Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932141AbcC2Ncr (ORCPT ); Tue, 29 Mar 2016 09:32:47 -0400 Received: from eusmtp01.atmel.com ([212.144.249.242]:41457 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756267AbcC2Ncp (ORCPT ); Tue, 29 Mar 2016 09:32:45 -0400 Subject: Re: [PATCH] arm: at91: do not disable/enable clocks in a row To: Sebastian Andrzej Siewior , Daniel Lezcano References: <1459258007-24968-1-git-send-email-bigeasy@linutronix.de> CC: Thomas Gleixner , , From: Nicolas Ferre Organization: atmel Message-ID: <56FA83F8.5060808@atmel.com> Date: Tue, 29 Mar 2016 15:32:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1459258007-24968-1-git-send-email-bigeasy@linutronix.de> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.161.30.18] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3311 Lines: 103 Le 29/03/2016 15:26, Sebastian Andrzej Siewior a ?crit : > Currently the driver will disable the clock and enable it one line later > if it is switching from periodic mode into one shot. > This can be avoided and causes a needless warning on -RT. > > Tested-by: Alexandre Belloni > Acked-by: Alexandre Belloni > Signed-off-by: Sebastian Andrzej Siewior Absolutely makes sense: Acked-by: Nicolas Ferre Thanks. > --- > drivers/clocksource/tcb_clksrc.c | 33 +++++++++++++++++++++++++++++---- > 1 file changed, 29 insertions(+), 4 deletions(-) > > diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c > index 4da2af9694a2..ed1ae4445e8d 100644 > --- a/drivers/clocksource/tcb_clksrc.c > +++ b/drivers/clocksource/tcb_clksrc.c > @@ -74,6 +74,7 @@ static struct clocksource clksrc = { > struct tc_clkevt_device { > struct clock_event_device clkevt; > struct clk *clk; > + bool clk_enabled; > void __iomem *regs; > }; > > @@ -91,6 +92,24 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt) > */ > static u32 timer_clock; > > +static void tc_clk_disable(struct clock_event_device *d) > +{ > + struct tc_clkevt_device *tcd = to_tc_clkevt(d); > + > + clk_disable(tcd->clk); > + tcd->clk_enabled = false; > +} > + > +static void tc_clk_enable(struct clock_event_device *d) > +{ > + struct tc_clkevt_device *tcd = to_tc_clkevt(d); > + > + if (tcd->clk_enabled) > + return; > + clk_enable(tcd->clk); > + tcd->clk_enabled = true; > +} > + > static int tc_shutdown(struct clock_event_device *d) > { > struct tc_clkevt_device *tcd = to_tc_clkevt(d); > @@ -98,8 +117,14 @@ static int tc_shutdown(struct clock_event_device *d) > > __raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR)); > __raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR)); > + return 0; > +} > + > +static int tc_shutdown_clk_off(struct clock_event_device *d) > +{ > + tc_shutdown(d); > if (!clockevent_state_detached(d)) > - clk_disable(tcd->clk); > + tc_clk_disable(d); > > return 0; > } > @@ -112,7 +137,7 @@ static int tc_set_oneshot(struct clock_event_device *d) > if (clockevent_state_oneshot(d) || clockevent_state_periodic(d)) > tc_shutdown(d); > > - clk_enable(tcd->clk); > + tc_clk_enable(d); > > /* slow clock, count up to RC, then irq and stop */ > __raw_writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE | > @@ -134,7 +159,7 @@ static int tc_set_periodic(struct clock_event_device *d) > /* By not making the gentime core emulate periodic mode on top > * of oneshot, we get lower overhead and improved accuracy. > */ > - clk_enable(tcd->clk); > + tc_clk_enable(d); > > /* slow clock, count up to RC, then irq and restart */ > __raw_writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, > @@ -168,7 +193,7 @@ static struct tc_clkevt_device clkevt = { > /* Should be lower than at91rm9200's system timer */ > .rating = 125, > .set_next_event = tc_next_event, > - .set_state_shutdown = tc_shutdown, > + .set_state_shutdown = tc_shutdown_clk_off, > .set_state_periodic = tc_set_periodic, > .set_state_oneshot = tc_set_oneshot, > }, > -- Nicolas Ferre