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Re: [PATCH] spmi-pmic-arb: support configurable number of peripherals

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  Re: [PATCH] spmi-pmic-arb: support configurable number of peripherals Stephen Boyd <sboyd@codeaurora.org> - 2015-10-15 00:50 +0200
    Re: [PATCH] spmi-pmic-arb: support configurable number of peripherals "Ivan T. Ivanov" <iivanov.xz@gmail.com> - 2015-10-15 11:30 +0200
      Re: [PATCH] spmi-pmic-arb: support configurable number of peripherals Stephen Boyd <sboyd@codeaurora.org> - 2015-10-15 20:30 +0200

#1247238 — Re: [PATCH] spmi-pmic-arb: support configurable number of peripherals

On 09/15/2015 11:27 AM, Stephen Boyd wrote:
> On 09/15, Ivan T. Ivanov wrote:
>> On Mon, 2015-09-14 at 18:28 -0700, Stephen Boyd wrote:
>>> On 09/14/2015 02:54 PM, Stephen Boyd wrote:
>>>> The current driver implementation supports only 128 peripherals.
>>>> Add support for more than 128 peripherals by taking a lazy
>>>> caching approach to the mapping tables. Instead of reading the
>>>> tables at boot given some fixed size, read them on an as needed
>>>> basis and cache the results. We still assume a max number of 512
>>>> peripherals, trading off some space for simplicity.
>>>>
>>>> Based on a patch by Gilad Avidov <gavidov@codeaurora.org> and
>>>> Sagar Dharia <sdharia@codeaurora.org>.
>>>>
>>>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>>>> ---
>>> Hi Ivan,
>>>
>>> This patch causes 8916 to crash, because there isn't a mapping for ppid
>>> 257 in the ppid to channel table. It seems that we're reading the revid
>>> from the slave id 1 pmic by going through channel 0, which seems to be
>>> setup for ppid 9 (slave id 0 and the peripheral starting at 0x900). Can
>>> we stop reading the revid registers from non-zero slave id pmic devices?
>>> That would be one solution to fix this problem. Or maybe we need to
>>> special case this in the pmic arbiter code to fold ppid 0xN01 (slave id
>>> N and address 0x100) onto channel 0 all the time?
>>>
>> Yes, we can. We are not using this information at the moment.
>> Right now, revision read is more or less for debug purposes.
>>
>> Would following patch work for you? Of course it will be difficult
> Yes the patch works fine. Feel free to add a
>
> Tested-by: Stephen Boyd <sboyd@codeaurora.org>
>
>

I have to take this back. I missed the part where some pmics are on
slave id 2 or slave id 4, so this check isn't going to work. I've
adjusted it to use sid % 2 instead and I'll resend these two patches,
but I imagine to be more robust we're going to need to add a revid node
to the DT under the SID that actually has it. Then we can search the
child nodes for a revid compatible node and do the rev probing stuff.

-- 
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a Linux Foundation Collaborative Project

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#1247613

> On Oct 15, 2015, at 1:43 AM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> 
> On 09/15/2015 11:27 AM, Stephen Boyd wrote:
>> On 09/15, Ivan T. Ivanov wrote:
>>> On Mon, 2015-09-14 at 18:28 -0700, Stephen Boyd wrote:
>>>> On 09/14/2015 02:54 PM, Stephen Boyd wrote:
>>>>> The current driver implementation supports only 128 peripherals.
>>>>> Add support for more than 128 peripherals by taking a lazy
>>>>> caching approach to the mapping tables. Instead of reading the
>>>>> tables at boot given some fixed size, read them on an as needed
>>>>> basis and cache the results. We still assume a max number of 512
>>>>> peripherals, trading off some space for simplicity.
>>>>> 
>>>>> Based on a patch by Gilad Avidov <gavidov@codeaurora.org> and
>>>>> Sagar Dharia <sdharia@codeaurora.org>.
>>>>> 
>>>>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>>>>> ---
>>>> Hi Ivan,
>>>> 
>>>> This patch causes 8916 to crash, because there isn't a mapping for ppid
>>>> 257 in the ppid to channel table. It seems that we're reading the revid
>>>> from the slave id 1 pmic by going through channel 0, which seems to be
>>>> setup for ppid 9 (slave id 0 and the peripheral starting at 0x900). Can
>>>> we stop reading the revid registers from non-zero slave id pmic devices?
>>>> That would be one solution to fix this problem. Or maybe we need to
>>>> special case this in the pmic arbiter code to fold ppid 0xN01 (slave id
>>>> N and address 0x100) onto channel 0 all the time?
>>>> 
>>> Yes, we can. We are not using this information at the moment.
>>> Right now, revision read is more or less for debug purposes.
>>> 
>>> Would following patch work for you? Of course it will be difficult
>> Yes the patch works fine. Feel free to add a
>> 
>> Tested-by: Stephen Boyd <sboyd@codeaurora.org>
>> 
>> 
> 
> I have to take this back. I missed the part where some pmics are on
> slave id 2 or slave id 4, so this check isn't going to work. I've
> adjusted it to use sid % 2 instead and I'll resend these two patches,
> but I imagine to be more robust we're going to need to add a revid node
> to the DT under the SID that actually has it. Then we can search the
> child nodes for a revid compatible node and do the rev probing stuff.

Ah, yes. We don’t use revision information for now. 
I suppose we can just remove these reads until we need
this information?

Regards,
Ivan

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#1248063

On 10/15, Ivan T. Ivanov wrote:
> 
> > On Oct 15, 2015, at 1:43 AM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> > 
> > I have to take this back. I missed the part where some pmics are on
> > slave id 2 or slave id 4, so this check isn't going to work. I've
> > adjusted it to use sid % 2 instead and I'll resend these two patches,
> > but I imagine to be more robust we're going to need to add a revid node
> > to the DT under the SID that actually has it. Then we can search the
> > child nodes for a revid compatible node and do the rev probing stuff.
> 
> Ah, yes. We don’t use revision information for now. 
> I suppose we can just remove these reads until we need
> this information?
> 

True, we could just remove all the code and make it look for a
revid node at some later time. But later would be soon because
I'm working on patches to add the read/write/volatile regmap
tables to this driver. I guess I'll just go all the way and do
the revid node part.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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