On Mon, Feb 24, 2020 at 12:54:25PM -0800, Tim Harvey wrote:
> The Gateworks System Controller has a hwmon sub-component that exposes
> up to 16 ADC's, some of which are temperature sensors, others which are
> voltage inputs. The ADC configuration (register mapping and name) is
> configured via device-tree and varies board to board.
>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
Couple of minor comments, otherwise looks good from my perspective.
>
> v5:
> - fix various checkpatch issues
> - correct gsc-hwmon.rst in MAINTAINERS
> - switch to SENSOR_DEVICE_ATTR_{RW,RO}
> - use tmp value to avoid excessive pointer deference
> - simplify shift operation
> - scale voffset once
> - simplify is_visible function
> - remove empty line at end of file
>
> v4:
> - adjust for uV offset from device-tree
> - remove unnecessary optional write function
> - remove register range check
> - change dev_err prints to use gsc dev
> - hard-code resolution/scaling for raw adcs
> - describe units of ADC resolution
> - move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
> - ensure space before/after operators
> - remove unnecessary parens
> - remove more debugging
> - add default case and comment for type_voltage
> - remove unnecessary index bounds checks for channel
> - remove unnecessary clearing of struct fields
> - added Documentation/hwmon/gsc-hwmon.rst
>
> v3:
> - add voltage_raw input type and supporting fields
> - add channel validation to is_visible function
> - remove unnecessary channel validation from read/write functions
>
> v2:
> - change license comment style
> - remove DEBUG
> - simplify regmap_bulk_read err check
> - remove break after returns in switch statement
> - fix fan setpoint buffer address
> - remove unnecessary parens
> - consistently use struct device *dev pointer
> - change license/comment block
> - add validation for hwmon child node props
> - move parsing of of to own function
> - use strlcpy to ensure null termination
> - fix static array sizes and removed unnecessary initializers
> - dynamically allocate channels
> - fix fan input label
> - support platform data
> - fixed whitespace issues
> ---
> Documentation/hwmon/gsc-hwmon.rst | 53 +++++
> Documentation/hwmon/index.rst | 1 +
> MAINTAINERS | 3 +
> drivers/hwmon/Kconfig | 9 +
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/gsc-hwmon.c | 371 ++++++++++++++++++++++++++++++++
> include/linux/platform_data/gsc_hwmon.h | 44 ++++
> 7 files changed, 482 insertions(+)
> create mode 100644 Documentation/hwmon/gsc-hwmon.rst
> create mode 100644 drivers/hwmon/gsc-hwmon.c
> create mode 100644 include/linux/platform_data/gsc_hwmon.h
>
> diff --git a/Documentation/hwmon/gsc-hwmon.rst b/Documentation/hwmon/gsc-hwmon.rst
> new file mode 100644
> index 00000000..d34e508
> --- /dev/null
> +++ b/Documentation/hwmon/gsc-hwmon.rst
> @@ -0,0 +1,53 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Kernel driver gsc-hwmon
> +=======================
> +
> +Supported chips: Gateworks GSC
> +Datasheet: http://trac.gateworks.com/wiki/gsc
> +Author: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> +
> +Description:
> +------------
> +
> +This driver supports hardware monitoring for the temperature sensor,
> +various ADC's connected to the GSC, and optional FAN controller available
> +on some boards.
> +
> +
> +Voltage Monitoring
> +------------------
> +
> +The voltage inputs are scaled either internally or by the driver depending
> +on the GSC version and firmware. The values returned by the driver do not need
> +further scaling. The voltage input labels provide the voltage rail name:
> +
> +inX_input Measured voltage (mV).
> +inX_label Name of voltage rail.
> +
> +
> +Temperature Monitoring
> +----------------------
> +
> +Temperatures are measured with 12-bit or 10-bit resolution and are scaled
> +either internally or by the driver depending on the GSC version and firmware.
> +The values returned by the driver reflect millidegree Celcius:
> +
> +tempX_input Measured temperature.
> +tempX_label Name of temperature input.
> +
> +
> +PWM Output Control
> +------------------
> +
> +The GSC features 1 PWM output that operates in automatic mode where the
> +PWM value will be scalled depending on 6 temperature boundaries.
> +The tempeature boundaries are read-write and in millidegree Celcius and the
> +read-only PWM values range from 0 (off) to 255 (full speed).
