On Monday 08 June 2009 14:39:32 Jean Delvare wrote:
> Hi Hans,
>
> On Sat, 6 Jun 2009 15:00:48 +0200, Hans Verkuil wrote:
> > 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));
> >
> > Comments?
>
> I'm not a big fan of macros which hide how things work, but if this
> makes your life easier, why not. Just send a patch and I'll queue it up
> for 2.6.31.
Hi Jean,
Here it is:
--- linux-git/include/linux/i2c.h.orig 2009-06-09 14:53:32.000000000 +0200
+++ linux-git/include/linux/i2c.h 2009-06-09 15:03:24.000000000 +0200
@@ -412,6 +412,10 @@
/* 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 */
Signed-off-by: Hans Verkuil <hverkuil@xxxxxxxxx>
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).
Thanks,
Hans
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
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