linux-surface/patches/6.10/0007-surface-sam.patch

From 3e6733db885b3a91339039897cbf0f3e05cda2a5 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 30 Dec 2023 18:07:54 +0100
Subject: [PATCH] hwmon: Add thermal sensor driver for Surface Aggregator
 Module

Some of the newer Microsoft Surface devices (such as the Surface Book
3 and Pro 9) have thermal sensors connected via the Surface Aggregator
Module (the embedded controller on those devices). Add a basic driver
to read out the temperature values of those sensors.

Link: https://github.com/linux-surface/surface-aggregator-module/issues/59
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/hwmon/Kconfig        |  10 +++
 drivers/hwmon/Makefile       |   1 +
 drivers/hwmon/surface_temp.c | 165 +++++++++++++++++++++++++++++++++++
 3 files changed, 176 insertions(+)
 create mode 100644 drivers/hwmon/surface_temp.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e14ae18a973b..76eabe3e4435 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2093,6 +2093,16 @@ config SENSORS_SURFACE_FAN
 
 	  Select M or Y here, if you want to be able to read the fan's speed.
 
+config SENSORS_SURFACE_TEMP
+	tristate "Microsoft Surface Thermal Sensor Driver"
+	depends on SURFACE_AGGREGATOR
+	help
+	  Driver for monitoring thermal sensors connected via the Surface
+	  Aggregator Module (embedded controller) on Microsoft Surface devices.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called surface_temp.
+
 config SENSORS_ADC128D818
 	tristate "Texas Instruments ADC128D818"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e3f25475d1f0..eff74ab7f720 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -209,6 +209,7 @@ obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
 obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
 obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
+obj-$(CONFIG_SENSORS_SURFACE_TEMP)+= surface_temp.o
 obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
 obj-$(CONFIG_SENSORS_AMC6821)	+= amc6821.o
 obj-$(CONFIG_SENSORS_TC74)	+= tc74.o
diff --git a/drivers/hwmon/surface_temp.c b/drivers/hwmon/surface_temp.c
new file mode 100644
index 000000000000..48c3e826713f
--- /dev/null
+++ b/drivers/hwmon/surface_temp.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Thermal sensor subsystem driver for Surface System Aggregator Module (SSAM).
+ *
+ * Copyright (C) 2022-2023 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/device.h>
+
+
+/* -- SAM interface. -------------------------------------------------------- */
+
+SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_tmp_get_available_sensors, __le16, {
+	.target_category = SSAM_SSH_TC_TMP,
+	.command_id      = 0x04,
+});
+
+SSAM_DEFINE_SYNC_REQUEST_MD_R(__ssam_tmp_get_temperature, __le16, {
+	.target_category = SSAM_SSH_TC_TMP,
+	.command_id      = 0x01,
+});
+
+static int ssam_tmp_get_available_sensors(struct ssam_device *sdev, s16 *sensors)
+{
+	__le16 sensors_le;
+	int status;
+
+	status = __ssam_tmp_get_available_sensors(sdev, &sensors_le);
+	if (status)
+		return status;
+
+	*sensors = le16_to_cpu(sensors_le);
+	return 0;
+}
+
+static int ssam_tmp_get_temperature(struct ssam_device *sdev, u8 iid, long *temperature)
+{
+	__le16 temp_le;
+	int status;
+
+	status = __ssam_tmp_get_temperature(sdev->ctrl, sdev->uid.target, iid, &temp_le);
+	if (status)
+		return status;
+
+	/* Convert 1/10 °K to 1/1000 °C */
+	*temperature = (le16_to_cpu(temp_le) - 2731) * 100L;
+	return 0;
+}
+
+
+/* -- Driver.---------------------------------------------------------------- */
+
+struct ssam_temp {
+	struct ssam_device *sdev;
+	s16 sensors;
+};
+
+static umode_t ssam_temp_hwmon_is_visible(const void *data,
+					  enum hwmon_sensor_types type,
+					  u32 attr, int channel)
+{
+	const struct ssam_temp *ssam_temp = data;
+
+	if (!(ssam_temp->sensors & BIT(channel)))
+		return 0;
+
+	return 0444;
+}
+
+static int ssam_temp_hwmon_read(struct device *dev,
+				enum hwmon_sensor_types type,
+				u32 attr, int channel, long *value)
+{
+	const struct ssam_temp *ssam_temp = dev_get_drvdata(dev);
+
+	return ssam_tmp_get_temperature(ssam_temp->sdev, channel + 1, value);
+}
+
+static const struct hwmon_channel_info * const ssam_temp_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_REGISTER_TZ),
+	/* We have at most 16 thermal sensor channels. */
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ssam_temp_hwmon_ops = {
+	.is_visible = ssam_temp_hwmon_is_visible,
+	.read = ssam_temp_hwmon_read,
+};
+
+static const struct hwmon_chip_info ssam_temp_hwmon_chip_info = {
+	.ops = &ssam_temp_hwmon_ops,
+	.info = ssam_temp_hwmon_info,
+};
+
+static int ssam_temp_probe(struct ssam_device *sdev)
+{
+	struct ssam_temp *ssam_temp;
+	struct device *hwmon_dev;
+	s16 sensors;
+	int status;
+
+	status = ssam_tmp_get_available_sensors(sdev, &sensors);
+	if (status)
+		return status;
+
+	ssam_temp = devm_kzalloc(&sdev->dev, sizeof(*ssam_temp), GFP_KERNEL);
+	if (!ssam_temp)
+		return -ENOMEM;
+
+	ssam_temp->sdev = sdev;
+	ssam_temp->sensors = sensors;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&sdev->dev,
+			"surface_thermal", ssam_temp, &ssam_temp_hwmon_chip_info,
+			NULL);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	return 0;
+}
+
+static const struct ssam_device_id ssam_temp_match[] = {
+	{ SSAM_SDEV(TMP, SAM, 0x00, 0x02) },
+	{ },
+};
+MODULE_DEVICE_TABLE(ssam, ssam_temp_match);
+
+static struct ssam_device_driver ssam_temp = {
+	.probe = ssam_temp_probe,
+	.match_table = ssam_temp_match,
+	.driver = {
+		.name = "surface_temp",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+module_ssam_device_driver(ssam_temp);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("Thermal sensor subsystem driver for Surface System Aggregator Module");
+MODULE_LICENSE("GPL");
-- 
2.46.1

