From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751192AbeAVJ7z (ORCPT ); Mon, 22 Jan 2018 04:59:55 -0500 Received: from eddie.linux-mips.org ([148.251.95.138]:51546 "EHLO cvs.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751024AbeAVJ7x (ORCPT ); Mon, 22 Jan 2018 04:59:53 -0500 Date: Mon, 22 Jan 2018 10:59:50 +0100 From: Ladislav Michl To: Claudiu Beznea Cc: linux-omap@vger.kernel.org, linux-pwm@vger.kernel.org, Keerthy , daniel.lezcano@linaro.org, thierry.reding@gmail.com, tony@atomide.com, aaro.koskinen@iki.fi, narmstrong@baylibre.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, sebastian.reichel@collabora.co.uk, robh+dt@kernel.org, t-kristo@ti.com, grygorii.strashko@ti.com Subject: Re: [PATCH 1/3] clocksource: timer-dm: Check prescaler value Message-ID: <20180122095950.GA19401@lenoch> References: <20180117214629.GA11952@lenoch> <20180117214714.GB11952@lenoch> <4688ef73-99ac-1295-2e3b-ed79e8670262@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4688ef73-99ac-1295-2e3b-ed79e8670262@microchip.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 22, 2018 at 11:00:15AM +0200, Claudiu Beznea wrote: > > > On 17.01.2018 23:47, Ladislav Michl wrote: > > Invalid value silently disables use of the prescaler. > > Use -1 explicitely for that purpose and error out on > > invalid value. > > > > Signed-off-by: Ladislav Michl > > --- > > drivers/clocksource/timer-dm.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/clocksource/timer-dm.c b/drivers/clocksource/timer-dm.c > > index 60db1734ea3b..324ec93d3dd2 100644 > > --- a/drivers/clocksource/timer-dm.c > > +++ b/drivers/clocksource/timer-dm.c > > @@ -663,13 +663,13 @@ int omap_dm_timer_set_prescaler(struct omap_dm_timer *timer, int prescaler) > > { > > u32 l; > > > > - if (unlikely(!timer)) > > + if (unlikely(!timer) || prescaler < -1 || prescaler > 7) > You are checking the prescaller here to be in [0, 7] interval. You mean [-1, 7] I suppose. > > return -EINVAL; > > > > omap_dm_timer_enable(timer); > > l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); > > l &= ~(OMAP_TIMER_CTRL_PRE | (0x07 << 2)); > > - if (prescaler >= 0x00 && prescaler <= 0x07) { > > + if (prescaler >= 0) { > Is this check still necessary? Yes, as we need also some way to disable prescaler, see commit message. > > l |= OMAP_TIMER_CTRL_PRE; > > l |= prescaler << 2; > > } Best regards, ladis