diff mbox series

[14/18] hwmon: add support for the sl28cpld hardware monitoring controller

Message ID 20200317205017.28280-15-michael@walle.cc (mailing list archive)
State Changes Requested
Headers show
Series Add support for Kontron sl28cpld | expand

Commit Message

Michael Walle March 17, 2020, 8:50 p.m. UTC
This adds support for the hardware monitoring controller of the sl28cpld
board management controller. This driver is part of a multi-function
device.

Signed-off-by: Michael Walle <michael@walle.cc>
---
 drivers/hwmon/Kconfig          |  10 +++
 drivers/hwmon/Makefile         |   1 +
 drivers/hwmon/sl28cpld-hwmon.c | 146 +++++++++++++++++++++++++++++++++
 3 files changed, 157 insertions(+)
 create mode 100644 drivers/hwmon/sl28cpld-hwmon.c

Comments

Guenter Roeck March 18, 2020, 3:27 a.m. UTC | #1
On 3/17/20 1:50 PM, Michael Walle wrote:
> This adds support for the hardware monitoring controller of the sl28cpld
> board management controller. This driver is part of a multi-function
> device.
> 
> Signed-off-by: Michael Walle <michael@walle.cc>
> ---
>  drivers/hwmon/Kconfig          |  10 +++
>  drivers/hwmon/Makefile         |   1 +
>  drivers/hwmon/sl28cpld-hwmon.c | 146 +++++++++++++++++++++++++++++++++

Please also provide Documentation/hwmon/sl28cpld.

>  3 files changed, 157 insertions(+)
>  create mode 100644 drivers/hwmon/sl28cpld-hwmon.c
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 05a30832c6ba..c98716f78cfa 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1412,6 +1412,16 @@ config SENSORS_RASPBERRYPI_HWMON
>  	  This driver can also be built as a module. If so, the module
>  	  will be called raspberrypi-hwmon.
>  
> +config SENSORS_SL28CPLD
> +	tristate "Kontron's SMARC-sAL28 hardware monitoring driver"
> +	depends on MFD_SL28CPLD
> +	help
> +	  If you say yes here you get support for a fan connected to the
> +	  input of the SMARC connector of Kontron's SMARC-sAL28 module.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called sl28cpld-hwmon.
> +
>  config SENSORS_SHT15
>  	tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
>  	depends on GPIOLIB || COMPILE_TEST
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index b0b9c8e57176..dfb0f8cda2dd 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -155,6 +155,7 @@ obj-$(CONFIG_SENSORS_S3C)	+= s3c-hwmon.o
>  obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
>  obj-$(CONFIG_SENSORS_SCH5627)	+= sch5627.o
>  obj-$(CONFIG_SENSORS_SCH5636)	+= sch5636.o
> +obj-$(CONFIG_SENSORS_SL28CPLD)	+= sl28cpld-hwmon.o
>  obj-$(CONFIG_SENSORS_SHT15)	+= sht15.o
>  obj-$(CONFIG_SENSORS_SHT21)	+= sht21.o
>  obj-$(CONFIG_SENSORS_SHT3x)	+= sht3x.o
> diff --git a/drivers/hwmon/sl28cpld-hwmon.c b/drivers/hwmon/sl28cpld-hwmon.c
> new file mode 100644
> index 000000000000..7ac42bb0a48c
> --- /dev/null
> +++ b/drivers/hwmon/sl28cpld-hwmon.c
> @@ -0,0 +1,146 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * SMARC-sAL28 fan hardware monitoring driver.
> + *
> + * Copyright 2019 Kontron Europe GmbH
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/bitfield.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_address.h>
> +#include <linux/regmap.h>
> +#include <linux/platform_device.h>
> +#include <linux/hwmon.h>
> +
Alphabetic order of include files, please.

