From: Sean Anderson <sean.anderson@seco.com> To: "Michal Simek" <michal.simek@xilinx.com>, "Michal Simek" <monstr@monstr.eu>, 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: Fri, 2 Jul 2021 13:31:54 -0400 [thread overview] Message-ID: <45b3c713-952e-610f-0a98-ed8e48825e97@seco.com> (raw) In-Reply-To: <5e7c9d00-bacb-325a-c8f6-413ad9da5f73@xilinx.com> On 7/2/21 8:40 AM, Michal Simek wrote: > > > On 7/1/21 5:32 PM, Sean Anderson wrote: >> >> >> On 6/30/21 9:47 AM, 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. >> >> Ok, I will move this under bindings/timer. >> >>> >>> 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. >> >> I don't think that is a good model, since several bits (GENERATE, PWM, >> etc) need to be set in the TCSR, and we need to coordinate changes >> between timers closely to keep our contract for apply_state(). Although >> that is how the hardware is organized, the requirements of the >> clocksource and pwm subsystems are very different. > > There is another upstream solution done by samsung. Where they use > samsung,pwm-outputs property to identify PWMs. As I understand it, the samsung PWM/timer has 5 timers, four of which may be independently configured as PWMs. To contrast, this device has at most two timers, both of which must be used for a single PWM output. Because of this, it is sufficient to have a single property whose presence indicates that the device is to be configured as a PWM. > I think that make sense to consider to identify which timer should be > clocksource/clockevent because with MB SMP this has to be done to pair > timer with cpu for clockevents. This is not done by the current driver. The first timer in the system always binds itself to CPU 0. --Sean
WARNING: multiple messages have this Message-ID (diff)
From: Sean Anderson <sean.anderson@seco.com> To: "Michal Simek" <michal.simek@xilinx.com>, "Michal Simek" <monstr@monstr.eu>, 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: Fri, 2 Jul 2021 13:31:54 -0400 [thread overview] Message-ID: <45b3c713-952e-610f-0a98-ed8e48825e97@seco.com> (raw) In-Reply-To: <5e7c9d00-bacb-325a-c8f6-413ad9da5f73@xilinx.com> On 7/2/21 8:40 AM, Michal Simek wrote: > > > On 7/1/21 5:32 PM, Sean Anderson wrote: >> >> >> On 6/30/21 9:47 AM, 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. >> >> Ok, I will move this under bindings/timer. >> >>> >>> 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. >> >> I don't think that is a good model, since several bits (GENERATE, PWM, >> etc) need to be set in the TCSR, and we need to coordinate changes >> between timers closely to keep our contract for apply_state(). Although >> that is how the hardware is organized, the requirements of the >> clocksource and pwm subsystems are very different. > > There is another upstream solution done by samsung. Where they use > samsung,pwm-outputs property to identify PWMs. As I understand it, the samsung PWM/timer has 5 timers, four of which may be independently configured as PWMs. To contrast, this device has at most two timers, both of which must be used for a single PWM output. Because of this, it is sufficient to have a single property whose presence indicates that the device is to be configured as a PWM. > I think that make sense to consider to identify which timer should be > clocksource/clockevent because with MB SMP this has to be done