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From: Alexandru M Stan <amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
To: Max Schwarz <max.schwarz-BGeptl67XyCzQB+pC5nmwQ@public.gmane.org>,
	Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
Cc: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Sonny Rao <sonnyrao-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	addy ke <addy.ke-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	ZhengShunQian <zhengsq-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Alexandru M Stan <amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH] i2c: rk3x: fix 0 length write transfers
Date: Wed,  1 Oct 2014 10:40:41 -0700	[thread overview]
Message-ID: <1412185241-24950-1-git-send-email-amstan@chromium.org> (raw)

i2cdetect -q was broken (everything was a false positive, and no transfers were
actually being sent over i2c). The way it works is by sending a 0 length write
request and checking for NACK. This patch fixes the 0 length writes and actually
sends them.

Reported-by: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Signed-off-by: Alexandru M Stan <amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 drivers/i2c/busses/i2c-rk3x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index b41d979..f486d0e 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -238,7 +238,7 @@ static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
 	for (i = 0; i < 8; ++i) {
 		val = 0;
 		for (j = 0; j < 4; ++j) {
-			if (i2c->processed == i2c->msg->len)
+			if ((i2c->processed == i2c->msg->len) && (cnt != 0))
 				break;
 
 			if (i2c->processed == 0 && cnt == 0)
-- 
2.1.0.rc2.206.gedb03e5

             reply	other threads:[~2014-10-01 17:40 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-01 17:40 Alexandru M Stan [this message]
     [not found] ` <1412185241-24950-1-git-send-email-amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2014-10-01 22:47   ` [PATCH] i2c: rk3x: fix 0 length write transfers Doug Anderson
2014-10-02 13:30   ` Max Schwarz
2014-10-03  0:27     ` Wolfram Sang
2014-10-03  0:27   ` Wolfram Sang

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