> +#define FAN_INPUT		0
> +#define   FAN_SCALE_X8		BIT(7)
> +#define   FAN_VALUE_MASK	GENMASK(6, 0)
> +
> +struct sl28cpld_hwmon {
> +	struct regmap *regmap;
> +	u32 offset;
> +};
> +
> +static umode_t sl28cpld_hwmon_is_visible(const void *data,
> +					 enum hwmon_sensor_types type,
> +					 u32 attr, int channel)
> +{
> +	return 0444;
> +}
> +
> +static int sl28cpld_hwmon_read(struct device *dev,
> +			       enum hwmon_sensor_types type, u32 attr,
> +			       int channel, long *input)
> +{
> +	struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev);
> +	unsigned int value;
> +	int ret;
> +
> +	switch (attr) {
> +	case hwmon_fan_input:
> +		ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT,
> +				  &value);
> +		if (ret)
> +			return ret;
> +		/*
> +		 * The register has a 7 bit value and 1 bit which indicates the
> +		 * scale. If the MSB is set, then the lower 7 bit has to be
> +		 * multiplied by 8, to get the correct reading.
> +		 */
> +		if (value & FAN_SCALE_X8)
> +			value = FIELD_GET(FAN_VALUE_MASK, value) << 3;
> +
> +		/*
> +		 * The counter period is 1000ms and the sysfs specification
> +		 * says we should asssume 2 pulses per revolution.
> +		 */
> +		value *= 60 / 2;
> +
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	*input = value;
> +	return 0;
> +}
> +
> +static const u32 sl28cpld_hwmon_fan_config[] = {
> +	HWMON_F_INPUT,
> +	0
> +};
> +
> +static const struct hwmon_channel_info sl28cpld_hwmon_fan = {
> +	.type = hwmon_fan,
> +	.config = sl28cpld_hwmon_fan_config,
> +};
> +
> +static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = {
> +	&sl28cpld_hwmon_fan,
> +	NULL
> +};
> +
> +static const struct hwmon_ops sl28cpld_hwmon_ops = {
> +	.is_visible = sl28cpld_hwmon_is_visible,
> +	.read = sl28cpld_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = {
> +	.ops = &sl28cpld_hwmon_ops,
> +	.info = sl28cpld_hwmon_info,
> +};
> +
> +static int sl28cpld_hwmon_probe(struct platform_device *pdev)
> +{
> +	struct device *hwmon_dev;
> +	struct sl28cpld_hwmon *hwmon;
> +	struct resource *res;
> +
> +	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
> +	if (!hwmon)
> +		return -ENOMEM;
> +
> +	if (!pdev->dev.parent)
> +		return -ENODEV;
> +
Maybe do this first ?

> +	hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!hwmon->regmap)
> +		return -ENODEV;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
> +	if (!res)
> +		return -EINVAL;
> +	hwmon->offset = res->start;
> +
> +	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
> +							 "sl28cpld_hwmon",
> +							 hwmon,
> +							 &sl28cpld_hwmon_chip_info,
> +							 NULL);
> +	if (IS_ERR(hwmon_dev)) {
> +		dev_err(&pdev->dev, "failed to register as hwmon device");
> +		return PTR_ERR(hwmon_dev);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id sl28cpld_hwmon_id_table[] = {
> +	{"sl28cpld-fan", 0},
> +};
> +MODULE_DEVICE_TABLE(platform, sl28cpld_hwmon_id_table);
> +
> +static struct platform_driver sl28cpld_hwmon_driver = {
> +	.probe = sl28cpld_hwmon_probe,
> +	.id_table = sl28cpld_hwmon_id_table,

I'd have expected an of_match_table.

> +	.driver = {
> +		.name = "sl28cpld-hwmon",
> +	},
> +};
> +module_platform_driver(sl28cpld_hwmon_driver);
> +
> +MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver");
> +MODULE_LICENSE("GPL");
>
Michael Walle March 18, 2020, 4:32 p.m. UTC | #2
Hi Guenter,