to pair > timer with cpu for clockevents. This is not done by the current driver. The first timer in the system always binds itself to CPU 0. --Sean _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-07-02 17:32 UTC|newest] Thread overview: 78+ 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 ` Sean Anderson 2021-05-28 21:45 ` [PATCH v4 2/3] clocksource: Rewrite Xilinx AXI timer driver Sean Anderson 2021-05-28 21:45 ` Sean Anderson 2021-06-01 8:47 ` Lee Jones 2021-06-01 8:47 ` Lee Jones 2021-06-01 14:24 ` Sean Anderson 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 2021-05-28 21:45 ` Sean Anderson 2021-06-10 16:15 ` Sean Anderson 2021-06-10 16:15 ` Sean Anderson 2021-06-25 6:19 ` Uwe Kleine-König 2021-06-25 6:19 ` Uwe Kleine-König 2021-06-25 15:13 ` Sean Anderson 2021-06-25 15:13 ` Sean Anderson 2021-06-25 16:56 ` Uwe Kleine-König 2021-06-25 16:56 ` Uwe Kleine-König 2021-06-25 17:46 ` Sean Anderson 2021-06-25 17:46 ` Sean Anderson 2021-06-25 17:46 ` Sean Anderson 2021-06-25 17:46 ` Sean Anderson 2021-06-27 18:19 ` Uwe Kleine-König 2021-06-27 18:19 ` Uwe Kleine-König 2021-06-28 15:50 ` Sean Anderson 2021-06-28 15:50 ` Sean Anderson 2021-06-28 16:24 ` Uwe Kleine-König 2021-06-28 16:24 ` Uwe Kleine-König 2021-06-28 16:35 ` Sean Anderson 2021-06-28 16:35 ` Sean Anderson 2021-06-28 17:20 ` Uwe Kleine-König 2021-06-28 17:20 ` Uwe Kleine-König 2021-06-28 17:41 ` Sean Anderson 2021-06-28 17:41 ` Sean Anderson 2021-06-29 8:31 ` Uwe Kleine-König 2021-06-29 8:31 ` Uwe Kleine-König 2021-06-29 18:01 ` Sean Anderson 2021-06-29 18:01 ` Sean Anderson 2021-06-29 20:51 ` Uwe Kleine-König 2021-06-29 20:51 ` Uwe Kleine-König 2021-06-29 22:21 ` Sean Anderson 2021-06-29 22:21 ` Sean Anderson 2021-06-29 22:26 ` Sean Anderson 2021-06-29 22:26 ` Sean Anderson 2021-06-30 8:35 ` Uwe Kleine-König 2021-06-30 8:35 ` Uwe Kleine-König 2021-07-08 16:59 ` Sean Anderson 2021-07-08 16:59 ` Sean Anderson 2021-07-08 19:43 ` Uwe Kleine-König 2021-07-08 19:43 ` Uwe Kleine-König 2021-07-12 16:26 ` Sean Anderson 2021-07-12 16:26 ` Sean Anderson 2021-07-12 19:49 ` Uwe Kleine-König 2021-07-12 19:49 ` Uwe Kleine-König 2021-07-13 21:49 ` Sean Anderson 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 13:32 ` Rob Herring 2021-06-01 16:47 ` Sean Anderson 2021-06-01 16:47 ` Sean Anderson 2021-06-29 8:38 ` Uwe Kleine-König 2021-06-29 8:38 ` Uwe Kleine-König 2021-06-29 14:53 ` Sean Anderson 2021-06-29 14:53 ` Sean Anderson 2021-06-30 13:47 ` Michal Simek 2021-06-30 13:47 ` Michal Simek 2021-06-30 13:58 ` Michal Simek 2021-06-30 13:58 ` Michal Simek 2021-07-01 15:38 ` Sean Anderson 2021-07-01 15:38 ` Sean Anderson 2021-07-02 11:36 ` Michal Simek 2021-07-02 11:36 ` Michal Simek 2021-07-01 15:32 ` Sean Anderson 2021-07-01 15:32 ` Sean Anderson 2021-07-02 12:40 ` Michal Simek 2021-07-02 12:40 ` Michal Simek 2021-07-02 17:31 ` Sean Anderson [this message] 2021-07-02 17:31 ` Sean Anderson
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=45b3c713-952e-610f-0a98-ed8e48825e97@seco.com \ --to=sean.anderson@seco.com \ --cc=alvaro.gamez@hazent.com \ --cc=devicetree@vger.kernel.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-pwm@vger.kernel.org \ --cc=michal.simek@xilinx.com \ --cc=monstr@monstr.eu \ --cc=robh@kernel.org \ --cc=s.hauer@pengutronix.de \ --cc=u.kleine-koenig@pengutronix.de \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.