i2c: Add i2c_board_info and i2c_new_device()
This provides partial support for new-style I2C driver binding. It builds
on "struct i2c_board_info" declarations that identify I2C devices on a given
board. This is needed on systems with I2C devices that can't be fully probed
and/or autoconfigured, such as many embedded Linux configurations where the
way a given I2C device is wired may affect how it must be used.
There are two models for declaring such devices:
* LATE -- using a public function i2c_new_device(). This lets modules
declare I2C devices found *AFTER* a given I2C adapter becomes available.
For example, a PCI card could create adapters giving access to utility
chips on that card, and this would be used to associate those chips with
those adapters.
* EARLY -- from arch_initcall() level code, using a non-exported function
i2c_register_board_info(). This copies the declarations *BEFORE* such
an i2c_adapter becomes available, arranging that i2c_new_device() will
be called later when i2c-core registers the relevant i2c_adapter.
For example, arch/.../.../board-*.c files would declare the I2C devices
along with their platform data, and I2C devices would behave much like
PNPACPI devices. (That is, both enumerate from board-specific tables.)
To match the exported i2c_new_device(), the previously-private function
i2c_unregister_device() is now exported.
Pending later patches using these new APIs, this is effectively a NOP.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/Makefile b/drivers/Makefile
index 920c975..26ca903 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -58,7 +58,7 @@
obj-$(CONFIG_INPUT) += input/
obj-$(CONFIG_I2O) += message/
obj-$(CONFIG_RTC_LIB) += rtc/
-obj-$(CONFIG_I2C) += i2c/
+obj-y += i2c/
obj-$(CONFIG_W1) += w1/
obj-$(CONFIG_HWMON) += hwmon/
obj-$(CONFIG_PHONE) += telephony/
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 11935f6..74c8518 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -22,6 +22,11 @@
This I2C support can also be built as a module. If so, the module
will be called i2c-core.
+config I2C_BOARDINFO
+ boolean
+ depends on I2C
+ default y
+
config I2C_CHARDEV
tristate "I2C device interface"
depends on I2C
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 71c5a85..ba26e6c 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -2,6 +2,7 @@
# Makefile for the i2c core.
#
+obj-$(CONFIG_I2C_BOARDINFO) += i2c-boardinfo.o
obj-$(CONFIG_I2C) += i2c-core.o
obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o
obj-y += busses/ chips/ algos/
diff --git a/drivers/i2c/i2c-boardinfo.c b/drivers/i2c/i2c-boardinfo.c
new file mode 100644
index 0000000..ffb35f0
--- /dev/null
+++ b/drivers/i2c/i2c-boardinfo.c
@@ -0,0 +1,90 @@
+/*
+ * i2c-boardinfo.h - collect pre-declarations of I2C devices
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+
+#include "i2c-core.h"
+
+
+/* These symbols are exported ONLY FOR the i2c core.
+ * No other users will be supported.
+ */
+DEFINE_MUTEX(__i2c_board_lock);
+EXPORT_SYMBOL_GPL(__i2c_board_lock);
+
+LIST_HEAD(__i2c_board_list);
+EXPORT_SYMBOL_GPL(__i2c_board_list);
+
+int __i2c_first_dynamic_bus_num;
+EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num);
+
+
+/**
+ * i2c_register_board_info - statically declare I2C devices
+ * @busnum: identifies the bus to which these devices belong
+ * @info: vector of i2c device descriptors
+ * @len: how many descriptors in the vector; may be zero to reserve
+ * the specified bus number.
+ *
+ * Systems using the Linux I2C driver stack can declare tables of board info
+ * while they initialize. This should be done in board-specific init code
+ * near arch_initcall() time, or equivalent, before any I2C adapter driver is
+ * registered. For example, mainboard init code could define several devices,
+ * as could the init code for each daughtercard in a board stack.
+ *
+ * The I2C devices will be created later, after the adapter for the relevant
+ * bus has been registered. After that moment, standard driver model tools
+ * are used to bind "new style" I2C drivers to the devices. The bus number
+ * for any device declared using this routine is not available for dynamic
+ * allocation.
+ *
+ * The board info passed can safely be __initdata, but be careful of embedded
+ * pointers (for platform_data, functions, etc) since that won't be copied.
