1/*
2    pca9539.c - 16-bit I/O port with interrupt and reset
3
4    Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
5
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; version 2 of the License.
9*/
10
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/slab.h>
14#include <linux/i2c.h>
15#include <linux/hwmon-sysfs.h>
16
17/* Addresses to scan */
18static unsigned short normal_i2c[] = {0x74, 0x75, 0x76, 0x77, I2C_CLIENT_END};
19
20/* Insmod parameters */
21I2C_CLIENT_INSMOD_1(pca9539);
22
23enum pca9539_cmd
24{
25	PCA9539_INPUT_0		= 0,
26	PCA9539_INPUT_1		= 1,
27	PCA9539_OUTPUT_0	= 2,
28	PCA9539_OUTPUT_1	= 3,
29	PCA9539_INVERT_0	= 4,
30	PCA9539_INVERT_1	= 5,
31	PCA9539_DIRECTION_0	= 6,
32	PCA9539_DIRECTION_1	= 7,
33};
34
35static int pca9539_attach_adapter(struct i2c_adapter *adapter);
36static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind);
37static int pca9539_detach_client(struct i2c_client *client);
38
39/* This is the driver that will be inserted */
40static struct i2c_driver pca9539_driver = {
41	.driver = {
42		.name	= "pca9539",
43	},
44	.attach_adapter	= pca9539_attach_adapter,
45	.detach_client	= pca9539_detach_client,
46};
47
48struct pca9539_data {
49	struct i2c_client client;
50};
51
52/* following are the sysfs callback functions */
53static ssize_t pca9539_show(struct device *dev, struct device_attribute *attr,
54			    char *buf)
55{
56	struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
57	struct i2c_client *client = to_i2c_client(dev);
58	return sprintf(buf, "%d\n", i2c_smbus_read_byte_data(client,
59							     psa->index));
60}
61
62static ssize_t pca9539_store(struct device *dev, struct device_attribute *attr,
63			     const char *buf, size_t count)
64{
65	struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
66	struct i2c_client *client = to_i2c_client(dev);
67	unsigned long val = simple_strtoul(buf, NULL, 0);
68	if (val > 0xff)
69		return -EINVAL;
70	i2c_smbus_write_byte_data(client, psa->index, val);
71	return count;
72}
73
74/* Define the device attributes */
75
76#define PCA9539_ENTRY_RO(name, cmd_idx) \
77	static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9539_show, NULL, cmd_idx)
78
79#define PCA9539_ENTRY_RW(name, cmd_idx) \
80	static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, pca9539_show, \
81				  pca9539_store, cmd_idx)
82
83PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
84PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
85PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
86PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
87PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
88PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
89PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
90PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);
91
92static struct attribute *pca9539_attributes[] = {
93	&sensor_dev_attr_input0.dev_attr.attr,
94	&sensor_dev_attr_input1.dev_attr.attr,
95	&sensor_dev_attr_output0.dev_attr.attr,
96	&sensor_dev_attr_output1.dev_attr.attr,
97	&sensor_dev_attr_invert0.dev_attr.attr,
98	&sensor_dev_attr_invert1.dev_attr.attr,
99	&sensor_dev_attr_direction0.dev_attr.attr,
100	&sensor_dev_attr_direction1.dev_attr.attr,
101	NULL
102};
103
104static struct attribute_group pca9539_defattr_group = {
105	.attrs = pca9539_attributes,
106};
107
108static int pca9539_attach_adapter(struct i2c_adapter *adapter)
109{
110	return i2c_probe(adapter, &addr_data, pca9539_detect);
111}
112
113/* This function is called by i2c_probe */
114static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind)
115{
116	struct i2c_client *new_client;
117	struct pca9539_data *data;
118	int err = 0;
119
120	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
121		goto exit;
122
123	/* OK. For now, we presume we have a valid client. We now create the
124	   client structure, even though we cannot fill it completely yet. */
125	if (!(data = kzalloc(sizeof(struct pca9539_data), GFP_KERNEL))) {
126		err = -ENOMEM;
127		goto exit;
128	}
129
130	new_client = &data->client;
131	i2c_set_clientdata(new_client, data);
132	new_client->addr = address;
133	new_client->adapter = adapter;
134	new_client->driver = &pca9539_driver;
135	new_client->flags = 0;
136
137	if (kind < 0) {
138		/* Detection: the pca9539 only has 8 registers (0-7).
139		   A read of 7 should succeed, but a read of 8 should fail. */
140		if ((i2c_smbus_read_byte_data(new_client, 7) < 0) ||
141		    (i2c_smbus_read_byte_data(new_client, 8) >= 0))
142			goto exit_kfree;
143	}
144
145	strlcpy(new_client->name, "pca9539", I2C_NAME_SIZE);
146
147	/* Tell the I2C layer a new client has arrived */
148	if ((err = i2c_attach_client(new_client)))
149		goto exit_kfree;
150
151	/* Register sysfs hooks */
152	err = sysfs_create_group(&new_client->dev.kobj,
153				 &pca9539_defattr_group);
154	if (err)
155		goto exit_detach;
156
157	return 0;
158
159exit_detach:
160	i2c_detach_client(new_client);
161exit_kfree:
162	kfree(data);
163exit:
164	return err;
165}
166
167static int pca9539_detach_client(struct i2c_client *client)
168{
169	int err;
170
171	sysfs_remove_group(&client->dev.kobj, &pca9539_defattr_group);
172
173	if ((err = i2c_detach_client(client)))
174		return err;
175
176	kfree(i2c_get_clientdata(client));
177	return 0;
178}
179
180static int __init pca9539_init(void)
181{
182	return i2c_add_driver(&pca9539_driver);
183}
184
185static void __exit pca9539_exit(void)
186{
187	i2c_del_driver(&pca9539_driver);
188}
189
190MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
191MODULE_DESCRIPTION("PCA9539 driver");
192MODULE_LICENSE("GPL");
193
194module_init(pca9539_init);
195module_exit(pca9539_exit);
196