include/media/v4l2-i2c-drv-legacy.h

   1 /*
   2  * v4l2-i2c-drv-legacy.h - contains I2C handling code that's identical
   3  *                  for all V4L2 I2C drivers. Use this header if the
   4  *                  I2C driver is used by both legacy drivers and
   5  *                  drivers converted to the bus-based I2C API.
   6  *
   7  * Copyright (C) 2007 Hans Verkuil <hverkuil@xs4all.nl>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  */
  23
  24 /* NOTE: the full version of this header is in the v4l-dvb repository
  25  * and allows v4l i2c drivers to be compiled on older kernels as well.
  26  * The version of this header as it appears in the kernel is a stripped
  27  * version (without all the backwards compatibility stuff) and so it
  28  * looks a bit odd.
  29  *
  30  * If you look at the full version then you will understand the reason
  31  * for introducing this header since you really don't want to have all
  32  * the tricky backwards compatibility code in each and every i2c driver.
  33  */
  34
  35 struct v4l2_i2c_driver_data {
  36         const char * const name;
  37         int driverid;
  38         int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
  39         int (*probe)(struct i2c_client *client, const struct i2c_device_id *id);
  40         int (*remove)(struct i2c_client *client);
  41         int (*suspend)(struct i2c_client *client, pm_message_t state);
  42         int (*resume)(struct i2c_client *client);
  43         int (*legacy_probe)(struct i2c_adapter *adapter);
  44         int legacy_class;
  45         const struct i2c_device_id *id_table;
  46 };
  47
  48 static struct v4l2_i2c_driver_data v4l2_i2c_data;
  49 static const struct i2c_client_address_data addr_data;
  50 static struct i2c_driver v4l2_i2c_driver_legacy;
  51 static char v4l2_i2c_drv_name_legacy[32];
  52
  53 static int v4l2_i2c_drv_attach_legacy(struct i2c_adapter *adapter, int address, int kind)
  54 {
  55         return v4l2_i2c_attach(adapter, address, &v4l2_i2c_driver_legacy,
  56                         v4l2_i2c_drv_name_legacy, v4l2_i2c_data.probe);
  57 }
  58
  59 static int v4l2_i2c_drv_probe_legacy(struct i2c_adapter *adapter)
  60 {
  61         if (v4l2_i2c_data.legacy_probe) {
  62                 if (v4l2_i2c_data.legacy_probe(adapter))
  63                         return i2c_probe(adapter, &addr_data, v4l2_i2c_drv_attach_legacy);
  64                 return 0;
  65         }
  66         if (adapter->class & v4l2_i2c_data.legacy_class)
  67                 return i2c_probe(adapter, &addr_data, v4l2_i2c_drv_attach_legacy);
  68         return 0;
  69 }
  70
  71 static int v4l2_i2c_drv_detach_legacy(struct i2c_client *client)
  72 {
  73         int err;
  74
  75         if (v4l2_i2c_data.remove)
  76                 v4l2_i2c_data.remove(client);
  77
  78         err = i2c_detach_client(client);
  79         if (err)
  80                 return err;
  81         kfree(client);
  82         return 0;
  83 }
  84
  85 static int v4l2_i2c_drv_suspend_helper(struct i2c_client *client, pm_message_t state)
  86 {
  87         return v4l2_i2c_data.suspend ? v4l2_i2c_data.suspend(client, state) : 0;
  88 }
  89
  90 static int v4l2_i2c_drv_resume_helper(struct i2c_client *client)
  91 {
  92         return v4l2_i2c_data.resume ? v4l2_i2c_data.resume(client) : 0;
  93 }
  94
  95 /* ----------------------------------------------------------------------- */
  96
  97 /* i2c implementation */
  98 static struct i2c_driver v4l2_i2c_driver_legacy = {
  99         .driver = {
 100                 .owner = THIS_MODULE,
 101         },
 102         .attach_adapter = v4l2_i2c_drv_probe_legacy,
 103         .detach_client = v4l2_i2c_drv_detach_legacy,
 104         .suspend = v4l2_i2c_drv_suspend_helper,
 105         .resume  = v4l2_i2c_drv_resume_helper,
 106 };
 107
 108 /* ----------------------------------------------------------------------- */
 109
 110 /* i2c implementation */
 111 static struct i2c_driver v4l2_i2c_driver = {
 112         .suspend        = v4l2_i2c_drv_suspend_helper,
 113         .resume         = v4l2_i2c_drv_resume_helper,
 114 };
 115
 116 static int __init v4l2_i2c_drv_init(void)
 117 {
 118         int err;
 119
 120         strlcpy(v4l2_i2c_drv_name_legacy, v4l2_i2c_data.name, sizeof(v4l2_i2c_drv_name_legacy));
 121         strlcat(v4l2_i2c_drv_name_legacy, "'", sizeof(v4l2_i2c_drv_name_legacy));
 122
 123         if (v4l2_i2c_data.legacy_class == 0)
 124                 v4l2_i2c_data.legacy_class = I2C_CLASS_TV_ANALOG;
 125
 126         v4l2_i2c_driver_legacy.driver.name = v4l2_i2c_drv_name_legacy;
 127         v4l2_i2c_driver_legacy.id = v4l2_i2c_data.driverid;
 128         v4l2_i2c_driver_legacy.command = v4l2_i2c_data.command;
 129         err = i2c_add_driver(&v4l2_i2c_driver_legacy);
 130
 131         if (err)
 132                 return err;
 133         v4l2_i2c_driver.driver.name = v4l2_i2c_data.name;
 134         v4l2_i2c_driver.id = v4l2_i2c_data.driverid;
 135         v4l2_i2c_driver.command = v4l2_i2c_data.command;
 136         v4l2_i2c_driver.probe = v4l2_i2c_data.probe;
 137         v4l2_i2c_driver.remove = v4l2_i2c_data.remove;
 138         v4l2_i2c_driver.id_table = v4l2_i2c_data.id_table;
 139         err = i2c_add_driver(&v4l2_i2c_driver);
 140         if (err)
 141                 i2c_del_driver(&v4l2_i2c_driver_legacy);
 142         return err;
 143 }
 144
 145 static void __exit v4l2_i2c_drv_cleanup(void)
 146 {
 147         i2c_del_driver(&v4l2_i2c_driver_legacy);
 148         i2c_del_driver(&v4l2_i2c_driver);
 149 }
 150
 151 module_init(v4l2_i2c_drv_init);
 152 module_exit(v4l2_i2c_drv_cleanup);