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Message-Id: <200811251848.47637.hverkuil@xs4all.nl>
Date: Tue, 25 Nov 2008 18:48:47 +0100
From: Hans Verkuil <hverkuil@...all.nl>
To: "Trilok Soni" <soni.trilok@...il.com>
Cc: v4l <video4linux-list@...hat.com>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
"davinci-linux-open-source@...ux.davincidsp.com"
<davinci-linux-open-source@...ux.davincidsp.com>,
linux-kernel@...r.kernel.org
Subject: Re: v4l2_device/v4l2_subdev: please review (PATCH 2/3)
# HG changeset patch
# User Hans Verkuil <hverkuil@...all.nl>
# Date 1227453585 -3600
# Node ID aaf944b194f95c0cc47603c1fc5105cca073c7db
# Parent d9ec70c0b0c55e18813f91218c6da6212ca9b7e6
v4l2-common: add i2c helper functions
From: Hans Verkuil <hverkuil@...all.nl>
Add helper functions to load i2c sub-devices, integrating them
into the v4l2-framework.
Priority: normal
Signed-off-by: Hans Verkuil <hverkuil@...all.nl>
--- a/linux/drivers/media/video/v4l2-common.c Mon Nov 24 22:09:50 2008
+0100
+++ b/linux/drivers/media/video/v4l2-common.c Sun Nov 23 16:19:45 2008
+0100
@@ -58,6 +58,7 @@
#include <asm/div64.h>
#define __OLD_VIDIOC_ /* To allow fixing old calls*/
#include <media/v4l2-common.h>
+#include <media/v4l2-device.h>
#include <media/v4l2-chip-ident.h>
#include <linux/videodev2.h>
@@ -802,4 +803,173 @@ int v4l2_i2c_attach(struct i2c_adapter *
return err != -ENOMEM ? 0 : err;
}
EXPORT_SYMBOL(v4l2_i2c_attach);
-#endif
+
+void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client
*client,
+ const struct v4l2_subdev_ops *ops)
+{
+ v4l2_subdev_init(sd, ops);
+ /* the owner is the same as the i2c_client's driver owner */
+ sd->owner = client->driver->driver.owner;
+ /* i2c_client and v4l2_subdev point to one another */
+ v4l2_set_subdevdata(sd, client);
+ i2c_set_clientdata(client, sd);
+ /* initialize name */
+ snprintf(sd->name, sizeof(sd->name), "%s %d-%04x",
+ client->driver->driver.name, i2c_adapter_id(client->adapter),
+ client->addr);
+}
+EXPORT_SYMBOL(v4l2_i2c_subdev_init);
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 22)
+/* Supporting function to find a client on a specific address on the
+ given adapter. Used for legacy i2c drivers. */
+static struct i2c_client *v4l2_i2c_legacy_find_client(struct
i2c_adapter *adap, u8 addr)
+{
+ struct i2c_client *result = NULL;
+ struct i2c_client *client;
+ struct list_head *item;
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 16)
+ down(&adap->clist_lock);
+#else
+ mutex_lock(&adap->clist_lock);
+#endif
+ list_for_each(item, &adap->clients) {
+ client = list_entry(item, struct i2c_client, list);
+ if (client->addr == addr) {
+ result = client;
+ break;
+ }
+ }
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 16)
+ up(&adap->clist_lock);
+#else
+ mutex_unlock(&adap->clist_lock);
+#endif
+ return result;
+}
+#endif
+
+
+/* Load an i2c sub-device. It assumes that i2c_get_adapdata(adapter)
+ returns the v4l2_device and that i2c_get_clientdata(client)
+ returns the v4l2_subdev. */
+struct v4l2_subdev *v4l2_i2c_new_subdev(struct i2c_adapter *adapter,
+ const char *module_name, const char *client_type, u8 addr)
+{
+ struct v4l2_device *dev = i2c_get_adapdata(adapter);
+ struct v4l2_subdev *sd = NULL;
+ struct i2c_client *client;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 22)
+ struct i2c_board_info info;
+#endif
+
+ BUG_ON(!dev);
+#ifdef MODULE
+ if (module_name)
+ request_module(module_name);
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 22)
+ /* Setup the i2c board info with the device type and
+ the device address. */
+ memset(&info, 0, sizeof(info));
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+ strlcpy(info.driver_name, client_type, sizeof(info.driver_name));
+#else
+ strlcpy(info.type, client_type, sizeof(info.type));
+#endif
+ info.addr = addr;
+
+ /* Create the i2c client */
+ client = i2c_new_device(adapter, &info);
+#else
+ /* Legacy code: loading the module automatically
+ probes and creates the i2c_client on the adapter.
+ Try to find the client by walking the adapter's client list. */
+ client = v4l2_i2c_legacy_find_client(adapter, addr);
+#endif
+ /* Note: it is possible in the future that
+ c->driver is NULL if the driver is still being loaded.
