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 #include <linux/i2c-sensor.h>
  17
  18 /* Addresses to scan */
  19 static unsigned short normal_i2c[] = {0x74, 0x75, 0x76, 0x77, I2C_CLIENT_END};
  20 static unsigned int normal_isa[] = {I2C_CLIENT_ISA_END};
  21
  22 /* Insmod parameters */
  23 SENSORS_INSMOD_1(pca9539);
  24
  25 enum pca9539_cmd
  26 {
  27         PCA9539_INPUT_0         = 0,
  28         PCA9539_INPUT_1         = 1,
  29         PCA9539_OUTPUT_0        = 2,
  30         PCA9539_OUTPUT_1        = 3,
  31         PCA9539_INVERT_0        = 4,
  32         PCA9539_INVERT_1        = 5,
  33         PCA9539_DIRECTION_0     = 6,
  34         PCA9539_DIRECTION_1     = 7,
  35 };
  36
  37 static int pca9539_attach_adapter(struct i2c_adapter *adapter);
  38 static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind);
  39 static int pca9539_detach_client(struct i2c_client *client);
  40
  41 /* This is the driver that will be inserted */
  42 static struct i2c_driver pca9539_driver = {
  43         .owner          = THIS_MODULE,
  44         .name           = "pca9539",
  45         .flags          = I2C_DF_NOTIFY,
  46         .attach_adapter = pca9539_attach_adapter,
  47         .detach_client  = pca9539_detach_client,
  48 };
  49
  50 struct pca9539_data {
  51         struct i2c_client client;
  52 };
  53
  54 /* following are the sysfs callback functions */
  55 static ssize_t pca9539_show(struct device *dev, struct device_attribute *attr,
  56                             char *buf)
  57 {
  58         struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
  59         struct i2c_client *client = to_i2c_client(dev);
  60         return sprintf(buf, "%d\n", i2c_smbus_read_byte_data(client,
  61                                                              psa->index));
  62 }
  63
  64 static ssize_t pca9539_store(struct device *dev, struct device_attribute *attr,
  65                              const char *buf, size_t count)
  66 {
  67         struct sensor_device_attribute *psa = to_sensor_dev_attr(attr);
  68         struct i2c_client *client = to_i2c_client(dev);
  69         unsigned long val = simple_strtoul(buf, NULL, 0);
  70         if (val > 0xff)
  71                 return -EINVAL;
  72         i2c_smbus_write_byte_data(client, psa->index, val);
  73         return count;
  74 }
  75
  76 /* Define the device attributes */
  77
  78 #define PCA9539_ENTRY_RO(name, cmd_idx) \
  79         static SENSOR_DEVICE_ATTR(name, S_IRUGO, pca9539_show, NULL, cmd_idx)
  80
  81 #define PCA9539_ENTRY_RW(name, cmd_idx) \
  82         static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, pca9539_show, \
  83                                   pca9539_store, cmd_idx)
  84
  85 PCA9539_ENTRY_RO(input0, PCA9539_INPUT_0);
  86 PCA9539_ENTRY_RO(input1, PCA9539_INPUT_1);
  87 PCA9539_ENTRY_RW(output0, PCA9539_OUTPUT_0);
  88 PCA9539_ENTRY_RW(output1, PCA9539_OUTPUT_1);
  89 PCA9539_ENTRY_RW(invert0, PCA9539_INVERT_0);
  90 PCA9539_ENTRY_RW(invert1, PCA9539_INVERT_1);
  91 PCA9539_ENTRY_RW(direction0, PCA9539_DIRECTION_0);
  92 PCA9539_ENTRY_RW(direction1, PCA9539_DIRECTION_1);
  93
  94 static struct attribute *pca9539_attributes[] = {
  95         &sensor_dev_attr_input0.dev_attr.attr,
  96         &sensor_dev_attr_input1.dev_attr.attr,
  97         &sensor_dev_attr_output0.dev_attr.attr,
  98         &sensor_dev_attr_output1.dev_attr.attr,
  99         &sensor_dev_attr_invert0.dev_attr.attr,
 100         &sensor_dev_attr_invert1.dev_attr.attr,
 101         &sensor_dev_attr_direction0.dev_attr.attr,
 102         &sensor_dev_attr_direction1.dev_attr.attr,
 103         NULL
 104 };
 105
 106 static struct attribute_group pca9539_defattr_group = {
 107         .attrs = pca9539_attributes,
 108 };
 109
 110 static int pca9539_attach_adapter(struct i2c_adapter *adapter)
 111 {
 112         return i2c_detect(adapter, &addr_data, pca9539_detect);
 113 }
 114
 115 /* This function is called by i2c_detect */
 116 static int pca9539_detect(struct i2c_adapter *adapter, int address, int kind)
 117 {
 118         struct i2c_client *new_client;
 119         struct pca9539_data *data;
 120         int err = 0;
 121
 122         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 123                 goto exit;
 124
 125         /* OK. For now, we presume we have a valid client. We now create the
 126            client structure, even though we cannot fill it completely yet. */
 127         if (!(data = kmalloc(sizeof(struct pca9539_data), GFP_KERNEL))) {
 128                 err = -ENOMEM;
 129                 goto exit;
 130         }
 131         memset(data, 0, sizeof(struct pca9539_data));
 132
 133         new_client = &data->client;
 134         i2c_set_clientdata(new_client, data);
 135         new_client->addr = address;
 136         new_client->adapter = adapter;
 137         new_client->driver = &pca9539_driver;
 138         new_client->flags = 0;
 139
 140         /* Detection: the pca9539 only has 8 registers (0-7).
 141            A read of 7 should succeed, but a read of 8 should fail. */
 142         if ((i2c_smbus_read_byte_data(new_client, 7) < 0) ||
 143             (i2c_smbus_read_byte_data(new_client, 8) >= 0))
 144                 goto exit_kfree;
 145
 146         strlcpy(new_client->name, "pca9539", I2C_NAME_SIZE);
 147
 148         /* Tell the I2C layer a new client has arrived */
 149         if ((err = i2c_attach_client(new_client)))
 150                 goto exit_kfree;
 151
 152         /* Register sysfs hooks (don't care about failure) */
 153         sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);
 154
 155         return 0;
 156
 157 exit_kfree:
 158         kfree(data);
 159 exit:
 160         return err;
 161 }
 162
 163 static int pca9539_detach_client(struct i2c_client *client)
 164 {
 165         int err;
 166
 167         if ((err = i2c_detach_client(client))) {
 168                 dev_err(&client->dev, "Client deregistration failed.\n");
 169                 return err;
 170         }
 171
 172         kfree(i2c_get_clientdata(client));
 173         return 0;
 174 }
 175
 176 static int __init pca9539_init(void)
 177 {
 178         return i2c_add_driver(&pca9539_driver);
 179 }
 180
 181 static void __exit pca9539_exit(void)
 182 {
 183         i2c_del_driver(&pca9539_driver);
 184 }
 185
 186 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 187 MODULE_DESCRIPTION("PCA9539 driver");
 188 MODULE_LICENSE("GPL");
 189
 190 module_init(pca9539_init);
 191 module_exit(pca9539_exit);
 192