i2c: Shrink struct i2c_client
This shrinks the size of "struct i2c_client" by 40 bytes:
- Substantially shrinks the string used to identify the chip type
- The "flags" don't need to be so big
- Removes some internal padding
It also adds kerneldoc for that struct, explaining how "name" is really a
chip type identifier; it's otherwise potentially confusing.
Because the I2C_NAME_SIZE symbol was abused for both i2c_client.name
and for i2c_adapter.name, this needed to affect i2c_adapter too. The
adapters which used that symbol now use the more-obviously-correct
idiom of taking the size of that field.
JD: Shorten i2c_adapter.name from 50 to 48 bytes while we're here, to
avoid wasting space in padding.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 47c2a19..953e71f 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -140,25 +140,30 @@
};
#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
-#define I2C_NAME_SIZE 50
+#define I2C_NAME_SIZE 20
-/*
- * i2c_client identifies a single device (i.e. chip) that is connected to an
- * i2c bus. The behaviour is defined by the routines of the driver. This
- * function is mainly used for lookup & other admin. functions.
+/**
+ * struct i2c_client - represent an I2C slave device
+ * @addr: Address used on the I2C bus connected to the parent adapter.
+ * @name: Indicates the type of the device, usually a chip name that's
+ * generic enough to hide second-sourcing and compatible revisions.
+ * @dev: Driver model device node for the slave.
+ *
+ * An i2c_client identifies a single device (i.e. chip) connected to an
+ * i2c bus. The behaviour is defined by the routines of the driver.
*/
struct i2c_client {
- unsigned int flags; /* div., see below */
+ unsigned short flags; /* div., see below */
unsigned short addr; /* chip address - NOTE: 7bit */
/* addresses are stored in the */
/* _LOWER_ 7 bits */
+ char name[I2C_NAME_SIZE];
struct i2c_adapter *adapter; /* the adapter we sit on */
struct i2c_driver *driver; /* and our access routines */
int usage_count; /* How many accesses currently */
/* to the client */
struct device dev; /* the device structure */
struct list_head list;
- char name[I2C_NAME_SIZE];
struct completion released;
};
#define to_i2c_client(d) container_of(d, struct i2c_client, dev)
@@ -231,7 +236,7 @@
int nr;
struct list_head clients;
struct list_head list;
- char name[I2C_NAME_SIZE];
+ char name[48];
struct completion dev_released;
};
#define dev_to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)