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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 C388FC4707A for ; Sun, 23 May 2021 17:53:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A05236117A for ; Sun, 23 May 2021 17:53:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231899AbhEWRy0 (ORCPT ); Sun, 23 May 2021 13:54:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231862AbhEWRyZ (ORCPT ); Sun, 23 May 2021 13:54:25 -0400 Received: from mail-il1-x12d.google.com (mail-il1-x12d.google.com [IPv6:2607:f8b0:4864:20::12d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B72DC06138A for ; Sun, 23 May 2021 10:52:58 -0700 (PDT) Received: by mail-il1-x12d.google.com with SMTP id m1so21158409ilg.10 for ; Sun, 23 May 2021 10:52:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=metormote-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=05vz9I/MF5N8EuBmgeaTm3kpG3BPBz43NAejnYDL8rg=; b=jf3CN50MczZ8g0QtUQ5SHGWmUfOajk6RPW78SGcf4uf3X4XfbIpggpM3ZQI+ujYj+z sdKE1k0RKe8RtOyZZwvdq1vuBrpuqPBLG72zdqU9xp108iTkCqypjC8LV2334khNfi38 TwmmWE2Ti1q2hYQVKA5hVX+TGDO70GlV6xL/3aCuxfIwomWcELEUku+z05YIzs3uPu9h h89Sf1LqLjIu0pjwmvFd+ElC1/o4wO6GZnxd5MYbz1e2/FPj16pIxnpUpB3VBJxyXbuY 718G2xCm9VIuAwLwXrSUBaJu+m0x2p91e6aRUHTs39EFuV9jeVGCFhh/UvH1ud6kT8Te 6zOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=05vz9I/MF5N8EuBmgeaTm3kpG3BPBz43NAejnYDL8rg=; b=VSeoJnqejgRzGJBbu0kTIwpTHD0IytBZbElYoJM5DlWtz72JkMkpZ0Ew1EEF7EWgI+ 5HO3QgvAeeZetGf7pLt1wnKaQu3QKHvbNOAwu+Iml/xGoGdOJRtLar3J3/d+2MZvBnYO WUQaD45f1sm8mjZU1LSrQPzNu4pl1Ugz/mVx7+YqrwQPwkbo6KrEzZaTjSE+bleVgy9v r2k73+LzUfxExCLg2rikuQJ8HFQst4eVFJheEv8TAWUIuJBBmwa23FTUbfD04qR+fDCp Kyjxqqcf/vSpeH62pUvtuz9ANJ3v8X0YdqY5Bgjt2gTwdN6E/gY04OKBFi18UFtKZmvR AWgw== X-Gm-Message-State: AOAM532Ba96RAsvgNnoDD9YdYXS21WkMUcqbc3XgPUmFMwoojteYTuUn dLyiXYbtZLnGXHEw78aABOQI4Gt3jfMaE0irpqYbZA== X-Google-Smtp-Source: ABdhPJyhSlBBavDbjIHB/GTOjMKky9wJKFaoO/4oLDlpN3uOlp4AE60rTIHditZTdxbLb7xZcpA3a/vGxx1Tvdsigxs= X-Received: by 2002:a05:6e02:f81:: with SMTP id v1mr13126189ilo.243.1621792377638; Sun, 23 May 2021 10:52:57 -0700 (PDT) MIME-Version: 1.0 References: <20210522105528.87629-1-erik.rosen@metormote.com> <20210522105528.87629-4-erik.rosen@metormote.com> <24ff79b6-29f5-6921-7418-9ba93bcf7193@roeck-us.net> In-Reply-To: <24ff79b6-29f5-6921-7418-9ba93bcf7193@roeck-us.net> From: Erik Rosen Date: Sun, 23 May 2021 19:52:46 +0200 Message-ID: Subject: Re: [PATCH v2 3/6] hwmon: (pmbus/pim4328) Add support for reading direct format coefficients To: Guenter Roeck Cc: Jean Delvare , Jonathan Corbet , linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Sat, May 22, 2021 at 3:41 PM Guenter Roeck wrote: > > On 5/22/21 3:55 AM, Erik Rosen wrote: > > Add support for reading and decoding direct format coefficients to > > the PMBus core driver. If the new flag PMBUS_USE_COEFFICIENTS_CMD > > is set, the driver will use the COEFFICIENTS register together with > > the information in the pmbus_sensor_attr structs to initialize > > relevant coefficients for the direct mode format. > > > > Signed-off-by: Erik Rosen > > --- > > drivers/hwmon/pmbus/pmbus_core.c | 93 ++++++++++++++++++++++++++++++++ > > include/linux/pmbus.h | 8 +++ > > 2 files changed, 101 insertions(+) > > > > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c > > index 460cbfd716e4..03c169bf5633 100644 > > --- a/drivers/hwmon/pmbus/pmbus_core.c > > +++ b/drivers/hwmon/pmbus/pmbus_core.c > > @@ -2177,6 +2177,38 @@ static int pmbus_find_attributes(struct i2c_client *client, > > return ret; > > } > > > > +static int pmbus_init_coefficients(struct i2c_client *client, > > + struct pmbus_data *data, int page, > > This seems wrong. Coefficients are not maintained per page but per class, > and (re-)reading them for each supported page doesn't really add value or > even make sense. > > > + enum pmbus_sensor_classes sensor_class, > > + const struct pmbus_sensor_attr *attrs, > > + int nattrs) > > +{ > > + int i, status; > > + > > + for (i = 0; i < nattrs; i++) { > > + if (attrs->class == sensor_class && > > + (attrs->func & data->info->func[page])) { > > + status = pmbus_read_coefficients(client, > > + (struct pmbus_driver_info *)data->info, > > + sensor_class, > > + attrs->reg); > > + if (status < 0) { > > + dev_err(&client->dev, > > + "Failed to read coefficients for register: %x\n", > > + attrs->reg); > > + return status; > > + } > > + return 