From: Paul Cercueil <paul@crapouillou.net>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
Marc Zyngier <marc.zyngier@arm.com>,
Lee Jones <lee.jones@linaro.org>,
Ralf Baechle <ralf@linux-mips.org>,
Rob Herring <robh+dt@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Mark Rutland <mark.rutland@arm.com>,
James Hogan <jhogan@kernel.org>,
Maarten ter Huurne <maarten@treewalker.org>,
linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mips@linux-mips.org,
linux-doc@vger.kernel.org
Subject: Re: [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver
Date: Thu, 29 Mar 2018 16:52:29 +0200 [thread overview]
Message-ID: <1522335149.1792.0@smtp.crapouillou.net> (raw)
In-Reply-To: <af33e522-7f87-d62a-0a35-d56a403387b7@linaro.org>
Le mer. 28 mars 2018 à 18:25, Daniel Lezcano
<daniel.lezcano@linaro.org> a écrit :
> On 28/03/2018 17:15, Paul Cercueil wrote:
>> Le 2018-03-24 07:26, Daniel Lezcano a écrit :
>>> On 18/03/2018 00:29, Paul Cercueil wrote:
>>>> This driver will use the TCU (Timer Counter Unit) present on the
>>>> Ingenic
>>>> JZ47xx SoCs to provide the kernel with a clocksource and timers.
>>>
>>> Please provide a more detailed description about the timer.
>>
>> There's a doc file for that :)
>
> Usually, when there is a new driver I ask for a description in the
> changelog for reference.
>
>>> Where is the clocksource ?
>>
>> Right, there is no clocksource, just timers.
>>
>>> I don't see the point of using channel idx and pwm checking here.
>>>
>>> There is one clockevent, why create multiple channels ? Can't you
>>> stick
>>> to the usual init routine for a timer.
>>
>> So the idea is that we use all the TCU channels that won't be used
>> for PWM
>> as timers. Hence the PWM checking. Why is this bad?
>
> It is not bad but arguable. By checking the channels used by the pwm
> in
> the code, you introduce an adherence between two subsystems even if it
> is just related to the DT parsing part.
>
> As it is not needed to have more than one timer in the time framework
> (at least with the same characteristics), the pwm channels check is
> pointless. We can assume the author of the DT file is smart enough to
> prevent conflicts and define a pwm and a timer properly instead of
> adding more code complexity.
>
> In addition, simplifying the code will allow you to use the timer-of
> code and reduce very significantly the init function.
That's what I had in my V1 and V2, my DT node for the timer-ingenic
driver
had a "timers" property (e.g. "timers = <4 5>;") to select the channels
that
should be used as timers. Then Rob told me I shouldn't do that, and
instead
detect the channels that will be used for PWM.
>>>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>>> ---
>>>> drivers/clocksource/Kconfig | 8 ++
>>>> drivers/clocksource/Makefile | 1 +
>>>> drivers/clocksource/timer-ingenic.c | 278
>>>> ++++++++++++++++++++++++++++++++++++
>>>> 3 files changed, 287 insertions(+)
>>>> create mode 100644 drivers/clocksource/timer-ingenic.c
>>>>
>>>> v2: Use SPDX identifier for the license
>>>> v3: - Move documentation to its own patch
>>>> - Search the devicetree for PWM clients, and use all the TCU
>>>> channels that won't be used for PWM
>>>> v4: - Add documentation about why we search for PWM clients
>>>> - Verify that the PWM clients are for the TCU PWM driver
>>>>
>>>> diff --git a/drivers/clocksource/Kconfig
>>>> b/drivers/clocksource/Kconfig
>>>> index d2e5382821a4..481422145fb4 100644
>>>> --- a/drivers/clocksource/Kconfig
>>>> +++ b/drivers/clocksource/Kconfig
>>>> @@ -592,4 +592,12 @@ config CLKSRC_ST_LPC
>>>> Enable this option to use the Low Power controller timer
>>>> as clocksource.
>>>>
>>>> +config INGENIC_TIMER
>>>> + bool "Clocksource/timer using the TCU in Ingenic JZ SoCs"
>>>> + depends on MACH_INGENIC || COMPILE_TEST
>>>
>>> bool "Clocksource/timer using the TCU in Ingenic JZ SoCs" if
>>> COMPILE_TEST
>>>
>>> Remove the depends MACH_INGENIC.