From 3e4479ac556ff21b45485822edb0980bbb27fdba Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 30 Dec 2023 18:12:23 +0100
Subject: [PATCH] hwmon: surface_temp: Add support for sensor names

The thermal subsystem of the Surface Aggregator Module allows us to
query the names of the respective thermal sensors. Forward those to
userspace.

Signed-off-by: Ivor Wanders <ivor@iwanders.net>
Co-Developed-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/hwmon/surface_temp.c | 113 +++++++++++++++++++++++++++++------
 1 file changed, 96 insertions(+), 17 deletions(-)

diff --git a/drivers/hwmon/surface_temp.c b/drivers/hwmon/surface_temp.c
index 48c3e826713f..4c08926139db 100644
--- a/drivers/hwmon/surface_temp.c
+++ b/drivers/hwmon/surface_temp.c
@@ -17,6 +17,27 @@
 
 /* -- SAM interface. -------------------------------------------------------- */
 
+/*
+ * Available sensors are indicated by a 16-bit bitfield, where a 1 marks the
+ * presence of a sensor. So we have at most 16 possible sensors/channels.
+ */
+#define SSAM_TMP_SENSOR_MAX_COUNT 16
+
+/*
+ * All names observed so far are 6 characters long, but there's only
+ * zeros after the name, so perhaps they can be longer. This number reflects
+ * the maximum zero-padded space observed in the returned buffer.
+ */
+#define SSAM_TMP_SENSOR_NAME_LENGTH 18
+
+struct ssam_tmp_get_name_rsp {
+	__le16 unknown1;
+	char unknown2;
+	char name[SSAM_TMP_SENSOR_NAME_LENGTH];
+} __packed;
+
+static_assert(sizeof(struct ssam_tmp_get_name_rsp) == 21);
+
 SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_tmp_get_available_sensors, __le16, {
 	.target_category = SSAM_SSH_TC_TMP,
 	.command_id      = 0x04,
@@ -27,6 +48,11 @@ SSAM_DEFINE_SYNC_REQUEST_MD_R(__ssam_tmp_get_temperature, __le16, {
 	.command_id      = 0x01,
 });
 
