[PATCH v3 2/2] platform/x86: portwell-ec: Add hwmon support for voltage and temperature
From: Yen-Chi Huang
Date: Mon Jul 28 2025 - 08:02:30 EST
Integrates Vcore, VDIMM, 3.3V, 5V, 12V voltage and system temperature
monitoring into the driver via the hwmon subsystem, enabling
standardized reporting via tools like lm-sensors.
Signed-off-by: Yen-Chi Huang <jesse.huang@xxxxxxxxxxxxxxx>
---
drivers/platform/x86/portwell-ec.c | 175 ++++++++++++++++++++++++++++-
1 file changed, 173 insertions(+), 2 deletions(-)
diff --git a/drivers/platform/x86/portwell-ec.c b/drivers/platform/x86/portwell-ec.c
index 7f473e3032e2..a3b28fc1a35c 100644
--- a/drivers/platform/x86/portwell-ec.c
+++ b/drivers/platform/x86/portwell-ec.c
@@ -25,6 +25,7 @@
#include <linux/bitfield.h>
#include <linux/dmi.h>
#include <linux/gpio/driver.h>
+#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
@@ -32,6 +33,7 @@
#include <linux/platform_device.h>
#include <linux/sizes.h>
#include <linux/string.h>
+#include <linux/units.h>
#include <linux/watchdog.h>
#define PORTWELL_EC_IOSPACE 0xe300
@@ -52,16 +54,64 @@
#define PORTWELL_EC_FW_VENDOR_LENGTH 3
#define PORTWELL_EC_FW_VENDOR_NAME "PWG"
+#define PORTWELL_EC_ADC_MAX 1023
+
static bool force;
module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "Force loading EC driver without checking DMI boardname");
+struct pwec_hwmon_data {
+ const char *label;
+ u8 lsb_reg;
+ u32 scale;
+};
+
+struct pwec_data {
+ const struct pwec_hwmon_data *hwmon_in_data;
+ int hwmon_in_num;
+ const struct pwec_hwmon_data *hwmon_temp_data;
+ int hwmon_temp_num;
+ const struct hwmon_channel_info * const *hwmon_info;
+};
+
+static const struct pwec_hwmon_data pwec_nano_hwmon_in[] = {
+ { "Vcore", 0x20, 3000 },
+ { "VDIMM", 0x32, 3000 },
+ { "3.3V", 0x22, 6000 },
+ { "5V", 0x24, 9600 },
+ { "12V", 0x30, 19800 },
+};
+
+static const struct pwec_hwmon_data pwec_nano_hwmon_temp[] = {
+ { "System Temperature", 0x02, 0 },
+};
+
+static const struct hwmon_channel_info *pwec_nano_hwmon_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_LABEL),
+ HWMON_CHANNEL_INFO(in,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL),
+ NULL
+};
+
+static const struct pwec_data pwec_board_data_nano = {
+ .hwmon_in_data = pwec_nano_hwmon_in,
+ .hwmon_in_num = ARRAY_SIZE(pwec_nano_hwmon_in),
+ .hwmon_temp_data = pwec_nano_hwmon_temp,
+ .hwmon_temp_num = ARRAY_SIZE(pwec_nano_hwmon_temp),
+ .hwmon_info = pwec_nano_hwmon_info,
+};
+
static const struct dmi_system_id pwec_dmi_table[] = {
{
.ident = "NANO-6064 series",
.matches = {
DMI_MATCH(DMI_BOARD_NAME, "NANO-6064"),
},
+ .driver_data = (void *)&pwec_board_data_nano,
},
{ }
};
@@ -79,6 +129,19 @@ static u8 pwec_read(u8 address)
return inb(PORTWELL_EC_IOSPACE + address);
}
+static u16 pwec_read16_stable(u8 lsb_reg)
+{
+ u8 lsb, msb, old_msb;
+
+ do {
+ old_msb = pwec_read(lsb_reg + 1);
+ lsb = pwec_read(lsb_reg);
+ msb = pwec_read(lsb_reg + 1);
+ } while (msb != old_msb);
+
+ return (msb << 8) | lsb;
+}
+
/* GPIO functions */
static int pwec_gpio_get(struct gpio_chip *chip, unsigned int offset)
@@ -204,6 +267,106 @@ static struct watchdog_device ec_wdt_dev = {