>>
>> This driver is not useful on anything else than Ingenic SoCs, why
>> should I
>> remove MACH_INGENIC then?
>
> For COMPILE_TEST on x86.
Well that's a logical OR right here, so it will work...
>>>> + select CLKSRC_OF
>>>> + default y
>>>
>>> No default, Kconfig platform selects the timer.
>>
>> Alright.
> [ ... ]
>
> --
> <http://www.linaro.org/> Linaro.org │ Open source software for ARM
> SoCs
>
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next prev parent reply other threads:[~2018-03-29 14:52 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-29 12:59 [PATCH 0/6] Ingenic JZ47xx TCU drivers Paul Cercueil
2017-12-29 12:59 ` [PATCH 1/6] mfd: syscon: Add ingenic-tcu.h header Paul Cercueil
2018-01-01 14:33 ` [PATCH v2 " Paul Cercueil
2018-01-01 14:33 ` [PATCH v2 2/6] dt-bindings: ingenic: Add DT bindings for TCU clocks Paul Cercueil
2018-01-03 20:49 ` Rob Herring
2018-01-01 14:33 ` [PATCH v2 3/6] irqchip: Add the ingenic-tcu-intc driver Paul Cercueil
2018-01-03 20:58 ` Rob Herring
2018-01-03 21:50 ` Paul Cercueil
2018-01-01 14:33 ` [PATCH v2 4/6] clk: ingenic: Add JZ47xx TCU clocks driver Paul Cercueil
2018-01-02 19:13 ` Stephen Boyd
2018-01-02 20:08 ` Paul Cercueil
2018-01-02 22:59 ` Stephen Boyd
2018-01-01 14:33 ` [PATCH v2 5/6] clocksource: Add a new timer-ingenic driver Paul Cercueil
2018-01-03 21:08 ` Rob Herring
2018-01-03 21:56 ` Paul Cercueil
2018-01-05 23:27 ` Rob Herring
2018-01-05 23:48 ` Paul Cercueil
2018-01-09 1:09 ` Rob Herring
2018-01-01 14:33 ` [PATCH v2 6/6] MAINTAINERS: Add myself as maintainer for Ingenic TCU drivers Paul Cercueil
2018-01-02 15:51 ` [PATCH v2 1/6] mfd: syscon: Add ingenic-tcu.h header Lee Jones
2018-01-10 22:48 ` [PATCH v3 1/9] " Paul Cercueil
2018-01-10 22:48 ` [PATCH v3 2/9] dt-bindings: ingenic: Add DT bindings for TCU clocks Paul Cercueil
2018-03-17 23:28 ` [PATCH v4 0/8] Ingenic JZ47xx Timer/Counter Unit drivers Paul Cercueil
2018-03-17 23:28 ` [PATCH v4 1/8] mfd: syscon: Add ingenic-tcu.h header Paul Cercueil
2018-03-17 23:28 ` [PATCH v4 2/8] dt-bindings: ingenic: Add DT bindings for TCU clocks Paul Cercueil
2018-03-19 21:27 ` Stephen Boyd
2018-03-20 7:15 ` Mathieu Malaterre
2018-03-28 15:04 ` [PATCH v4 2/8] dt-bindings: ingenic: Add DT bindings for TCU clocks, Paul Cercueil
2018-03-28 18:35 ` [PATCH v4 2/8] dt-bindings: ingenic: Add DT bindings for TCU clocks Mathieu Malaterre
2018-03-17 23:28 ` [PATCH v4 3/8] doc: Add doc for the Ingenic TCU hardware Paul Cercueil
2018-03-17 23:52 ` Randy Dunlap
2018-03-28 14:59 ` [PATCH v4 3/8] doc: Add doc for the Ingenic TCU hardware, Paul Cercueil
2018-03-17 23:28 ` [PATCH v4 4/8] dt-bindings: Add doc for the Ingenic TCU drivers Paul Cercueil
2018-03-20 8:52 ` Marc Zyngier
2018-03-28 15:09 ` [PATCH v4 4/8] dt-bindings: Add doc for the Ingenic TCU drivers, Paul Cercueil
2018-03-27 14:46 ` [PATCH v4 4/8] dt-bindings: Add doc for the Ingenic TCU drivers Rob Herring
2018-03-28 15:33 ` [PATCH v4 4/8] dt-bindings: Add doc for the Ingenic TCU drivers, Paul Cercueil