+SSAM_DEFINE_SYNC_REQUEST_MD_R(__ssam_tmp_get_name, struct ssam_tmp_get_name_rsp, {
+	.target_category = SSAM_SSH_TC_TMP,
+	.command_id      = 0x0e,
+});
+
 static int ssam_tmp_get_available_sensors(struct ssam_device *sdev, s16 *sensors)
 {
 	__le16 sensors_le;
@@ -54,12 +80,37 @@ static int ssam_tmp_get_temperature(struct ssam_device *sdev, u8 iid, long *temp
 	return 0;
 }
 
+static int ssam_tmp_get_name(struct ssam_device *sdev, u8 iid, char *buf, size_t buf_len)
+{
+	struct ssam_tmp_get_name_rsp name_rsp;
+	int status;
+
+	status =  __ssam_tmp_get_name(sdev->ctrl, sdev->uid.target, iid, &name_rsp);
+	if (status)
+		return status;
+
+	/*
+	 * This should not fail unless the name in the returned struct is not
+	 * null-terminated or someone changed something in the struct
+	 * definitions above, since our buffer and struct have the same
+	 * capacity by design. So if this fails blow this up with a warning.
+	 * Since the more likely cause is that the returned string isn't
+	 * null-terminated, we might have received garbage (as opposed to just
+	 * an incomplete string), so also fail the function.
+	 */
+	status = strscpy(buf, name_rsp.name, buf_len);
+	WARN_ON(status < 0);
+
+	return status < 0 ? status : 0;
+}
+
 
 /* -- Driver.---------------------------------------------------------------- */
 
 struct ssam_temp {
 	struct ssam_device *sdev;
 	s16 sensors;
+	char names[SSAM_TMP_SENSOR_MAX_COUNT][SSAM_TMP_SENSOR_NAME_LENGTH];
 };
 
 static umode_t ssam_temp_hwmon_is_visible(const void *data,
@@ -83,33 +134,47 @@ static int ssam_temp_hwmon_read(struct device *dev,
 	return ssam_tmp_get_temperature(ssam_temp->sdev, channel + 1, value);
 }
 
+static int ssam_temp_hwmon_read_string(struct device *dev,
+				       enum hwmon_sensor_types type,
+				       u32 attr, int channel, const char **str)
+{
+	const struct ssam_temp *ssam_temp = dev_get_drvdata(dev);
+
+	*str = ssam_temp->names[channel];
+	return 0;
+}
+
 static const struct hwmon_channel_info * const ssam_temp_hwmon_info[] = {
 	HWMON_CHANNEL_INFO(chip,
 			   HWMON_C_REGISTER_TZ),
-	/* We have at most 16 thermal sensor channels. */
+	/*
+	 * We have at most SSAM_TMP_SENSOR_MAX_COUNT = 16 thermal sensor
+	 * channels.
+	 */
 	HWMON_CHANNEL_INFO(temp,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT,
-			   HWMON_T_INPUT),
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
 	NULL
 };
 
 static const struct hwmon_ops ssam_temp_hwmon_ops = {
 	.is_visible = ssam_temp_hwmon_is_visible,
 	.read = ssam_temp_hwmon_read,
+	.read_string = ssam_temp_hwmon_read_string,
 };
 
 static const struct hwmon_chip_info ssam_temp_hwmon_chip_info = {
@@ -122,6 +187,7 @@ static int ssam_temp_probe(struct ssam_device *sdev)
 	struct ssam_temp *ssam_temp;
 	struct device *hwmon_dev;
 	s16 sensors;
+	int channel;
 	int status;
 
 	status = ssam_tmp_get_available_sensors(sdev, &sensors);
@@ -135,6 +201,19 @@ static int ssam_temp_probe(struct ssam_device *sdev)
 	ssam_temp->sdev = sdev;
 	ssam_temp->sensors = sensors;
 
+	/* Retrieve the name for each available sensor. */
+	for (channel = 0; channel < SSAM_TMP_SENSOR_MAX_COUNT; channel++)
+	{
+		if (!(sensors & BIT(channel)))
+			continue;
+
+		status = ssam_tmp_get_name(sdev, channel + 1,
+					   ssam_temp->names[channel],
+					   SSAM_TMP_SENSOR_NAME_LENGTH);
+		if (status)
+			return status;
+	}
+
 	hwmon_dev = devm_hwmon_device_register_with_info(&sdev->dev,
 			"surface_thermal", ssam_temp, &ssam_temp_hwmon_chip_info,
 			NULL);
-- 
2.46.1