From patchwork Mon May 25 14:12:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 211971 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 390D9C433DF for ; Mon, 25 May 2020 14:12:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1802120899 for ; Mon, 25 May 2020 14:12:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590415934; bh=4J38MidBihyKODDqhruO+ael6y9jTfLnvI1Z4aDlbFE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VNf3LwwdEj1mjjDULNLkqqmRGdWr1uE3cGf6ZhdCgX60Ezsn4o/+3YBFUm7e23x65 PNWExjxST46XoSawGvtCrDqHFljTqwYQv/erwHdoTMi2U1RWM4ZUk/q/cM3bMjUqJZ Q+3GxK+UG2WWUgWNAw5qwTWauDyC8mySeX4cbBHM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388771AbgEYOMN (ORCPT ); Mon, 25 May 2020 10:12:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:57704 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388862AbgEYOMM (ORCPT ); Mon, 25 May 2020 10:12:12 -0400 Received: from kozik-lap.mshome.net (unknown [194.230.155.118]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 73951208A7; Mon, 25 May 2020 14:12:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590415932; bh=4J38MidBihyKODDqhruO+ael6y9jTfLnvI1Z4aDlbFE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B9o7RA9oI5Kye0q9iCchyRyIL21EWhvh6bv/rY761ReIRig06ZaRi8rubQpI91ZRV 9pykULK5id5wU0m0wRpqZTyItnDTVuc7tETrW9cTANnku1CKeQZWfjJLdhRNqLzoWT qQvmud0/LxMUoLJA7h/lDhaJZ1VuGZ8+r0VriZPo= From: Krzysztof Kozlowski To: "Andrew F. Davis" , =?utf-8?q?Pali_Roh=C3=A1r?= , Sebastian Reichel , Krzysztof Kozlowski , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Krzysztof Kozlowski Subject: [PATCH 2/2] power: supply: bq27xxx_battery: Notify about voltage and current changes Date: Mon, 25 May 2020 16:12:00 +0200 Message-Id: <20200525141200.17199-2-krzk@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200525141200.17199-1-krzk@kernel.org> References: <20200525141200.17199-1-krzk@kernel.org> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Read voltage and current and store them in the cache (like other properties). This has benefits: 1. User-space will be notified on voltage or current change. These are important properties of charging so user-space might be interested in getting them. 2. Closes possible resource exhaustion attack through continuous I2C reads triggered by unprivileged power supply sysfs API. User could just keep reading voltage_now or current_now sysfs entries leading to excessive I2C transfers. Signed-off-by: Krzysztof Kozlowski --- drivers/power/supply/bq27xxx_battery.c | 97 ++++++++++++-------------- include/linux/power/bq27xxx_battery.h | 2 + 2 files changed, 48 insertions(+), 51 deletions(-) diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c index 33c26d42cd02..048618c13e17 100644 --- a/drivers/power/supply/bq27xxx_battery.c +++ b/drivers/power/supply/bq27xxx_battery.c @@ -1520,6 +1520,48 @@ static int bq27xxx_battery_read_pwr_avg(struct bq27xxx_device_info *di) return tval; } +/* + * Return the battery average current in µA + * Note that current can be negative signed as well + * Or 0 if something fails. + */ +static int bq27xxx_battery_read_current(struct bq27xxx_device_info *di, + int flags) +{ + int curr; + + curr = bq27xxx_read(di, BQ27XXX_REG_AI, false); + if (curr < 0) { + dev_err(di->dev, "error reading current\n"); + return 0; + } + + if (di->opts & BQ27XXX_O_ZERO) { + if (flags & BQ27000_FLAG_CHGS) { + dev_dbg(di->dev, "negative current!\n"); + curr = -curr; + } + + return curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS; + } + + /* else: Other gauges return signed value */ + return (int)((s16)curr) * 1000; +} + +static int bq27xxx_battery_read_voltage(struct bq27xxx_device_info *di) +{ + int volt; + + volt = bq27xxx_read(di, BQ27XXX_REG_VOLT, false); + if (volt < 0) { + dev_err(di->dev, "error reading voltage\n"); + return volt; + } + + return volt * 1000; +} + /* * Returns true if a battery over temperature condition is detected */ @@ -1606,6 +1648,8 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di) cache.cycle_count = bq27xxx_battery_read_cyct(di); if (di->regs[BQ27XXX_REG_AP] != INVALID_REG_ADDR) cache.power_avg = bq27xxx_battery_read_pwr_avg(di); + cache.curr = bq27xxx_battery_read_current(di, cache.flags); + cache.voltage = bq27xxx_battery_read_voltage(di); /* We only have to read charge design full once */ if (di->charge_design_full <= 0) @@ -1633,39 +1677,6 @@ static void bq27xxx_battery_poll(struct work_struct *work) schedule_delayed_work(&di->work, poll_interval * HZ); } -/* - * Return the battery average current in µA - * Note that current can be negative signed as well - * Or 0 if something fails. - */ -static int bq27xxx_battery_current(struct bq27xxx_device_info *di, - union power_supply_propval *val) -{ - int curr; - int flags; - - curr = bq27xxx_read(di, BQ27XXX_REG_AI, false); - if (curr < 0) { - dev_err(di->dev, "error reading current\n"); - return curr; - } - - if (di->opts & BQ27XXX_O_ZERO) { - flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true); - if (flags & BQ27000_FLAG_CHGS) { - dev_dbg(di->dev, "negative current!\n"); - curr = -curr; - } - - val->intval = curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS; - } else { - /* Other gauges return signed value */ - val->intval = (int)((s16)curr) * 1000; - } - - return 0; -} - static int bq27xxx_battery_status(struct bq27xxx_device_info *di, union power_supply_propval *val) { @@ -1728,22 +1739,6 @@ static int bq27xxx_battery_capacity_level(struct bq27xxx_device_info *di, * Return the battery Voltage in millivolts * Or < 0 if something fails. */ -static int bq27xxx_battery_voltage(struct bq27xxx_device_info *di, - union power_supply_propval *val) -{ - int volt; - - volt = bq27xxx_read(di, BQ27XXX_REG_VOLT, false); - if (volt < 0) { - dev_err(di->dev, "error reading voltage\n"); - return volt; - } - - val->intval = volt * 1000; - - return 0; -} - static int bq27xxx_simple_value(int value, union power_supply_propval *val) { @@ -1777,13 +1772,13 @@ static int bq27xxx_battery_get_property(struct power_supply *psy, ret = bq27xxx_battery_status(di, val); break; case POWER_SUPPLY_PROP_VOLTAGE_NOW: - ret = bq27xxx_battery_voltage(di, val); + ret = bq27xxx_simple_value(di->cache.voltage, val); break; case POWER_SUPPLY_PROP_PRESENT: val->intval = di->cache.flags < 0 ? 0 : 1; break; case POWER_SUPPLY_PROP_CURRENT_NOW: - ret = bq27xxx_battery_current(di, val); + val->intval = di->cache.curr; /* Can be negative */ break; case POWER_SUPPLY_PROP_CAPACITY: ret = bq27xxx_simple_value(di->cache.capacity, val); diff --git a/include/linux/power/bq27xxx_battery.h b/include/linux/power/bq27xxx_battery.h index 507c5e214c42..418ba5e4029a 100644 --- a/include/linux/power/bq27xxx_battery.h +++ b/include/linux/power/bq27xxx_battery.h @@ -49,6 +49,8 @@ struct bq27xxx_reg_cache { int cycle_count; int capacity; int energy; + int curr; + int voltage; int flags; int power_avg; int health;