From nobody Tue Apr 7 04:36:42 2026 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1CF0739DBE6 for ; Mon, 16 Mar 2026 14:05:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773669941; cv=none; b=ugmkW/84QURQhd/Nq/4LBL0ayIxBDPdxLA39ZFnQj0f2/bWZKrA1EVUO19dii0GLtD4r7yCOFy0HEgdsb9fdICt+0Ozt901zkaEryNh7BhgPxninP1B/Zhh05xCKzIbO33BUmvcIxVkBvmSMKcHOtUbNfvMjtfQWXbSHsb1PZ/0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773669941; c=relaxed/simple; bh=1YcDh1qKv3SetDH+xiVtx465vfbCcbpot1n81OY1QEk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=SZjpRjn0wlT2mqpe6E5SE8nziD2fnBTuaAfajzX1pg8nZ0YPqLHXqADjX4l3/FoWV89V6e90dFIAacvFRg6xuqWeyka4g/FhJD1r64nsziNEgf22/AVc1mYSMwgMRdXWOnaETwrJKYLNnWB0iHtCSbYMDl3L4fUyZthzk+tYJOY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1w28ZI-0002G8-E8; Mon, 16 Mar 2026 15:05:16 +0100 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac] helo=dude04) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1w28ZH-000a8S-2t; Mon, 16 Mar 2026 15:05:15 +0100 Received: from ore by dude04 with local (Exim 4.98.2) (envelope-from ) id 1w28ZH-00000005txJ-3Hn3; Mon, 16 Mar 2026 15:05:15 +0100 From: Oleksij Rempel To: Guenter Roeck , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Lee Jones , Peter Rosin , Linus Walleij Cc: Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-gpio@vger.kernel.org, David Jander Subject: [PATCH v5 6/7] hwmon: add NXP MC33978/MC34978 driver Date: Mon, 16 Mar 2026 15:05:11 +0100 Message-ID: <20260316140514.1406588-7-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260316140514.1406588-1-o.rempel@pengutronix.de> References: <20260316140514.1406588-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Add hardware monitoring support for the NXP MC33978/MC34978 MSDI. The driver exposes static operating thresholds (thermal, over-voltage, under-voltage) and reports dynamic hardware fault alarms. Signed-off-by: Oleksij Rempel --- changes v5: - no changes changes v4: - no changes changes v3: - no changes changes v2: - Switch from OF match table to platform_device_id --- drivers/hwmon/Kconfig | 10 + drivers/hwmon/Makefile | 1 + drivers/hwmon/mc33978-hwmon.c | 430 ++++++++++++++++++++++++++++++++++ 3 files changed, 441 insertions(+) create mode 100644 drivers/hwmon/mc33978-hwmon.c diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 486152a8ea77..afe691539df3 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -700,6 +700,16 @@ config SENSORS_MC13783_ADC help Support for the A/D converter on MC13783 and MC13892 PMIC. =20 +config SENSORS_MC33978 + tristate "NXP MC33978/MC34978 fault monitoring" + depends on MFD_MC33978 + help + If you say yes here you get fault monitoring support for the + NXP MC33978/MC34978 Multiple Switch Detection Interface (MSDI). + + This driver can also be built as a module. If so, the module + will be called mc33978-hwmon. + config SENSORS_MC33XS2410 tristate "MC33XS2410 HWMON support" depends on PWM_MC33XS2410 diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 5833c807c688..4c3db5433a10 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -167,6 +167,7 @@ obj-$(CONFIG_SENSORS_MAX31790) +=3D max31790.o obj-$(CONFIG_MAX31827) +=3D max31827.o obj-$(CONFIG_SENSORS_MAX77705) +=3D max77705-hwmon.o obj-$(CONFIG_SENSORS_MC13783_ADC)+=3D mc13783-adc.o +obj-$(CONFIG_SENSORS_MC33978) +=3D mc33978-hwmon.o obj-$(CONFIG_SENSORS_MC33XS2410) +=3D mc33xs2410_hwmon.o obj-$(CONFIG_SENSORS_MC34VR500) +=3D mc34vr500.o obj-$(CONFIG_SENSORS_MCP3021) +=3D mcp3021.o diff --git a/drivers/hwmon/mc33978-hwmon.c b/drivers/hwmon/mc33978-hwmon.c