From c70366732f67dbdb32f7fe9c6aa59299b76feca6 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 19 Jun 2009 16:58:21 +0200 Subject: [PATCH] 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 Signed-off-by: Jean Delvare --- include/linux/i2c.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/i2c.h b/include/linux/i2c.h index bc17f7fa7d39..f4784c0fe975 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 */ -- 2.20.1