Hi guys,
Any comments?
2013/7/2 James Lebron <leileishangchina@xxxxxxxxx>:
> Hi Wolfram
>
> Have you finished reading datasheet?
>
> 2013/6/15 Wolfram Sang <wsa@xxxxxxxxxxxxx>:
>> Hi,
>>
>> On Fri, Jun 07, 2013 at 02:38:17PM +0800, Leilei Shang wrote:
>>> To enter high speed mode, following steps should be done:
>>> 1. When running in high speed mode, i2c clock rate is different
>>> from standard mode. Clock rate must be set according to
>>> specification first.
>>> 2. When i2c controller sends a master code and wins arbitration,
>>> high speed mode is entered.
>>>
>>> If you want to enable high speed mode, the following members of
>>> platform data should be set to proper value:
>>
>> I couldn't find any support for hs-mode in pxa2xx and pxa3xx. So it
>> shouldn't be set in platform data, but depending on checks if this is
>> supported on this device at all. And why don't simply switch to it if
>> rate is bigger than what is supported without hs-mode?
>>
>
> 1. High speed mode is hardware feature, you can't read it from
> software. It's similar to fast mode, and fast mode is set in platform
> data.
>
> The only method I can think of is to add a platform, like pxa910.
> And if you enable hs mode and platform is not pxa910, we'll set it to
> normal mode. Is this OK?
>
> 2. About hs mode clock setting. We don't know whether currently hs
> mode clock will be changed in future. Do you think below code is OK?
>
> if (i2c->rate)
> clk_set_rate(i2c->clk, i2c->rate);
> else
> clk_set_rate(i2c->clk, 62400000);
>
> pr_info("i2c: <%s> set rate to %ld\n",
> i2c->adap.name, clk_get_rate(i2c->clk));
>
>>> 1. "high_mode" should be set to "1".
>>> 2. "master_code" should be set to "8'b 0000_1xxx"(x is 0 or 1).
>>> If no master_code is set, set to default value 0xe.
>>> 3. "rate" should be set according to specification.
>>
>> Note that you should fall back to full-speed mode after sending the stop
>> bit in high-speed mode. I can't find this in the code?
>>
>
> 3. Will fall back to normal mode when stop bit is sent.
>
>>>
>>> Signed-off-by: Leilei Shang <shangll@xxxxxxxxxxx>
>>
>> Which SoC supports this? I'd like to have a look at the datasheet.
>>
>> Thanks,
>>
>> Wolfram
>>
>
> Hope you can reply soon!
>
> Best regards
> Leilei
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