Date: Sun, 06 Jun 2010 10:02:31 -0500 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: freebsd-embedded@freebsd.org Subject: Review request: iicbus_transfer_gen() repeated start support Message-ID: <4C0BB887.5070103@freebsd.org>
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I committed yesterday some changes to the iicbus_transfer() API that
allow using that interface to send messages containing repeated starts.
The attached patch implements this for the iicbus_transfer_gen() case,
but I don't have any I2C controllers that use this routine, so I can't
test it. I would much appreciate it if someone could review and test the
patch for me.
-Nathan
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Index: iiconf.c
===================================================================
--- iiconf.c (revision 208832)
+++ iiconf.c (working copy)
@@ -363,7 +363,7 @@
int
iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
{
- int i, error, lenread, lenwrote, nkid;
+ int i, error, lenread, lenwrote, nkid, rpstart, addr;
device_t *children, bus;
if ((error = device_get_children(dev, &children, &nkid)) != 0)
@@ -373,14 +373,38 @@
return (EIO);
}
bus = children[0];
+ rpstart = 0;
free(children, M_TEMP);
for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
+ addr = msgs[i].slave;
if (msgs[i].flags & IIC_M_RD)
- error = iicbus_block_read(bus, msgs[i].slave,
- msgs[i].buf, msgs[i].len, &lenread);
+ addr |= LSB;
else
- error = iicbus_block_write(bus, msgs[i].slave,
- msgs[i].buf, msgs[i].len, &lenwrote);
+ addr &= ~LSB;
+
+ if (!(msgs[i].flags & IIC_M_NOSTART)) {
+ if (rpstart)
+ error = iicbus_repeated_start(bus, addr, 0);
+ else
+ error = iicbus_start(bus, addr, 0);
+ }
+
+ if (error)
+ break;
+
+ if (msgs[i].flags & IIC_M_RD)
+ error = iicbus_read(bus, msgs[i].buf, msgs[i].len,
+ &lenread, IIC_LAST_READ, 0);
+ else
+ error = iicbus_write(bus, msgs[i].buf, msgs[i].len,
+ &lenwrote, 0);
+
+ if (!(msgs[i].flags & IIC_M_NOSTOP)) {
+ rpstart = 0;
+ iicbus_stop(bus);
+ } else {
+ rpstart = 1; /* Next message gets repeated start */
+ }
}
return (error);
}
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