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=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 76AF9C28CC0 for ; Thu, 30 May 2019 20:32:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2921326163 for ; Thu, 30 May 2019 20:32:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fGvVeOZS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726275AbfE3UcF (ORCPT ); Thu, 30 May 2019 16:32:05 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:32994 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726169AbfE3UcF (ORCPT ); Thu, 30 May 2019 16:32:05 -0400 Received: by mail-pl1-f196.google.com with SMTP id g21so3033722plq.0; Thu, 30 May 2019 13:32:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=kguosYeFwg0UQb+y10YIE7iIZLNffVxVTFmnvc3bap8=; b=fGvVeOZSE0ET9SO/bO/OPxJ5yvsV1UHHYcsckRtI1SVNBgTAGyjAWyvXAx66N4W2jl GrNqwi7ZhmDlL5FiBdznmWlMBD/kV1ceCIfMqVh3JMvA8pCunpPDxWUPiRufwF4Lyp5X rKcsx3AkQ6Ml4GWgfhH6laJzBAo8FmYSWYLBjRbCAyf5KXiwfNr5PyuraW4/6NK8Gu5v TvPRGQq7AAt2Hy/ih8bsKf1iLqaj8rpGhsPHcd/QX8kutMeTuP7whyUXKsLy6CrZTZNh IGHf5ZCTkj3yzBNzkYO/Xz39hk4WNw/aulmxJehwmKsBIEVYejsm8oi6PpZ9+EUVgs1J Fy3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=kguosYeFwg0UQb+y10YIE7iIZLNffVxVTFmnvc3bap8=; b=lYCNUL4vqwgLqMr4lXi+rV/38BVwWpfwsHalhakCIc4JRIssCYphfRIpp80X0mcLsE dhEHg1RAmVncc4fWchahrGoX2qb1Qov/t/JnWE78UPDl19uGvLDFX+DSQoxFz4RStN0f vE+c7Zb3oMKdRML5uFnOQG0NFNjQKb/f17YNXS7r22t7zgmOmrl8uJhD/fmH0X56MiFm +ozLtWZtdwpivmF3GbQG531WTPeG6VVRdskF2WpDBqNWgA0XME7tAQLZMofSBqb+cxpT LUfQhCLlbjiRFwzj62A8pOIWcH16MyZxdocEFVxZPC+L+Qq65xC41Xnzd8fUZEvNU91U Iszg== X-Gm-Message-State: APjAAAW8nojjnwuhcT2CZ4sjqdxhcDFLWOcYfxU9VXr7lF2fKntzgl06 Tjj8QKYUX8wpj5d0p9L7Csc= X-Google-Smtp-Source: APXvYqz3Cxdgk8TW1rHHu3MlWR0sJbYNWQWDNc8q7gYGplLRcrTWWHS3rocG1QiSmnMTBKOErj1JOg== X-Received: by 2002:a17:902:4e:: with SMTP id 72mr5561546pla.80.1559248324265; Thu, 30 May 2019 13:32:04 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id t4sm3256666pjq.19.2019.05.30.13.32.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 May 2019 13:32:03 -0700 (PDT) Date: Thu, 30 May 2019 13:32:02 -0700 From: Guenter Roeck To: Andrey Smirnov Cc: Linux PM list , Chris Healy , Lucas Stach , Fabio Estevam , Sebastian Reichel , linux-kernel Subject: Re: [PATCH 1/2] power: supply: Add HWMON compatibility layer Message-ID: <20190530203202.GD12310@roeck-us.net> References: <20190529071112.16849-1-andrew.smirnov@gmail.com> <20190529071112.16849-2-andrew.smirnov@gmail.com> <22dcfea4-00a2-3de8-8313-35d8d1350493@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Thu, May 30, 2019 at 01:08:35PM -0700, Andrey Smirnov wrote: > On Wed, May 29, 2019 at 5:40 AM Guenter Roeck wrote: > > > > On 5/29/19 12:11 AM, Andrey Smirnov wrote: > > > Add code implementing HWMON adapter/compatibility layer to allow > > > expositing various sensors present on power supply devices via HWMON > > > subsystem. This is done in order to allow userspace to use single > > > ABI/library(libsensors) to access/manipulate all of the sensors of the > > > system. > > > > > > Signed-off-by: Andrey Smirnov > > > Cc: Chris Healy > > > Cc: Lucas Stach > > > Cc: Fabio Estevam > > > Cc: Guenter Roeck > > > Cc: Sebastian Reichel > > > Cc: linux-kernel@vger.kernel.org > > > Cc: linux-pm@vger.kernel.org > > > --- > > > drivers/power/supply/Kconfig | 14 + > > > drivers/power/supply/Makefile | 1 + > > > drivers/power/supply/power_supply_hwmon.c | 329 ++++++++++++++++++++++ > > > include/linux/power_supply.h | 11 + > > > 4 files changed, 355 insertions(+) > > > create