> +Fan speed will be set to minimum (off) when the temperature sensor reads
> +less than pwm1_auto_point1_temp and maximum when the temperature sensor
> +equals or exceeds pwm1_auto_point6_temp.
> +
> +pwm1_auto_point1_pwm PWM value.
> +pwm1_auto_point1_temp Temperature boundary.
Should be something like
pwm1_auto_point[1-6]_pwm PWM value.
pwm1_auto_point[1-6]_temp Temperature boundary.
> +
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 43cc605..a4fab69 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -58,6 +58,7 @@ Hardware Monitoring Kernel Drivers
> ftsteutates
> g760a
> g762
> + gsc-hwmon
> gl518sm
> hih6130
> ibmaem
> diff --git a/MAINTAINERS b/MAINTAINERS
> index bb79b60..3f15542 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6846,6 +6846,9 @@ S: Maintained
> F: Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
> F: drivers/mfd/gateworks-gsc.c
> F: include/linux/mfd/gsc.h
> +F: Documentation/hwmon/gsc-hwmon.rst
> +F: drivers/hwmon/gsc-hwmon.c
> +F: include/linux/platform_data/gsc_hwmon.h
>
> GCC PLUGINS
> M: Kees Cook <keescook@xxxxxxxxxxxx>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 23dfe84..99dae13 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -494,6 +494,15 @@ config SENSORS_F75375S
> This driver can also be built as a module. If so, the module
> will be called f75375s.
>
> +config SENSORS_GSC
> + tristate "Gateworks System Controller ADC"
> + depends on MFD_GATEWORKS_GSC
> + help
> + Support for the Gateworks System Controller A/D converters.
> +
> + To compile this driver as a module, choose M here:
> + the module will be called gsc-hwmon.
> +
> config SENSORS_MC13783_ADC
> tristate "Freescale MC13783/MC13892 ADC"
> depends on MFD_MC13XXX
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 6db5db9..259cba7 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -71,6 +71,7 @@ obj-$(CONFIG_SENSORS_G760A) += g760a.o
> obj-$(CONFIG_SENSORS_G762) += g762.o
> obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
> obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o
> +obj-$(CONFIG_SENSORS_GSC) += gsc-hwmon.o
> obj-$(CONFIG_SENSORS_GPIO_FAN) += gpio-fan.o
> obj-$(CONFIG_SENSORS_HIH6130) += hih6130.o
> obj-$(CONFIG_SENSORS_ULTRA45) += ultra45_env.o
> diff --git a/drivers/hwmon/gsc-hwmon.c b/drivers/hwmon/gsc-hwmon.c
> new file mode 100644
> index 00000000..d9164a6
> --- /dev/null
> +++ b/drivers/hwmon/gsc-hwmon.c
> @@ -0,0 +1,371 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for Gateworks System Controller Hardware Monitor module
> + *
> + * Copyright (C) 2020 Gateworks Corporation
> + */
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/mfd/gsc.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +#include <linux/platform_data/gsc_hwmon.h>
> +
> +#define GSC_HWMON_MAX_TEMP_CH 16
> +#define GSC_HWMON_MAX_IN_CH 16
> +
> +#define GSC_HWMON_RESOLUTION 12
> +#define GSC_HWMON_VREF 2500
> +
> +struct gsc_hwmon_data {
> + struct gsc_dev *gsc;
> + struct device *dev;
> + struct gsc_hwmon_platform_data *pdata;
> + const struct gsc_hwmon_channel *temp_ch[GSC_HWMON_MAX_TEMP_CH];
> + const struct gsc_hwmon_channel *in_ch[GSC_HWMON_MAX_IN_CH];
> + u32 temp_config[GSC_HWMON_MAX_TEMP_CH + 1];
> + u32 in_config[GSC_HWMON_MAX_IN_CH + 1];
> + struct hwmon_channel_info temp_info;
> + struct hwmon_channel_info in_info;
> + const struct hwmon_channel_info *info[4];
Unless I am missing something, info[3] should be sufficient.
