This is a driver for the PCA9539, a 16 bit digital I/O chip.
It uses the new i2c-sysfs interfaces.
Signed-off-by: Ben Gardner <bgardner at wabtec.com>
--- linux-2.6.12-rc5-mm2-clean/drivers/i2c/chips/pca9539.c
1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.12-rc5-mm2-pca9539/drivers/i2c/chips/pca9539.c
2005-06-03 15:15:02.000000000 -0500
@@ -0,0 +1,188 @@
+/*
+ pca9539.c - 16 port digital I/O with interrupt and reset
+
+ Copyright (C) 2005 Ben Gardner <bgardner at 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/i2c-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_CONFIG_0 = 6,
+ PCA9539_CONFIG_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 pca9539_data *data =
i2c_get_clientdata(to_i2c_client(dev));
+ return sprintf(buf, "%d\n",
i2c_smbus_read_byte_data(&data->client, (u8)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 pca9539_data *data =
i2c_get_clientdata(to_i2c_client(dev));
+ u8 val = simple_strtoul(buf, NULL, 0);
+ i2c_smbus_write_byte_data(&data->client, (u8)psa->index, val);
+ return count;
+}
+
+/* Define the device attributes */
+
+#define PCA9539_ENTRY_RO(name,enum_name) \
+ static
SENSOR_DEVICE_ATTR(name,S_IRUGO,pca9539_show,NULL,enum_name)
+
+#define PCA9539_ENTRY_RW(name,enum_name) \
+ static
SENSOR_DEVICE_ATTR(name,S_IRUGO|S_IWUSR,pca9539_show,pca9539_store,enum_
name)
+
+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(config0, PCA9539_CONFIG_0);
+PCA9539_ENTRY_RW(config1, PCA9539_CONFIG_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_config0.dev_attr.attr,
+ &sensor_dev_attr_config1.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
+ | I2C_FUNC_SMBUS_WRITE_BYTE_DATA
+ | I2C_FUNC_SMBUS_READ_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: not sure how to do that...
+ * possibility: toggle the value read from invert0 and see if
input0
+ * changes polarity.
+ * However, if the inputs are changing, this won't work.
+ */
+ 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 */
+ return sysfs_create_group(&new_client->dev.kobj,
&pca9539_defattr_group);
+
+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, client not
detached.\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 at wabtec.com>");
+MODULE_DESCRIPTION("PCA9539 driver");
+MODULE_LICENSE("GPL");
+
+module_init(pca9539_init);
+module_exit(pca9539_exit);
+
