LXR linux/drivers/gpu/drm/drm_encoder

   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 */
  47int 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
  90fail_unregister:
  91        i2c_unregister_device(client);
  92        module_put(module);
  93fail:
  94        return err;
  95}
  96EXPORT_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 */
 105void 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}
 116EXPORT_SYMBOL(drm_i2c_encoder_destroy);
 117