+ We need better support from the kernel so that we
+ can easily wait for the load to finish. */
+ if (client == NULL || client->driver == NULL)
+ return NULL;
+
+ /* Lock the module so we can safely get the v4l2_subdev pointer */
+ if (!try_module_get(client->driver->driver.owner))
+ return NULL;
+ sd = i2c_get_clientdata(client);
+
+ /* Register with the v4l2_device which increases the module's
+ use count as well. */
+ if (v4l2_device_register_subdev(dev, sd))
+ sd = NULL;
+ /* Decrease the module use count to match the first try_module_get. */
+ module_put(client->driver->driver.owner);
+ return sd;
+
+}
+EXPORT_SYMBOL(v4l2_i2c_new_subdev);
+
+/* Probe and load an i2c sub-device. It assumes that
i2c_get_adapdata(adapter)
+ returns the v4l2_device and that i2c_get_clientdata(client)
+ returns the v4l2_subdev. */
+struct v4l2_subdev *v4l2_i2c_new_probed_subdev(struct i2c_adapter
*adapter,
+ const char *module_name, const char *client_type,
+ const unsigned short *addrs)
+{
+ struct v4l2_device *dev = i2c_get_adapdata(adapter);
+ struct v4l2_subdev *sd = NULL;
+ struct i2c_client *client = NULL;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 22)
+ struct i2c_board_info info;
+#endif
+
+ BUG_ON(!dev);
+#ifdef MODULE
+ if (module_name)
+ request_module(module_name);
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 22)
+ /* Setup the i2c board info with the device type and
+ the device address. */
+ memset(&info, 0, sizeof(info));
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+ strlcpy(info.driver_name, client_type, sizeof(info.driver_name));
+#else
+ strlcpy(info.type, client_type, sizeof(info.type));
+#endif
+
+ /* Probe and create the i2c client */
+ client = i2c_new_probed_device(adapter, &info, addrs);
+#else
+ /* Legacy code: loading the module should automatically
+ probe and create the i2c_client on the adapter.
+ Try to find the client by walking the adapter's client list
+ for each of the possible addresses. */
+ while (!client && *addrs != I2C_CLIENT_END)
+ client = v4l2_i2c_legacy_find_client(adapter, *addrs++);
+#endif
+ /* Note: it is possible in the future that
+ c->driver is NULL if the driver is still being loaded.
+ We need better support from the kernel so that we
+ can easily wait for the load to finish. */
+ if (client == NULL || client->driver == NULL)
+ return NULL;
+
+ /* Lock the module so we can safely get the v4l2_subdev pointer */
+ if (!try_module_get(client->driver->driver.owner))
+ return NULL;
+ sd = i2c_get_clientdata(client);
+
+ /* Register with the v4l2_device which increases the module's
+ use count as well. */
+ if (v4l2_device_register_subdev(dev, sd))
+ sd = NULL;
+ /* Decrease the module use count to match the first try_module_get. */
+ module_put(client->driver->driver.owner);
+ return sd;
+}
+EXPORT_SYMBOL(v4l2_i2c_new_probed_subdev);
+
+#endif
--- a/linux/include/media/v4l2-common.h Mon Nov 24 22:09:50 2008 +0100
+++ b/linux/include/media/v4l2-common.h Sun Nov 23 16:19:45 2008 +0100
@@ -53,6 +53,29 @@
do { \
if (debug >= (level)) \
v4l_client_printk(KERN_DEBUG, client, fmt , ## arg); \
+ } while (0)
+
+/* -------------------------------------------------------------------------
*/
+
+/* These printk constructs can be used with v4l2_device and v4l2_subdev
*/
+#define v4l2_printk(level, dev, fmt, arg...) \
+ printk(level "%s: " fmt, (dev)->name , ## arg)
+
+#define v4l2_err(dev, fmt, arg...) \
+ v4l2_printk(KERN_ERR, dev, fmt , ## arg)
+
+#define v4l2_warn(dev, fmt, arg...) \
+ v4l2_printk(KERN_WARNING, dev, fmt , ## arg)
+
+#define v4l2_info(dev, fmt, arg...) \
+ v4l2_printk(KERN_INFO, dev, fmt , ## arg)
+
+/* These three macros assume that the debug level is set with a module
+ parameter called 'debug'. */
+#define v4l2_dbg(level, debug, dev, fmt, arg...) \
+ do { \
+ if (debug >= (level)) \
+ v4l2_printk(KERN_DEBUG, dev, fmt , ## arg); \
} while (0)
/* -------------------------------------------------------------------------
*/
@@ -104,10 +127,28 @@ struct i2c_adapter;
struct i2c_adapter;
struct i2c_client;
struct i2c_device_id;
+struct v4l2_device;
+struct v4l2_subdev;
+struct v4l2_subdev_ops;
int v4l2_i2c_attach(struct i2c_adapter *adapter, int address, struct
i2c_driver *driver,
const char *name,
int (*probe)(struct i2c_client *, const struct i2c_device_id *));
+
+/* Load an i2c module and return an initialized v4l2_subdev struct.
+ Only call request_module if module_name != NULL.
+ The client_type argument is the name of the chip that's on the
adapter. */
+struct v4l2_subdev *v4l2_i2c_new_subdev(struct i2c_adapter *adapter,
+ const char *module_name, const char *client_type, u8 addr);
+/* Probe and load an i2c module and return an initialized v4l2_subdev
struct.
+ Only call request_module if module_name != NULL.
+ The client_type argument is the name of the chip that's on the
adapter. */
+struct v4l2_subdev *v4l2_i2c_new_probed_subdev(struct i2c_adapter
*adapter,
+ const char *module_name, const char *client_type,
+ const unsigned short *addrs);
+/* Initialize an v4l2_subdev with data from an i2c_client struct */
+void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client
*client,
+ const struct v4l2_subdev_ops *ops);
/* -------------------------------------------------------------------------
*/
--
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