From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?U8O2cmVu?= Brinkmann Subject: Re: [RFC LINUX PATCH] dt: xilinx: xadc: provision to control clock frequency Date: Wed, 23 Dec 2015 03:49:08 -0800 Message-ID: <20151223114908.GG6491@xsjsorenbubuntu> References: <1450866505-22069-1-git-send-email-ranjit.waghmode@xilinx.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1450866505-22069-1-git-send-email-ranjit.waghmode@xilinx.com> Sender: linux-kernel-owner@vger.kernel.org To: Ranjit Waghmode Cc: robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, michal.simek@xilinx.com, corbet@lwn.net, lars@metafoo.de, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, punnaia@xilinx.com, anirudh@xilinx.com List-Id: devicetree@vger.kernel.org On Wed, 2015-12-23 at 03:58PM +0530, Ranjit Waghmode wrote: > This patch adds parameter to the xilinx-xadc node for controlling > clock frequency. >=20 > Following are the possible options for user to control the frequency: > * 00 : 1/2 of clock frequency > * 01 : 1/4 of clock frequency > * 10 : 1/8 of clock frequency > * 11 : 1/16 of clock frequency How is this chosen? Are these just arbitrary values that you need for some use-case? Or are these the options HW allows? >=20 > So this patch adds parameter tck-rate to set user defined values from > above pool to control the clock frequency. This is no longer describing HW, but configuring driver/HW. Why does this have to be in DT? Why can't the driver request/set the frequency a= s operation requires it? Thanks, S=C3=B6ren