drivers/gpu/drm/drm_encoder_slave.c

   1 /*
   2  * Copyright (C) 2009 Francisco Jerez.
   3  * All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining
   6  * a copy of this software and associated documentation files (the
   7  * "Software"), to deal in the Software without restriction, including
   8  * without limitation the rights to use, copy, modify, merge, publish,
   9  * distribute, sublicense, and/or sell copies of the Software, and to
  10  * permit persons to whom the Software is furnished to do so, subject to
  11  * the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the
  14  * next paragraph) shall be included in all copies or substantial
  15  * portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  20  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
  21  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  22  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  23  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  */
  26
  27 #include "drm_encoder_slave.h"
  28
  29 /**
  30  * drm_i2c_encoder_init - Initialize an I2C slave encoder
  31  * @dev:        DRM device.
  32  * @encoder:    Encoder to be attached to the I2C device. You aren't
  33  *              required to have called drm_encoder_init() before.
  34  * @adap:       I2C adapter that will be used to communicate with
  35  *              the device.
  36  * @info:       Information that will be used to create the I2C device.
  37  *              Required fields are @addr and @type.
  38  *
  39  * Create an I2C device on the specified bus (the module containing its
  40  * driver is transparently loaded) and attach it to the specified
  41  * &drm_encoder_slave. The @slave_funcs field will be initialized with
  42  * the hooks provided by the slave driver.
  43  *
  44  * Returns 0 on success or a negative errno on failure, in particular,
  45  * -ENODEV is returned when no matching driver is found.
  46  */
  47 int drm_i2c_encoder_init(struct drm_device *dev,
  48                          struct drm_encoder_slave *encoder,
  49                          struct i2c_adapter *adap,
  50                          const struct i2c_board_info *info)
  51 {
  52         char modalias[sizeof(I2C_MODULE_PREFIX)
  53                       + I2C_NAME_SIZE];
  54         struct module *module = NULL;
  55         struct i2c_client *client;
  56         struct drm_i2c_encoder_driver *encoder_drv;
  57         int err = 0;
  58
  59         snprintf(modalias, sizeof(modalias),
  60                  "%s%s", I2C_MODULE_PREFIX, info->type);
  61         request_module(modalias);
  62
  63         client = i2c_new_device(adap, info);
  64         if (!client) {
  65                 err = -ENOMEM;
  66                 goto fail;
  67         }
  68
  69         if (!client->driver) {
  70                 err = -ENODEV;
  71                 goto fail_unregister;
  72         }
  73
  74         module = client->driver->driver.owner;
  75         if (!try_module_get(module)) {
  76                 err = -ENODEV;
  77                 goto fail_unregister;
  78         }
  79
  80         encoder->bus_priv = client;
  81
  82         encoder_drv = to_drm_i2c_encoder_driver(client->driver);
  83
  84         err = encoder_drv->encoder_init(client, dev, encoder);
  85         if (err)
  86                 goto fail_unregister;
  87
  88         return 0;
  89
  90 fail_unregister:
  91         i2c_unregister_device(client);
  92         module_put(module);
  93 fail:
  94         return err;
  95 }
  96 EXPORT_SYMBOL(drm_i2c_encoder_init);
  97
  98 /**
  99  * drm_i2c_encoder_destroy - Unregister the I2C device backing an encoder
 100  * @drm_encoder:        Encoder to be unregistered.
 101  *
 102  * This should be called from the @destroy method of an I2C slave
 103  * encoder driver once I2C access is no longer needed.
 104  */
 105 void drm_i2c_encoder_destroy(struct drm_encoder *drm_encoder)
 106 {
 107         struct drm_encoder_slave *encoder = to_encoder_slave(drm_encoder);
 108         struct i2c_client *client = drm_i2c_encoder_get_client(drm_encoder);
 109         struct module *module = client->driver->driver.owner;
 110
 111         i2c_unregister_device(client);
 112         encoder->bus_priv = NULL;
 113
 114         module_put(module);
 115 }
 116 EXPORT_SYMBOL(drm_i2c_encoder_destroy);