Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754138Ab3J3LZ7 (ORCPT ); Wed, 30 Oct 2013 07:25:59 -0400 Received: from mail-la0-f53.google.com ([209.85.215.53]:54726 "EHLO mail-la0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753920Ab3J3LZ4 (ORCPT ); Wed, 30 Oct 2013 07:25:56 -0400 Date: Wed, 30 Oct 2013 12:25:51 +0100 From: Johan Hovold To: Greg Kroah-Hartman Cc: Arnd Bergmann , linux-kernel@vger.kernel.org, Nicolas Ferre , linux-arm-kernel@lists.infradead.org, Johan Hovold , stable@vger.kernel.org Subject: Re: [PATCH 1/2] misc: atmel_pwm: add deferred-probing support Message-ID: <20131030112551.GB29813@localhost> References: <1382459560-26596-1-git-send-email-jhovold@gmail.com> <1382459560-26596-2-git-send-email-jhovold@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1382459560-26596-2-git-send-email-jhovold@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1651 Lines: 50 On Tue, Oct 22, 2013 at 06:32:39PM +0200, Johan Hovold wrote: > Two drivers (atmel-pwm-bl and leds-atmel-pwm) currently depend on the > atmel_pwm driver to have bound to any pwm-device before their devices > are probed. > > Support deferred probing of such devices by making sure to return > -EPROBE_DEFER from pwm_channel_alloc when no pwm-device has yet been > bound. > > Signed-off-by: Johan Hovold This patch, 5c6d6fd1 ("misc: atmel_pwm: add deferred-probing support"), and 9d3fde86 ("backlight: atmel-pwm-bl: fix deferred probe from __init") in linux-next should probably be considered for inclusion in stable. Without them the atmel-pwm-bl driver may always fail to probe depending on link order. Thanks, Johan > --- > drivers/misc/atmel_pwm.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/misc/atmel_pwm.c b/drivers/misc/atmel_pwm.c > index 494d050..a6dc56e 100644 > --- a/drivers/misc/atmel_pwm.c > +++ b/drivers/misc/atmel_pwm.c > @@ -90,8 +90,10 @@ int pwm_channel_alloc(int index, struct pwm_channel *ch) > unsigned long flags; > int status = 0; > > - /* insist on PWM init, with this signal pinned out */ > - if (!pwm || !(pwm->mask & 1 << index)) > + if (!pwm) > + return -EPROBE_DEFER; > + > + if (!(pwm->mask & 1 << index)) > return -ENODEV; > > if (index < 0 || index >= PWM_NCHAN || !ch) > -- > 1.8.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/