/* 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);