.max_timeout = PORTWELL_WDT_EC_MAX_COUNT_SECOND,
};
+/* HWMON functions */
+
+static umode_t pwec_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct pwec_data *d = data;
+
+ switch (type) {
+ case hwmon_temp:
+ return channel < d->hwmon_temp_num ? 0444 : 0;
+ case hwmon_in:
+ return channel < d->hwmon_in_num ? 0444 : 0;
+ default:
+ return 0;
+ }
+}
+
+static int pwec_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct pwec_data *data = dev_get_drvdata(dev);
+ u8 tmp8;
+ u16 tmp16;
+
+ switch (type) {
+ case hwmon_temp:
+ if (channel < data->hwmon_temp_num) {
+ tmp8 = pwec_read(data->hwmon_temp_data[channel].lsb_reg);
+ *val = tmp8 * MILLIDEGREE_PER_DEGREE;
+ return 0;
+ }
+ break;
+ case hwmon_in:
+ if (channel < data->hwmon_in_num) {
+ tmp16 = pwec_read16_stable(data->hwmon_in_data[channel].lsb_reg);
+ *val = (data->hwmon_in_data[channel].scale * tmp16) / PORTWELL_EC_ADC_MAX;
+ return 0;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+static int pwec_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, const char **str)
+{
+ struct pwec_data *data = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_temp:
+ if (channel < data->hwmon_temp_num) {
+ *str = data->hwmon_temp_data[channel].label;
+ return 0;
+ }
+ break;
+ case hwmon_in:
+ if (channel < data->hwmon_in_num) {
+ *str = data->hwmon_in_data[channel].label;
+ return 0;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+static const struct hwmon_ops pwec_hwmon_ops = {
+ .is_visible = pwec_hwmon_is_visible,
+ .read = pwec_hwmon_read,
+ .read_string = pwec_hwmon_read_string,
+};
+
+static struct hwmon_chip_info pwec_chip_info = {
+ .ops = &pwec_hwmon_ops,
+};
+
+static int pwec_hwmon_init(struct device *dev)
+{
+ struct pwec_data *data = dev_get_platdata(dev);
+ void *hwmon;
+ int ret;
+
+ if (!IS_REACHABLE(CONFIG_HWMON))
+ return 0;
+
+ pwec_chip_info.info = data->hwmon_info;
+ hwmon = devm_hwmon_device_register_with_info(dev, "portwell_ec", data, &pwec_chip_info,
+ NULL);
+ ret = PTR_ERR_OR_ZERO(hwmon);
+ if (ret)
+ dev_err(dev, "Failed to register hwmon_dev: %d\n", ret);
+
+ return ret;
+}
+
static int pwec_firmware_vendor_check(void)
{
u8 buf[PORTWELL_EC_FW_VENDOR_LENGTH + 1];
@@ -243,6 +406,10 @@ static int pwec_probe(struct platform_device *pdev)
return ret;
}
+ ret = pwec_hwmon_init(&pdev->dev);
+ if (ret < 0)
+ return ret;
+
return 0;
}
@@ -275,11 +442,14 @@ static struct platform_device *pwec_dev;
static int __init pwec_init(void)
{
+ const struct dmi_system_id *match;
int ret;
- if (!dmi_check_system(pwec_dmi_table)) {
+ match = dmi_first_match(pwec_dmi_table);
+ if (!match) {
if (!force)
return -ENODEV;
+ match = &pwec_dmi_table[0];
pr_warn("force load portwell-ec without DMI check\n");
}
@@ -287,7 +457,8 @@ static int __init pwec_init(void)
if (ret)
return ret;
- pwec_dev = platform_device_register_simple("portwell-ec", -1, NULL, 0);
+ pwec_dev = platform_device_register_data(NULL, "portwell-ec", -1, match->driver_data,
+ sizeof(struct pwec_data));
if (IS_ERR(pwec_dev)) {
platform_driver_unregister(&pwec_driver);
return PTR_ERR(pwec_dev);
--
2.34.1