new file mode 100644 index 000000000000..8740523773f7 --- /dev/null +++ b/drivers/hwmon/mc33978-hwmon.c @@ -0,0 +1,430 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (c) 2026 Pengutronix, Oleksij Rempel +/* + * MC33978/MC34978 Hardware Monitor Driver + * + * CRITICAL HARDWARE BEHAVIOR - THERMAL (tLIM): + * When the thermal limit (>155=C2=B0C) is reached, the IC autonomously + * reduces the continuous wetting current (CWET) to 2.0 mA to prevent + * thermal destruction. This throttling persists until the silicon cools + * down below 140=C2=B0C (15=C2=B0C hysteresis). + * + * WARNING FOR PINCTRL/GPIO CONSUMERS: + * During an active tLIM fault, the switch state detection becomes + * inherently unreliable. A throttled wetting current of 2.0 mA may + * be insufficient to break through the oxide layer of mechanical + * contacts in the field, leading to false-open GPIO readings. + * + * VOLTAGE DEGRADATION WARNING (VBATP): + * While the hard Undervoltage Lockout (UVLO) asserts strictly at 4.5V, + * the silicon operates with degraded parametrics whenever the supply + * drops below 6.0V. System designers must be aware that analog routing + * (AMUX) and switch detection logic may behave non-deterministically + * before the actual UV alarm triggers. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +/* Thermal Warning threshold (~120C) */ +#define MC33978_TEMP_WARN_MC 120000 + +/* Thermal Limit / tLIM (>155C) - Hardware enters CWET throttling */ +#define MC33978_TEMP_CRIT_MC 155000 + +/* Hysteresis for tLIM recovery (Silicon must cool to <140C) */ +#define MC33978_TEMP_HYST_MC 15000 + +/* VBATP (in0) IC Level thresholds */ +#define MC33978_VBATP_OV_MV 36000 /* Overvoltage limit */ +#define MC33978_VBATP_FUNC_MV 28000 /* Functional/Normal boundary */ +#define MC33978_VBATP_DEGRADED_MV 6000 /* Degraded parametrics start */ +#define MC33978_VBATP_UVLO_MV 4500 /* UV Rising Threshold max */ + +/* VDDQ (in1) Logic Supply thresholds */ +#define MC33978_VDDQ_MAX_MV 5250 /* Operating Condition max */ +#define MC33978_VDDQ_MIN_MV 3000 /* Operating Condition min */ +#define MC33978_VDDQ_UV_MV 2800 /* UV Falling Threshold max */ + +enum mc33978_hwmon_in_channels { + MC33978_IN_VBATP, + MC33978_IN_VDDQ, +}; + +struct mc33978_hwmon_priv { + struct device *dev; + struct device *hwmon_dev; + struct regmap *map; + int fault_irq; + u32 last_faults; +}; + +static int mc33978_hwmon_read_fault(struct mc33978_hwmon_priv *priv, + u32 *faults) +{ + unsigned int val; + int ret; + + ret =3D regmap_read(priv->map, MC33978_REG_FAULT, &val); + if (ret) + return ret; + + *faults =3D val; + + return 0; +} + +static void mc33978_hwmon_report_faults(struct mc33978_hwmon_priv *priv, + u32 new_faults) +{ + /* + * Log only newly asserted critical faults to prevent kernel log spam + * during persistent hardware fault conditions. + * dev_*_ratelimited provides an additional safety net against noisy IRQs. + */ + if (!new_faults) + return; + + if (new_faults & MC33978_FAULT_OT) + dev_crit_ratelimited(priv->dev, "Over-temperature fault detected!\n"); + + if (new_faults & MC33978_FAULT_OV) + dev_crit_ratelimited(priv->dev, "Over-voltage fault detected!\n"); + + if (new_faults & MC33978_FAULT_UV) + dev_err_ratelimited(priv->dev, "Under-voltage fault detected!