V4L/DVB (6451): v4l2: add support for bus-based I2C drivers

Two new headers were added: one for I2C drivers that are only used
by V4L2 drivers converted to the new bus-based I2C API, and one that
can be used by both converted and unconverted drivers (at the expense of
some additional overhead).

To support the legacy I2C API a helper function was added to v4l2-common.c.

These headers take care of all the 'boilerplate' code that all V4L2 I2C drivers
have in common and will automatically support the bus-based I2C API introduced
in kernel 2.6.22.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/v4l2-common.c

@@ -1013,6 +1013,35 @@ int v4l2_chip_match_host(u32 match_type, u32 match_chip)
 
 /* ----------------------------------------------------------------- */
 
+/* Helper function for I2C legacy drivers */
+
+int v4l2_i2c_attach(struct i2c_adapter *adapter, int address, struct i2c_driver *driver,
+		const char *name, int (*probe)(struct i2c_client *))
+{
+	struct i2c_client *client;
+	int err;
+
+	client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+	if (client == 0)
+		return -ENOMEM;
+
+	client->addr = address;
+	client->adapter = adapter;
+	client->driver = driver;
+	snprintf(client->name, sizeof(client->name) - 1, name);
+
+	err = probe(client);
+	if (err == 0) {
+		i2c_attach_client(client);
+	}
+	else {
+		kfree(client);
+	}
+	return err;
+}
+
+/* ----------------------------------------------------------------- */
+
 EXPORT_SYMBOL(v4l2_norm_to_name);
 EXPORT_SYMBOL(v4l2_video_std_construct);
 
@@ -1038,6 +1067,8 @@ EXPORT_SYMBOL(v4l2_chip_match_i2c_client);
 EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);
 EXPORT_SYMBOL(v4l2_chip_match_host);
 
+EXPORT_SYMBOL(v4l2_i2c_attach);
+
 /*
  * Local variables:
  * c-basic-offset: 8

include/media/v4l2-common.h

@@ -104,6 +104,17 @@ int v4l2_chip_match_host(u32 id_type, u32 chip_id);
 
 /* ------------------------------------------------------------------------- */
 
+/* Helper function for I2C legacy drivers */
+
+struct i2c_driver;
+struct i2c_adapter;
+struct i2c_client;
+
+int v4l2_i2c_attach(struct i2c_adapter *adapter, int address, struct i2c_driver *driver,
+		const char *name, int (*probe)(struct i2c_client *));
+
+/* ------------------------------------------------------------------------- */
+
 /* Internal ioctls */
 
