drivers/i2c/chips/pca9539.c

   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         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
 159 exit_detach:
 160         i2c_detach_client(new_client);
 161 exit_kfree:
 162         kfree(data);
 163 exit:
 164         return err;
 165 }
 166
 167 static 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
 180 static int __init pca9539_init(void)
 181 {
 182         return i2c_add_driver(&pca9539_driver);
 183 }
 184
 185 static void __exit pca9539_exit(void)
 186 {
 187         i2c_del_driver(&pca9539_driver);
 188 }
 189
 190 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 191 MODULE_DESCRIPTION("PCA9539 driver");
 192 MODULE_LICENSE("GPL");
 193
 194 module_init(pca9539_init);
 195 module_exit(pca9539_exit);
 196