> + struct hwmon_chip_info chip;
> +};
> +
> +static ssize_t pwm_auto_point_temp_show(struct device *dev,
> + struct device_attribute *devattr,
> + char *buf)
> +{
> + struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + u8 reg = hwmon->pdata->fan_base + (2 * attr->index);
> + u8 regs[2];
> + int ret;
> +
> + ret = regmap_bulk_read(hwmon->gsc->regmap_hwmon, reg, regs, 2);
> + if (ret)
> + return ret;
> +
> + ret = regs[0] | regs[1] << 8;
> + return sprintf(buf, "%d\n", ret * 10);
> +}
> +
> +static ssize_t pwm_auto_point_temp_store(struct device *dev,
> + struct device_attribute *devattr,
> + const char *buf, size_t count)
> +{
> + struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + u8 reg = hwmon->pdata->fan_base + (2 * attr->index);
> + u8 regs[2];
> + long temp;
> + int err;
> +
> + if (kstrtol(buf, 10, &temp))
> + return -EINVAL;
> +
> + temp = clamp_val(temp, 0, 10000);
> + temp = DIV_ROUND_CLOSEST(temp, 10);
> +
> + regs[0] = temp & 0xff;
> + regs[1] = (temp >> 8) & 0xff;
> + err = regmap_bulk_write(hwmon->gsc->regmap_hwmon, reg, regs, 2);
> + if (err)
> + return err;
> +
> + return count;
> +}
> +
> +static ssize_t pwm_auto_point_pwm_show(struct device *dev,
> + struct device_attribute *devattr,
> + char *buf)
> +{
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> +
> + return sprintf(buf, "%d\n", 255 * (50 + (attr->index * 10)) / 100);
> +}
> +
> +static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point1_pwm, pwm_auto_point_pwm, 0);
> +static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp, pwm_auto_point_temp, 0);
> +
> +static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point2_pwm, pwm_auto_point_pwm, 1);
> +static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp, pwm_auto_point_temp, 1);
> +
> +static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point3_pwm, pwm_auto_point_pwm, 2);
> +static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp, pwm_auto_point_temp, 2);
> +
> +static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point4_pwm, pwm_auto_point_pwm, 3);
> +static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp, pwm_auto_point_temp, 3);
> +
> +static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point5_pwm, pwm_auto_point_pwm, 4);
> +static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point5_temp, pwm_auto_point_temp, 4);
> +
> +static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point6_pwm, pwm_auto_point_pwm, 5);
> +static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point6_temp, pwm_auto_point_temp, 5);
> +
> +static struct attribute *gsc_hwmon_attributes[] = {
> + &sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point1_temp.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point2_temp.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point3_pwm.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point3_temp.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point4_pwm.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point4_temp.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point5_pwm.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point5_temp.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point6_pwm.dev_attr.attr,
> + &sensor_dev_attr_pwm1_auto_point6_temp.dev_attr.attr,
> + NULL
> +};
> +
> +static const struct attribute_group gsc_hwmon_group = {
> + .attrs = gsc_hwmon_attributes,
> +};
> +__ATTRIBUTE_GROUPS(gsc_hwmon);
> +
> +static int
> +gsc_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
> + int channel, long *val)
> +{
> + struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
> + const struct gsc_hwmon_channel *ch;
> + int sz, ret;
> + long tmp;
> + u8 buf[3];
> +
> + switch (type) {
> + case hwmon_in:
> + ch = hwmon->in_ch[channel];
> + break;
