[PATCH v3 0/2] platform/x86: portwell-ec: Add watchdog suspend/resume and hwmon

[PATCH v3 0/2] platform/x86: portwell-ec: Add watchdog suspend/resume and hwmon

[Yen-Chi Huang]

This patch series adds suspend/resume support for the watchdog (patch 1/2)
and hwmon monitoring functionality (patch 2/2) to the Portwell EC driver.
These changes enable better power management and sensor reporting.

Tested on Portwell NANO-6064.
---
V2->V3:

Patch 1/2:
  - Unchanged

Patch 2/2:
  - Replace hardcoded `1000` with `MILLIDEGREE_PER_DEGREE` and double check
  - Fix comma placement and spacing coding style issues
  - Simplify pwec_hwmon_is_visible() with ternary operator

V1->V2:

- Added watchdog mailing list to Cc.

Patch 1/2:
  - unchanged

Patch 2/2:
  - Removed `msb_reg` from `strucit pwec_hwmon_data`
  - Updated `pwec_read16_stable()` to assume MSB follows LSB
  - Moved `hwmon_channel_info` to per-board data and assigned it to `.info` at runtime
  - Replaced the `pwec_board_data[]` array with a standalone struct
  - Replaced literal `1000` with `MILLIDEGREE_PER_DEGREE`
  - Removed unused include and sorted header includes

---
Yen-Chi Huang (2):
  platform/x86: portwell-ec: Add suspend/resume support for watchdog
  platform/x86: portwell-ec: Add hwmon support for voltage and temperature

 drivers/platform/x86/portwell-ec.c | 193 ++++++++++++++++++++++++++++-
 1 file changed, 191 insertions(+), 2 deletions(-)

-- 
2.34.1

[PATCH v3 1/2] platform/x86: portwell-ec: Add suspend/resume support for watchdog

[Yen-Chi Huang]

Portwell EC does not disable the watchdog during suspend. To avoid unwanted
resets, this patch adds suspend and resume callbacks (pwec_suspend() and
pwec_resume()) to the driver.

The watchdog is stopped in pwec_suspend() and restarted in pwec_resume() if
it was active before suspend.

Signed-off-by: Yen-Chi Huang <jesse.huang@portwell.com.tw>
---
 drivers/platform/x86/portwell-ec.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/platform/x86/portwell-ec.c b/drivers/platform/x86/portwell-ec.c
index 3e019c51913e..7f473e3032e2 100644
--- a/drivers/platform/x86/portwell-ec.c
+++ b/drivers/platform/x86/portwell-ec.c
@@ -246,11 +246,29 @@ static int pwec_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int pwec_suspend(struct platform_device *pdev, pm_message_t message)
+{
+	if (watchdog_active(&ec_wdt_dev))
+		return pwec_wdt_stop(&ec_wdt_dev);
+
+	return 0;
+}
+
+static int pwec_resume(struct platform_device *pdev)
+{
+	if (watchdog_active(&ec_wdt_dev))
+		return pwec_wdt_start(&ec_wdt_dev);
+
+	return 0;
+}
+
 static struct platform_driver pwec_driver = {
 	.driver = {
 		.name = "portwell-ec",
 	},
 	.probe = pwec_probe,
+	.suspend = pm_ptr(pwec_suspend),
+	.resume = pm_ptr(pwec_resume),
 };
 
 static struct platform_device *pwec_dev;
-- 
2.34.1

[PATCH v3 2/2] platform/x86: portwell-ec: Add hwmon support for voltage and temperature

[Yen-Chi Huang]

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@portwell.com.tw>
---
 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

Re: [PATCH v3 0/2] platform/x86: portwell-ec: Add watchdog suspend/resume and hwmon

[Yen-Chi Huang]

Hi Ilpo, Guenter,

Gentle ping on this patch series.

If patch 2/2 (hwmon) still requires further work,
would it be possible to apply patch 1/2 (watchdog suspend/resume support)
independently?

For completeness: I kept the `(void *)` cast in `.driver_data` because
`pwec_board_data_nano` is `const`. As discussed in v2, removing it triggers
a compiler warning about discarding the qualifier.

Thanks again for your time and feedback.

