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

Ivan T. Ivanov iivanov.xz at gmail.com
Thu Oct 15 02:23:18 PDT 2015

> On Oct 15, 2015, at 1:43 AM, Stephen Boyd <sboyd at 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 at codeaurora.org> and
>>>>> Sagar Dharia <sdharia at codeaurora.org>.
>>>>> Signed-off-by: Stephen Boyd <sboyd at 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 at 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?


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