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authorHans Verkuil <hverkuil@xs4all.nl>2009-06-19 16:58:21 +0200
committerJean Delvare <khali@linux-fr.org>2009-06-19 16:58:21 +0200
commitc70366732f67dbdb32f7fe9c6aa59299b76feca6 (patch)
tree3e091c303c478759f5bf67bcc7f06cfd3f989adb /include/linux/i2c.h
parent23af8400571ac4431fac0caefeac18f8aef490df (diff)
i2c: New macro to initialize i2c address lists on the fly
For video4linux we sometimes need to probe for a single i2c address. Normally you would do it like this: static const unsigned short addrs[] = { addr, I2C_CLIENT_END }; client = i2c_new_probed_device(adapter, &info, addrs); This is a bit awkward and I came up with this macro: #define V4L2_I2C_ADDRS(addr, addrs...) \ ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END }) This can construct a list of one or more i2c addresses on the fly. But this is something that really belongs in i2c.h, renamed to I2C_ADDRS. With this macro we can just do: client = i2c_new_probed_device(adapter, &info, I2C_ADDRS(addr)); Note that this can also be used to initialize an array: static const unsigned short addrs[] = I2C_ADDRS(0x2a, 0x2c); Whether you want to is another matter, but it works. This functionality is also available in the oldest supported gcc (3.2). Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'include/linux/i2c.h')
-rw-r--r--include/linux/i2c.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index bc17f7fa7d3..f4784c0fe97 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -393,6 +393,10 @@ struct i2c_client_address_data {
/* The numbers to use to set I2C bus address */
#define ANY_I2C_BUS 0xffff
+/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
+#define I2C_ADDRS(addr, addrs...) \
+ ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
+
/* ----- functions exported by i2c.o */