[PATCH 4.8 001/138] i2c: rk3x: Give the tuning value 0 during rk3x_i2c_v0_calc_timings

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Wu <david.wu@xxxxxxxxxxxxxx>

commit 399c168ab5ab5e12ed55b6c91d61c24eb84c9164 upstream.

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@xxxxxxxxxxxxxx>
Tested-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/i2c/busses/i2c-rk3x.c |    2 ++
 1 file changed, 2 insertions(+)

--- 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(unsi
 	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;