0; > > + } > > + attrs++; > > + } > > + > > + dev_err(&client->dev, "No coefficients found for register: %x\n", > > + attrs->reg); > > + > > attrs points beyond the array size here, so attrs->reg does not point > to a valid array element. The problem would also not be the register > this happens to point to, but the class (ie the chip does not support > a sensor of the requested class). > > Not sure if this should trigger a message or error in the first place. > It won't matter since the chip will never need those coefficients. > If anything, this would be a misconfiguration (the driver should > not set direct format for this sensor class), and the return value > should be -EINVAL. > > Either case, I wonder if this can be handled with less complex code, > ie without having to check data->info->func[] for all pages. How > about just walking through attrs and try all class matches until > one is found that works (ie not return on error but keep trying) ? Ok, I'll send a new version based on your comments. I'm not entirely comfortable with just silently ignoring any failure to retrieve the coefficients for a sensor class. I mean it could be due to any reason; a bus error for instance. I'll return a -EINVAL for now if you don't disagree. /Erik > > > + return -ENODEV; > > +} > > + > > /* > > * Identify chip parameters. > > * This function is called for all chips. > > @@ -2185,6 +2217,7 @@ static int pmbus_identify_common(struct i2c_client *client, > > struct pmbus_data *data, int page) > > { > > int vout_mode = -1; > > + int ret; > > > > if (pmbus_check_byte_register(client, page, PMBUS_VOUT_MODE)) > > vout_mode = _pmbus_read_byte_data(client, page, > > @@ -2214,6 +2247,66 @@ static int pmbus_identify_common(struct i2c_client *client, > > } > > } > > > > + if (data->flags & PMBUS_USE_COEFFICIENTS_CMD) { > > I think there should be a separate function to handle that, > to be called only once, not once per page. > > > + if (!i2c_check_functionality(client->adapter, > > + I2C_FUNC_SMBUS_BLOCK_PROC_CALL)) > > + return -ENODEV; > > + > > + if (data->info->format[PSC_VOLTAGE_IN] == direct) { > > + ret = pmbus_init_coefficients(client, data, page, > > + PSC_VOLTAGE_IN, > > + voltage_attributes, > > + ARRAY_SIZE(voltage_attributes)); > > + if (ret) > > + return ret; > > + } > > It might be useful to have a little structure with {class, attribute list pointer, > attribute list size} and walk through that in a loop instead of repeating essentially > the same code multiple times. > > > + > > + if (data->info->format[PSC_VOLTAGE_OUT] == direct) { > > + ret = pmbus_init_coefficients(client, data, page, > > + PSC_VOLTAGE_OUT, > > + voltage_attributes, > > + ARRAY_SIZE(voltage_attributes)); > > + if (ret) > > + return ret; > > + } > > + > > + if (data->info->format[PSC_CURRENT_IN] == direct) { > > + ret = pmbus_init_coefficients(client, data, page, > > + PSC_CURRENT_IN, > > + current_attributes, > > + ARRAY_SIZE(current_attributes)); > > + if (ret) > > + return ret; > > + } > > + > > + if (data->info->format[PSC_CURRENT_OUT] == direct) { > > + ret = pmbus_init_coefficients(client, data, page, > > + PSC_CURRENT_OUT, > > + current_attributes, > > + ARRAY_SIZE(current_attributes)); > > + if (ret) > > + return ret; > > + } > > + > > + if (data->info->format[PSC_POWER] == direct) { > > + ret = pmbus_init_coefficients(client, data, page, > > + PSC_POWER, > > + power_attributes, > > + ARRAY_SIZE(power_attributes)); > > + if (ret) > > + return ret; > > + } > > + > > + if (data->info->format[PSC_TEMPERATURE] == direct) { > > + ret = pmbus_init_coefficients(client, data, page, > > + PSC_TEMPERATURE, > > + temp_attributes, > > + ARRAY_SIZE(temp_attributes)); > > + if (ret) > > + return ret; > > + } > > + } > > + > > pmbus_clear_fault_page(client, page); > > return 0; > > } > > diff --git a/include/linux/pmbus.h b/include/linux/pmbus.h > > index f720470b1bab..7fdc282dab5a 100644 > > --- a/include/linux/pmbus.h > > +++ b/include/linux/pmbus.h > > @@ -52,6 +52,14 @@ > > */ > > #define PMBUS_NO_WRITE_PROTECT BIT(4) > > > > +/* > > + * PMBUS_USE_COEFFICIENTS_CMD > > + * > > + * When this flag is set the PMBus core driver will use the COEFFICIENTS > > + * register to initialize the coefficients for the direct mode format. > > + */ > > +#define PMBUS_USE_COEFFICIENTS_CMD BIT(5) > > + > > struct pmbus_platform_data { > > u32 flags; /* Device specific flags */ > > > > >