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Fri, 24 May 2024 23:13:13 +0000 Received: from SY4P282MB3063.AUSP282.PROD.OUTLOOK.COM ([fe80::37cc:3733:d1e9:d8e4]) by SY4P282MB3063.AUSP282.PROD.OUTLOOK.COM ([fe80::37cc:3733:d1e9:d8e4%3]) with mapi id 15.20.7611.025; Fri, 24 May 2024 23:13:13 +0000 Message-ID: Date: Sat, 25 May 2024 09:13:09 +1000 User-Agent: Mozilla Thunderbird From: Stephen Horvath Subject: Re: [PATCH v2 1/2] hwmon: add ChromeOS EC driver To: =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= , Jean Delvare , Guenter Roeck , Benson Leung , Lee Jones Cc: Guenter Roeck , linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, chrome-platform@lists.linux.dev, Dustin Howett , Mario Limonciello , Moritz Fischer References: <20240507-cros_ec-hwmon-v2-0-1222c5fca0f7@weissschuh.net> <20240507-cros_ec-hwmon-v2-1-1222c5fca0f7@weissschuh.net> Content-Language: en-AU, en-US, en-GB In-Reply-To: <20240507-cros_ec-hwmon-v2-1-1222c5fca0f7@weissschuh.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TMN: [8dmodNvU81XLQ/SOLpCp2nXX4mS/WQaOxdqEJhN9vpjUJfb1ZV1qcbVD/alxJRPXxUCUwsSHV7Y=] X-ClientProxiedBy: SY6PR01CA0079.ausprd01.prod.outlook.com (2603:10c6:10:110::12) To SY4P282MB3063.AUSP282.PROD.OUTLOOK.COM (2603:10c6:10:159::9) X-Microsoft-Original-Message-ID: <5286705f-8e96-40de-8b2b-3cab25895fc4@outlook.com.au> Precedence: bulk X-Mailing-List: chrome-platform@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SY4P282MB3063:EE_|SYYP282MB1534:EE_ X-MS-Office365-Filtering-Correlation-Id: 5f1cfc11-6b4d-4c83-6ad8-08dc7c47160c X-Microsoft-Antispam: BCL:0;ARA:14566002|461199019|440099019|3412199016; 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SPDX-License-Identifier: GPL-2.0-or-later > + > +Kernel driver cros_ec_hwmon > +=========================== > + > +Supported chips: > + > + * ChromeOS embedded controllers connected via LPC > + > + Prefix: 'cros_ec' > + > + Addresses scanned: - > + > +Author: > + > + - Thomas Weißschuh > + > +Description > +----------- > + > +This driver implements support for hardware monitoring commands exposed by the > +ChromeOS embedded controller used in Chromebooks and other devices. > + > +The channel labels exposed via hwmon are retrieved from the EC itself. > + > +Fan and temperature readings are supported. > diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst > index 1ca7a4fe1f8f..355a83e66928 100644 > --- a/Documentation/hwmon/index.rst > +++ b/Documentation/hwmon/index.rst > @@ -57,6 +57,7 @@ Hardware Monitoring Kernel Drivers > coretemp > corsair-cpro > corsair-psu > + cros_ec_hwmon > da9052 > da9055 > dell-smm-hwmon > diff --git a/MAINTAINERS b/MAINTAINERS > index c23fda1aa1f0..aa5689169eca 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -4988,6 +4988,14 @@ S: Maintained > F: Documentation/devicetree/bindings/sound/google,cros-ec-codec.yaml > F: sound/soc/codecs/cros_ec_codec.* > > +CHROMEOS EC HARDWARE MONITORING > +M: Thomas Weißschuh > +L: chrome-platform@lists.linux.dev > +L: linux-hwmon@vger.kernel.org > +S: Maintained > +F: Documentation/hwmon/chros_ec_hwmon.rst > +F: drivers/hwmon/cros_ec_hwmon.c > + > CHROMEOS EC SUBDRIVERS > M: Benson Leung > R: Guenter Roeck > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 83945397b6eb..c1284d42697f 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -506,6 +506,17 @@ config SENSORS_CORSAIR_PSU > This driver can also be built as a module. If so, the module > will be called corsair-psu. > > +config SENSORS_CROS_EC > + tristate "ChromeOS Embedded Controller sensors" > + depends on MFD_CROS_EC_DEV > + default MFD_CROS_EC_DEV > + help > + If you say yes here you get support for ChromeOS Embedded Controller > + sensors. > + > + This driver can also be built as a module. If so, the module > + will be called cros_ec_hwmon. > + > config SENSORS_DRIVETEMP > tristate "Hard disk drives with temperature sensors" > depends on SCSI && ATA > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index 5c31808f6378..8519a6b36c00 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -64,6 +64,7 @@ obj-$(CONFIG_SENSORS_CHIPCAP2) += chipcap2.o > obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o > obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o > obj-$(CONFIG_SENSORS_CORSAIR_PSU) += corsair-psu.o > +obj-$(CONFIG_SENSORS_CROS_EC) += cros_ec_hwmon.o > obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o > obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o > obj-$(CONFIG_SENSORS_DELL_SMM) += dell-smm-hwmon.o > diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c > new file mode 100644 > index 000000000000..d59d39df2ac4 > --- /dev/null > +++ b/drivers/hwmon/cros_ec_hwmon.c > @@ -0,0 +1,269 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * ChromesOS EC driver for hwmon > + * > + * Copyright (C) 2024 Thomas Weißschuh > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define DRV_NAME "cros-ec-hwmon" > + > +struct cros_ec_hwmon_priv { > + struct cros_ec_device *cros_ec; > + u8 thermal_version; > + const char *temp_sensor_names[EC_TEMP_SENSOR_ENTRIES + EC_TEMP_SENSOR_B_ENTRIES]; > +}; > + > +static int cros_ec_hwmon_read_fan_speed(struct cros_ec_device *cros_ec, u8 index, u16 *speed) > +{ > + u16 data; > + int ret; > + > + ret = cros_ec->cmd_readmem(cros_ec, EC_MEMMAP_FAN + index * 2, 2, &data); > + if (ret < 0) > + return ret; > + > + data = le16_to_cpu(data); > + > + if (data == EC_FAN_SPEED_NOT_PRESENT) > + return -ENODEV; > + Don't forget it can also return `EC_FAN_SPEED_STALLED`. Like Guenter, I also don't like returning `-ENODEV`, but I don't have a problem with checking for `EC_FAN_SPEED_NOT_PRESENT` in case it was removed since init or something. My approach was to return the speed as `0`, since the fan probably isn't spinning, but set HWMON_F_FAULT for `EC_FAN_SPEED_NOT_PRESENT` and HWMON_F_ALARM for `EC_FAN_SPEED_STALLED`. No idea if this is correct though. > + *speed = data; > + return 0; > +} > + > +static int cros_ec_hwmon_read_temp(struct cros_ec_device *cros_ec, u8 thermal_version, > + u8 index, u8 *data) > +{ > + unsigned int offset; > + int ret; > + > + if (index < EC_TEMP_SENSOR_ENTRIES) > + offset = EC_MEMMAP_TEMP_SENSOR + index; > + else > + offset = EC_MEMMAP_TEMP_SENSOR_B + index - EC_TEMP_SENSOR_ENTRIES; > + > + ret = cros_ec->cmd_readmem(cros_ec, offset, 1, data); > + if (ret < 0) > + return ret; > + > + if (*data == EC_TEMP_SENSOR_NOT_PRESENT || > + *data == EC_TEMP_SENSOR_ERROR || > + *data == EC_TEMP_SENSOR_NOT_POWERED || > + *data == EC_TEMP_SENSOR_NOT_CALIBRATED) > + return -ENODEV; > + > + return 0; > +} > + > +static int cros_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, long *val) > +{ > + struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev); > + int ret = -ENODATA; > + u16 speed; > + u8 temp; > + > + if (type == hwmon_fan) { > + ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, channel, &speed); > + if (ret == 0) > + *val = speed; > + } else if (type == hwmon_temp) { > + ret = cros_ec_hwmon_read_temp(priv->cros_ec, priv->thermal_version, channel, &temp); > + if (ret == 0) > + *val = kelvin_to_millicelsius((((long)temp) + EC_TEMP_SENSOR_OFFSET)); > + } > + > + return ret; > +} > + > +static int cros_ec_hwmon_get_temp_sensor_info(struct cros_ec_device *cros_ec, u8 id, > + struct ec_response_temp_sensor_get_info *resp) > +{ > + int ret; > + struct { > + struct cros_ec_command msg; > + union { > + struct ec_params_temp_sensor_get_info req; > + struct ec_response_temp_sensor_get_info resp; > + } __packed data; > + } __packed buf = { > + .msg = { > + .version = 0, > + .command = EC_CMD_TEMP_SENSOR_GET_INFO, > + .insize = sizeof(buf.data.resp), > + .outsize = sizeof(buf.data.req), > + }, > + .data.req.id = id, > + }; > + > + ret = cros_ec_cmd_xfer_status(cros_ec, &buf.msg); > + if (ret < 0) > + return ret; > + > + *resp = buf.data.resp; > + return 0; > +} > + > +static int cros_ec_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, const char **str) > +{ > + struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev); > + > + if (type == hwmon_temp && attr == hwmon_temp_label) { > + *str = priv->temp_sensor_names[channel]; > + return 0; > + } > + > + return -ENODATA; > +} > + > +static umode_t cros_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_types type, > + u32 attr, int channel) > +{ > + const struct cros_ec_hwmon_priv *priv = data; > + u16 speed; > + > + if (type == hwmon_fan) { > + if (cros_ec_hwmon_read_fan_speed(priv->cros_ec, channel, &speed) == 0) > + return 0444; > + } else if (type == hwmon_temp) { > + if (priv->temp_sensor_names[channel]) > + return 0444; > + } > + > + return 0; > +} > + > +static const struct hwmon_channel_info * const cros_ec_hwmon_info[] = { > + HWMON_CHANNEL_INFO(fan, > + HWMON_F_INPUT, > + HWMON_F_INPUT, > + HWMON_F_INPUT, > + HWMON_F_INPUT), > + HWMON_CHANNEL_INFO(temp, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL, > + HWMON_T_INPUT | HWMON_T_LABEL), > + NULL > +}; > + > +static const struct hwmon_ops cros_ec_hwmon_ops = { > + .read = cros_ec_hwmon_read, > + .read_string = cros_ec_hwmon_read_string, > + .is_visible = cros_ec_hwmon_is_visible, > +}; > + > +static const struct hwmon_chip_info cros_ec_hwmon_chip_info = { > + .ops = &cros_ec_hwmon_ops, > + .info = cros_ec_hwmon_info, > +}; > + > +static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_hwmon_priv *priv) > +{ > + struct ec_response_temp_sensor_get_info info; > + size_t candidates, i; > + int ret; > + u8 temp; > + > + if (priv->thermal_version < 2) > + candidates = EC_TEMP_SENSOR_ENTRIES; > + else > + candidates = ARRAY_SIZE(priv->temp_sensor_names); > + > + for (i = 0; i < candidates; i++) { > + if (cros_ec_hwmon_read_temp(priv->cros_ec, priv->thermal_version, i, &temp) != 0) > + continue; > + > + ret = cros_ec_hwmon_get_temp_sensor_info(priv->cros_ec, i, &info); > + if (ret < 0) > + continue; > + > + priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%*s", > + (int)sizeof(info.sensor_name), > + info.sensor_name); > + } > +} > + > +static int cros_ec_hwmon_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent); > + struct cros_ec_device *cros_ec = ec_dev->ec_dev; > + struct cros_ec_hwmon_priv *priv; > + struct device *hwmon_dev; > + int ret; > + > + /* Not every platform supports direct reads */ > + if (!cros_ec->cmd_readmem) > + return -ENODEV; > + > + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->cros_ec = cros_ec; > + > + ret = priv->cros_ec->cmd_readmem(cros_ec, EC_MEMMAP_THERMAL_VERSION, > + 1, &priv->thermal_version); > + if (ret < 0) > + return ret; > + > + /* Covers both fan and temp sensors */ > + if (!priv->thermal_version) > + return -ENODEV; > + > + cros_ec_hwmon_probe_temp_sensors(dev, priv); > + > + hwmon_dev = devm_hwmon_device_register_with_info(dev, "cros_ec", priv, > + &cros_ec_hwmon_chip_info, NULL); > + > + return PTR_ERR_OR_ZERO(hwmon_dev); > +} > + > +static const struct platform_device_id cros_ec_hwmon_id[] = { > + { DRV_NAME, 0 }, > + { } > +}; > + > +static struct platform_driver cros_ec_hwmon_driver = { > + .driver.name = DRV_NAME, > + .probe = cros_ec_hwmon_probe, > + .id_table = cros_ec_hwmon_id, > +}; > +module_platform_driver(cros_ec_hwmon_driver); > + > +MODULE_DEVICE_TABLE(platform, cros_ec_hwmon_id); > +MODULE_DESCRIPTION("ChromeOS EC Hardware Monitoring Driver"); > +MODULE_AUTHOR("Thomas Weißschuh +MODULE_LICENSE("GPL"); > But feel free to ignore me if I'm completly wrong about this, since I really don't have much experience with kernel dev. Thanks, Steve