From patchwork Thu Dec 13 12:09:43 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Enric Balletbo i Serra X-Patchwork-Id: 10728569 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A6A461759 for ; Thu, 13 Dec 2018 12:10:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9831E2BF7C for ; Thu, 13 Dec 2018 12:10:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8C4FB2BF9B; Thu, 13 Dec 2018 12:10:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1515C2BF7C for ; Thu, 13 Dec 2018 12:10:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729109AbeLMMJ4 (ORCPT ); Thu, 13 Dec 2018 07:09:56 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:57486 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729088AbeLMMJ4 (ORCPT ); Thu, 13 Dec 2018 07:09:56 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id 823252606B8 From: Enric Balletbo i Serra To: linux-pm@vger.kernel.org, sre@kernel.org Cc: Sameer Nanda , bleung@chromium.org, gwendal@chromium.org, linux-kernel@vger.kernel.org, groeck@chromium.org, Adam.Thomson.Opensource@diasemi.com, kernel@collabora.com, Pavel Machek , "Rafael J. Wysocki" , Len Brown Subject: [PATCH v3 1/2] power: supply: add input voltage limit property Date: Thu, 13 Dec 2018 13:09:43 +0100 Message-Id: <20181213120944.30967-1-enric.balletbo@collabora.com> X-Mailer: git-send-email 2.19.2 MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is part of the Pixel C's thermal management strategy to effectively limit the input power to 5V 3A when the screen is on. When the screen is on, the display, the CPU, and the GPU all contribute more heat to the system than while the screen is off, and we made a tradeoff to throttle the charger in order to give more of the thermal budget to those other components. So there's nothing fundamentally broken about the hardware that would cause the Pixel C to malfunction if we were charging at 9V or 12V instead of 5V when the screen is on, ie if userspace doesn't change this. What would happen is that you wouldn't meet Google's skin temperature targets on the system if the charger was allowed to run at 9V or 12V with the screen on. For folks hacking on Pixel Cs (which is now outside of Google's official support window for Android) and customizing their own kernel and userspace this would be acceptable, but we wanted to expose this feature in the power supply properties because the feature does exist in the Emedded Controller firmware of the Pixel C and all of Google's Chromebooks with USB-C made since 2015 in case someone running an up to date kernel wanted to limit the charging power for thermal or other reasons. This patch exposes a new property, similar to input current limit, to re-configure the maximum voltage from the external supply at runtime based on system-level knowledge or user input. Signed-off-by: Enric Balletbo i Serra Reviewed-by: Guenter Roeck Acked-by: Adam Thomson --- Changes in v3: - Improve commit log and documentation with Benson comments. Changes in v2: - Document the new property in ABI/testing/sysfs-class-power. - Add the Reviewed-by Guenter Roeck tag. Documentation/ABI/testing/sysfs-class-power | 15 +++++++++++++++ Documentation/power/power_supply_class.txt | 2 ++ drivers/power/supply/power_supply_sysfs.c | 1 + include/linux/power_supply.h | 1 + 4 files changed, 19 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power index 5e23e22dce1b..6dee5c105a28 100644 --- a/Documentation/ABI/testing/sysfs-class-power +++ b/Documentation/ABI/testing/sysfs-class-power @@ -335,6 +335,21 @@ Description: Access: Read, Write Valid values: Represented in microamps +What: /sys/class/power_supply//input_voltage_limit +Date: Nov 2018 +Contact: linux-pm@vger.kernel.org +Description: + This entry configures the incoming VBUS voltage limit currently + set in the supply. Normally this is configured based on + system-level knowledge or user input (e.g. This is part of the + Pixel C's thermal management strategy to effectively limit the + input power to 5V when the screen is on to meet Google's skin + temperature targets). Note that this feature should not be + used for safety critical things. + + Access: Read, Write + Valid values: Represented in microvolts + What: /sys/class/power_supply//online, Date: May 2007 Contact: linux-pm@vger.kernel.org diff --git a/Documentation/power/power_supply_class.txt b/Documentation/power/power_supply_class.txt