1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_encoder_slave.c b/drivers/gpu/drm/drm_encoder_slave.c
new file mode 100644
index 000000000000..6ffd600ccfae
--- /dev/null
+++ b/drivers/gpu/drm/drm_encoder_slave.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2009 Francisco Jerez.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#include <drm/drm_encoder_slave.h>
+
+/**
+ * drm_i2c_encoder_init - Initialize an I2C slave encoder
+ * @dev:	DRM device.
+ * @encoder:    Encoder to be attached to the I2C device. You aren't
+ *		required to have called drm_encoder_init() before.
+ * @adap:	I2C adapter that will be used to communicate with
+ *		the device.
+ * @info:	Information that will be used to create the I2C device.
+ *		Required fields are @addr and @type.
+ *
+ * Create an I2C device on the specified bus (the module containing its
+ * driver is transparently loaded) and attach it to the specified
+ * &drm_encoder_slave. The @slave_funcs field will be initialized with
+ * the hooks provided by the slave driver.
+ *
+ * Returns 0 on success or a negative errno on failure, in particular,
+ * -ENODEV is returned when no matching driver is found.
+ */
+int drm_i2c_encoder_init(struct drm_device *dev,
+			 struct drm_encoder_slave *encoder,
+			 struct i2c_adapter *adap,
+			 const struct i2c_board_info *info)
+{
+	char modalias[sizeof(I2C_MODULE_PREFIX)
+		      + I2C_NAME_SIZE];
+	struct module *module = NULL;
+	struct i2c_client *client;
+	struct drm_i2c_encoder_driver *encoder_drv;
+	int err = 0;
+
+	snprintf(modalias, sizeof(modalias),
+		 "%s%s", I2C_MODULE_PREFIX, info->type);
+	request_module(modalias);
+
+	client = i2c_new_device(adap, info);
+	if (!client) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	if (!client->driver) {
+		err = -ENODEV;
+		goto fail_unregister;
+	}
+
+	module = client->driver->driver.owner;
+	if (!try_module_get(module)) {
+		err = -ENODEV;
+		goto fail_unregister;
+	}
+
+	encoder->bus_priv = client;
+
+	encoder_drv = to_drm_i2c_encoder_driver(client->driver);
+
+	err = encoder_drv->encoder_init(client, dev, encoder);
+	if (err)
+		goto fail_unregister;
+
+	return 0;
+
+fail_unregister:
+	i2c_unregister_device(client);
+	module_put(module);
+fail:
+	return err;
+}
+EXPORT_SYMBOL(drm_i2c_encoder_init);
+
+/**
+ * drm_i2c_encoder_destroy - Unregister the I2C device backing an encoder
+ * @drm_encoder:	Encoder to be unregistered.
+ *
+ * This should be called from the @destroy method of an I2C slave
+ * encoder driver once I2C access is no longer needed.
+ */
+void drm_i2c_encoder_destroy(struct drm_encoder *drm_encoder)
+{
+	struct drm_encoder_slave *encoder = to_encoder_slave(drm_encoder);
+	struct i2c_client *client = drm_i2c_encoder_get_client(drm_encoder);
+	struct module *module = client->driver->driver.owner;
+
+	i2c_unregister_device(client);
+	encoder->bus_priv = NULL;
+
+	module_put(module);
+}
+EXPORT_SYMBOL(drm_i2c_encoder_destroy);