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mwalle
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hwmon: add SMARC-sAM67 support
Add a new driver for the Kontron SMARC-sAM67 board management controller. It has two voltage sensors and one temperature sensor. Signed-off-by: Michael Walle <mwalle@kernel.org> Link: https://lore.kernel.org/r/20250912120745.2295115-7-mwalle@kernel.org [groeck: Added sa67 to index.rst] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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‎Documentation/hwmon/index.rst‎

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@@ -214,6 +214,7 @@ Hardware Monitoring Kernel Drivers
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q54sj108a2
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qnap-mcu-hwmon
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raspberrypi-hwmon
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sa67
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sbrmi
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sbtsi_temp
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sch5627

‎Documentation/hwmon/sa67.rst‎

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.. SPDX-License-Identifier: GPL-2.0-only
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Kernel driver sa67mcu
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=====================
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Supported chips:
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* Kontron sa67mcu
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Prefix: 'sa67mcu'
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Datasheet: not available
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Authors: Michael Walle <mwalle@kernel.org>
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Description
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-----------
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The sa67mcu is a board management controller which also exposes a hardware
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monitoring controller.
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The controller has two voltage and one temperature sensor. The values are
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hold in two 8 bit registers to form one 16 bit value. Reading the lower byte
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will also capture the high byte to make the access atomic. The unit of the
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volatge sensors are 1mV and the unit of the temperature sensor is 0.1degC.
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Sysfs entries
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-------------
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The following attributes are supported.
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======================= ========================================================
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in0_label "VDDIN"
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in0_input Measured VDDIN voltage.
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in1_label "VDD_RTC"
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in1_input Measured VDD_RTC voltage.
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temp1_input MCU temperature. Roughly the board temperature.
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======================= ========================================================
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‎MAINTAINERS‎

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@@ -23231,6 +23231,7 @@ F: Documentation/devicetree/bindings/mfd/kontron,sl28cpld.yaml
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F: Documentation/devicetree/bindings/pwm/kontron,sl28cpld-pwm.yaml
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F: Documentation/devicetree/bindings/watchdog/kontron,sl28cpld-wdt.yaml
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F: drivers/gpio/gpio-sl28cpld.c
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F: drivers/hwmon/sa67mcu-hwmon.c
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F: drivers/hwmon/sl28cpld-hwmon.c
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F: drivers/irqchip/irq-sl28cpld.c
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F: drivers/pwm/pwm-sl28cpld.c

‎drivers/hwmon/Kconfig‎

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This driver can also be built as a module. If so, the module
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will be called raspberrypi-hwmon.
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config SENSORS_SA67MCU
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tristate "Kontron sa67mcu hardware monitoring driver"
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depends on MFD_SL28CPLD || COMPILE_TEST
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help
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If you say yes here you get support for the voltage and temperature
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monitor of the sa67 board management controller.
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This driver can also be built as a module. If so, the module
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will be called sa67mcu-hwmon.
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config SENSORS_SL28CPLD
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tristate "Kontron sl28cpld hardware monitoring driver"
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depends on MFD_SL28CPLD || COMPILE_TEST

‎drivers/hwmon/Makefile‎

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@@ -197,6 +197,7 @@ obj-$(CONFIG_SENSORS_PT5161L) += pt5161l.o
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obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o
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obj-$(CONFIG_SENSORS_QNAP_MCU_HWMON) += qnap-mcu-hwmon.o
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obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o
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obj-$(CONFIG_SENSORS_SA67MCU) += sa67mcu-hwmon.o
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obj-$(CONFIG_SENSORS_SBTSI) += sbtsi_temp.o
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obj-$(CONFIG_SENSORS_SBRMI) += sbrmi.o
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obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o