thanks for the review

Am 2020-03-18 04:27, schrieb Guenter Roeck:
> On 3/17/20 1:50 PM, Michael Walle wrote:
>> This adds support for the hardware monitoring controller of the 
>> sl28cpld
>> board management controller. This driver is part of a multi-function
>> device.
>> 
>> Signed-off-by: Michael Walle <michael@walle.cc>
>> ---
>>  drivers/hwmon/Kconfig          |  10 +++
>>  drivers/hwmon/Makefile         |   1 +
>>  drivers/hwmon/sl28cpld-hwmon.c | 146 
>> +++++++++++++++++++++++++++++++++
> 
> Please also provide Documentation/hwmon/sl28cpld.
> 
>>  3 files changed, 157 insertions(+)
>>  create mode 100644 drivers/hwmon/sl28cpld-hwmon.c
>> 
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index 05a30832c6ba..c98716f78cfa 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -1412,6 +1412,16 @@ config SENSORS_RASPBERRYPI_HWMON
>>  	  This driver can also be built as a module. If so, the module
>>  	  will be called raspberrypi-hwmon.
>> 
>> +config SENSORS_SL28CPLD
>> +	tristate "Kontron's SMARC-sAL28 hardware monitoring driver"
>> +	depends on MFD_SL28CPLD
>> +	help
>> +	  If you say yes here you get support for a fan connected to the
>> +	  input of the SMARC connector of Kontron's SMARC-sAL28 module.
>> +
>> +	  This driver can also be built as a module.  If so, the module
>> +	  will be called sl28cpld-hwmon.
>> +
>>  config SENSORS_SHT15
>>  	tristate "Sensiron humidity and temperature sensors. SHT15 and 
>> compat."
>>  	depends on GPIOLIB || COMPILE_TEST
>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>> index b0b9c8e57176..dfb0f8cda2dd 100644
>> --- a/drivers/hwmon/Makefile
>> +++ b/drivers/hwmon/Makefile
>> @@ -155,6 +155,7 @@ obj-$(CONFIG_SENSORS_S3C)	+= s3c-hwmon.o
>>  obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
>>  obj-$(CONFIG_SENSORS_SCH5627)	+= sch5627.o
>>  obj-$(CONFIG_SENSORS_SCH5636)	+= sch5636.o
>> +obj-$(CONFIG_SENSORS_SL28CPLD)	+= sl28cpld-hwmon.o
>>  obj-$(CONFIG_SENSORS_SHT15)	+= sht15.o
>>  obj-$(CONFIG_SENSORS_SHT21)	+= sht21.o
>>  obj-$(CONFIG_SENSORS_SHT3x)	+= sht3x.o
>> diff --git a/drivers/hwmon/sl28cpld-hwmon.c 
>> b/drivers/hwmon/sl28cpld-hwmon.c
>> new file mode 100644
>> index 000000000000..7ac42bb0a48c
>> --- /dev/null
>> +++ b/drivers/hwmon/sl28cpld-hwmon.c
>> @@ -0,0 +1,146 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * SMARC-sAL28 fan hardware monitoring driver.
>> + *
>> + * Copyright 2019 Kontron Europe GmbH
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/bitfield.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_address.h>
>> +#include <linux/regmap.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/hwmon.h>
>> +
> Alphabetic order of include files, please.

ok, I guess that applies to all of the new files.


>> +#define FAN_INPUT		0
>> +#define   FAN_SCALE_X8		BIT(7)
>> +#define   FAN_VALUE_MASK	GENMASK(6, 0)
>> +
>> +struct sl28cpld_hwmon {
>> +	struct regmap *regmap;
>> +	u32 offset;
>> +};
>> +
>> +static umode_t sl28cpld_hwmon_is_visible(const void *data,
>> +					 enum hwmon_sensor_types type,
>> +					 u32 attr, int channel)
>> +{
>> +	return 0444;
>> +}
>> +
>> +static int sl28cpld_hwmon_read(struct device *dev,
>> +			       enum hwmon_sensor_types type, u32 attr,
>> +			       int channel, long *input)
>> +{
>> +	struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev);
>> +	unsigned int value;
>> +	int ret;
>> +
>> +	switch (attr) {
>> +	case hwmon_fan_input:
>> +		ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT,
>> +				  &value);
>> +		if (ret)
>> +			return ret;
>> +		/*
>> +		 * The register has a 7 bit value and 1 bit which indicates the
>> +		 * scale. If the MSB is set, then the lower 7 bit has to be
>> +		 * multiplied by 8, to get the correct reading.
>> +		 */
>> +		if (value & FAN_SCALE_X8)
>> +			value = FIELD_GET(FAN_VALUE_MASK, value) << 3;
>> +
>> +		/*
>> +		 * The counter period is 1000ms and the sysfs specification
>> +		 * says we should asssume 2 pulses per revolution.
>> +		 */
>> +		value *= 60 / 2;
>> +
>> +		break;
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	*input = value;
>> +	return 0;
>> +}
>> +
>> +static const u32 sl28cpld_hwmon_fan_config[] = {
>> +	HWMON_F_INPUT,
>> +	0
>> +};
>> +
>> +static const struct hwmon_channel_info sl28cpld_hwmon_fan = {
>> +	.type = hwmon_fan,
>> +	.config = sl28cpld_hwmon_fan_config,
>> +};
>> +
>> +static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = {
>> +	&sl28cpld_hwmon_fan,
>> +	NULL
>> +};
>> +
>> +static const struct hwmon_ops sl28cpld_hwmon_ops = {
>> +	.is_visible = sl28cpld_hwmon_is_visible,
>> +	.read = sl28cpld_hwmon_read,
>> +};
>> +
>> +static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = {
>> +	.ops = &sl28cpld_hwmon_ops,
>> +	.info = sl28cpld_hwmon_info,
>> +};
>> +
>> +static int sl28cpld_hwmon_probe(struct platform_device *pdev)
>> +{
>> +	struct device *hwmon_dev;
>> +	struct sl28cpld_hwmon *hwmon;
>> +	struct resource *res;
>> +
>> +	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
>> +	if (!hwmon)
>> +		return -ENOMEM;
>> +
>> +	if (!pdev->dev.parent)
>> +		return -ENODEV;
>> +
> Maybe do this first ?