mode 100644 drivers/power/supply/power_supply_hwmon.c > > > > > > diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig > > > index 26dacdab03cc..1f2252cb95fd 100644 > > > --- a/drivers/power/supply/Kconfig > > > +++ b/drivers/power/supply/Kconfig > > > @@ -14,6 +14,20 @@ config POWER_SUPPLY_DEBUG > > > Say Y here to enable debugging messages for power supply class > > > and drivers. > > > > > > +config POWER_SUPPLY_HWMON > > > + bool > > > + prompt "Expose power supply sensors as hwmon device" > > > + depends on HWMON=y || HWMON=POWER_SUPPLY > > > + default y > > > > Not sure if you want to enable that by default. > > > > That's what THERMAL_HWMON does which seems pretty analogous to this code. > maintainer call to make. > > > + help > > > + This options enables API that allows sensors found on a > > > + power supply device (current, voltage, temperature) to be > > > + exposed as a hwmon device. > > > + > > > + Say 'Y' here if you want power supplies to > > > + have hwmon sysfs interface too. > > > + > > > + > > > config PDA_POWER > > > tristate "Generic PDA/phone power driver" > > > depends on !S390 > > > diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile > > > index f208273f9686..c47e88ba16b9 100644 > > > --- a/drivers/power/supply/Makefile > > > +++ b/drivers/power/supply/Makefile > > > @@ -6,6 +6,7 @@ power_supply-$(CONFIG_SYSFS) += power_supply_sysfs.o > > > power_supply-$(CONFIG_LEDS_TRIGGERS) += power_supply_leds.o > > > > > > obj-$(CONFIG_POWER_SUPPLY) += power_supply.o > > > +obj-$(CONFIG_POWER_SUPPLY_HWMON) += power_supply_hwmon.o > > > obj-$(CONFIG_GENERIC_ADC_BATTERY) += generic-adc-battery.o > > > > > > obj-$(CONFIG_PDA_POWER) += pda_power.o > > > diff --git a/drivers/power/supply/power_supply_hwmon.c b/drivers/power/supply/power_supply_hwmon.c > > > new file mode 100644 > > > index 000000000000..dca7f79fae6e > > > --- /dev/null > > > +++ b/drivers/power/supply/power_supply_hwmon.c > > > @@ -0,0 +1,329 @@ > > > +// SPDX-License-Identifier: GPL-2.0 > > > +/* > > > + * power_supply_hwmon.c - power supply hwmon support. > > > + */ > > > + > > > +#include > > > +#include > > > +#include > > > +#include > > > + > > Alphabetic order ? > > > > Sure, will do in v2. > > > > +struct power_supply_hwmon { > > > + struct power_supply *psy; > > > + unsigned long *props; > > > +}; > > > + > > > +static int power_supply_hwmon_in_to_property(u32 attr) > > > +{ > > > + switch (attr) { > > > + case hwmon_in_average: > > > + return POWER_SUPPLY_PROP_VOLTAGE_AVG; > > > + case hwmon_in_min: > > > + return POWER_SUPPLY_PROP_VOLTAGE_MIN; > > > + case hwmon_in_max: > > > + return POWER_SUPPLY_PROP_VOLTAGE_MAX; > > > + case hwmon_in_input: > > > + return POWER_SUPPLY_PROP_VOLTAGE_NOW; > > > + default: > > > + break; > > > + } > > > + > > > + return -EINVAL; > > > +} > > > + > > > +static int power_supply_hwmon_curr_to_property(u32 attr) > > > +{ > > > + switch (attr) { > > > + case hwmon_curr_average: > > > + return POWER_SUPPLY_PROP_CURRENT_AVG; > > > + case hwmon_curr_max: > > > + return POWER_SUPPLY_PROP_CURRENT_MAX; > > > + case hwmon_curr_input: > > > + return POWER_SUPPLY_PROP_CURRENT_NOW; > > > + default: > > > + break; > > > + } > > > + > > > + return -EINVAL; > > > +} > > > + > > > +static int power_supply_hwmon_temp_to_property(u32 attr, int channel) > > > +{ > > > + if (channel) { > > > + switch (attr) { > > > + case hwmon_temp_input: > > > + return POWER_SUPPLY_PROP_TEMP_AMBIENT; > > > + case hwmon_temp_min_alarm: > > > + return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN; > > > + case