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 <linux/module.h>
  28
  29 #include "drm_encoder_slave.h"
  30
  31 /**
  32  * drm_i2c_encoder_init - Initialize an I2C slave encoder
  33  * @dev:        DRM device.
  34  * @encoder:    Encoder to be attached to the I2C device. You aren't
  35  *              required to have called drm_encoder_init() before.
  36  * @adap:       I2C adapter that will be used to communicate with
  37  *              the device.
  38  * @info:       Information that will be used to create the I2C device.
  39  *              Required fields are @addr and @type.
  40  *
  41  * Create an I2C device on the specified bus (the module containing its
  42  * driver is transparently loaded) and attach it to the specified
  43  * &drm_encoder_slave. The @slave_funcs field will be initialized with
  44  * the hooks provided by the slave driver.
  45  *
  46  * If @info->platform_data is non-NULL it will be used as the initial
  47  * slave config.
  48  *
  49  * Returns 0 on success or a negative errno on failure, in particular,
  50  * -ENODEV is returned when no matching driver is found.
  51  */
  52 int drm_i2c_encoder_init(struct drm_device *dev,
  53                          struct drm_encoder_slave *encoder,
  54                          struct i2c_adapter *adap,
  55                          const struct i2c_board_info *info)
  56 {
  57         char modalias[sizeof(I2C_MODULE_PREFIX)
  58                       + I2C_NAME_SIZE];
  59         struct module *module = NULL;
  60         struct i2c_client *client;
  61         struct drm_i2c_encoder_driver *encoder_drv;
  62         int err = 0;
  63
  64         snprintf(modalias, sizeof(modalias),
  65                  "%s%s", I2C_MODULE_PREFIX, info->type);
  66         request_module(modalias);
  67
  68         client = i2c_new_device(adap, info);
  69         if (!client) {
  70                 err = -ENOMEM;
  71                 goto fail;
  72         }
  73
  74         if (!client->driver) {
  75                 err = -ENODEV;
  76                 goto fail_unregister;
  77         }
  78
  79         module = client->driver->driver.owner;
  80         if (!try_module_get(module)) {
  81                 err = -ENODEV;
  82                 goto fail_unregister;
  83         }
  84
  85         encoder->bus_priv = client;
  86
  87         encoder_drv = to_drm_i2c_encoder_driver(client->driver);
  88
  89         err = encoder_drv->encoder_init(client, dev, encoder);
  90         if (err)
  91                 goto fail_unregister;
  92
  93         if (info->platform_data)
  94                 encoder->slave_funcs->set_config(&encoder->base,
  95                                                  info->platform_data);
  96
  97         return 0;
  98
  99 fail_unregister:
 100         i2c_unregister_device(client);
 101         module_put(module);
 102 fail:
 103         return err;
 104 }
 105 EXPORT_SYMBOL(drm_i2c_encoder_init);
 106
 107 /**
 108  * drm_i2c_encoder_destroy - Unregister the I2C device backing an encoder
 109  * @drm_encoder:        Encoder to be unregistered.
 110  *
 111  * This should be called from the @destroy method of an I2C slave
 112  * encoder driver once I2C access is no longer needed.
 113  */
 114 void drm_i2c_encoder_destroy(struct drm_encoder *drm_encoder)
 115 {
 116         struct drm_encoder_slave *encoder = to_encoder_slave(drm_encoder);
 117         struct i2c_client *client = drm_i2c_encoder_get_client(drm_encoder);
 118         struct module *module = client->driver->driver.owner;
 119
 120         i2c_unregister_device(client);
 121         encoder->bus_priv = NULL;
 122
 123         module_put(module);
 124 }
 125 EXPORT_SYMBOL(drm_i2c_encoder_destroy);