From: Mike Ditto <mditto-Vjf7OWgA3BLqlBn2x/YWAg@public.gmane.org>
To: Jochen Friedrich <jochen-NIgtFMG+Po8@public.gmane.org>,
linuxppc-dev-mnsaURCQ41sdnm+yROfE0A@public.gmane.org,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH] i2c-cpm: Detect and report NAK right away instead of timing out.
Date: Fri, 31 Oct 2008 17:29:25 -0700 [thread overview]
Message-ID: <490BA2E5.8010309@consentry.com> (raw)
Make the driver report an ENXIO error immediately upon NAK instead of
waiting for another interrupt and getting a timeout.
Signed-off-by: Mike Ditto <mditto-Vjf7OWgA3BLqlBn2x/YWAg@public.gmane.org>
---
When reading from a device that is not present or declines to respond
to, e.g., a non-existent register address, CPM immediately reports a
NAK condition in the TxBD, but the driver kept waiting until a timeout,
which takes 1 second and causes an ugly console error message.
Index: linux/drivers/i2c/busses/i2c-cpm.c
===================================================================
retrieving revision 1.3
diff -u -p -r1.3 i2c-cpm.c
--- linux/drivers/i2c/busses/i2c-cpm.c 31 Oct 2008 06:36:08 -0000 1.3
+++ linux/drivers/i2c/busses/i2c-cpm.c 1 Nov 2008 00:12:45 -0000
@@ -369,6 +369,7 @@ static int cpm_i2c_xfer(struct i2c_adapt
pmsg = &msgs[tptr];
if (pmsg->flags & I2C_M_RD)
ret = wait_event_interruptible_timeout(cpm->i2c_wait,
+ (in_be16(&tbdf[tptr].cbd_sc) & BD_SC_NAK) ||
!(in_be16(&rbdf[rptr].cbd_sc) & BD_SC_EMPTY),
1 * HZ);
else
WARNING: multiple messages have this Message-ID (diff)
From: Mike Ditto <mditto@consentry.com>
To: Jochen Friedrich <jochen@scram.de>,
linuxppc-dev@ozlabs.org, linux-i2c@vger.kernel.org
Subject: [PATCH] i2c-cpm: Detect and report NAK right away instead of timing out.
Date: Fri, 31 Oct 2008 17:29:25 -0700 [thread overview]
Message-ID: <490BA2E5.8010309@consentry.com> (raw)
Make the driver report an ENXIO error immediately upon NAK instead of
waiting for another interrupt and getting a timeout.
Signed-off-by: Mike Ditto <mditto@consentry.com>
---
When reading from a device that is not present or declines to respond
to, e.g., a non-existent register address, CPM immediately reports a
NAK condition in the TxBD, but the driver kept waiting until a timeout,
which takes 1 second and causes an ugly console error message.
Index: linux/drivers/i2c/busses/i2c-cpm.c
===================================================================
retrieving revision 1.3
diff -u -p -r1.3 i2c-cpm.c
--- linux/drivers/i2c/busses/i2c-cpm.c 31 Oct 2008 06:36:08 -0000 1.3
+++ linux/drivers/i2c/busses/i2c-cpm.c 1 Nov 2008 00:12:45 -0000
@@ -369,6 +369,7 @@ static int cpm_i2c_xfer(struct i2c_adapt
pmsg = &msgs[tptr];
if (pmsg->flags & I2C_M_RD)
ret = wait_event_interruptible_timeout(cpm->i2c_wait,
+ (in_be16(&tbdf[tptr].cbd_sc) & BD_SC_NAK) ||
!(in_be16(&rbdf[rptr].cbd_sc) & BD_SC_EMPTY),
1 * HZ);
else
next reply other threads:[~2008-11-01 0:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-01 0:29 Mike Ditto [this message]
2008-11-01 0:29 ` [PATCH] i2c-cpm: Detect and report NAK right away instead of timing out Mike Ditto
[not found] ` <490BA2E5.8010309-Vjf7OWgA3BLqlBn2x/YWAg@public.gmane.org>
2008-11-03 0:23 ` Ben Dooks
2008-11-03 0:23 ` Ben Dooks
[not found] ` <20081103002328.GC30438-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2008-11-03 3:50 ` Mike Ditto
2008-11-03 3:50 ` Mike Ditto
2008-11-03 11:44 ` Jochen Friedrich
2008-11-03 11:44 ` Jochen Friedrich
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