From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40409C4361B for ; Sun, 13 Dec 2020 19:35:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E495022A84 for ; Sun, 13 Dec 2020 19:35:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728345AbgLMTfU (ORCPT ); Sun, 13 Dec 2020 14:35:20 -0500 Received: from relay12.mail.gandi.net ([217.70.178.232]:37243 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727909AbgLMTfU (ORCPT ); Sun, 13 Dec 2020 14:35:20 -0500 Received: from localhost (lfbn-lyo-1-997-19.w86-194.abo.wanadoo.fr [86.194.74.19]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id B61F8200003; Sun, 13 Dec 2020 19:34:36 +0000 (UTC) Date: Sun, 13 Dec 2020 20:34:36 +0100 From: Alexandre Belloni To: Jonathan Cameron Cc: Lars-Peter Clausen , Peter Meerwald-Stadler , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/6] iio:common:ms_sensors:ms_sensors_i2c: add support for alternative PROM layout Message-ID: <20201213193436.GM1781038@piout.net> References: <20201209234857.1521453-1-alexandre.belloni@bootlin.com> <20201209234857.1521453-6-alexandre.belloni@bootlin.com> <20201213172042.76b2e028@archlinux> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201213172042.76b2e028@archlinux> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 13/12/2020 17:20:42+0000, Jonathan Cameron wrote: > > +/** > > + * ms_sensors_tp_crc_valid_112() - CRC check function for > > + * Temperature and pressure devices for 112bit PROM. > > + * This function is only used when reading PROM coefficients > > + * > > + * @prom: pointer to PROM coefficients array > > + * > > + * Return: CRC. > > That's a bit confusing. Perhaps return if CRC correct > Sometimes CRC is used to refer to particular bits and sometimes > to the check (i.e. whether it is right). > Roght, this should have been "Return: True if CRC is ok." > > + */ > > +static bool ms_sensors_tp_crc_valid_112(u16 *prom) > > +{ > > + u16 w0 = prom[0], crc_read = (w0 & 0xF000) >> 12; > > + u8 crc; > > + > > + prom[0] &= 0x0FFF; /* Clear the CRC computation part */ > > + prom[MS_SENSORS_TP_PROM_WORDS_NB - 1] = 0; > > + > > + crc = ms_sensors_tp_crc4(prom); > > + > > + prom[0] = w0; > > + > > + return crc == crc_read; > > +} > > + > > +/** > > + * ms_sensors_tp_crc_valid_128() - CRC check function for > > + * Temperature and pressure devices for 128bit PROM. > > + * This function is only used when reading PROM coefficients > > + * > > + * @prom: pointer to PROM coefficients array > > + * > > + * Return: CRC. > > + */ > > +static bool ms_sensors_tp_crc_valid_128(u16 *prom) > > +{ > > + u16 w7 = prom[7], crc_read = w7 & 0x000F; > > + u8 crc; > > + > > + prom[7] &= 0xFF00; /* Clear the CRC and LSB part */ > > + > > + crc = ms_sensors_tp_crc4(prom); > > + > > + prom[7] = w7; > > + > > + return crc == crc_read; > > } > > > > /** > > @@ -535,6 +577,7 @@ static bool ms_sensors_tp_crc_valid(u16 *prom) > > int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data) > > { > > int i, ret; > > + bool valid; > > > > for (i = 0; i < dev_data->hw->prom_len; i++) { > > ret = ms_sensors_read_prom_word( > > @@ -546,7 +589,12 @@ int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data) > > return ret; > > } > > > > - if (!ms_sensors_tp_crc_valid(dev_data->prom)) { > > + if (dev_data->hw->prom_len == 8) > > + valid = ms_sensors_tp_crc_valid_128(dev_data->prom); > > + else > > + valid = ms_sensors_tp_crc_valid_112(dev_data->prom); > > + > > + if (!valid) { > > dev_err(&dev_data->client->dev, > > "Calibration coefficients crc check error\n"); > > return -ENODEV; > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com