new_client->addr = address;
new_client->adapter = adapter;
new_client->driver = &pca9539_driver;
new_client->flags = 0;
/* Detection: the pca9539 only has 8 registers (0-7).
A read of 7 should succeed, but a read of 8 should fail. */
if ((i2c_smbus_read_byte_data(new_client, 7) < 0) ||
(i2c_smbus_read_byte_data(new_client, 8) >= 0))
goto exit_kfree;
strlcpy(new_client->name, "pca9539", I2C_NAME_SIZE);
/* Tell the I2C layer a new client has arrived */
if ((err = i2c_attach_client(new_client)))
goto exit_kfree;
/* Register sysfs hooks (don't care about failure) */
sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);
return 0;
exit_kfree:
kfree(data);
exit:
return err;
}
static int pca9539_detach_client(struct i2c_client *client)
{
int err;
if ((err = i2c_detach_client(client))) {
dev_err(&client->dev, "Client deregistration failed.\n");
return err;
}
kfree(i2c_get_clientdata(client));
return 0;
}
static int __init pca9539_init(void)
{
return i2c_add_driver(&pca9539_driver);
}
static void __exit pca9539_exit(void)
{
i2c_del_driver(&pca9539_driver);
}
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("PCA9539 driver");
MODULE_LICENSE("GPL");
module_init(pca9539_init);
module_exit(pca9539_exit);
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