From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v3 4/5] dt: bindings: i2c-mux-pca954x: Add documentation for i2c-mux-irq-mask-en Date: Mon, 9 Jan 2017 23:36:08 -0600 Message-ID: <20170110053608.xhoe4xmtmcycaayn@rob-hp-laptop> References: <1483952576-5308-1-git-send-email-preid@electromag.com.au> <1483952576-5308-5-git-send-email-preid@electromag.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:34321 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033249AbdAJFgM (ORCPT ); Tue, 10 Jan 2017 00:36:12 -0500 Content-Disposition: inline In-Reply-To: <1483952576-5308-5-git-send-email-preid@electromag.com.au> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Phil Reid Cc: peda@axentia.se, wsa@the-dreams.de, mark.rutland@arm.com, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org On Mon, Jan 09, 2017 at 05:02:55PM +0800, Phil Reid wrote: > Unfortunately some hardware device will assert their irq line immediately > on power on and provide no mechanism to mask the irq. As the i2c muxes > provide no method to mask irq line this provides a work around by keeping > the parent irq masked until enough device drivers have loaded to service > all pending interrupts. > > For example the the ltc1760 assert its SMBALERT irq immediately on power > on. With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first > device is registered irq are enabled and fire continuously as the second > device driver has not yet loaded. Setting this parameter to 0x3 while > delay the irq being enabled until both devices are ready. > > Acked-by: Peter Rosin > Signed-off-by: Phil Reid > --- > Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt | 3 +++ > 1 file changed, 3 insertions(+) Acked-by: Rob Herring