‎drivers/hwmon/sa67mcu-hwmon.c‎

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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* sl67mcu hardware monitoring driver
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*
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* Copyright 2025 Kontron Europe GmbH
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*/
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#include <linux/bitfield.h>
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#include <linux/hwmon.h>
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#include <linux/kernel.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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#include <linux/regmap.h>
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#define SA67MCU_VOLTAGE(n) (0x00 + ((n) * 2))
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#define SA67MCU_TEMP(n) (0x04 + ((n) * 2))
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struct sa67mcu_hwmon {
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struct regmap *regmap;
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u32 offset;
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};
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static int sa67mcu_hwmon_read(struct device *dev,
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enum hwmon_sensor_types type, u32 attr,
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int channel, long *input)
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{
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struct sa67mcu_hwmon *hwmon = dev_get_drvdata(dev);
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unsigned int offset;
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u8 reg[2];
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int ret;
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switch (type) {
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case hwmon_in:
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switch (attr) {
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case hwmon_in_input:
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offset = hwmon->offset + SA67MCU_VOLTAGE(channel);
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break;
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default:
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return -EOPNOTSUPP;
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}
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break;
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case hwmon_temp:
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switch (attr) {
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case hwmon_temp_input:
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offset = hwmon->offset + SA67MCU_TEMP(channel);
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break;
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default:
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return -EOPNOTSUPP;
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}
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break;
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default:
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return -EOPNOTSUPP;
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}
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/* Reading the low byte will capture the value */
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ret = regmap_bulk_read(hwmon->regmap, offset, reg, ARRAY_SIZE(reg));
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if (ret)
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return ret;
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*input = reg[1] << 8 | reg[0];
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/* Temperatures are s16 and in 0.1degC steps. */
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if (type == hwmon_temp)
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*input = sign_extend32(*input, 15) * 100;
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return 0;
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}
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static const struct hwmon_channel_info * const sa67mcu_hwmon_info[] = {
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HWMON_CHANNEL_INFO(in,
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HWMON_I_INPUT | HWMON_I_LABEL,
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HWMON_I_INPUT | HWMON_I_LABEL),
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HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
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NULL
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};
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static const char *const sa67mcu_hwmon_in_labels[] = {
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"VDDIN",
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"VDD_RTC",
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};
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static int sa67mcu_hwmon_read_string(struct device *dev,
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enum hwmon_sensor_types type, u32 attr,
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int channel, const char **str)
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{
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switch (type) {
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case hwmon_in:
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switch (attr) {
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case hwmon_in_label:
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*str = sa67mcu_hwmon_in_labels[channel];
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return 0;
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default:
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return -EOPNOTSUPP;
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}
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default:
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return -EOPNOTSUPP;
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}
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}
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static const struct hwmon_ops sa67mcu_hwmon_ops = {
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.visible = 0444,
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.read = sa67mcu_hwmon_read,
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.read_string = sa67mcu_hwmon_read_string,
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};
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static const struct hwmon_chip_info sa67mcu_hwmon_chip_info = {
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.ops = &sa67mcu_hwmon_ops,
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.info = sa67mcu_hwmon_info,
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};
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static int sa67mcu_hwmon_probe(struct platform_device *pdev)
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{
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struct sa67mcu_hwmon *hwmon;
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struct device *hwmon_dev;
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int ret;
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if (!pdev->dev.parent)
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return -ENODEV;
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hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
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if (!hwmon)
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return -ENOMEM;
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hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
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if (!hwmon->regmap)
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return -ENODEV;
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ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset);
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if (ret)
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return -EINVAL;
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hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
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"sa67mcu_hwmon", hwmon,
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&sa67mcu_hwmon_chip_info,
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NULL);
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if (IS_ERR(hwmon_dev))
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dev_err(&pdev->dev, "failed to register as hwmon device");
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static const struct of_device_id sa67mcu_hwmon_of_match[] = {
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{ .compatible = "kontron,sa67mcu-hwmon", },
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{}
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};
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MODULE_DEVICE_TABLE(of, sa67mcu_hwmon_of_match);
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static struct platform_driver sa67mcu_hwmon_driver = {
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.probe = sa67mcu_hwmon_probe,
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.driver = {
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.name = "sa67mcu-hwmon",
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.of_match_table = sa67mcu_hwmon_of_match,
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},
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};
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module_platform_driver(sa67mcu_hwmon_driver);
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MODULE_DESCRIPTION("sa67mcu Hardware Monitoring Driver");
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MODULE_AUTHOR("Michael Walle <mwalle@kernel.org>");
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MODULE_LICENSE("GPL");

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