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authorWolfram Sang <wsa@the-dreams.de>2014-02-10 11:03:56 +0100
committerWolfram Sang <wsa@the-dreams.de>2014-03-05 17:16:45 +0100
commit0c176170089c3a7f2a891f9860f5cdc5f481ff78 (patch)
treeb86e44370013676481e49c57c7e46d65190d9203
parent624df09f3a20b7073289d7f7d8672734ca1339a9 (diff)
i2c: add deprecation warning for class based instantiation
Class based instantiation can cause noticeable delays when booting. This mechanism is used when it is not possible to describe slaves on I2C busses. As we do have other mechanisms, most embedded I2C will not need classes and for embedded it is explicitly not recommended to use them. Add a deprecation warning for drivers which want to disable class based instantiation in the near future to gain boot-up time, so users relying on this technique can switch to something better. They really should. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
-rw-r--r--drivers/i2c/i2c-core.c7
-rw-r--r--include/linux/i2c.h1
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 5fb80b8962a2..98a5fd950f16 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1941,6 +1941,13 @@ static int i2c_detect_address(struct i2c_client *temp_client,
struct i2c_client *client;
/* Detection succeeded, instantiate the device */
+ if (adapter->class & I2C_CLASS_DEPRECATED)
+ dev_warn(&adapter->dev,
+ "This adapter will soon drop class based instantiation of devices. "
+ "Please make sure client 0x%02x gets instantiated by other means. "
+ "Check 'Documentation/i2c/instantiating-devices' for details.\n",
+ info.addr);
+
dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
info.type, info.addr);
client = i2c_new_device(adapter, &info);
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index deddeb8c337c..b556e0ab946f 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -487,6 +487,7 @@ void i2c_unlock_adapter(struct i2c_adapter *);
#define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
#define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
#define I2C_CLASS_SPD (1<<7) /* Memory modules */
+#define I2C_CLASS_DEPRECATED (1<<8) /* Warn users that adapter will stop using classes */
/* Internal numbers to terminate lists */
#define I2C_CLIENT_END 0xfffeU