drm/kms: slave encoder interface.

Define some helper functions to make easier to detach a KMS encoder
implementation from the drm module of the GPU it's used in. This is
mainly useful for some external I2C encoders known to be present on
cards with GPUs from several different manufacturers.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/Makefile

@@ -11,7 +11,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_agpsupport.o drm_scatter.o ati_pcigart.o drm_pci.o \
 		drm_sysfs.o drm_hashtab.o drm_sman.o drm_mm.o \
 		drm_crtc.o drm_crtc_helper.o drm_modes.o drm_edid.o \
-		drm_info.o drm_debugfs.o
+		drm_info.o drm_debugfs.o drm_encoder_slave.o
 
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 

drivers/gpu/drm/drm_encoder_slave.c

+/*
+ * 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);

include/drm/drm_encoder_slave.h

+/*
+ * 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.
+ *
+ */
+
+#ifndef __DRM_ENCODER_SLAVE_H__
+#define __DRM_ENCODER_SLAVE_H__
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+
+/**
+ * struct drm_encoder_slave_funcs - Entry points exposed by a slave encoder driver
+ * @set_config:	Initialize any encoder-specific modesetting parameters.
+ *		The meaning of the @params parameter is implementation
+ *		dependent. It will usually be a structure with DVO port
+ *		data format settings or timings. It's not required for
+ *		the new parameters to take effect until the next mode
+ *		is set.
+ *
+ * Most of its members are analogous to the function pointers in
+ * &drm_encoder_helper_funcs and they can optionally be used to
+ * initialize the latter. Connector-like methods (e.g. @get_modes and
+ * @set_property) will typically be wrapped around and only be called
+ * if the encoder is the currently selected one for the connector.
+ */
+struct drm_encoder_slave_funcs {
+	void (*set_config)(struct drm_encoder *encoder,
+			   void *params);
+
+	void (*destroy)(struct drm_encoder *encoder);
+	void (*dpms)(struct drm_encoder *encoder, int mode);
+	void (*save)(struct drm_encoder *encoder);
+	void (*restore)(struct drm_encoder *encoder);
+	bool (*mode_fixup)(struct drm_encoder *encoder,
+			   struct drm_display_mode *mode,
+			   struct drm_display_mode *adjusted_mode);
+	int (*mode_valid)(struct drm_encoder *encoder,
+			  struct drm_display_mode *mode);
+	void (*mode_set)(struct drm_encoder *encoder,
+			 struct drm_display_mode *mode,
+			 struct drm_display_mode *adjusted_mode);
+
+	enum drm_connector_status (*detect)(struct drm_encoder *encoder,
+					    struct drm_connector *connector);
+	int (*get_modes)(struct drm_encoder *encoder,
+			 struct drm_connector *connector);
+	int (*create_resources)(struct drm_encoder *encoder,
+				 struct drm_connector *connector);
+	int (*set_property)(struct drm_encoder *encoder,
+			    struct drm_connector *connector,
+			    struct drm_property *property,
+			    uint64_t val);
+
+};
+
+/**
+ * struct drm_encoder_slave - Slave encoder struct
+ * @base: DRM encoder object.
+ * @slave_funcs: Slave encoder callbacks.
+ * @slave_priv: Slave encoder private data.
+ * @bus_priv: Bus specific data.
+ *
+ * A &drm_encoder_slave has two sets of callbacks, @slave_funcs and the
+ * ones in @base. The former are never actually called by the common
+ * CRTC code, it's just a convenience for splitting the encoder
+ * functions in an upper, GPU-specific layer and a (hopefully)
+ * GPU-agnostic lower layer: It's the GPU driver responsibility to
+ * call the slave methods when appropriate.
+ *
+ * drm_i2c_encoder_init() provides a way to get an implementation of
+ * this.
+ */
+struct drm_encoder_slave {
+	struct drm_encoder base;
+
+	struct drm_encoder_slave_funcs *slave_funcs;
+	void *slave_priv;
+	void *bus_priv;
+};
+#define to_encoder_slave(x) container_of((x), struct drm_encoder_slave, base)
+
+int drm_i2c_encoder_init(struct drm_device *dev,
+			 struct drm_encoder_slave *encoder,
+			 struct i2c_adapter *adap,
+			 const struct i2c_board_info *info);
+
+
+/**
+ * struct drm_i2c_encoder_driver
+ *
+ * Describes a device driver for an encoder connected to the GPU
+ * through an I2C bus. In addition to the entry points in @i2c_driver
+ * an @encoder_init function should be provided. It will be called to
+ * give the driver an opportunity to allocate any per-encoder data
+ * structures and to initialize the @slave_funcs and (optionally)
+ * @slave_priv members of @encoder.
+ */
+struct drm_i2c_encoder_driver {
+	struct i2c_driver i2c_driver;
+
+	int (*encoder_init)(struct i2c_client *client,
+			    struct drm_device *dev,
+			    struct drm_encoder_slave *encoder);
+
+};
+#define to_drm_i2c_encoder_driver(x) container_of((x),			\
+						  struct drm_i2c_encoder_driver, \
+						  i2c_driver)
+
+/**
+ * drm_i2c_encoder_get_client - Get the I2C client corresponding to an encoder
+ */
+static inline struct i2c_client *drm_i2c_encoder_get_client(struct drm_encoder *encoder)
+{
+	return (struct i2c_client *)to_encoder_slave(encoder)->bus_priv;
+}
+
+/**
+ * drm_i2c_encoder_register - Register an I2C encoder driver
+ * @owner:	Module containing the driver.
+ * @driver:	Driver to be registered.
+ */
+static inline int drm_i2c_encoder_register(struct module *owner,
+					   struct drm_i2c_encoder_driver *driver)
+{
+	return i2c_register_driver(owner, &driver->i2c_driver);
+}
+
+/**
+ * drm_i2c_encoder_unregister - Unregister an I2C encoder driver
+ * @driver:	Driver to be unregistered.
+ */
+static inline void drm_i2c_encoder_unregister(struct drm_i2c_encoder_driver *driver)
+{
+	return i2c_del_driver(&driver->i2c_driver);
+}
+
+void drm_i2c_encoder_destroy(struct drm_encoder *encoder);
+
+#endif