From: "David.Wu" <david.wu@rock-chips.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: heiko@sntech.de, dianders@chromium.org,
andy.shevchenko@gmail.com, huangtao@rock-chips.com,
hl@rock-chips.com, xjq@rock-chips.com, zyw@rock-chips.com,
cf@rock-chips.com, linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-i2c@vger.kernel.org,
linux-kernel@vger.kernel.org, David Wu <wdc@rock-chips.com>
Subject: Re: [PATCH v5 2/2] i2c: rk3x: add i2c support for rk3399 soc
Date: Fri, 15 Apr 2016 20:10:16 +0800 [thread overview]
Message-ID: <5710DA28.6010104@rock-chips.com> (raw)
In-Reply-To: <20160414184848.GB2338@katana>
Hi Wolfram,
在 2016/4/15 2:48, Wolfram Sang 写道:
>> + - input-clk-rate : frequency rate of function clock used(in Hz). If omitted,
>> + the default clock rate is used. It is just used at rk3399 soc.
> Why is this needed? Why don't we simply use the default or calculate the
> best value somehow?
The default frequency rate of function clock is 50M Hz, it can match F/S
mode,
but HS mode not. If use default rate 50M to get 1.7M scl-frequency rate
, we could not
get accurately 1.7M frequecy rate. The input-clk-rate is more higher, we
get more
accurately scl-frequency rate, as 200M is a suitable input-clk-rate.
If 200M was used for F/S mode, it would increase power consumption, so
add a option that
could be configured from DT.
>> + * @t_calc: Caculated rk3x private timings that would
>> + * be written into regs
> double space
>
next prev parent reply other threads:[~2016-04-15 12:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-16 16:57 [PATCH v5 0/2] updates for rk3399 i2c support David Wu
2016-03-16 16:57 ` [PATCH v5 1/2] i2c: rk3x: switch to i2c generic dt parsing David Wu
2016-04-14 18:39 ` Wolfram Sang
2016-03-16 16:57 ` [PATCH v5 2/2] i2c: rk3x: add i2c support for rk3399 soc David Wu
2016-04-14 18:48 ` Wolfram Sang
2016-04-15 7:31 ` Heiko Stübner
2016-04-15 12:12 ` David.Wu
2016-04-15 12:10 ` David.Wu [this message]
2016-04-15 17:58 ` Wolfram Sang
2016-04-18 13:15 ` David.Wu
2016-04-15 12:17 ` Heiko Stübner
2016-04-19 13:55 ` [PATCH v6] " David Wu
2016-04-21 22:00 ` Andy Shevchenko
2016-04-27 20:56 ` Doug Anderson
[not found] ` <572212AE.5060904@rock-chips.com>
2016-04-28 21:28 ` Doug Anderson
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