From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754414Ab3LNVAO (ORCPT ); Sat, 14 Dec 2013 16:00:14 -0500 Received: from moutng.kundenserver.de ([212.227.126.187]:51995 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753870Ab3LNVAN (ORCPT ); Sat, 14 Dec 2013 16:00:13 -0500 From: Arnd Bergmann To: Sergei Ianovich Subject: Re: [PATCH v2 16/16] misc: support for I-8024 in LP-8x4x Date: Sat, 14 Dec 2013 21:59:39 +0100 User-Agent: KMail/1.12.2 (Linux/3.8.0-22-generic; KDE/4.3.2; x86_64; ; ) Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Rob Landley , "Greg Kroah-Hartman" , "open list:DOCUMENTATION" References: <1386543229-1542-1-git-send-email-ynvich@gmail.com> <1386901645-28895-1-git-send-email-ynvich@gmail.com> <1386901645-28895-17-git-send-email-ynvich@gmail.com> In-Reply-To: <1386901645-28895-17-git-send-email-ynvich@gmail.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201312142159.40250.arnd@arndb.de> X-Provags-ID: V02:K0:F8ufDW9WOdwBA2QWFK3vFP2+LXqiSrEDZYk/fU41Tau EwEkPtIjadfYyj8QZ8SDkzH+yFbJ5SGzJ3IJ4U22FX0B7gUX2Y w31nU4F2a0ZYJ8ytzsTTbjOxy+J0zUMF5B4+7Rn2HC1J+N35aJ vP1cWN8q7QbVi8BP9V03XWl+Qf0hA6ObaNVVmxf27s/JgT/MkU TAYzFsj/sQLteYxWwcVyTOZqGYmKZ+UTTWJbWi8lwmjIu4LG9s OlGnsWg+yf+L1ijtxLMeQ/6OgCVl0QGUEnFMVXshHrAPIEj5Im a8jmsW81jxDt7udpd5uh0o7iwfG50sad75hKOlw+tVma/ofQ7Y DNfruw5+eZ0s8VV6Ks2M= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 13 December 2013, Sergei Ianovich wrote: > +void nsleep(unsigned long nanosec) > +{ > + ktime_t t = ns_to_ktime(nanosec); > + long state = current->state; > + > + __set_current_state(TASK_UNINTERRUPTIBLE); > + schedule_hrtimeout(&t, HRTIMER_MODE_REL); > + __set_current_state(state); > +} > + > +static void lp8x4x_slot_reset_AO(struct lp8x4x_slot *s) > +{ > + int i; > + mutex_lock(&s->lock); > + for (i = 0; i < s->AO_len; i++) > + s->AO[i] = 0x2000; > + iowrite8(0x00, s->data_addr); > + nsleep(450); > + iowrite8(0xff, s->data_addr); > + mutex_unlock(&s->lock); > +} Have you checked that the nsleep definition actually does the right thing here? 450 nanoseconds must be close the latency you get from calling schedule_hrtimeout(). I'd suggest using either ndelay() or usleep_range() instead, depending on your needs. If nsleep is really useful here, we should probably add that as a generic API rather than having it in one driver. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Sat, 14 Dec 2013 21:59:39 +0100 Subject: [PATCH v2 16/16] misc: support for I-8024 in LP-8x4x In-Reply-To: <1386901645-28895-17-git-send-email-ynvich@gmail.com> References: <1386543229-1542-1-git-send-email-ynvich@gmail.com> <1386901645-28895-1-git-send-email-ynvich@gmail.com> <1386901645-28895-17-git-send-email-ynvich@gmail.com> Message-ID: <201312142159.40250.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 13 December 2013, Sergei Ianovich wrote: > +void nsleep(unsigned long nanosec) > +{ > + ktime_t t = ns_to_ktime(nanosec); > + long state = current->state; > + > + __set_current_state(TASK_UNINTERRUPTIBLE); > + schedule_hrtimeout(&t, HRTIMER_MODE_REL); > + __set_current_state(state); > +} > + > +static void lp8x4x_slot_reset_AO(struct lp8x4x_slot *s) > +{ > + int i; > + mutex_lock(&s->lock); > + for (i = 0; i < s->AO_len; i++) > + s->AO[i] = 0x2000; > + iowrite8(0x00, s->data_addr); > + nsleep(450); > + iowrite8(0xff, s->data_addr); > + mutex_unlock(&s->lock); > +} Have you checked that the nsleep definition actually does the right thing here? 450 nanoseconds must be close the latency you get from calling schedule_hrtimeout(). I'd suggest using either ndelay() or usleep_range() instead, depending on your needs. If nsleep is really useful here, we should probably add that as a generic API rather than having it in one driver. Arnd