2018-03-28 16:28 ` [PATCH v4 4/8] dt-bindings: Add doc for the Ingenic TCU drivers Rob Herring
2018-03-29 15:59 ` Paul Cercueil
2018-03-17 23:28 ` [PATCH v4 5/8] irqchip: Add the ingenic-tcu-intc driver Paul Cercueil
2018-03-17 23:28 ` [PATCH v4 6/8] clk: ingenic: Add JZ47xx TCU clocks driver Paul Cercueil
2018-03-17 23:29 ` [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver Paul Cercueil
2018-03-24 6:26 ` Daniel Lezcano
2018-03-28 15:15 ` [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver, Paul Cercueil
2018-03-28 16:25 ` [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver Daniel Lezcano
2018-03-29 14:52 ` Paul Cercueil [this message]
2018-03-31 8:10 ` Daniel Lezcano
2018-03-31 17:46 ` [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver, Paul Cercueil
2018-04-03 9:59 ` [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver Daniel Lezcano
2018-03-17 23:29 ` [PATCH v4 8/8] MAINTAINERS: Add myself as maintainer for Ingenic TCU drivers Paul Cercueil
2018-03-18 22:13 ` [PATCH v4 0/8] Ingenic JZ47xx Timer/Counter Unit drivers Daniel Lezcano
2018-03-28 15:01 ` [PATCH v4 0/8] Ingenic JZ47xx Timer/Counter Unit drivers, Paul Cercueil
2018-03-28 15:10 ` [PATCH v4 0/8] Ingenic JZ47xx Timer/Counter Unit drivers Daniel Lezcano
2018-01-10 22:48 ` [PATCH v3 3/9] doc: dt-bindings: Add doc for Ingenic TCU IRQ driver Paul Cercueil
2018-01-19 21:05 ` Rob Herring
2018-01-10 22:48 ` [PATCH v3 4/9] doc: dt-bindings: Add doc for the Ingenic TCU clocks driver Paul Cercueil
2018-01-19 21:11 ` Rob Herring
2018-01-10 22:48 ` [PATCH v3 5/9] doc: dt-bindings: Add doc for the Ingenic TCU timers driver Paul Cercueil
2018-01-19 21:12 ` Rob Herring
2018-01-10 22:48 ` [PATCH v3 6/9] irqchip: Add the ingenic-tcu-intc driver Paul Cercueil
2018-01-11 15:38 ` Marc Zyngier
2018-01-11 16:25 ` Paul Cercueil
2018-01-20 13:06 ` Marc Zyngier
2018-01-22 9:26 ` Lee Jones
2018-01-22 9:55 ` Marc Zyngier
2018-01-22 11:46 ` Lee Jones
2018-01-10 22:48 ` [PATCH v3 7/9] clk: ingenic: Add JZ47xx TCU clocks driver Paul Cercueil
2018-01-27 0:37 ` Stephen Boyd
2018-01-10 22:48 ` [PATCH v3 8/9] clocksource: Add a new timer-ingenic driver Paul Cercueil
2018-01-11 14:53 ` Rob Herring
2018-01-11 16:16 ` Paul Cercueil
2018-01-10 22:48 ` [PATCH v3 9/9] MAINTAINERS: Add myself as maintainer for Ingenic TCU drivers Paul Cercueil
2018-01-23 9:52 ` [PATCH v3 1/9] mfd: syscon: Add ingenic-tcu.h header Lee Jones
2017-12-29 12:59 ` [PATCH 2/6] dt-bindings: ingenic: Add DT bindings for TCU clocks Paul Cercueil
2017-12-29 12:59 ` [PATCH 3/6] irqchip: Add the ingenic-tcu-intc driver Paul Cercueil
2017-12-29 12:59 ` [PATCH 4/6] clk: ingenic: Add JZ47xx TCU clocks driver Paul Cercueil
2017-12-29 14:02 ` Paul Cercueil
2018-01-01 12:47 ` kbuild test robot
2017-12-29 12:59 ` [PATCH 5/6] clocksource: Add a new timer-ingenic driver Paul Cercueil
2017-12-29 12:59 ` [PATCH 6/6] MAINTAINERS: Add myself as maintainer for Ingenic TCU drivers Paul Cercueil
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