\n"); +} + +static irqreturn_t mc33978_hwmon_fault_irq(int irq, void *data) +{ + struct mc33978_hwmon_priv *priv =3D data; + u32 faults, new_faults, changed_faults; + int ret; + + ret =3D mc33978_hwmon_read_fault(priv, &faults); + if (ret) { + dev_err_ratelimited(priv->dev, "Failed to read fault register: %pe\n", + ERR_PTR(ret)); + return IRQ_NONE; + } + + changed_faults =3D faults ^ priv->last_faults; + if (!changed_faults) + return IRQ_HANDLED; + + new_faults =3D faults & ~priv->last_faults; + if (new_faults) + mc33978_hwmon_report_faults(priv, new_faults); + + priv->last_faults =3D faults; + + if (changed_faults & MC33978_FAULT_UV) + hwmon_notify_event(priv->hwmon_dev, hwmon_in, + hwmon_in_lcrit_alarm, MC33978_IN_VBATP); + + if (changed_faults & MC33978_FAULT_OV) + hwmon_notify_event(priv->hwmon_dev, hwmon_in, + hwmon_in_crit_alarm, MC33978_IN_VBATP); + + if (changed_faults & MC33978_FAULT_TEMP_WARN) + hwmon_notify_event(priv->hwmon_dev, hwmon_temp, + hwmon_temp_max_alarm, 0); + + if (changed_faults & MC33978_FAULT_OT) + hwmon_notify_event(priv->hwmon_dev, hwmon_temp, + hwmon_temp_crit_alarm, 0); + + /* Push a chip-level alarm on any hardware status change */ + hwmon_notify_event(priv->hwmon_dev, hwmon_chip, + hwmon_chip_alarms, 0); + + return IRQ_HANDLED; +} + +static umode_t mc33978_hwmon_is_visible(const void *data, + enum hwmon_sensor_types type, + u32 attr, int channel) +{ + switch (type) { + case hwmon_chip: + if (attr =3D=3D hwmon_chip_alarms) + return 0444; + break; + + case hwmon_temp: + switch (attr) { + case hwmon_temp_max: + case hwmon_temp_crit: + case hwmon_temp_crit_hyst: + case hwmon_temp_max_alarm: + case hwmon_temp_crit_alarm: + return 0444; + default: + break; + } + break; + + case hwmon_in: + switch (attr) { + case hwmon_in_label: + case hwmon_in_max: + case hwmon_in_min: + case hwmon_in_lcrit: + return 0444; + case hwmon_in_crit: + if (channel =3D=3D MC33978_IN_VBATP) + return 0444; + break; + case hwmon_in_crit_alarm: + case hwmon_in_lcrit_alarm: + if (channel =3D=3D MC33978_IN_VBATP) + return 0444; + break; + } + break; + default: + break; + } + + return 0; +} + +static int mc33978_hwmon_read(struct device *dev, + enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct mc33978_hwmon_priv *priv =3D dev_get_drvdata(dev); + u32 faults; + int ret; + + switch (type) { + case hwmon_in: + if (channel =3D=3D MC33978_IN_VBATP) { + switch (attr) { + case hwmon_in_crit: + *val =3D MC33978_VBATP_OV_MV; + return 0; + case hwmon_in_max: + *val =3D MC33978_VBATP_FUNC_MV; + return 0; + case hwmon_in_min: + *val =3D MC33978_VBATP_DEGRADED_MV; + return 0; + case hwmon_in_lcrit: + *val =3D MC33978_VBATP_UVLO_MV; + return 0; + default: + break; + } + } else if (channel =3D=3D MC33978_IN_VDDQ) { + switch (attr) { + case hwmon_in_max: + *val =3D MC33978_VDDQ_MAX_MV; + return 0; + case hwmon_in_min: + *val =3D MC33978_VDDQ_MIN_MV; + return 0; + case hwmon_in_lcrit: + *val =3D MC33978_VDDQ_UV_MV; + return 0; + default: + break; + } + } + break; + + case hwmon_temp: + switch (attr) { + case hwmon_temp_max: + *val =3D MC33978_TEMP_WARN_MC; + return 0; + case hwmon_temp_crit: + *val =3D MC33978_TEMP_CRIT_MC; + return 0; + case hwmon_temp_crit_hyst: + *val =3D MC33978_TEMP_CRIT_MC - MC33978_TEMP_HYST_MC; + return 0; + default: + break; + } + break; + + default: + break; + } + + /* 2. Dynamic alarms (read hardware flags) */ + ret =3D mc33978_hwmon_read_fault(priv, &faults); + if (ret) + return ret; + + switch (type) { + case hwmon_chip: + if (attr =3D=3D hwmon_chip_alarms) { + *val =3D faults; + return 0; + } + break; + + case hwmon_in: + if (channel =3D=3D MC33978_IN_VBATP) { + switch (attr) { + case hwmon_in_crit_alarm: + *val =3D !!(faults & MC33978_FAULT_OV); + return 0; + case hwmon_in_lcrit_alarm: + *val =3D !!