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   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         .owner          = THIS_MODULE,
  42         .name           = "pca9539",
  43         .attach_adapter = pca9539_attach_adapter,
  44         .detach_client  = pca9539_detach_client,
  45 };
  46
  47 struct pca9539_data {
  48         struct i2c_client client;
  49 };
  50
  51 /* following are the sysfs callback functions */
  52 static ssize_t pca9539_show(struct device *dev, struct device_attribute *attr,
  53                             char *buf)
  54 {
  55         struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
  56         struct i2c_client *client = to_i2c_client(dev);
  57         return sprintf(buf, "%d\n", i2c_smbus_read_byte_data(client,
  58                                                              psa->index));
  59 }
  60
  61 static ssize_t pca9539_store(struct device *dev, struct device_attribute *attr,
  62                              const char *buf, size_t count)
  63 {
  64         struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
  65         struct i2c_client *client = to_i2c_client(dev);
  66         unsigned long val = simple_strtoul(buf, NULL, 0);
  67         if (val > 0xff)
  68                 return -EINVAL;
  69         i2c_smbus_write_byte_data(client, psa->index, val);
  70         return count;
  71 }
  72
  73 /* Define the device attributes */
  74
  75 #define PCA9539_ENTRY_RO(name, cmd_idx) \
  76         static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9539_show, NULL, cmd_idx)
  77
  78 #define PCA9539_ENTRY_RW(name, cmd_idx) \
  79         static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, pca9539_show, \
  80                                   pca9539_store, cmd_idx)
  81
  82 PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
  83 PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
  84 PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
  85 PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
  86 PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
  87 PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
  88 PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
  89 PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);
  90
  91 static struct attribute *pca9539_attributes[] = {
  92         &sensor_dev_attr_input0.dev_attr.attr,
  93         &sensor_dev_attr_input1.dev_attr.attr,
  94         &sensor_dev_attr_output0.dev_attr.attr,
  95         &sensor_dev_attr_output1.dev_attr.attr,
  96         &sensor_dev_attr_invert0.dev_attr.attr,
  97         &sensor_dev_attr_invert1.dev_attr.attr,
  98         &sensor_dev_attr_direction0.dev_attr.attr,
  99         &sensor_dev_attr_direction1.dev_attr.attr,
 100         NULL
 101 };
 102
 103 static struct attribute_group pca9539_defattr_group = {
 104         .attrs = pca9539_attributes,
 105 };
 106
 107 static int pca9539_attach_adapter(struct i2c_adapter *adapter)
 108 {
 109         return i2c_probe(adapter, &addr_data, pca9539_detect);
 110 }
 111
 112 /* This function is called by i2c_probe */
 113 static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind)
 114 {
 115         struct i2c_client *new_client;
 116         struct pca9539_data *data;
 117         int err = 0;
 118
 119         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 120                 goto exit;
 121
 122         /* OK. For now, we presume we have a valid client. We now create the
 123            client structure, even though we cannot fill it completely yet. */
 124         if (!(data = kzalloc(sizeof(struct pca9539_data), GFP_KERNEL))) {
 125                 err = -ENOMEM;
 126                 goto exit;
 127         }
 128
 129         new_client = &data->client;
 130         i2c_set_clientdata(new_client, data);
 131         new_client->addr = address;
 132         new_client->adapter = adapter;
 133         new_client->driver = &pca9539_driver;
 134         new_client->flags = 0;
 135
 136         /* Detection: the pca9539 only has 8 registers (0-7).
 137            A read of 7 should succeed, but a read of 8 should fail. */
 138         if ((i2c_smbus_read_byte_data(new_client, 7) < 0) ||
 139             (i2c_smbus_read_byte_data(new_client, 8) >= 0))
 140                 goto exit_kfree;
 141
 142         strlcpy(new_client->name, "pca9539", I2C_NAME_SIZE);
 143
 144         /* Tell the I2C layer a new client has arrived */
 145         if ((err = i2c_attach_client(new_client)))
 146                 goto exit_kfree;
 147
 148         /* Register sysfs hooks (don't care about failure) */
 149         sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);
 150
 151         return 0;
 152
 153 exit_kfree:
 154         kfree(data);
 155 exit:
 156         return err;
 157 }
 158
 159 static int pca9539_detach_client(struct i2c_client *client)
 160 {
 161         int err;
 162
 163         if ((err = i2c_detach_client(client)))
 164                 return err;
 165
 166         kfree(i2c_get_clientdata(client));
 167         return 0;
 168 }
 169
 170 static int __init pca9539_init(void)
 171 {
 172         return i2c_add_driver(&pca9539_driver);
 173 }
 174
 175 static void __exit pca9539_exit(void)
 176 {
 177         i2c_del_driver(&pca9539_driver);
 178 }
 179
 180 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 181 MODULE_DESCRIPTION("PCA9539 driver");
 182 MODULE_LICENSE("GPL");
 183
 184 module_init(pca9539_init);
 185 module_exit(pca9539_exit);
 186