> + case hwmon_temp:
> + ch = hwmon->temp_ch[channel];
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + sz = (ch->type == type_voltage) ? 3 : 2;
> + ret = regmap_bulk_read(hwmon->gsc->regmap_hwmon, ch->reg, buf, sz);
> + if (ret)
> + return ret;
> +
> + tmp = 0;
> + while (sz-- > 0)
> + tmp |= (buf[sz] << (8 * sz));
> +
> + switch (ch->type) {
> + case type_temperature:
> + if (tmp > 0x8000)
> + tmp -= 0xffff;
> + break;
> + case type_voltage_raw:
> + tmp = clamp_val(tmp, 0, BIT(GSC_HWMON_RESOLUTION));
> + /* scale based on ref voltage and ADC resolution */
> + tmp *= GSC_HWMON_VREF;
> + tmp >>= GSC_HWMON_RESOLUTION;
> + /* scale based on optional voltage divider */
> + if (ch->vdiv[0] && ch->vdiv[1]) {
> + tmp *= (ch->vdiv[0] + ch->vdiv[1]);
> + tmp /= ch->vdiv[1];
> + }
> + /* adjust by uV offset */
> + tmp += ch->mvoffset;
> + break;
> + case type_voltage:
> + /* no adjustment needed */
> + break;
> + }
> +
> + *val = tmp;
> +
> + return 0;
> +}
> +
> +static int
> +gsc_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, const char **buf)
> +{
> + struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
> +
> + switch (type) {
> + case hwmon_in:
> + *buf = hwmon->in_ch[channel]->name;
> + break;
> + case hwmon_temp:
> + *buf = hwmon->temp_ch[channel]->name;
> + break;
> + default:
> + return -ENOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static umode_t
> +gsc_hwmon_is_visible(const void *_data, enum hwmon_sensor_types type, u32 attr,
> + int ch)
> +{
> + return 0444;
> +}
> +
> +static const struct hwmon_ops gsc_hwmon_ops = {
> + .is_visible = gsc_hwmon_is_visible,
> + .read = gsc_hwmon_read,
> + .read_string = gsc_hwmon_read_string,
> +};
> +
> +static struct gsc_hwmon_platform_data *
> +gsc_hwmon_get_devtree_pdata(struct device *dev)
> +{
> + struct gsc_hwmon_platform_data *pdata;
> + struct gsc_hwmon_channel *ch;
> + struct fwnode_handle *child;
> + const char *type;
> + int nchannels;
> +
> + nchannels = device_get_child_node_count(dev);
> + if (nchannels == 0)
> + return ERR_PTR(-ENODEV);
> +
> + pdata = devm_kzalloc(dev,
> + sizeof(*pdata) + nchannels * sizeof(*ch),
> + GFP_KERNEL);
> + if (!pdata)
> + return ERR_PTR(-ENOMEM);
> + ch = (struct gsc_hwmon_channel *)(pdata + 1);
> + pdata->channels = ch;
> + pdata->nchannels = nchannels;
> +
> + device_property_read_u32(dev, "gw,fan-base", &pdata->fan_base);
> +
> + /* allocate structures for channels and count instances of each type */
> + device_for_each_child_node(dev, child) {
> + if (fwnode_property_read_string(child, "label", &ch->name)) {
> + dev_err(dev, "channel without label\n");
> + fwnode_handle_put(child);
> + return ERR_PTR(-EINVAL);
> + }
> + if (fwnode_property_read_u32(child, "reg", &ch->reg)) {
> + dev_err(dev, "channel without reg\n");
> + fwnode_handle_put(child);
> + return ERR_PTR(-EINVAL);
> + }
> + if (fwnode_property_read_string(child, "type", &type)) {
> + dev_err(dev, "channel without type\n");
> + fwnode_handle_put(child);
> + return ERR_PTR(-EINVAL);
> + }
> + if (!strcasecmp(type, "temperature")) {
> + ch->type = type_temperature;
> + } else if (!strcasecmp(type, "voltage")) {
> + ch->type = type_voltage;
> + } else if (!strcasecmp(type, "voltage-raw")) {
> + ch->type = type_voltage_raw;
> + } else {
> + dev_err(dev, "channel without type\n");
> + fwnode_handle_put(child);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (fwnode_property_read_u32(child, "gw,voltage-offset",
> + &ch->mvoffset))
> + ch->mvoffset /= 1000;
> + fwnode_property_read_u32_array(child, "gw,voltage-divider",
> + ch->vdiv, ARRAY_SIZE(ch->vdiv));
> + ch++;
> + }
> +
> + return pdata;
> +}
> +
> +static int gsc_hwmon_probe(struct platform_device *pdev)
> +{
> + struct gsc_dev *gsc = dev_get_drvdata(pdev->dev.parent);
