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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 #include <linux/i2c-sensor.h>
  17
  18 /* Addresses to scan */
  19 static unsigned short normal_i2c[] = {0x74, 0x75, 0x76, 0x77, I2C_CLIENT_END};
  20
  21 /* Insmod parameters */
  22 SENSORS_INSMOD_1(pca9539);
  23
  24 enum pca9539_cmd
  25 {
  26         PCA9539_INPUT_0         = 0,
  27         PCA9539_INPUT_1         = 1,
  28         PCA9539_OUTPUT_0        = 2,
  29         PCA9539_OUTPUT_1        = 3,
  30         PCA9539_INVERT_0        = 4,
  31         PCA9539_INVERT_1        = 5,
  32         PCA9539_DIRECTION_0     = 6,
  33         PCA9539_DIRECTION_1     = 7,
  34 };
  35
  36 static int pca9539_attach_adapter(struct i2c_adapter *adapter);
  37 static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind);
  38 static int pca9539_detach_client(struct i2c_client *client);
  39
  40 /* This is the driver that will be inserted */
  41 static struct i2c_driver pca9539_driver = {
  42         .owner          = THIS_MODULE,
  43         .name           = "pca9539",
  44         .flags          = I2C_DF_NOTIFY,
  45         .attach_adapter = pca9539_attach_adapter,
  46         .detach_client  = pca9539_detach_client,
  47 };
  48
  49 struct pca9539_data {
  50         struct i2c_client client;
  51 };
  52
  53 /* following are the sysfs callback functions */
  54 static ssize_t pca9539_show(struct device *dev, struct device_attribute *attr,
  55                             char *buf)
  56 {
  57         struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
  58         struct i2c_client *client = to_i2c_client(dev);
  59         return sprintf(buf, "%d\n", i2c_smbus_read_byte_data(client,
  60                                                              psa->index));
  61 }
  62
  63 static ssize_t pca9539_store(struct device *dev, struct device_attribute *attr,
  64                              const char *buf, size_t count)
  65 {
  66         struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
  67         struct i2c_client *client = to_i2c_client(dev);
  68         unsigned long val = simple_strtoul(buf, NULL, 0);
  69         if (val > 0xff)
  70                 return -EINVAL;
  71         i2c_smbus_write_byte_data(client, psa->index, val);
  72         return count;
  73 }
  74
  75 /* Define the device attributes */
  76
  77 #define PCA9539_ENTRY_RO(name, cmd_idx) \
  78         static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9539_show, NULL, cmd_idx)
  79
  80 #define PCA9539_ENTRY_RW(name, cmd_idx) \
  81         static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, pca9539_show, \
  82                                   pca9539_store, cmd_idx)
  83
  84 PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
  85 PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
  86 PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
  87 PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
  88 PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
  89 PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
  90 PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
  91 PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);
  92
  93 static struct attribute *pca9539_attributes[] = {
  94         &sensor_dev_attr_input0.dev_attr.attr,
  95         &sensor_dev_attr_input1.dev_attr.attr,
  96         &sensor_dev_attr_output0.dev_attr.attr,
  97         &sensor_dev_attr_output1.dev_attr.attr,
  98         &sensor_dev_attr_invert0.dev_attr.attr,
  99         &sensor_dev_attr_invert1.dev_attr.attr,
 100         &sensor_dev_attr_direction0.dev_attr.attr,
 101         &sensor_dev_attr_direction1.dev_attr.attr,
 102         NULL
 103 };
 104
 105 static struct attribute_group pca9539_defattr_group = {
 106         .attrs = pca9539_attributes,
 107 };
 108
 109 static int pca9539_attach_adapter(struct i2c_adapter *adapter)
 110 {
 111         return i2c_probe(adapter, &addr_data, pca9539_detect);
 112 }
 113
 114 /* This function is called by i2c_probe */
 115 static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind)
 116 {
 117         struct i2c_client *new_client;
 118         struct pca9539_data *data;
 119         int err = 0;
 120
 121         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 122                 goto exit;
 123
 124         /* OK. For now, we presume we have a valid client. We now create the
 125            client structure, even though we cannot fill it completely yet. */
 126         if (!(data = kmalloc(sizeof(struct pca9539_data), GFP_KERNEL))) {
 127                 err = -ENOMEM;
 128                 goto exit;
 129         }
 130         memset(data, 0, sizeof(struct pca9539_data));
 131
 132         new_client = &data->client;
 133         i2c_set_clientdata(new_client, data);
 134         new_client->addr = address;
 135         new_client->adapter = adapter;
 136         new_client->driver = &pca9539_driver;
 137         new_client->flags = 0;
 138
 139         /* Detection: the pca9539 only has 8 registers (0-7).
 140            A read of 7 should succeed, but a read of 8 should fail. */
 141         if ((i2c_smbus_read_byte_data(new_client, 7) < 0) ||
 142             (i2c_smbus_read_byte_data(new_client, 8) >= 0))
 143                 goto exit_kfree;
 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 (don't care about failure) */
 152         sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);
 153
 154         return 0;
 155
 156 exit_kfree:
 157         kfree(data);
 158 exit:
 159         return err;
 160 }
 161
 162 static int pca9539_detach_client(struct i2c_client *client)
 163 {
 164         int err;
 165
 166         if ((err = i2c_detach_client(client)))
 167                 return err;
 168
 169         kfree(i2c_get_clientdata(client));
 170         return 0;
 171 }
 172
 173 static int __init pca9539_init(void)
 174 {
 175         return i2c_add_driver(&pca9539_driver);
 176 }
 177
 178 static void __exit pca9539_exit(void)
 179 {
 180         i2c_del_driver(&pca9539_driver);
 181 }
 182
 183 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 184 MODULE_DESCRIPTION("PCA9539 driver");
 185 MODULE_LICENSE("GPL");
 186
 187 module_init(pca9539_init);
 188 module_exit(pca9539_exit);
 189