+ */
+int __init
+i2c_register_board_info(int busnum,
+ struct i2c_board_info const *info, unsigned len)
+{
+ int status;
+
+ mutex_lock(&__i2c_board_lock);
+
+ /* dynamic bus numbers will be assigned after the last static one */
+ if (busnum >= __i2c_first_dynamic_bus_num)
+ __i2c_first_dynamic_bus_num = busnum + 1;
+
+ for (status = 0; len; len--, info++) {
+ struct i2c_devinfo *devinfo;
+
+ devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
+ if (!devinfo) {
+ pr_debug("i2c-core: can't register boardinfo!\n");
+ status = -ENOMEM;
+ break;
+ }
+
+ devinfo->busnum = busnum;
+ devinfo->board_info = *info;
+ list_add_tail(&devinfo->list, &__i2c_board_list);
+ }
+
+ mutex_unlock(&__i2c_board_lock);
+
+ return status;
+}
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 3aac1b5..a7dcdc6 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -35,6 +35,8 @@
#include <linux/completion.h>
#include <asm/uaccess.h>
+#include "i2c-core.h"
+
static LIST_HEAD(adapters);
static LIST_HEAD(drivers);
@@ -162,6 +164,11 @@
complete(&client->released);
}
+static void i2c_client_dev_release(struct device *dev)
+{
+ kfree(to_i2c_client(dev));
+}
+
static ssize_t show_client_name(struct device *dev, struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
@@ -195,7 +202,60 @@
.resume = i2c_device_resume,
};
-static void i2c_unregister_device(struct i2c_client *client)
+/**
+ * i2c_new_device - instantiate an i2c device for use with a new style driver
+ * @adap: the adapter managing the device
+ * @info: describes one I2C device; bus_num is ignored
+ *
+ * Create a device to work with a new style i2c driver, where binding is
+ * handled through driver model probe()/remove() methods. This call is not
+ * appropriate for use by mainboad initialization logic, which usually runs
+ * during an arch_initcall() long before any i2c_adapter could exist.
+ *
+ * This returns the new i2c client, which may be saved for later use with
+ * i2c_unregister_device(); or NULL to indicate an error.
+ */
+struct i2c_client *
+i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
+{
+ struct i2c_client *client;
+ int status;
+
+ client = kzalloc(sizeof *client, GFP_KERNEL);
+ if (!client)
+ return NULL;
+
+ client->adapter = adap;
+
+ client->dev.platform_data = info->platform_data;
+ client->flags = info->flags;
+ client->addr = info->addr;
+ client->irq = info->irq;
+
+ strlcpy(client->driver_name, info->driver_name,
+ sizeof(client->driver_name));
+ strlcpy(client->name, info->type, sizeof(client->name));
+
+ /* a new style driver may be bound to this device when we
+ * return from this function, or any later moment (e.g. maybe
+ * hotplugging will load the driver module). and the device
+ * refcount model is the standard driver model one.
+ */
+ status = i2c_attach_client(client);
+ if (status < 0) {
+ kfree(client);
+ client = NULL;
+ }
+ return client;
+}
+EXPORT_SYMBOL_GPL(i2c_new_device);
+
+
+/**
+ * i2c_unregister_device - reverse effect of i2c_new_device()
+ * @client: value returned from i2c_new_device()
+ */
+void i2c_unregister_device(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct i2c_driver *driver = client->driver;
@@ -213,6 +273,7 @@
device_unregister(&client->dev);
}
+EXPORT_SYMBOL_GPL(i2c_unregister_device);
/* ------------------------------------------------------------------------- */
@@ -243,6 +304,22 @@
.dev_attrs = i2c_adapter_attrs,
};
+static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
+{
+ struct i2c_devinfo *devinfo;
+
+ mutex_lock(&__i2c_board_lock);
+ list_for_each_entry(devinfo, &__i2c_board_list, list) {
+ if (devinfo->busnum == adapter->nr
+ && !i2c_new_device(adapter,
+ &devinfo->board_info))
+ printk(KERN_ERR "i2c-core: can't create i2c%d-%04x\n",
+ i2c_adapter_id(adapter),
+ devinfo->board_info.addr);
+ }
+ mutex_unlock(&__i2c_board_lock);
+}
+
/* -----
* i2c_add_adapter is called from within the algorithm layer,
@@ -311,7 +388,6 @@
goto out_unlock;
}
-
int i2c_del_adapter(struct i2c_adapter *adap)
{
struct list_head *item, *_n;
@@ -541,9 +617,15 @@
client->usage_count = 0;
client->dev.parent = &client->adapter->dev;
- client->dev.driver = &client->driver->driver;
client->dev.bus = &i2c_bus_type;
- client->dev.release = &i2c_client_release;
+
+ if (client->driver)
+ client->dev.driver = &client->driver->driver;
+
+ if (client->driver && !is_newstyle_driver(client->driver))
+ client->dev.release = i2c_client_release;
+ else
+ client->dev.release = i2c_client_dev_release;
snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),
"%d-%04x", i2c_adapter_id(adapter), client->addr);
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
new file mode 100644
index 0000000..cd5bff8
--- /dev/null
+++ b/drivers/i2c/i2c-core.h
@@ -0,0 +1,31 @@
+/*
+ * i2c-core.h - interfaces internal to the I2C framework
+ *
+ * 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 i2c_devinfo {
+ struct list_head list;
+ int busnum;
+ struct i2c_board_info board_info;
+};
+
+/* board_lock protects board_list and first_dynamic_bus_num.
+ * only i2c core components are allowed to use these symbols.
+ */
+extern struct mutex __i2c_board_lock;
+extern struct list_head __i2c_board_list;
+extern int __i2c_first_dynamic_bus_num;
+