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From: David Wu <david.wu-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
To: heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org,
	wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org
Cc: dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	David Wu <david.wu-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
Subject: [PATCH] i2c: rk3x: Give the tuning value 0 during rk3x_i2c_v0_calc_timings
Date: Sat, 22 Oct 2016 16:43:42 +0800	[thread overview]
Message-ID: <1477125822-30644-1-git-send-email-david.wu@rock-chips.com> (raw)

We found a bug that i2c transfer sometimes failed on 3066a board with
stabel-4.8, the con register would be updated by uninitialized tuning
value, it made the i2c transfer failed.

So give the tuning value to be zero during rk3x_i2c_v0_calc_timings.

Signed-off-by: David Wu <david.wu-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
---
 drivers/i2c/busses/i2c-rk3x.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 50702c7..df22066 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -694,6 +694,8 @@ static int rk3x_i2c_v0_calc_timings(unsigned long clk_rate,
 	t_calc->div_low--;
 	t_calc->div_high--;
 
+	/* Give the tuning value 0, that would not update con register */
+	t_calc->tuning = 0;
 	/* Maximum divider supported by hw is 0xffff */
 	if (t_calc->div_low > 0xffff) {
 		t_calc->div_low = 0xffff;
-- 
1.9.1


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             reply	other threads:[~2016-10-22  8:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-22  8:43 David Wu [this message]
2016-10-24 11:55 ` [PATCH] i2c: rk3x: Give the tuning value 0 during rk3x_i2c_v0_calc_timings Andy Yan
2016-10-24 18:29 ` Doug Anderson
2016-10-25  9:12 ` Wolfram Sang
     [not found] ` <1477125822-30644-1-git-send-email-david.wu-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2016-10-27 13:11   ` Wolfram Sang

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