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/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); 126