hwmon_temp_max_alarm: > > > + return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX; > > > + default: > > > + break; > > > + } > > > + } else { > > > + switch (attr) { > > > + case hwmon_temp_input: > > > + return POWER_SUPPLY_PROP_TEMP; > > > + case hwmon_temp_max: > > > + return POWER_SUPPLY_PROP_TEMP_MAX; > > > + case hwmon_temp_min: > > > + return POWER_SUPPLY_PROP_TEMP_MIN; > > > + case hwmon_temp_min_alarm: > > > + return POWER_SUPPLY_PROP_TEMP_ALERT_MIN; > > > + case hwmon_temp_max_alarm: > > > + return POWER_SUPPLY_PROP_TEMP_ALERT_MAX; > > > + default: > > > + break; > > > + } > > > + } > > > + > > > + return -EINVAL; > > > +} > > > + > > > +static int > > > +power_supply_hwmon_to_property(enum hwmon_sensor_types type, > > > + u32 attr, int channel) > > > +{ > > > + switch (type) { > > > + case hwmon_in: > > > + return power_supply_hwmon_in_to_property(attr); > > > + case hwmon_curr: > > > + return power_supply_hwmon_curr_to_property(attr); > > > + case hwmon_temp: > > > + return power_supply_hwmon_temp_to_property(attr, channel); > > > + default: > > > + break; > > > + } > > > + > > > + return -EINVAL; > > > +} > > > + > > > +static bool power_supply_hwmon_is_a_label(enum hwmon_sensor_types type, > > > + u32 attr) > > > +{ > > > + return type == hwmon_temp && attr == hwmon_temp_label; > > > +} > > > + > > > +static umode_t power_supply_hwmon_is_visible(const void *data, > > > + enum hwmon_sensor_types type, > > > + u32 attr, int channel) > > > +{ > > > + const struct power_supply_hwmon *psyhw = data; > > > + int prop, is_writable; > > > + > > > + if (power_supply_hwmon_is_a_label(type, attr)) > > > + return 0444; > > > + > > > + prop = power_supply_hwmon_to_property(type, attr, channel); > > > + if (prop < 0 || !test_bit(prop, psyhw->props)) > > > + return 0; > > > + > > > + is_writable = power_supply_property_is_writeable(psyhw->psy, prop); > > > + > > > + return (is_writable <= 0) ? 0444 : 0644; > > > > I a a bit concerned that this can result in writeable voltage/current/temp > > values (not just for limits), which would be very undesirable. It might be > > better to add another check to ensure that this does not happen. > > > > OK, will do. > > > > +} > > > + > > > +static int power_supply_hwmon_read_string(struct device *dev, > > > + enum hwmon_sensor_types type, > > > + u32 attr, int channel, > > > + const char **str) > > > +{ > > > + *str = channel ? "temp" : "temp ambient"; > > > + return 0; > > > +} > > > + > > > +static int > > > +power_supply_hwmon_read(struct device *dev, enum hwmon_sensor_types type, > > > + u32 attr, int channel, long *val) > > > +{ > > > + struct power_supply_hwmon *psyhw = dev_get_drvdata(dev); > > > + struct power_supply *psy = psyhw->psy; > > > + union power_supply_propval pspval; > > > + int ret, prop; > > > + > > > + prop = power_supply_hwmon_to_property(type, attr, channel); > > > + if (prop < 0) > > > + return prop; > > > + > > > + ret = power_supply_get_property(psy, prop, &pspval); > > > + if (ret) > > > + return ret; > > > + > > > + switch (type) { > > > + /* > > > + * Both voltage and current is reported in units of > > > + * microvolts/microamps, so we need to adjust it to > > > + * milliamps(volts) > > > + */ > > > + case hwmon_curr: > > > + case hwmon_in: > > > + pspval.intval /= 1000; > > > > DIV_ROUND_CLOSEST() ? > > > > Yeah, good idea, will do. > > > > + break; > > > + /* > > > + * Temp needs to be converted from 1/10 C to milli-C > > > + */ > > > + case hwmon_temp: > > > + pspval.intval *= 100; > > > > intval is an int, so theoretically this could result in an overflow. > > > > Sure, will change the code to use check_mul_overflow() > > > > > > + break; > > > + default: > > > > Wouldn't this be an error ? > > > > Shouldn't happen, but adding a error path here won't hurt. > > > Personally I prefer direct value assignments. I don't see value in > > updating pspval.intval first only to assign it to *val later. > > > > This won't work once I convert the code to use check_mul_overflow() > since it expects its argument to have the same type and "*val" is > long. > > > > + break; > > > + } > > > + > > > + *val = pspval.intval; > > > + > > > + return 0; > > > +} > > > + > > > +static int > > > +power_supply_hwmon_write(struct device *dev, enum hwmon_sensor_types type, > > > + u32 attr, int channel, long val) > > > +{ > > > + struct power_supply_hwmon *psyhw = dev_get_drvdata(dev); > > > + struct power_supply *psy = psyhw->psy; > > > + union power_supply_propval pspval; > > > + int prop; > > > + > > > + prop = power_supply_hwmon_to_property(type, attr, channel); > > > + if (prop < 0) > > > + return prop; > > > + > > > + pspval.intval = val; > > > + > > > + switch (type) { > > > + /* > > > + * Both voltage and current is reported in units of > > > + * microvolts/microamps, so we need to adjust it to > > > + * milliamps(volts) > > > + */ > > > + case hwmon_curr: > > > + case hwmon_in: > > > + pspval.intval *= 1000; > > > > Range checks ? This can result in an overflow. > > > > Will add check_mul_overflow() here as well. > > > > + break; > > > + /* > > > + * Temp needs to be converted from 1/10 C to milli-C > > > + */ > > > + case hwmon_temp: > > > + pspval.intval /= 100; > > > + break; > > > + default: > > > + break; > > > > Wouldn't this be an error ? > > > > Will add an error path in v2. > > > > + } > > > + > > > + return power_supply_set_property(psy, prop, &pspval); > > > +} > > > + > > > +static const struct hwmon_ops power_supply_hwmon_ops = { > > > + .is_visible = power_supply_hwmon_is_visible, > > > + .read = power_supply_hwmon_read, > > > + .write = power_supply_hwmon_write, > > > + .read_string = power_supply_hwmon_read_string, > > > +}; > > > + > > > +static const struct hwmon_channel_info *power_supply_hwmon_info[] = { > > > + HWMON_CHANNEL_INFO(temp, > > > + HWMON_T_LABEL | > > > + HWMON_T_INPUT | > > > + HWMON_T_MAX | > > > + HWMON_T_MIN | > > > + HWMON_T_MIN_ALARM | > > > + HWMON_T_MIN_ALARM, > > > + > > > + HWMON_T_LABEL | > > > + HWMON_T_INPUT | > > > + HWMON_T_MIN_ALARM | > > > + HWMON_T_LABEL | > > > + HWMON_T_MAX_ALARM), > > > + > > > + HWMON_CHANNEL_INFO(curr, > > > + HWMON_C_AVERAGE | > > > + HWMON_C_MAX | > > > + HWMON_C_INPUT), > > > + > > > + HWMON_CHANNEL_INFO(in, > > > + HWMON_I_AVERAGE | > > > + HWMON_I_MIN | > > > + HWMON_I_MAX | > > > + HWMON_I_INPUT), > > > + NULL > > > +}; > > > + > > > +static const struct hwmon_chip_info power_supply_hwmon_chip_info = { > > > + .ops = &power_supply_hwmon_ops, > > > + .info = power_supply_hwmon_info, > > > +}; > > > + > > > +static void power_supply_hwmon_bitmap_free(void *data) > > > +{ > > > + bitmap_free(data); > > > +} > > > + > > > +struct device *devm_power_supply_add_hwmon_sysfs(struct power_supply *psy) > > > +{ > > > + const struct power_supply_desc *desc = psy->desc; > > > + struct power_supply_hwmon *psyhw; > > > + struct device *dev = &psy->dev; > > > + struct device *hwmon; > > > + int ret, i; > > > + > > > + if (!devres_open_group(dev, NULL, GFP_KERNEL)) > > > + return