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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 69DC2C433DF for ; Fri, 31 Jul 2020 10:53:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5190520838 for ; Fri, 31 Jul 2020 10:53:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732485AbgGaKxM (ORCPT ); Fri, 31 Jul 2020 06:53:12 -0400 Received: from mailout07.rmx.de ([94.199.90.95]:55415 "EHLO mailout07.rmx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729141AbgGaKxM (ORCPT ); Fri, 31 Jul 2020 06:53:12 -0400 Received: from kdin01.retarus.com (kdin01.dmz1.retloc [172.19.17.48]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout07.rmx.de (Postfix) with ESMTPS id 4BJ3z72b6fzBwbd; Fri, 31 Jul 2020 12:53:07 +0200 (CEST) Received: from mta.arri.de (unknown [217.111.95.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by kdin01.retarus.com (Postfix) with ESMTPS id 4BJ3yk4dddz2xFV; Fri, 31 Jul 2020 12:52:46 +0200 (CEST) Received: from n95hx1g2.localnet (192.168.54.39) by mta.arri.de (192.168.100.104) with Microsoft SMTP Server (TLS) id 14.3.408.0; Fri, 31 Jul 2020 12:52:23 +0200 From: Christian Eggers To: Andy Shevchenko CC: Rob Herring , Jonathan Cameron , Jonathan Cameron , "Hartmut Knaack" , Lars-Peter Clausen , "Peter Meerwald-Stadler" , linux-iio , devicetree , Linux Kernel Mailing List Subject: Re: [PATCH v4 2/2] iio: light: as73211: New driver Date: Fri, 31 Jul 2020 12:52:22 +0200 Message-ID: <2706267.JtmGt7LAV2@n95hx1g2> Organization: Arnold & Richter Cine Technik GmbH & Co. Betriebs KG In-Reply-To: References: <20200731070114.40471-1-ceggers@arri.de> <20200731070114.40471-3-ceggers@arri.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Originating-IP: [192.168.54.39] X-RMX-ID: 20200731-125248-4BJ3yk4dddz2xFV-0@kdin01 X-RMX-SOURCE: 217.111.95.66 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Andy, thanks for further review. If nobody else sends comments, I'll publish the next version tonight. Maybe we could clarify the questions below in time. Best regards Christian > W=1 (not V=1) runs kernel doc validation script. without V=1, I get nothing. Neither excess nor missing members are reported on my system. On Friday, 31 July 2020, 09:34:02 CEST, Andy Shevchenko wrote: > On Fri, Jul 31, 2020 at 10:03 AM Christian Eggers wrote: > > +static const int as73211_samp_freq_avail[] = { 1024000, 2048000, 4096000, > > 8192000 }; > This looks related to the below mentioned 1.024MHz. > > Perhaps add a definition above and comment here? > > #define AS73211_BASE_FREQ_1024KHZ 1024000 added similar define in v5. The array looks like the following now static const int as73211_samp_freq_avail[] = { AS73211_SAMPLE_FREQ_BASE, AS73211_SAMPLE_FREQ_BASE * 2, AS73211_SAMPLE_FREQ_BASE * 4, AS73211_SAMPLE_FREQ_BASE * 8 }; > > +/* integration time in units of 1024 clock cycles */ > > Unify this with below one. Or the other way around, i.o.w. join one of > them into the other. > > > +static unsigned int as73211_integration_time_1024cyc(struct as73211_data > > *data) +{ > > + /* integration time in CREG1 is in powers of 2 (x 1024 cycles) */ > > + return BIT(FIELD_GET(AS73211_CREG1_TIME_MASK, data->creg1)); > > +} I'm not sure, whether this is possible. as73211_integration_time_1024cyc() returns the current setting from hardware. as73211_integration_time_us() calculates the resulting time. But as73211_integration_time_us() is also called in as73211_integration_time_calc_avail() inside the loop. > > + unsigned int time_us = as73211_integration_time_us(data, > > + as73211_integration_time_1024cyc(data)); > One line? checkpatch complains... ignore? > > + int reg_bits, freq_kHz = val / 1000 /* HZ_PER_KHZ */; /* > > 1024, 2048, ... */ + > > + /* val must be 1024 * 2^x */ > > + if (val < 0 || (freq_kHz * 1000 /* HZ_PER_KHZ */) != val > > || > > + !is_power_of_2(freq_kHz) || val2) > > + return -EINVAL; > > Please, define HZ_PER_KHZ locally. It will really help when we move > these definitions to a global level. ok > > ... > > > + /* gain can be calculated from CREG1 as 2^(13 - > > CREG1_GAIN) */ + reg_bits = 13 - ilog2(val); > > 13 is the second time in the code. Deserves a descriptive definition. I'm unsure how to solve this. Possible values for gain: CREG1[7:4] | gain ----------------------------- 0 | 2048x 1 | 1024x 2 | 512x ... | ... 13 | 1x #define AS73211_CREG1_GAIN_1_NON_SHIFTED 13 // this define is CREG1 related, but not shifted to the right position static unsigned int as73211_gain(struct as73211_data *data) { /* gain can be calculated from CREG1 as 2^(13 - CREG1_GAIN) */ return BIT(AS73211_CREG1_GAIN_1_NON_SHIFTED - FIELD_GET(AS73211_CREG1_GAIN_MASK, data->creg1)); } ---- or ---- #define AS73211_CREG1_GAIN_1 FIELD_PREP(AS73211_CREG1_GAIN_MASK, 13) static unsigned int as73211_gain(struct as73211_data *data) { /* gain can be calculated from CREG1 as 2^(13 - CREG1_GAIN) */ return BIT(FIELD_GET(AS73211_CREG1_GAIN_MASK, AS73211_CREG1_GAIN_1) - FIELD_GET(AS73211_CREG1_GAIN_MASK, data->creg1)); } > > + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); > > + if (indio_dev == NULL) > > if (!indio_dev) > > > + return -ENOMEM; > > ... > > > + indio_dev->dev.parent = dev; > > Doesn't IIO core do this for you? devm_iio_device_alloc() doesn't pass 'dev' to iio_device_alloc(). I already looked around, but I didn't find. And after debugging v5.4, devm_iio_device_alloc() definitely doesn't do it. > > + ret = devm_iio_device_register(dev, indio_dev); > > + if (ret < 0) > > + goto powerdown; > > + > > + return 0; > > > > +powerdown: > > + as73211_power(indio_dev, false); > > + return ret; > > devm_*() is tricky. Here you broke ordering heavily. So, consider to > add this under devm_add_action_or_reset(). Sorry, my mistake! I already felt that something may be wrong here...