| Message ID | 1477125822-30644-1-git-send-email-david.wu@rock-chips.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi: On 2016年10月22日 16:43, David Wu wrote: > 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@rock-chips.com> > --- > 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; rk3066a based board can't boot up(with endless i2c irq messages print out) from linux-4.8 without this fix. Tested-by: Andy Yan <andy.yan@rock-chips.com>
Hi, On Sat, Oct 22, 2016 at 1:43 AM, David Wu <david.wu@rock-chips.com> wrote: > 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@rock-chips.com> > --- > drivers/i2c/busses/i2c-rk3x.c | 2 ++ > 1 file changed, 2 insertions(+) Reviewed-by: Douglas Anderson <dianders@chromium.org>
On Sat, Oct 22, 2016 at 04:43:42PM +0800, David Wu wrote: > 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@rock-chips.com> Added stable and applied to for-current, thanks!
On Sat, Oct 22, 2016 at 04:43:42PM +0800, David Wu wrote: > 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@rock-chips.com> What I missed to say in my review: Please use a subject line that describes WHY the change is needed not so much WHAT is done. Like: "fix missing initialization causing boot problems"
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;
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@rock-chips.com> --- drivers/i2c/busses/i2c-rk3x.c | 2 ++ 1 file changed, 2 insertions(+)