 /* VIDIOC_INT_DECODE_VBI_LINE */

include/media/v4l2-i2c-drv-legacy.h

@@ -0,0 +1,132 @@
+/*
+ * v4l2-i2c-drv-legacy.h - contains I2C handling code that's identical
+ *		    for all V4L2 I2C drivers. Use this header if the
+ *		    I2C driver is used by both legacy drivers and
+ *		    drivers converted to the bus-based I2C API.
+ *
+ * Copyright (C) 2007 Hans Verkuil <hverkuil@xs4all.nl>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+struct v4l2_i2c_driver_data {
+	const char * const name;
+	int driverid;
+	int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
+	int (*probe)(struct i2c_client *client);
+	int (*remove)(struct i2c_client *client);
+	int (*suspend)(struct i2c_client *client, pm_message_t state);
+	int (*resume)(struct i2c_client *client);
+	int legacy_class;
+};
+
+static struct v4l2_i2c_driver_data v4l2_i2c_data;
+static struct i2c_client_address_data addr_data;
+static struct i2c_driver v4l2_i2c_driver_legacy;
+static char v4l2_i2c_drv_name_legacy[32];
+
+static int v4l2_i2c_drv_attach_legacy(struct i2c_adapter *adapter, int address, int kind)
+{
+	return v4l2_i2c_attach(adapter, address, &v4l2_i2c_driver_legacy,
+			v4l2_i2c_drv_name_legacy, v4l2_i2c_data.probe);
+}
+
+static int v4l2_i2c_drv_probe_legacy(struct i2c_adapter *adapter)
+{
+	if (adapter->class & v4l2_i2c_data.legacy_class)
+		return i2c_probe(adapter, &addr_data, v4l2_i2c_drv_attach_legacy);
+	return 0;
+}
+
+static int v4l2_i2c_drv_detach_legacy(struct i2c_client *client)
+{
+	int err = i2c_detach_client(client);
+
+	if (err)
+		return err;
+	if (v4l2_i2c_data.remove)
+		v4l2_i2c_data.remove(client);
+	kfree(client);
+
+	return 0;
+}
+
+static int v4l2_i2c_drv_suspend_helper(struct i2c_client *client, pm_message_t state)
+{
+	return v4l2_i2c_data.suspend ? v4l2_i2c_data.suspend(client, state) : 0;
+}
+
+static int v4l2_i2c_drv_resume_helper(struct i2c_client *client)
+{
+	return v4l2_i2c_data.resume ? v4l2_i2c_data.resume(client) : 0;
+}
+
+/* ----------------------------------------------------------------------- */
+
+/* i2c implementation */
+static struct i2c_driver v4l2_i2c_driver_legacy = {
+	.driver = {
+		.owner = THIS_MODULE,
+	},
+	.attach_adapter = v4l2_i2c_drv_probe_legacy,
+	.detach_client = v4l2_i2c_drv_detach_legacy,
+	.suspend = v4l2_i2c_drv_suspend_helper,
+	.resume  = v4l2_i2c_drv_resume_helper,
+};
+
+/* ----------------------------------------------------------------------- */
+
+/* i2c implementation */
+static struct i2c_driver v4l2_i2c_driver = {
+	.suspend 	= v4l2_i2c_drv_suspend_helper,
+	.resume  	= v4l2_i2c_drv_resume_helper,
+};
+
+static int __init v4l2_i2c_drv_init(void)
+{
+	int err;
+
+	strlcpy(v4l2_i2c_drv_name_legacy, v4l2_i2c_data.name, sizeof(v4l2_i2c_drv_name_legacy));
+	strlcat(v4l2_i2c_drv_name_legacy, "'", sizeof(v4l2_i2c_drv_name_legacy));
+
+	if (v4l2_i2c_data.legacy_class == 0)
+		v4l2_i2c_data.legacy_class = I2C_CLASS_TV_ANALOG;
+
+	v4l2_i2c_driver_legacy.driver.name = v4l2_i2c_drv_name_legacy;
+	v4l2_i2c_driver_legacy.id = v4l2_i2c_data.driverid;
+	v4l2_i2c_driver_legacy.command = v4l2_i2c_data.command;
+	err = i2c_add_driver(&v4l2_i2c_driver_legacy);
+
+	if (err)
+		return err;
+	v4l2_i2c_driver.driver.name = v4l2_i2c_data.name;
+	v4l2_i2c_driver.id = v4l2_i2c_data.driverid;
+	v4l2_i2c_driver.command = v4l2_i2c_data.command;
+	v4l2_i2c_driver.probe = v4l2_i2c_data.probe;
+	v4l2_i2c_driver.remove = v4l2_i2c_data.remove;
+	err = i2c_add_driver(&v4l2_i2c_driver);
+	if (err)
+		i2c_del_driver(&v4l2_i2c_driver_legacy);
+	return err;
+}
+
+static void __exit v4l2_i2c_drv_cleanup(void)
+{
+	i2c_del_driver(&v4l2_i2c_driver_legacy);
+	i2c_del_driver(&v4l2_i2c_driver);
+}
+
+module_init(v4l2_i2c_drv_init);
+module_exit(v4l2_i2c_drv_cleanup);

include/media/v4l2-i2c-drv.h

@@ -0,0 +1,61 @@
+/*
+ * v4l2-i2c-drv.h - contains I2C handling code that's identical for
+ *		    all V4L2 I2C drivers. Use this header if the
+ *		    I2C driver is only used by drivers converted
+ *		    to the bus-based I2C API.
+ *
+ * Copyright (C) 2007 Hans Verkuil <hverkuil@xs4all.nl>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+struct v4l2_i2c_driver_data {
+	const char * const name;
+	int driverid;
+	int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
+	int (*probe)(struct i2c_client *client);
+	int (*remove)(struct i2c_client *client);
+	int (*suspend)(struct i2c_client *client, pm_message_t state);
+	int (*resume)(struct i2c_client *client);
+	int legacy_class;
+};
+
+static struct v4l2_i2c_driver_data v4l2_i2c_data;
+static struct i2c_client_address_data addr_data;
+static struct i2c_driver v4l2_i2c_driver;
+
+
+/* Bus-based I2C implementation for kernels >= 2.6.22 */
+
+static int __init v4l2_i2c_drv_init(void)
+{
+	v4l2_i2c_driver.driver.name = v4l2_i2c_data.name;
+	v4l2_i2c_driver.id = v4l2_i2c_data.driverid;
+	v4l2_i2c_driver.command = v4l2_i2c_data.command;
+	v4l2_i2c_driver.probe = v4l2_i2c_data.probe;
+	v4l2_i2c_driver.remove = v4l2_i2c_data.remove;
+	v4l2_i2c_driver.suspend = v4l2_i2c_data.suspend;
+	v4l2_i2c_driver.resume = v4l2_i2c_data.resume;
+	return i2c_add_driver(&v4l2_i2c_driver);
+}
+
+
+static void __exit v4l2_i2c_drv_cleanup(void)
+{
+	i2c_del_driver(&v4l2_i2c_driver);
+}
+
+module_init(v4l2_i2c_drv_init);
+module_exit(v4l2_i2c_drv_cleanup);