From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751621AbaI3VSz (ORCPT ); Tue, 30 Sep 2014 17:18:55 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:44995 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751182AbaI3VSy (ORCPT ); Tue, 30 Sep 2014 17:18:54 -0400 Message-ID: <542B1E38.4020702@ti.com> Date: Tue, 30 Sep 2014 16:18:48 -0500 From: Dan Murphy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: Lars-Peter Clausen , , CC: , Subject: Re: [PATCH] regmap: Allow read_reg_mask to be 0 References: <1412093220-24690-1-git-send-email-dmurphy@ti.com> <542B1ABE.5000900@metafoo.de> In-Reply-To: <542B1ABE.5000900@metafoo.de> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lars On 09/30/2014 04:03 PM, Lars-Peter Clausen wrote: > On 09/30/2014 06:07 PM, Dan Murphy wrote: >> There may be spi devices that do not require a >> register read mask to read the registers. >> >> Currently the code sets the read mask based on >> a non-zero value passed in from the driver or if that >> value is 0 sets the read mask to 0x80. > > It only sets it to the bus default if both read_flag_mask and write_flag_mask are 0. The assumption is that both of them being zero is a invalid configuration and either of them (or both) have to be non-zero for proper operation, since otherwise the device can't tell the difference between a read and a write. > > Do you have a device where both the read and the write mask is 0? > > - Lars Yes I do have a device that the read/write mask are both 0. The device, which is already in production, has a specific control register that sets either the reading or writing of the rest of the registers. Here is the data sheet http://www.ti.com/lit/ds/symlink/afe4403.pdf See page 61 control0. Driver is written for this part just want to get this lead patch in or maybe an alternate solution. Dan -- ------------------ Dan Murphy