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 */
18 static unsigned short normal_i2c[] = {0x74, 0x75, 0x76, 0x77, I2C_CLIENT_END};
19
20 /* Insmod parameters */
21 I2C_CLIENT_INSMOD_1(pca9539);
22
23 enum 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
35 static int pca9539_attach_adapter(struct i2c_adapter *adapter);
36 static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind);
37 static int pca9539_detach_client(struct i2c_client *client);
38
39 /* This is the driver that will be inserted */
40 static 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
48 struct pca9539_data {
49 struct i2c_client client;
50 };
51
52 /* following are the sysfs callback functions */
53 static 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
62 static 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
83 PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
84 PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
85 PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
86 PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
87 PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
88 PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
89 PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
90 PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);
91
92 static 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
104 static struct attribute_group pca9539_defattr_group = {
105 .attrs = pca9539_attributes,
106 };
107
108 static 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 */
114 static 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 /* Detection: the pca9539 only has 8 registers (0-7).
138 A read of 7 should succeed, but a read of 8 should fail. */
139 if ((i2c_smbus_read_byte_data(new_client, 7) < 0) ||
140 (i2c_smbus_read_byte_data(new_client, 8) >= 0))
141 goto exit_kfree;
142
143 strlcpy(new_client->name, "pca9539", I2C_NAME_SIZE);
144
145 /* Tell the I2C layer a new client has arrived */
146 if ((err = i2c_attach_client(new_client)))
147 goto exit_kfree;
148
149 /* Register sysfs hooks (don't care about failure) */
150 sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);
151
152 return 0;
153
154 exit_kfree:
155 kfree(data);
156 exit:
157 return err;
158 }
159
160 static int pca9539_detach_client(struct i2c_client *client)
161 {
162 int err;
163
164 if ((err = i2c_detach_client(client)))
165 return err;
166
167 kfree(i2c_get_clientdata(client));
168 return 0;
169 }
170
171 static int __init pca9539_init(void)
172 {
173 return i2c_add_driver(&pca9539_driver);
174 }
175
176 static void __exit pca9539_exit(void)
177 {
178 i2c_del_driver(&pca9539_driver);
179 }
180
181 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
182 MODULE_DESCRIPTION("PCA9539 driver");
183 MODULE_LICENSE("GPL");
184
185 module_init(pca9539_init);
186 module_exit(pca9539_exit);
187
188
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