Messages in this thread | | | Date | Sun, 12 Oct 2014 14:24:06 -0700 | Subject | Re: [PATCH v4] i2c: rk3x: adjust the LOW divison based on characteristics of SCL | From | Doug Anderson <> |
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Max,
On Sun, Oct 12, 2014 at 5:10 AM, Max Schwarz <max.schwarz@online.de> wrote: >> + /* Adjust to avoid overflow */ >> + i2c_rate_khz = DIV_ROUND_UP(i2c_rate, 1000); >> + scl_rate_khz = DIV_ROUND_UP(scl_rate, 1000); > > I'm not really comfortable with using DIV_ROUND_UP on the last line, since > this may violate the user's set SCL rate. Rounding up 1.1kHz SCL rate to 2kHz > is not good.
Ah, good point. So we round up for i2c_rate and down for scl_rate:
i2c_rate_khz = DIV_ROUND_UP(i2c_rate, 1000); scl_rate_khz = scl_rate / 1000;
> I suggest using scl_rate / 1000 and placing a > > if(WARN_ON(scl_rate < 1000)) > scl_rate = 1000; > > somewhere to prevent scl_rate_khz from becoming 0.
Ah, makes sense. Yeah, that should be at the top.
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