From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 42/48] clocksource/drivers: Add a new driver for the Atmel ARM TC blocks
Date: Tue, 16 May 2017 16:25:04 +0200 [thread overview]
Message-ID: <d2485b56-52fa-6532-76cb-222f0c139566@linaro.org> (raw)
In-Reply-To: <20170516115916.ip3ea34bofg3jpuo@piout.net>
On 16/05/2017 13:59, Alexandre Belloni wrote:
> Hi Daniel,
>
> Almost one year later, I'm back on that topic.
>
> On 24/06/2016 at 12:07:01 +0200, Daniel Lezcano wrote:
>>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>>> index 47352d25c15e..ff7f4022c749 100644
>>> --- a/drivers/clocksource/Kconfig
>>> +++ b/drivers/clocksource/Kconfig
>>> @@ -258,6 +258,19 @@ config ATMEL_ST
>>> select CLKSRC_OF
>>> select MFD_SYSCON
>>>
>>> +config ATMEL_ARM_TCB_CLKSRC
>>> + bool "TC Block Clocksource"
>>
>> The Kconfig options are set now with the COMPILE_TEST option in order to
>> increase the compilation test coverage.
>>
>> Please, add bool "TC Block Clocksource" if COMPILE_TEST, ...
>>
>>> + select REGMAP_MMIO
>>> + depends on GENERIC_CLOCKEVENTS
>>> + depends on SOC_AT91RM9200 || SOC_AT91SAM9 || SOC_SAMA5
>>> + default SOC_AT91RM9200 || SOC_AT91SAM9 || SOC_SAMA5
>>
>> ... remove these dependencies and let the SoC's Kconfig to select the timer
>> like the other timers are.
>>
>
> The main issue with what you suggest is that it removes the possibility
> to not compile the driver. This may be interesting for people using the
> PIT as the clocksource/clockevent and the TCBs for something else.
Is it really a problem? We tend as much as possible to make silent
options in order to let the platform config to select the right clock.
>>> +static cycle_t tc_get_cycles(struct clocksource *cs)
>>> +{
>>> + unsigned long flags;
>>> + u32 lower, upper, tmp;
>>> +
>>> + raw_local_irq_save(flags);
>>> + do {
>>> + regmap_read(tc.regmap, ATMEL_TC_CV(1), &upper);
>>> + regmap_read(tc.regmap, ATMEL_TC_CV(0), &lower);
>>> + regmap_read(tc.regmap, ATMEL_TC_CV(1), &tmp);
>>> + } while (upper != tmp);
>>> +
>>> + raw_local_irq_restore(flags);
>>
>> Why is this lock needed ?
>>
>
> I've taken that from the old driver, I'm not sure this is needed. Maybe
> to lower the chance to have upper != tmp.
>
>>> + return (upper << 16) | lower;
>>> +}
>>> +
I don't think this is needed.
>>> +static int tcb_clkevt_oneshot(struct clock_event_device *dev)
>>> +{
>>> + int ret;
>>> +
>>> + if (tc.irq_requested)
>>> + return 0;
>>> +
>>> + ret = request_irq(tc.irq, tc_clkevt_irq, IRQF_TIMER | IRQF_SHARED,
>>> + "tcb_clkevt", &tc);
>>> + if (!ret)
>>> + tc.irq_requested = true;
>>
>> The legacy driver checks clockevent_state_detached() and disables the clock.
>>
>
> This feature is different from the legacy driver. Here, the driver is
> using a single TCB channel for both clocksource and clockevent while the
> legacy driver always uses at least two channels.
>
>> Why is 'irq_requested' and request_irq/free_irq cleaner ?
>>
>> Isn't there a configuration with the TCB register to disable the clockevent
>> only ?
>>
>
> I'll try something cleaner anyway.
Ok.
