1 #include <linux/module.h>
2 #include <linux/fs.h>
3 #include <linux/cdev.h>
4 #include <linux/i2c.h>
5 #include <asm/uaccess.h>
6
7 static dev_t pca9555_dev_number;
8 static struct cdev *driver_object;
9 static struct class *pca9555_class;
0 static struct device *pca9555_dev;
1 static struct i2c_adapter *adapter;
2 static struct i2c_client *slave;
3
4 static struct i2c_device_id pca9555_idtable[] = {
5         { "pca9555", 0 }, { }
6 };
7 MODULE_DEVICE_TABLE(i2c, pca9555_idtable);
8
9 static struct i2c_board_info info_20 = {
0     I2C_BOARD_INFO("pca9555", 0x20),
1 };
2
3 static ssize_t driver_write( struct file *instanz,
4     const char __user *user, size_t count, loff_t *offset )
5 {
6     unsigned long not_copied, to_copy;
7     char value=0, buf[2];
8
9     to_copy = min( count, sizeof(value) );
0     not_copied=copy_from_user(&value, user, to_copy);
1     to_copy -= not_copied;
2
3     if( to_copy > 0 ) {
4         buf[0] = 0x02; // output port 0
5         buf[1] = value;
6         i2c_master_send( slave, buf, 2 );
7     }
8     return to_copy;
9 }
0 static ssize_t driver_read( struct file *instanz,
1     char __user *user, size_t count, loff_t *offset )
2 {
3     unsigned long not_copied, to_copy;
4     char value, command;
5
6     command = 0x01; // input port 1
7     i2c_master_send( slave, &command, 1 );
8     i2c_master_recv( slave, &value, 1 );
9
0     to_copy = min( count, sizeof(value) );
1     not_copied=copy_to_user( user, &value, to_copy);
2     return to_copy - not_copied;
3 }
4
5 static int pca9555_probe( struct i2c_client *client,
6     const struct i2c_device_id *id )
7 {
8     char buf[2];
9
0     printk("pca9555_probe: %p %p \"%s\"- ",client,id,id->name);
1     printk("slaveaddr: %d, name: %s\n",client->addr,client->name);
2     if (client->addr != 0x20 ) {
3         printk("i2c_probe: not found\n");
4         return -1;
5     }
6     // Konfiguration Port 0 als Output
7     buf[0] = 0x06; // direction port 0
8     buf[1] = 0x00; // output
9     i2c_master_send( client, buf, 2 );
0     return 0;
1 }
2
3 static int pca9555_remove( struct i2c_client *client )
4 {
5     return 0;
6 }
7 static struct file_operations fops = {
8     .owner= THIS_MODULE,
9     .write= driver_write,
0     .read = driver_read,
1 };
2
3 static struct i2c_driver pca9555_driver = {
4         .driver = {
5                 .name   = "pca9555",
6         },
7         .id_table       = pca9555_idtable,
8         .probe          = pca9555_probe,
9         .remove         = pca9555_remove,
0 };
1
2 static int __init mod_init( void )
3 {
4     if( alloc_chrdev_region(&pca9555_dev_number,0,1,"pca9555")<0 )
5         return -EIO;
6     driver_object = cdev_alloc();
7     if( driver_object==NULL )
8         goto free_device_number;
9     driver_object->owner = THIS_MODULE;
0     driver_object->ops = &fops;
1     if( cdev_add(driver_object,pca9555_dev_number,1) )
2         goto free_cdev;
3     pca9555_class = class_create( THIS_MODULE, "pca9555" );
4     if( IS_ERR( pca9555_class ) ) {
5         pr_err( "pca9555: no udev support\n");
6         goto free_cdev;
7     }
8     pca9555_dev = device_create( pca9555_class, NULL,
9         pca9555_dev_number, NULL, "%s", "pca9555" );
0     dev_info(pca9555_dev, "mod_init\n");
1
2     if (i2c_add_driver(&pca9555_driver)) {
3         pr_err("i2c_add_driver failed\n");
4         goto destroy_dev_class;
5     }
6     adapter = i2c_get_adapter(1); // Adapter sind durchnummeriert
7     if (adapter==NULL) {
8         pr_err("i2c_get_adapter failed\n");
9         goto del_i2c_driver;
0     }
1     slave = i2c_new_device( adapter, &info_20 );
2     if (slave==NULL) {
3         pr_err("i2c_new_device failed\n");
4         goto del_i2c_driver;
5     }
6     return 0;
7 del_i2c_driver:
8     i2c_del_driver(&pca9555_driver);
9 destroy_dev_class:
0     device_destroy( pca9555_class, pca9555_dev_number );
1     class_destroy( pca9555_class );
2 free_cdev:
3     kobject_put( &driver_object->kobj );
4 free_device_number:
5     unregister_chrdev_region( pca9555_dev_number, 1 );
6     return -EIO;
7 }
8
9 static void __exit mod_exit( void )
0 {
1     dev_info(pca9555_dev, "mod_exit");
2     device_destroy( pca9555_class, pca9555_dev_number );
3     class_destroy( pca9555_class );
4     cdev_del( driver_object );
5     unregister_chrdev_region( pca9555_dev_number, 1 );
6     i2c_unregister_device( slave );
7     i2c_del_driver(&pca9555_driver);
8     return;
9 }
0 module_init( mod_init );
1 module_exit( mod_exit );
2 MODULE_LICENSE("GPL");