(faults & MC33978_FAULT_UV); + return 0; + default: + *val =3D 0; + return 0; + } + } + /* VDDQ has no dedicated hardware fault flags */ + *val =3D 0; + return 0; + + case hwmon_temp: + switch (attr) { + case hwmon_temp_max_alarm: + *val =3D !!(faults & MC33978_FAULT_TEMP_WARN); + return 0; + case hwmon_temp_crit_alarm: + *val =3D !!(faults & MC33978_FAULT_OT); + return 0; + default: + break; + } + break; + + default: + return -EOPNOTSUPP; + } + + return -EOPNOTSUPP; +} + +static int mc33978_hwmon_read_string(struct device *dev, + enum hwmon_sensor_types type, + u32 attr, int channel, const char **str) +{ + /* Only in_label is supported for string reads */ + if (type !=3D hwmon_in || attr !=3D hwmon_in_label) + return -EOPNOTSUPP; + + switch (channel) { + case MC33978_IN_VBATP: + *str =3D "VBATP"; + return 0; + case MC33978_IN_VDDQ: + *str =3D "VDDQ"; + return 0; + default: + return -EINVAL; + } +} + +static const struct hwmon_channel_info * const mc33978_hwmon_info[] =3D { + HWMON_CHANNEL_INFO(chip, + HWMON_C_ALARMS), + HWMON_CHANNEL_INFO(temp, + HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_CRIT_HYST | + HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM), + HWMON_CHANNEL_INFO(in, + /* Index 0: MC33978_IN_VBATP */ + HWMON_I_LABEL | HWMON_I_CRIT | HWMON_I_MAX | + HWMON_I_MIN | HWMON_I_LCRIT | + HWMON_I_CRIT_ALARM | HWMON_I_LCRIT_ALARM, + + /* Index 1: MC33978_IN_VDDQ */ + HWMON_I_LABEL | HWMON_I_MAX | HWMON_I_MIN | + HWMON_I_LCRIT), + NULL +}; + +static const struct hwmon_ops mc33978_hwmon_ops =3D { + .is_visible =3D mc33978_hwmon_is_visible, + .read_string =3D mc33978_hwmon_read_string, + .read =3D mc33978_hwmon_read, +}; + +static const struct hwmon_chip_info mc33978_hwmon_chip_info =3D { + .ops =3D &mc33978_hwmon_ops, + .info =3D mc33978_hwmon_info, +}; + +static int mc33978_hwmon_probe(struct platform_device *pdev) +{ + struct device *dev =3D &pdev->dev; + struct mc33978_hwmon_priv *priv; + struct device *hwmon_dev; + int ret; + + priv =3D devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev =3D dev; + + priv->map =3D dev_get_regmap(dev->parent, NULL); + if (!priv->map) + return dev_err_probe(dev, -ENODEV, "failed to get regmap\n"); + + platform_set_drvdata(pdev, priv); + + priv->fault_irq =3D platform_get_irq(pdev, 0); + if (priv->fault_irq < 0) + return priv->fault_irq; + + ret =3D mc33978_hwmon_read_fault(priv, &priv->last_faults); + if (ret) + return dev_err_probe(dev, ret, "failed to read initial faults\n"); + + if (priv->last_faults & MC33978_FAULT_CRITICAL) + mc33978_hwmon_report_faults(priv, priv->last_faults); + + hwmon_dev =3D devm_hwmon_device_register_with_info(dev, "mc33978", priv, + &mc33978_hwmon_chip_info, + NULL); + if (IS_ERR(hwmon_dev)) + return dev_err_probe(dev, PTR_ERR(hwmon_dev), + "failed to register hwmon device\n"); + + priv->hwmon_dev =3D hwmon_dev; + + ret =3D devm_request_threaded_irq(dev, priv->fault_irq, NULL, + mc33978_hwmon_fault_irq, IRQF_ONESHOT, + dev_name(dev), priv); + if (ret) + return dev_err_probe(dev, ret, "failed to request fault IRQ\n"); + + return 0; +} + +static const struct platform_device_id mc33978_hwmon_id[] =3D { + { "mc33978-hwmon", }, + { "mc34978-hwmon", }, + { } +}; +MODULE_DEVICE_TABLE(platform, mc33978_hwmon_id); + +static struct platform_driver mc33978_hwmon_driver =3D { + .driver =3D { + .name =3D "mc33978-hwmon", + }, + .probe =3D mc33978_hwmon_probe, + .id_table =3D mc33978_hwmon_id, +}; +module_platform_driver(mc33978_hwmon_driver); + +MODULE_AUTHOR("Oleksij Rempel "); +MODULE_DESCRIPTION("NXP MC33978/MC34978 Hardware Monitor Driver"); +MODULE_LICENSE("GPL"); --=20 2.47.3