Root/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 */
52int 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
99fail_unregister:
100    i2c_unregister_device(client);
101    module_put(module);
102fail:
103    return err;
104}
105EXPORT_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 */
114void 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}
125EXPORT_SYMBOL(drm_i2c_encoder_destroy);
126

Archive Download this file



interactive