ok. like explained on another patch review comment, I had that
together with the following dev_get_regmap() which uses this.
But I was already not sure while writing the code whether I
should do it first and don't have to undo the devm_ in case of
an error. Well since already two reviewers stumbled on this,
I'll do it first on all the patches.


>> +	hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
>> +	if (!hwmon->regmap)
>> +		return -ENODEV;
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
>> +	if (!res)
>> +		return -EINVAL;
>> +	hwmon->offset = res->start;
>> +
>> +	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
>> +							 "sl28cpld_hwmon",
>> +							 hwmon,
>> +							 &sl28cpld_hwmon_chip_info,
>> +							 NULL);
>> +	if (IS_ERR(hwmon_dev)) {
>> +		dev_err(&pdev->dev, "failed to register as hwmon device");
>> +		return PTR_ERR(hwmon_dev);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct platform_device_id sl28cpld_hwmon_id_table[] = {
>> +	{"sl28cpld-fan", 0},
>> +};
>> +MODULE_DEVICE_TABLE(platform, sl28cpld_hwmon_id_table);
>> +
>> +static struct platform_driver sl28cpld_hwmon_driver = {
>> +	.probe = sl28cpld_hwmon_probe,
>> +	.id_table = sl28cpld_hwmon_id_table,
> 
> I'd have expected an of_match_table.

There was one, but, since I use mfd_add_devices() which uses the
platform driver name (or the id_table) I removed it. While it
doesn't really matter here in the hwmon part for now, the GPIO
driver uses the id_table data to distinguish between different
flavors of the GPIO controller. So there I'd have to duplicate
data in the tables (eg. the id_table as well as the
of_match_table) and get that data in the _probe(), although only
the id_table data is used.

-michael

> 
>> +	.driver = {
>> +		.name = "sl28cpld-hwmon",
>> +	},
>> +};
>> +module_platform_driver(sl28cpld_hwmon_driver);
>> +
>> +MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver");
>> +MODULE_LICENSE("GPL");
>>
diff mbox series

Patch

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 05a30832c6ba..c98716f78cfa 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1412,6 +1412,16 @@  config SENSORS_RASPBERRYPI_HWMON
 	  This driver can also be built as a module. If so, the module
 	  will be called raspberrypi-hwmon.
 