index 300d37896e51..7b4be615b4f8 100644 --- a/Documentation/power/power_supply_class.txt +++ b/Documentation/power/power_supply_class.txt @@ -137,6 +137,8 @@ power supply object. INPUT_CURRENT_LIMIT - input current limit programmed by charger. Indicates the current drawn from a charging source. +INPUT_VOLTAGE_LIMIT - input voltage limit programmed by charger. Indicates +the voltage limit from a charging source. CHARGE_CONTROL_LIMIT - current charge control limit setting CHARGE_CONTROL_LIMIT_MAX - maximum charge control limit setting diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c index dce24f596160..5848742ebb59 100644 --- a/drivers/power/supply/power_supply_sysfs.c +++ b/drivers/power/supply/power_supply_sysfs.c @@ -275,6 +275,7 @@ static struct device_attribute power_supply_attrs[] = { POWER_SUPPLY_ATTR(charge_control_limit), POWER_SUPPLY_ATTR(charge_control_limit_max), POWER_SUPPLY_ATTR(input_current_limit), + POWER_SUPPLY_ATTR(input_voltage_limit), POWER_SUPPLY_ATTR(energy_full_design), POWER_SUPPLY_ATTR(energy_empty_design), POWER_SUPPLY_ATTR(energy_full), diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h index f80769175c56..608ba88e32ee 100644 --- a/include/linux/power_supply.h +++ b/include/linux/power_supply.h @@ -122,6 +122,7 @@ enum power_supply_property { POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, + POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT, POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN, POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN, POWER_SUPPLY_PROP_ENERGY_FULL, From patchwork Thu Dec 13 12:09:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Enric Balletbo i Serra X-Patchwork-Id: 10728567 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 35F3C13AF for ; Thu, 13 Dec 2018 12:10:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 244572BF7C for ; Thu, 13 Dec 2018 12:10:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 15A2D2BF96; Thu, 13 Dec 2018 12:10:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 68E802BF7C for ; Thu, 13 Dec 2018 12:10:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729088AbeLMMJ5 (ORCPT ); Thu, 13 Dec 2018 07:09:57 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:57504 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729106AbeLMMJ5 (ORCPT ); Thu, 13 Dec 2018 07:09:57 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id 73ED227F010 From: Enric Balletbo i Serra To: linux-pm@vger.kernel.org, sre@kernel.org Cc: Sameer Nanda , bleung@chromium.org, gwendal@chromium.org, linux-kernel@vger.kernel.org, groeck@chromium.org, Adam.Thomson.Opensource@diasemi.com, kernel@collabora.com, Pavel Machek Subject: [PATCH v3 2/2] power: supply: cros: allow to set input voltage and current limit Date: Thu, 13 Dec 2018 13:09:44 +0100 Message-Id: <20181213120944.30967-2-enric.balletbo@collabora.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181213120944.30967-1-enric.balletbo@collabora.com> References: <20181213120944.30967-1-enric.balletbo@collabora.com> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch allows reading and writing the input voltage and current limit through the POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT and POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT sysfs properties. This allows userspace to see current values and to re-configure these values at runtime based on system-level knowledge or user input. By default there is no limit, this is reported as a -1 when reading from userspace. Writing a value will set the current or voltage limit in uA or uV, and writing any negative value will remove that limit. Signed-off-by: Enric Balletbo i Serra Reviewed-by: Guenter Roeck --- Changes in v3: None Changes in v2: - Fix the upper limit that can be set. - Remove unnecessary else. drivers/power/supply/cros_usbpd-charger.c | 116 ++++++++++++++++++++++ 1 file changed, 116 insertions(+) diff --git a/drivers/power/supply/cros_usbpd-charger.c b/drivers/power/supply/cros_usbpd-charger.c index 7e9c3984ef6a..3a9ea94c3de3 100644 --- a/drivers/power/supply/cros_usbpd-charger.c +++ b/drivers/power/supply/cros_usbpd-charger.c @@ -53,6 +53,8 @@ struct charger_data { }; static enum power_supply_property cros_usbpd_charger_props[] = { + POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, + POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT, POWER_SUPPLY_PROP_ONLINE, POWER_SUPPLY_PROP_STATUS, POWER_SUPPLY_PROP_CURRENT_MAX, @@ -80,6 +82,10 @@ static enum power_supply_usb_type cros_usbpd_charger_usb_types[] = { POWER_SUPPLY_USB_TYPE_APPLE_BRICK_ID }; +/* Input voltage/current limit in mV/mA. Default to none. */ +static u16 input_voltage_limit = EC_POWER_LIMIT_NONE; +static u16 input_current_limit = EC_POWER_LIMIT_NONE; + static bool cros_usbpd_charger_port_is_dedicated(struct port_data *port) { return port->port_number >= port->charger->num_usbpd_ports; @@ -324,6 +330,26 @@ static int cros_usbpd_charger_get_port_status(struct port_data *port, return ret; } +static int cros_usbpd_charger_set_ext_power_limit(struct charger_data *charger, + u16 current_lim, + u16 voltage_lim) +{ + struct ec_params_external_power_limit_v1 req; + int ret; + + req.current_lim = current_lim; + req.voltage_lim = voltage_lim; + + ret = cros_usbpd_charger_ec_command(charger, 0, + EC_CMD_EXTERNAL_POWER_LIMIT, + &req, sizeof(req), NULL, 0); + if (ret < 0) + dev_err(charger->dev, + "Unable to set the 'External Power Limit': %d\n", ret); + + return ret; +} + static void cros_usbpd_charger_power_changed(struct power_supply *psy) { struct port_data *port = power_supply_get_drvdata(psy); @@ -396,6 +422,18 @@ static int cros_usbpd_charger_get_prop(struct power_supply *psy, case POWER_SUPPLY_PROP_USB_TYPE: val->intval = port->psy_usb_type; break; + case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT: + if (input_current_limit == EC_POWER_LIMIT_NONE) + val->intval = -1; + else + val->intval = input_current_limit * 1000; + break; + case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT: + if (input_voltage_limit == EC_POWER_LIMIT_NONE) + val->intval = -1; + else + val->intval = input_voltage_limit * 1000; + break; case POWER_SUPPLY_PROP_MODEL_NAME: val->strval = port->model_name; break; @@ -409,6 +447,81 @@ static int cros_usbpd_charger_get_prop(struct power_supply *psy, return 0; } +static int cros_usbpd_charger_set_prop(struct power_supply *psy, + enum power_supply_property psp, + const union power_supply_propval *val) +{ + struct port_data *port = power_supply_get_drvdata(psy); + struct charger_data *charger = port->charger; + struct device *dev = charger->dev; + u16 intval; + int ret; + + /* U16_MAX in mV/mA is the maximum supported value */ + if (val->intval >= U16_MAX * 1000) + return -EINVAL; + /* A negative number is used to clear the limit */ + if (val->intval < 0) + intval = EC_POWER_LIMIT_NONE; + else /* Convert from uA/uV to mA/mV */ + intval = val->intval / 1000; + + switch (psp) { + case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT: + ret = cros_usbpd_charger_set_ext_power_limit(charger, intval, + input_voltage_limit); + if (ret < 0) + break; + + input_current_limit = intval; + if (input_current_limit == EC_POWER_LIMIT_NONE) + dev_info(dev, + "External Current Limit cleared for all ports\n"); + else + dev_info(dev, + "External Current Limit set to %dmA for all ports\n", + input_current_limit); + break; + case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT: + ret = cros_usbpd_charger_set_ext_power_limit(charger, + input_current_limit, + intval); + if (ret < 0) + break; + + input_voltage_limit = intval; + if (input_voltage_limit == EC_POWER_LIMIT_NONE) + dev_info(dev, + "External Voltage Limit cleared for all ports\n"); + else + dev_info(dev, + "External Voltage Limit set to %dmV for all ports\n", + input_voltage_limit); + break; + default: + ret = -EINVAL; + } + + return ret; +} + +static int cros_usbpd_charger_property_is_writeable(struct power_supply *psy, + enum power_supply_property psp) +{ + int ret; + + switch (psp) { + case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT: + case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT: + ret = 1; + break; + default: + ret = 0; + } + + return ret; +} + static int cros_usbpd_charger_ec_event(struct notifier_block *nb, unsigned long queued_during_suspend, void *_notify) @@ -525,6 +638,9 @@ static int cros_usbpd_charger_probe(struct platform_device *pd) psy_desc = &port->psy_desc; psy_desc->get_property = cros_usbpd_charger_get_prop; + psy_desc->set_property = cros_usbpd_charger_set_prop; + psy_desc->property_is_writeable = + cros_usbpd_charger_property_is_writeable; psy_desc->external_power_changed = cros_usbpd_charger_power_changed; psy_cfg.drv_data = port;