--
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next prev parent reply other threads:[~2017-05-16 14:25 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-10 22:03 [PATCH 00/48] ARM: at91: rework Atmel TCB drivers Alexandre Belloni
2016-06-10 22:03 ` [PATCH 01/48] clk: at91: replace usleep() by udelay() calls Alexandre Belloni
2016-06-10 22:30 ` Arnd Bergmann
2016-06-10 22:37 ` Alexandre Belloni
2016-06-13 15:24 ` Alexandre Belloni
2016-06-13 19:26 ` Arnd Bergmann
2016-06-14 16:05 ` Afzal Mohammed
2016-06-14 16:18 ` Boris Brezillon
2016-06-11 7:49 ` Boris Brezillon
2016-06-10 22:03 ` [PATCH 02/48] ARM: at91: Document new TCB bindings Alexandre Belloni
2016-06-14 21:47 ` Rob Herring
2016-06-15 7:29 ` Boris Brezillon
2016-06-21 20:08 ` Rob Herring
2016-06-21 20:28 ` Rob Herring
2016-06-10 22:03 ` [PATCH 03/48] ARM: dts: at91: at91rm9200: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 04/48] ARM: dts: at91: at91rm9200ek; use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 05/48] ARM: dts: at91: mpa1600; " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 06/48] ARM: dts: at91: at91sam9260: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 07/48] ARM: dts: at91: ethernut5: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 08/48] ARM: dts: at91: foxg20: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 09/48] ARM: dts: at91: animeo_ip: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 10/48] ARM: dts: at91: kizbox: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 11/48] ARM: dts: at91: at91sam9g20ek: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 12/48] ARM: dts: at91: ge863-pro3: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 13/48] ARM: dts: at91: at91sam9261: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 14/48] ARM: dts: at91: at91sam9261ek: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 15/48] ARM: dts: at91: at91sam9263: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 16/48] ARM: dts: at91: at91sam9263ek: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 17/48] ARM: dts: at91: calao: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 18/48] ARM: dts: at91: at91sam9g45: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 19/48] ARM: dts: at91: at91sam9m10g45ek: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 20/48] ARM: dts: at91: pm9g45: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 21/48] ARM: dts: at91: at91sam9rl: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 22/48] ARM: dts: at91: at91sam9rlek: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 23/48] ARM: dts: at91: at91sam9n12: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 24/48] ARM: dts: at91: at91sam9n12ek: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 25/48] ARM: dts: at91: at91sam9x5: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 26/48] ARM: dts: at91: at91sam9x5cm: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 27/48] ARM: dts: at91: acme/g25: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 28/48] ARM: dts: at91: cosino: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 29/48] ARM: dts: at91: kizboxmini: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 30/48] ARM: dts: at91: sama5d3: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 31/48] ARM: dts: at91: sama5d3xek; use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 32/48] ARM: dts: at91: sama5d3 Xplained: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 33/48] ARM: dts: at91: kizbox2: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 34/48] ARM: dts: at91: sama5d4: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 35/48] ARM: dts: at91: sama5d4: Add TCB2 Alexandre Belloni
2016-06-10 22:03 ` [PATCH 36/48] ARM: dts: at91: sama5d4ek: use TCB2 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 37/48] ARM: dts: at91: sama5d4 Xplained: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 38/48] ARM: dts: at91: ma5d4: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 39/48] ARM: dts: at91: vinco: " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 40/48] ARM: dts: at91: sama5d2: TC blocks are also simple-mfd and syscon devices Alexandre Belloni
2016-06-10 22:03 ` [PATCH 41/48] ARM: dts: at91: sama5d2 Xplained: use TCB0 as clocksource Alexandre Belloni
2016-06-10 22:03 ` [PATCH 42/48] clocksource/drivers: Add a new driver for the Atmel ARM TC blocks Alexandre Belloni
2016-06-11 12:48 ` Boris Brezillon
2016-06-22 13:07 ` Daniel Lezcano
2016-06-22 13:13 ` Boris Brezillon
2016-06-24 10:07 ` Daniel Lezcano
2017-05-16 11:59 ` Alexandre Belloni
2017-05-16 14:25 ` Daniel Lezcano [this message]
2017-05-16 14:35 ` Alexandre Belloni
2016-06-10 22:03 ` [PATCH 43/48] clocksource/drivers: Add a clockevent driver for Atmel " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 44/48] clocksource: atmel-pit: allow unselecting ATMEL_PIT Alexandre Belloni
2016-06-11 9:43 ` Thomas Gleixner
2016-06-11 10:53 ` Alexandre Belloni
2016-06-13 19:04 ` Boris Brezillon
2016-06-13 19:14 ` Thomas Gleixner
2016-06-16 14:41 ` Boris Brezillon
2016-06-10 22:03 ` [PATCH 45/48] ARM: at91/defconfig: sama5: unselect ATMEL_PIT Alexandre Belloni
2016-06-10 22:03 ` [PATCH 46/48] ARM: at91/defconfig: at91_dt " Alexandre Belloni
2016-06-10 22:03 ` [PATCH 47/48] PWM: atmel-tcb: switch to new binding Alexandre Belloni
2016-06-11 2:22 ` kbuild test robot
2016-06-10 22:03 ` [PATCH 48/48] ARM: dts: at91: kizbox: switch to new pwm-atmel-tcb binding Alexandre Belloni
2016-06-11 0:14 ` kbuild test robot
2016-06-11 10:25 ` Alexandre Belloni
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