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From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Nicolas Ferre <nicolas.ferre@atmel.com>,
	linux-kernel@vger.kernel.org,
	Cyrille Pitchen <cyrille.pitchen@atmel.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 01/48] clk: at91: replace usleep() by udelay() calls
Date: Tue, 14 Jun 2016 18:18:20 +0200	[thread overview]
Message-ID: <20160614181820.1b817ed3@bbrezillon> (raw)
In-Reply-To: <20160614160517.GA2490@afzalpc>

On Tue, 14 Jun 2016 21:35:17 +0530
Afzal Mohammed <afzal.mohd.ma@gmail.com> wrote:

> Hi,
> 
> On Mon, Jun 13, 2016 at 05:24:09PM +0200, Alexandre Belloni wrote:
> > On 11/06/2016 at 00:30:36 +0200, Arnd Bergmann wrote :  
> 
> > > Does this have to be called that early? It seems wasteful to always
> > > call udelay() here, when these are functions that are normally
> > > allowed to sleep.  
> 
> > So I've tested it and something like that would work:
> > 
> > 	if (system_state < SYSTEM_RUNNING)
> > 		udelay(osc->startup_usec);
> > 	else
> > 		usleep_range(osc->startup_usec, osc->startup_usec + 1);
> > 
> > But I'm afraid it would be the first driver to actually do something
> > like that (however, it is already the only driver trying to sleep).   
> 
> tglx has suggested to modify clock core to handle a somewhat similar
> kind of scenario (probably should work here too) and avoid driver
> changes,
> 
> http://lkml.kernel.org/r/alpine.DEB.2.11.1606061448010.28031@nanos

Oh, interesting. Definitely a better solution than this custom check.


-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

  reply	other threads:[~2016-06-14 16:18 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 [this message]
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
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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