Best regards,
Yen-Chi Huang

On 7/28/2025 7:56 PM, Yen-Chi Huang wrote:
> This patch series adds suspend/resume support for the watchdog (patch 1/2)
> and hwmon monitoring functionality (patch 2/2) to the Portwell EC driver.
> These changes enable better power management and sensor reporting.
> 
> Tested on Portwell NANO-6064.
> ---
> V2->V3:
> 
> Patch 1/2:
>   - Unchanged
> 
> Patch 2/2:
>   - Replace hardcoded `1000` with `MILLIDEGREE_PER_DEGREE` and double check
>   - Fix comma placement and spacing coding style issues
>   - Simplify pwec_hwmon_is_visible() with ternary operator
> 
> V1->V2:
> 
> - Added watchdog mailing list to Cc.
> 
> Patch 1/2:
>   - unchanged
> 
> Patch 2/2:
>   - Removed `msb_reg` from `strucit pwec_hwmon_data`
>   - Updated `pwec_read16_stable()` to assume MSB follows LSB
>   - Moved `hwmon_channel_info` to per-board data and assigned it to `.info` at runtime
>   - Replaced the `pwec_board_data[]` array with a standalone struct
>   - Replaced literal `1000` with `MILLIDEGREE_PER_DEGREE`
>   - Removed unused include and sorted header includes
> 
> ---
> Yen-Chi Huang (2):
>   platform/x86: portwell-ec: Add suspend/resume support for watchdog
>   platform/x86: portwell-ec: Add hwmon support for voltage and temperature
> 
>  drivers/platform/x86/portwell-ec.c | 193 ++++++++++++++++++++++++++++-
>  1 file changed, 191 insertions(+), 2 deletions(-)
> 

Re: [PATCH v3 1/2] platform/x86: portwell-ec: Add suspend/resume support for watchdog

[Ilpo Järvinen]

On Mon, 28 Jul 2025, Yen-Chi Huang wrote:

> Portwell EC does not disable the watchdog during suspend. To avoid unwanted
> resets, this patch adds suspend and resume callbacks (pwec_suspend() and
> pwec_resume()) to the driver.
> 
> The watchdog is stopped in pwec_suspend() and restarted in pwec_resume() if
> it was active before suspend.
> 
> Signed-off-by: Yen-Chi Huang <jesse.huang@portwell.com.tw>
> ---
>  drivers/platform/x86/portwell-ec.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/platform/x86/portwell-ec.c b/drivers/platform/x86/portwell-ec.c
> index 3e019c51913e..7f473e3032e2 100644
> --- a/drivers/platform/x86/portwell-ec.c
> +++ b/drivers/platform/x86/portwell-ec.c
> @@ -246,11 +246,29 @@ static int pwec_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static int pwec_suspend(struct platform_device *pdev, pm_message_t message)
> +{
> +	if (watchdog_active(&ec_wdt_dev))
> +		return pwec_wdt_stop(&ec_wdt_dev);
> +
> +	return 0;
> +}
> +
> +static int pwec_resume(struct platform_device *pdev)
> +{
> +	if (watchdog_active(&ec_wdt_dev))
> +		return pwec_wdt_start(&ec_wdt_dev);
> +
> +	return 0;
> +}
> +
>  static struct platform_driver pwec_driver = {
>  	.driver = {
>  		.name = "portwell-ec",
>  	},
>  	.probe = pwec_probe,
> +	.suspend = pm_ptr(pwec_suspend),
> +	.resume = pm_ptr(pwec_resume),

These are legacy handlers, please use .pm under .driver and the macros to 
create the struct dev_pm_ops.

-- 
 i.

Re: [PATCH v3 1/2] platform/x86: portwell-ec: Add suspend/resume support for watchdog

[Yen-Chi Huang]

On 8/19/2025 5:51 PM, Ilpo Jarvinen wrote:
> On Mon, 28 Jul 2025, Yen-Chi Huang wrote:
>>  static struct platform_driver pwec_driver = {
>>  	.driver = {
>>  		.name = "portwell-ec",
>>  	},
>>  	.probe = pwec_probe,
>> +	.suspend = pm_ptr(pwec_suspend),
>> +	.resume = pm_ptr(pwec_resume),
> 
> These are legacy handlers, please use .pm under .driver and the macros to 
> create the struct dev_pm_ops.
> 

Hi Ilpo,

Thanks for pointing this out. For v4, I have switched to .pm with
DEFINE_SIMPLE_DEV_PM_OPS as suggested.

Best regards,
Yen-Chi

Re: [PATCH v3 0/2] platform/x86: portwell-ec: Add watchdog suspend/resume and hwmon

[Yen-Chi Huang]

Hi all,

Thanks for the review and feedback.

To allow the watchdog suspend/resume handling to be merged sooner,
v4 will drop the hwmon patch and focus only on the watchdog changes. 

The hwmon support will be submitted later as a separate patch series.

Best regards,
Yen-Chi