Re: [PATCHv3 2/8] mailbox/omap: add support for parsing dt devices

[Suman Anna <s-anna@ti.com>]

On 08/08/2013 09:34 AM, Kumar Gala wrote:
> 
> On Aug 7, 2013, at 3:08 PM, Suman Anna wrote:
> 
>> On 08/07/2013 12:41 PM, Kumar Gala wrote:
>>>
>>> On Aug 7, 2013, at 11:59 AM, Suman Anna wrote:
>>>
>>>> Kumar,
>>>>
>>>>>> Logic has been added to the OMAP2+ mailbox code to
>>>>>> parse the mailbox dt nodes and construct the different
>>>>>> mailboxes associated with the instance. The design is
>>>>>> based on gathering the same information that was being
>>>>>> passed previously through the platform data, except for
>>>>>> the interrupt type configuration information.
>>>>>>
>>>>>> Signed-off-by: Suman Anna <s-anna@ti.com>
>>>>>> ---
>>>>>> .../devicetree/bindings/mailbox/omap-mailbox.txt   |  43 +++++++
>>>>>> drivers/mailbox/mailbox-omap2.c                    | 130 ++++++++++++++++++---
>>>>>> 2 files changed, 158 insertions(+), 15 deletions(-)
>>>>>> create mode 100644 Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt b/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>>>> new file mode 100644
>>>>>> index 0000000..8ffb08a
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
>>>>>> @@ -0,0 +1,43 @@
>>>>>> +OMAP2+ Mailbox Driver
>>>>>> +
>>>>>> +Required properties:
>>>>>> +- compatible:		Should be one of the following,
>>>>>> +			    "ti,omap2-mailbox" for
>>>>>> +				OMAP2420, OMAP2430, OMAP3430, OMAP3630 SoCs
>>>>>> +			    "ti,omap4-mailbox" for
>>>>>> +				OMAP44xx, OMAP54xx, AM33xx, AM43xx, DRA7xx SoCs
>>>>>> +- reg:			Contains the mailbox register address range (base address
>>>>>> +			and length)
>>>>>> +- interrupts: 		Contains the interrupt information for the mailbox
>>>>>> +			device. The format is dependent on which interrupt
>>>>>> +			controller the OMAP device uses
>>>>>> +- ti,hwmods:		Name of the hwmod associated with the mailbox
>>>>>> +- ti,mbox-num-users:	Number of targets (processor devices) that the mailbox device
>>>>>> +			can interrupt
>>>>>> +- ti,mbox-num-fifos:	Number of h/w fifos within the mailbox device
>>>>>
>>>>> Isn't "ti,mbox-num-users", "ti,mbox-num-fifos" this SoC specific, why do we need to encode in the device tree.  Can we not have a more SoC specific compatiable and encode such info in the driver as part of the .data field in of_device_id ?
>>>>
>>>> They are IP design parameters for the number of h/w fifos and interrupts
>>>> coming out of the IP block, with the functionality identical. This
>>>> information could not be read from any registers. Until OMAP5, we always
>>>> had a single IP in the SoC and so these could been encoded in the
>>>> driver. But in DRA7xx, a new SoC, we have 13 mailboxes which have
>>>> differing number of these properties even though the functional IP block
>>>> is same.
>>>
>>> Ah, I see.  Since you've got examples of the same IP with different design params in a given SoC than this makes sense.
>>>
>>> Is that true of ti,mbox-num-users?
>>
>> Yes, it is true of both "ti,mbox-num-users" and "ti,mbox-num-fifos".
> 
> So I think it would be good to update the binding to convey that SoCs might have multiple mbox units w/different design pararms (maybe a short blurb as part of the intro).

Sure will do. Will wait for Benoit also to come back on this series if I
need to address any further review comments.

regards
Suman