Re: [PATCH 1/2] net: dsa: b53: Add compatible strings for the Cygnus-family BCM11360.

[Florian Fainelli]

On 04/24/2017 04:15 PM, Arun Parameswaran wrote:
> 
> 
> On 17-04-24 04:07 PM, Florian Fainelli wrote:
>> On 04/24/2017 04:03 PM, Arun Parameswaran wrote:
>>> Hi Eric
>>>
>>> A comment on the Device ID.
>>>
>>>
>>> On 17-04-24 02:50 PM, Eric Anholt wrote:
>>>> Cygnus is a small family of SoCs, of which we currently have
>>>> devicetree for BCM11360 and BCM58300.  The 11360's B53 is mostly the
>>>> same as 58xx, just requiring a tiny bit of setup that was previously
>>>> missing.
>>>>
>>>> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
>>>> ---
>>>>  Documentation/devicetree/bindings/net/dsa/b53.txt | 3 +++
>>>>  drivers/net/dsa/b53/b53_srab.c                    | 2 ++
>>>>  2 files changed, 5 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/net/dsa/b53.txt b/Documentation/devicetree/bindings/net/dsa/b53.txt
>>>> index d6c6e41648d4..49c93d3c0839 100644
>>>> --- a/Documentation/devicetree/bindings/net/dsa/b53.txt
>>>> +++ b/Documentation/devicetree/bindings/net/dsa/b53.txt
>>>> @@ -29,6 +29,9 @@ Required properties:
>>>>        "brcm,bcm58625-srab"
>>>>        "brcm,bcm88312-srab" and the mandatory "brcm,nsp-srab string
>>>>  
>>>> +  For the BCM11360 SoC, must be:
>>>> +      "brcm,bcm11360-srab" and the mandatory "brcm,cygnus-srab string
>>>> +
>>>>    For the BCM63xx/33xx SoCs with an integrated switch, must be one of:
>>>>        "brcm,bcm3384-switch"
>>>>        "brcm,bcm6328-switch"
>>>> diff --git a/drivers/net/dsa/b53/b53_srab.c b/drivers/net/dsa/b53/b53_srab.c
>>>> index 8a62b6a69703..c37ffd1b6833 100644
>>>> --- a/drivers/net/dsa/b53/b53_srab.c
>>>> +++ b/drivers/net/dsa/b53/b53_srab.c
>>>> @@ -364,6 +364,7 @@ static const struct of_device_id b53_srab_of_match[] = {
>>>>  	{ .compatible = "brcm,bcm53018-srab" },
>>>>  	{ .compatible = "brcm,bcm53019-srab" },
>>>>  	{ .compatible = "brcm,bcm5301x-srab" },
>>>> +	{ .compatible = "brcm,bcm11360-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>>  	{ .compatible = "brcm,bcm58522-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>>  	{ .compatible = "brcm,bcm58525-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>>  	{ .compatible = "brcm,bcm58535-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>> @@ -371,6 +372,7 @@ static const struct of_device_id b53_srab_of_match[] = {
>>>>  	{ .compatible = "brcm,bcm58623-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>>  	{ .compatible = "brcm,bcm58625-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>>  	{ .compatible = "brcm,bcm88312-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>>> +	{ .compatible = "brcm,cygnus-srab", .data = (void *)BCM58XX_DEVICE_ID },
>>> The device ID should be 0xd300. This is the actual value read from the switch regs.
>>> This also requires an entry in the 'b53_switch_chips' structure in b53_common.c.
>> These are not real ID numbers, these are values that indicate the
>> generation of the switch being embedded into the SoC. Within
>> b53_common.c we don't have to differentiate a Starfighter 2 embedded in
>> BCM11360, NSP, or 7445 or 7278, which is why using 58XX_DEVICE_ID should
>> be good enough.
> Ok. Thanks.
> 
> I was under the impression, that these id's could be used in the b53_switch_detect()
> API to auto detect the switch. In that API, the switch ID is read from the
> Management page register.

For external switches that is the case, but for internal/integrated
switches, the ID is not always representative of the switch. This is why
the choice of a chip-type ID was used here while adding support for NSP
to the b53 driver.

-- 
Florian