From: Hans Verkuil <hverkuil@xs4all.nl>
Date: Fri, 19 Jun 2009 14:58:21 +0000 (+0200)
Subject: i2c: New macro to initialize i2c address lists on the fly
X-Git-Tag: v3.0~8748^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c70366732f67dbdb32f7fe9c6aa59299b76feca6;p=platform%2Fkernel%2Flinux-amlogic.git

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>
---

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index bc17f7f..f4784c0 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 */