> + struct device *dev = &pdev->dev;
> + struct gsc_hwmon_platform_data *pdata = dev_get_platdata(dev);
> + struct gsc_hwmon_data *hwmon;
> + const struct attribute_group **groups;
> + int i, i_in, i_temp;
> +
> + if (!pdata) {
> + pdata = gsc_hwmon_get_devtree_pdata(dev);
> + if (IS_ERR(pdata))
> + return PTR_ERR(pdata);
> + }
> +
> + hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
> + if (!hwmon)
> + return -ENOMEM;
> + hwmon->gsc = gsc;
> + hwmon->pdata = pdata;
> +
> + for (i = 0, i_in = 0, i_temp = 0; i < hwmon->pdata->nchannels; i++) {
> + const struct gsc_hwmon_channel *ch = &pdata->channels[i];
> +
> + switch (ch->type) {
> + case type_temperature:
> + if (i_temp == GSC_HWMON_MAX_TEMP_CH) {
> + dev_err(gsc->dev, "too many temp channels\n");
> + return -EINVAL;
> + }
> + hwmon->temp_ch[i_temp] = ch;
> + hwmon->temp_config[i_temp] = HWMON_T_INPUT |
> + HWMON_T_LABEL;
> + i_temp++;
> + break;
> + case type_voltage:
> + case type_voltage_raw:
> + if (i_in == GSC_HWMON_MAX_IN_CH) {
> + dev_err(gsc->dev, "too many input channels\n");
> + return -EINVAL;
> + }
> + hwmon->in_ch[i_in] = ch;
> + hwmon->in_config[i_in] =
> + HWMON_I_INPUT | HWMON_I_LABEL;
> + i_in++;
> + break;
> + default:
> + dev_err(gsc->dev, "invalid type: %d\n", ch->type);
> + return -EINVAL;
> + }
> + }
> +
> + /* setup config structures */
> + hwmon->chip.ops = &gsc_hwmon_ops;
> + hwmon->chip.info = hwmon->info;
> + hwmon->info[0] = &hwmon->temp_info;
> + hwmon->info[1] = &hwmon->in_info;
> + hwmon->temp_info.type = hwmon_temp;
> + hwmon->temp_info.config = hwmon->temp_config;
> + hwmon->in_info.type = hwmon_in;
> + hwmon->in_info.config = hwmon->in_config;
> +
> + groups = pdata->fan_base ? gsc_hwmon_groups : NULL;
> + hwmon->dev = devm_hwmon_device_register_with_info(dev,
> + KBUILD_MODNAME, hwmon,
> + &hwmon->chip, groups);
> + return PTR_ERR_OR_ZERO(hwmon->dev);
> +}
> +
> +static const struct of_device_id gsc_hwmon_of_match[] = {
> + { .compatible = "gw,gsc-hwmon", },
> + {}
> +};
> +
> +static struct platform_driver gsc_hwmon_driver = {
> + .driver = {
> + .name = "gsc-hwmon",
> + .of_match_table = gsc_hwmon_of_match,
> + },
> + .probe = gsc_hwmon_probe,
> +};
> +
> +module_platform_driver(gsc_hwmon_driver);
> +
> +MODULE_AUTHOR("Tim Harvey <tharvey@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("GSC hardware monitor driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/platform_data/gsc_hwmon.h b/include/linux/platform_data/gsc_hwmon.h
> new file mode 100644
> index 00000000..09465f8
> --- /dev/null
> +++ b/include/linux/platform_data/gsc_hwmon.h
> @@ -0,0 +1,44 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _GSC_HWMON_H
> +#define _GSC_HWMON_H
> +
> +enum gsc_hwmon_type {
> + type_temperature,
> + type_voltage,
> + type_voltage_raw,
> + type_fan,
> +};
> +
> +/**
> + * struct gsc_hwmon_channel - configuration parameters
> + * @reg: I2C register offset
> + * @type: channel type
> + * @name: channel name
> + * @mvoffset: voltage offset
> + * @vdiv: voltage divider array (2 resistor values in ohms)
> + */
> +struct gsc_hwmon_channel {
> + unsigned int reg;
> + unsigned int type;
> + const char *name;
> + unsigned int mvoffset;
> + unsigned int vdiv[2];
> +};
> +
> +/**
> + * struct gsc_hwmon_platform_data - platform data for gsc_hwmon driver
> + * @channels: pointer to array of gsc_hwmon_channel structures
> + * describing channels
> + * @nchannels: number of elements in @channels array
> + * @vreference: voltage reference (mV)
> + * @resolution: ADC bit resolution
> + * @fan_base: register base for FAN controller
> + */
> +struct gsc_hwmon_platform_data {
> + const struct gsc_hwmon_channel *channels;
> + int nchannels;
> + unsigned int resolution;
> + unsigned int vreference;
> + unsigned int fan_base;
> +};
> +#endif