ERR_PTR(-ENOMEM); > > > + > > > + psyhw = devm_kzalloc(dev, sizeof(*psyhw), GFP_KERNEL); > > > + if (!psyhw) { > > > + ret = -ENOMEM; > > > + goto error; > > > + } > > > + > > > + psyhw->psy = psy; > > > + psyhw->props = bitmap_zalloc(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG + 1, > > > + GFP_KERNEL); > > > + if (!psyhw->props) { > > > + ret = -ENOMEM; > > > + goto error; > > > + } > > > + > > > + ret = devm_add_action(dev, power_supply_hwmon_bitmap_free, > > > + psyhw->props); > > > + if (ret) > > > + goto error; > > > + > > > + for (i = 0; i < desc->num_properties; i++) { > > > + const enum power_supply_property prop = desc->properties[i]; > > > + > > > + switch (prop) { > > > + case POWER_SUPPLY_PROP_CURRENT_AVG: > > > + case POWER_SUPPLY_PROP_CURRENT_MAX: > > > + case POWER_SUPPLY_PROP_CURRENT_NOW: > > > + case POWER_SUPPLY_PROP_TEMP: > > > + case POWER_SUPPLY_PROP_TEMP_MAX: > > > + case POWER_SUPPLY_PROP_TEMP_MIN: > > > + case POWER_SUPPLY_PROP_TEMP_ALERT_MIN: > > > + case POWER_SUPPLY_PROP_TEMP_ALERT_MAX: > > > + case POWER_SUPPLY_PROP_TEMP_AMBIENT: > > > + case POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN: > > > + case POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX: > > > + case POWER_SUPPLY_PROP_VOLTAGE_AVG: > > > + case POWER_SUPPLY_PROP_VOLTAGE_MIN: > > > + case POWER_SUPPLY_PROP_VOLTAGE_MAX: > > > + case POWER_SUPPLY_PROP_VOLTAGE_NOW: > > > + set_bit(prop, psyhw->props); > > > + break; > > > + default: > > > + break; > > > + } > > > + } > > > + > > > + hwmon = devm_hwmon_device_register_with_info(dev, psy->desc->name, > > > + psyhw, > > > + &power_supply_hwmon_chip_info, > > > + NULL); > > > + ret = PTR_ERR_OR_ZERO(hwmon); > > > + if (ret) > > > + goto error; > > > + > > > + devres_remove_group(dev, NULL); > > > > Why devres_remove_group() and not devres_close_group() ? > > > > That's id-less group that'll never be used again, closing it and > keeping it around isn't really particularly useful to me. > Ok, fine with me if it works. I have no idea what the semantics of devres groups is, much less what the difference between devres_remove_group() and devres_close_group() is. > > > + return hwmon; > > > > Why return a pointer to the hwmon device and not just an error code ? > > > > Just to expose created hwmon device. > Sure, but what for ? > > > +error: > > > + devres_release_group(dev, NULL); > > > + return ERR_PTR(ret); > > > +} > > > diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h > > > index d9c0c094f8a0..839abfa2c640 100644 > > > --- a/include/linux/power_supply.h > > > +++ b/include/linux/power_supply.h > > > @@ -481,4 +481,15 @@ static inline bool power_supply_is_watt_property(enum power_supply_property psp) > > > return 0; > > > } > > > > > > +#ifdef CONFIG_POWER_SUPPLY_HWMON > > > +extern struct device * > > > +devm_power_supply_add_hwmon_sysfs(struct power_supply *psy); > > > +#else > > > +static struct device * > > > +devm_power_supply_add_hwmon_sysfs(struct power_supply *psy) > > > +{ > > > + return 0; > > > > You might consider making the return code an int. Otherwise this gets difficult > > for the caller, who would have to check for IS_ERR() and NULL (if the device > > pointer is supposed to be used for anything). > > > > Sure, if removing access to created hwmon device is OK, I am more than > happy to convert this to return an int. > Again, the question is the opposite: You should not return a pointer unless you have a use case. "to expose created hwmon device" is not a use case. Thanks, Guenter