+config SENSORS_SL28CPLD
+	tristate "Kontron's SMARC-sAL28 hardware monitoring driver"
+	depends on MFD_SL28CPLD
+	help
+	  If you say yes here you get support for a fan connected to the
+	  input of the SMARC connector of Kontron's SMARC-sAL28 module.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called sl28cpld-hwmon.
+
 config SENSORS_SHT15
 	tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
 	depends on GPIOLIB || COMPILE_TEST
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index b0b9c8e57176..dfb0f8cda2dd 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -155,6 +155,7 @@  obj-$(CONFIG_SENSORS_S3C)	+= s3c-hwmon.o
 obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
 obj-$(CONFIG_SENSORS_SCH5627)	+= sch5627.o
 obj-$(CONFIG_SENSORS_SCH5636)	+= sch5636.o
+obj-$(CONFIG_SENSORS_SL28CPLD)	+= sl28cpld-hwmon.o
 obj-$(CONFIG_SENSORS_SHT15)	+= sht15.o
 obj-$(CONFIG_SENSORS_SHT21)	+= sht21.o
 obj-$(CONFIG_SENSORS_SHT3x)	+= sht3x.o
diff --git a/drivers/hwmon/sl28cpld-hwmon.c b/drivers/hwmon/sl28cpld-hwmon.c
new file mode 100644
index 000000000000..7ac42bb0a48c
--- /dev/null
+++ b/drivers/hwmon/sl28cpld-hwmon.c
@@ -0,0 +1,146 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SMARC-sAL28 fan hardware monitoring driver.
+ *
+ * Copyright 2019 Kontron Europe GmbH
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bitfield.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/regmap.h>
+#include <linux/platform_device.h>
+#include <linux/hwmon.h>
+
+#define FAN_INPUT		0
+#define   FAN_SCALE_X8		BIT(7)
+#define   FAN_VALUE_MASK	GENMASK(6, 0)
+
+struct sl28cpld_hwmon {
+	struct regmap *regmap;
+	u32 offset;
+};
+
+static umode_t sl28cpld_hwmon_is_visible(const void *data,
+					 enum hwmon_sensor_types type,
+					 u32 attr, int channel)
+{
+	return 0444;
+}
+
+static int sl28cpld_hwmon_read(struct device *dev,
+			       enum hwmon_sensor_types type, u32 attr,
+			       int channel, long *input)
+{
+	struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	switch (attr) {
+	case hwmon_fan_input:
+		ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT,
+				  &value);
+		if (ret)
+			return ret;
+		/*
+		 * The register has a 7 bit value and 1 bit which indicates the
+		 * scale. If the MSB is set, then the lower 7 bit has to be
+		 * multiplied by 8, to get the correct reading.
+		 */
+		if (value & FAN_SCALE_X8)
+			value = FIELD_GET(FAN_VALUE_MASK, value) << 3;
+
+		/*
+		 * The counter period is 1000ms and the sysfs specification
+		 * says we should asssume 2 pulses per revolution.
+		 */
+		value *= 60 / 2;
+
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	*input = value;
+	return 0;
+}
+
+static const u32 sl28cpld_hwmon_fan_config[] = {
+	HWMON_F_INPUT,
+	0
+};
+
+static const struct hwmon_channel_info sl28cpld_hwmon_fan = {
+	.type = hwmon_fan,
+	.config = sl28cpld_hwmon_fan_config,
+};
+
+static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = {
+	&sl28cpld_hwmon_fan,
+	NULL
+};
+
+static const struct hwmon_ops sl28cpld_hwmon_ops = {
+	.is_visible = sl28cpld_hwmon_is_visible,
+	.read = sl28cpld_hwmon_read,
+};
+
+static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = {
+	.ops = &sl28cpld_hwmon_ops,
+	.info = sl28cpld_hwmon_info,
+};
+
+static int sl28cpld_hwmon_probe(struct platform_device *pdev)
+{
+	struct device *hwmon_dev;
+	struct sl28cpld_hwmon *hwmon;
+	struct resource *res;
+
+	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+
+	if (!pdev->dev.parent)
+		return -ENODEV;
+
+	hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!hwmon->regmap)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
+	if (!res)
+		return -EINVAL;
+	hwmon->offset = res->start;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+							 "sl28cpld_hwmon",
+							 hwmon,
+							 &sl28cpld_hwmon_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev)) {
+		dev_err(&pdev->dev, "failed to register as hwmon device");
+		return PTR_ERR(hwmon_dev);
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id sl28cpld_hwmon_id_table[] = {
+	{"sl28cpld-fan", 0},
+};
+MODULE_DEVICE_TABLE(platform, sl28cpld_hwmon_id_table);
+
+static struct platform_driver sl28cpld_hwmon_driver = {
+	.probe = sl28cpld_hwmon_probe,
+	.id_table = sl28cpld_hwmon_id_table,
+	.driver = {
+		.name = "sl28cpld-hwmon",
+	},
+};
+module_platform_driver(sl28cpld_hwmon_driver);
+
+MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver");
+MODULE_LICENSE("GPL");