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  * If @info->platform_data is non-NULL it will be used as the initial
  45  * slave config.
  46  *
  47  * Returns 0 on success or a negative errno on failure, in particular,
  48  * -ENODEV is returned when no matching driver is found.
  49  */
  50 int drm_i2c_encoder_init(struct drm_device *dev,
  51                          struct drm_encoder_slave *encoder,
  52                          struct i2c_adapter *adap,
  53                          const struct i2c_board_info *info)
  54 {
  55         char modalias[sizeof(I2C_MODULE_PREFIX)
  56                       + I2C_NAME_SIZE];
  57         struct module *module = NULL;
  58         struct i2c_client *client;
  59         struct drm_i2c_encoder_driver *encoder_drv;
  60         int err = 0;
  61
  62         snprintf(modalias, sizeof(modalias),
  63                  "%s%s", I2C_MODULE_PREFIX, info->type);
  64         request_module(modalias);
  65
  66         client = i2c_new_device(adap, info);
  67         if (!client) {
  68                 err = -ENOMEM;
  69                 goto fail;
  70         }
  71
  72         if (!client->driver) {
  73                 err = -ENODEV;
  74                 goto fail_unregister;
  75         }
  76
  77         module = client->driver->driver.owner;
  78         if (!try_module_get(module)) {
  79                 err = -ENODEV;
  80                 goto fail_unregister;
  81         }
  82
  83         encoder->bus_priv = client;
  84
  85         encoder_drv = to_drm_i2c_encoder_driver(client->driver);
  86
  87         err = encoder_drv->encoder_init(client, dev, encoder);
  88         if (err)
  89                 goto fail_unregister;
  90
  91         if (info->platform_data)
  92                 encoder->slave_funcs->set_config(&encoder->base,
  93                                                  info->platform_data);
  94
  95         return 0;
  96
  97 fail_unregister:
  98         i2c_unregister_device(client);
  99         module_put(module);
 100 fail:
 101         return err;
 102 }
 103 EXPORT_SYMBOL(drm_i2c_encoder_init);
 104
 105 /**
 106  * drm_i2c_encoder_destroy - Unregister the I2C device backing an encoder
 107  * @drm_encoder:        Encoder to be unregistered.
 108  *
 109  * This should be called from the @destroy method of an I2C slave
 110  * encoder driver once I2C access is no longer needed.
 111  */
 112 void drm_i2c_encoder_destroy(struct drm_encoder *drm_encoder)
 113 {
 114         struct drm_encoder_slave *encoder = to_encoder_slave(drm_encoder);
 115         struct i2c_client *client = drm_i2c_encoder_get_client(drm_encoder);
 116         struct module *module = client->driver->driver.owner;
 117
 118         i2c_unregister_device(client);
 119         encoder->bus_priv = NULL;
 120
 121         module_put(module);
 122 }
 123 EXPORT_SYMBOL(drm_i2c_encoder_destroy);