From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753715AbeAVJAX (ORCPT ); Mon, 22 Jan 2018 04:00:23 -0500 Received: from esa4.microchip.iphmx.com ([68.232.154.123]:39972 "EHLO esa4.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752388AbeAVJAU (ORCPT ); Mon, 22 Jan 2018 04:00:20 -0500 X-IronPort-AV: E=Sophos;i="5.46,395,1511852400"; d="scan'208";a="10431555" Subject: Re: [PATCH 1/3] clocksource: timer-dm: Check prescaler value To: Ladislav Michl , , CC: Keerthy , , , , , , , , , , , References: <20180117214629.GA11952@lenoch> <20180117214714.GB11952@lenoch> From: Claudiu Beznea Message-ID: <4688ef73-99ac-1295-2e3b-ed79e8670262@microchip.com> Date: Mon, 22 Jan 2018 11:00:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <20180117214714.GB11952@lenoch> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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? > l |= OMAP_TIMER_CTRL_PRE; > l |= prescaler << 2; > } >