From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandru M Stan Subject: [PATCH] i2c: rk3x: fix 0 length write transfers Date: Wed, 1 Oct 2014 10:40:41 -0700 Message-ID: <1412185241-24950-1-git-send-email-amstan@chromium.org> Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Max Schwarz , Wolfram Sang Cc: Doug Anderson , Sonny Rao , addy ke , Jeffy Chen , ZhengShunQian , linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Alexandru M Stan , 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 List-Id: linux-i2c@vger.kernel.org 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 Signed-off-by: Alexandru M Stan --- 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