From: Sean Anderson <sean.anderson@seco.com>
To: "Michal Simek" <michal.simek@xilinx.com>,
linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Sascha Hauer" <s.hauer@pengutronix.de>
Cc: linux-kernel@vger.kernel.org,
Alvaro Gamez <alvaro.gamez@hazent.com>,
linux-arm-kernel@lists.infradead.org,
Rob Herring <robh@kernel.org>
Subject: Re: [PATCH v4 1/3] dt-bindings: pwm: Add Xilinx AXI Timer
Date: Thu, 1 Jul 2021 11:38:47 -0400 [thread overview]
Message-ID: <006fcbf8-d79b-3723-9a9c-03c6350f0a9c@seco.com> (raw)
In-Reply-To: <7a1e89bc-65fc-76b5-2383-19f0613d0a82@xilinx.com>
On 6/30/21 9:58 AM, Michal Simek wrote:
>
>
> On 6/30/21 3:47 PM, Michal Simek wrote:
>>
>>
>> On 5/28/21 11:45 PM, Sean Anderson wrote:
>>> This adds a binding for the Xilinx LogiCORE IP AXI Timer. This device is
>>> a "soft" block, so it has many parameters which would not be
>>> configurable in most hardware. This binding is usually automatically
>>> generated by Xilinx's tools, so the names and values of some properties
>>> must be kept as they are. Replacement properties have been provided for
>>> new device trees.
>>>
>>> Because we need to init timer devices so early in boot, the easiest way
>>> to configure things is to use a device tree property. For the moment
>>> this is 'xlnx,pwm', but this could be extended/renamed/etc. in the
>>> future if these is a need for a generic property.
>>>
>>> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
>>> ---
>>>
>>> Changes in v4:
>>> - Remove references to generate polarity so this can get merged
>>> - Predicate PWM driver on the presence of #pwm-cells
>>> - Make some properties optional for clocksource drivers
>>>
>>> Changes in v3:
>>> - Mark all boolean-as-int properties as deprecated
>>> - Add xlnx,pwm and xlnx,gen?-active-low properties.
>>> - Make newer replacement properties mutually-exclusive with what they
>>> replace
>>> - Add an example with non-deprecated properties only.
>>>
>>> Changes in v2:
>>> - Use 32-bit addresses for example binding
>>>
>>> .../bindings/pwm/xlnx,axi-timer.yaml | 85 +++++++++++++++++++
>>> 1 file changed, 85 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/pwm/xlnx,axi-timer.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/pwm/xlnx,axi-timer.yaml b/Documentation/devicetree/bindings/pwm/xlnx,axi-timer.yaml
>>> new file mode 100644
>>> index 000000000000..48a280f96e63
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/pwm/xlnx,axi-timer.yaml
>>
>> I don't think this is the right location for this.
>>
>> I have done some grepping and I think this should be done in a different
>> way. I pretty much like solution around "ti,omap3430-timer" which is
>> calling dmtimer_systimer_select_best() and later dmtimer_is_preferred()
>> which in this case would allow us to get rid of cases which are not
>> suitable for clocksource and clockevent.
>>
>> And there is drivers/pwm/pwm-omap-dmtimer.c which has link to timer
>> which is providing functions for it's functionality.
>>
>> I have also looked at
>> Documentation/devicetree/bindings/timer/nxp,tpm-timer.yaml which is also
>> the same device.
>>
>> And sort of curious if you look at
>> https://www.xilinx.com/support/documentation/ip_documentation/axi_timer/v2_0/pg079-axi-timer.pdf
>> ( Figure 1-1)
>> that PWM is taking input from generate out 0 and generate out 1 which is
>> maybe can be modeled is any output and pwm driver can register inputs
>> for pwm driver.
>>
>>
>>> @@ -0,0 +1,85 @@
>>> +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/pwm/xlnx,axi-timer.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Xilinx LogiCORE IP AXI Timer Device Tree Binding
>>> +
>>> +maintainers:
>>> + - Sean Anderson <sean.anderson@seco.com>
>>> +
>>> +properties:
>>> + compatible:
>>> + oneOf:
>>> + - items:
>>> + - const: xlnx,axi-timer-2.0
>
> I am not quite sure if make sense also to list 2.0 version.
> There were likely also 1.0 version which is compatible with origin xps
> version which IIRC was PLB based. And the same driver was using in past
> with OPB bus.
It's required to list all compatible properties which may be used in a
binding. And AFAIK it is good practice to add a new compatible string
for new releases of an IP, in case incompatibilities are discovered.
--Sean
next prev parent reply other threads:[~2021-07-01 15:38 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-28 21:45 [PATCH v4 1/3] dt-bindings: pwm: Add Xilinx AXI Timer Sean Anderson
2021-05-28 21:45 ` [PATCH v4 2/3] clocksource: Rewrite Xilinx AXI timer driver Sean Anderson
2021-06-01 8:47 ` Lee Jones
2021-06-01 14:24 ` Sean Anderson
2021-05-28 21:45 ` [PATCH v4 3/3] pwm: Add support for Xilinx AXI Timer Sean Anderson
2021-06-10 16:15 ` Sean Anderson
2021-06-25 6:19 ` Uwe Kleine-König
2021-06-25 15:13 ` Sean Anderson
2021-06-25 16:56 ` Uwe Kleine-König
2021-06-25 17:46 ` Sean Anderson
2021-06-25 17:46 ` Sean Anderson
2021-06-27 18:19 ` Uwe Kleine-König
2021-06-28 15:50 ` Sean Anderson
2021-06-28 16:24 ` Uwe Kleine-König
2021-06-28 16:35 ` Sean Anderson
2021-06-28 17:20 ` Uwe Kleine-König
2021-06-28 17:41 ` Sean Anderson
2021-06-29 8:31 ` Uwe Kleine-König
2021-06-29 18:01 ` Sean Anderson
2021-06-29 20:51 ` Uwe Kleine-König
2021-06-29 22:21 ` Sean Anderson
2021-06-29 22:26 ` Sean Anderson
2021-06-30 8:35 ` Uwe Kleine-König
2021-07-08 16:59 ` Sean Anderson
2021-07-08 19:43 ` Uwe Kleine-König
2021-07-12 16:26 ` Sean Anderson
2021-07-12 19:49 ` Uwe Kleine-König
2021-07-13 21:49 ` Sean Anderson
2021-06-01 13:32 ` [PATCH v4 1/3] dt-bindings: pwm: Add " Rob Herring
2021-06-01 16:47 ` Sean Anderson
2021-06-29 8:38 ` Uwe Kleine-König
2021-06-29 14:53 ` Sean Anderson
2021-06-30 13:47 ` Michal Simek
2021-06-30 13:58 ` Michal Simek
2021-07-01 15:38 ` Sean Anderson [this message]
2021-07-02 11:36 ` Michal Simek
2021-07-01 15:32 ` Sean Anderson
2021-07-02 12:40 ` Michal Simek
2021-07-02 17:31 ` Sean Anderson
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