From 8a02361d90820e1dcbf26e48fa69e6155feaa61d Mon Sep 17 00:00:00 2001
From: Andrey Smirnov <andrew.smirnov@gmail.com>
Date: Sat, 19 Feb 2022 16:09:45 -0800
Subject: [PATCH 05/21] hwmon: Add driver for Steam Deck's EC sensors

Add driver for sensors exposed by EC firmware on Steam Deck hardware.

(cherry picked from commit 6917aac77bee6185ae3920b936cdbe7876118c0b)
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/hwmon/Kconfig           |  11 ++
 drivers/hwmon/Makefile          |   1 +
 drivers/hwmon/steamdeck-hwmon.c | 224 ++++++++++++++++++++++++++++++++
 3 files changed, 236 insertions(+)
 create mode 100644 drivers/hwmon/steamdeck-hwmon.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e14ae18a973b..595708f955b6 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2059,6 +2059,17 @@ config SENSORS_SCH5636
 	  This driver can also be built as a module. If so, the module
 	  will be called sch5636.
 
+config SENSORS_STEAMDECK
+	tristate "Steam Deck EC sensors"
+	depends on MFD_STEAMDECK
+	help
+	  If you say yes here you get support for the hardware
+	  monitoring features exposed by EC firmware on Steam Deck
+	  devices
+
+	  This driver can also be built as a module. If so, the module
+	  will be called steamdeck-hwmon.
+
 config SENSORS_STTS751
 	tristate "ST Microelectronics STTS751"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e3f25475d1f0..c6eaee13917d 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -207,6 +207,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
 obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
+obj-$(CONFIG_SENSORS_STEAMDECK) += steamdeck-hwmon.o
 obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
 obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
 obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
diff --git a/drivers/hwmon/steamdeck-hwmon.c b/drivers/hwmon/steamdeck-hwmon.c
new file mode 100644
index 000000000000..fab9e9460bd4
--- /dev/null
+++ b/drivers/hwmon/steamdeck-hwmon.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Steam Deck EC sensors driver
+ *
+ * Copyright (C) 2021-2022 Valve Corporation
+ */
+
+#include <linux/acpi.h>
+#include <linux/hwmon.h>
+#include <linux/platform_device.h>
+
+#define STEAMDECK_HWMON_NAME	"steamdeck-hwmon"
+
+struct steamdeck_hwmon {
+	struct acpi_device *adev;
+};
+
+static long
+steamdeck_hwmon_get(struct steamdeck_hwmon *sd, const char *method)
+{
+	unsigned long long val;
+	if (ACPI_FAILURE(acpi_evaluate_integer(sd->adev->handle,
+					       (char *)method, NULL, &val)))
+		return -EIO;
+
+	return val;
+}
+
+static int
+steamdeck_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+		     u32 attr, int channel, long *out)
+{
+	struct steamdeck_hwmon *sd = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_curr:
+		if (attr != hwmon_curr_input)
+			return -EOPNOTSUPP;
+
+		*out = steamdeck_hwmon_get(sd, "PDAM");
+		if (*out < 0)
+			return *out;
+		break;
+	case hwmon_in:
+		if (attr != hwmon_in_input)
+			return -EOPNOTSUPP;
+
+		*out = steamdeck_hwmon_get(sd, "PDVL");
+		if (*out < 0)
+			return *out;
+		break;
+	case hwmon_temp:
+		if (attr != hwmon_temp_input)
+			return -EOPNOTSUPP;
+
+		*out = steamdeck_hwmon_get(sd, "BATT");
+		if (*out < 0)
+			return *out;
+		/*
+		 * Assuming BATT returns deg C we need to mutiply it
+		 * by 1000 to convert to mC
+		 */
+		*out *= 1000;
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			*out = steamdeck_hwmon_get(sd, "FANR");
+			if (*out < 0)
+				return *out;
+			break;
+		case hwmon_fan_target:
+			*out = steamdeck_hwmon_get(sd, "FSSR");
+			if (*out < 0)
+				return *out;
+			break;
+		case hwmon_fan_fault:
+			*out = steamdeck_hwmon_get(sd, "FANC");
+			if (*out < 0)
+				return *out;
+			/*
+			 * FANC (Fan check):
+			 * 0: Abnormal
+			 * 1: Normal
+			 */
+			*out = !*out;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int
+steamdeck_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+			    u32 attr, int channel, const char **str)
+{
+	switch (type) {
+		/*
+		 * These two aren't, strictly speaking, measured. EC
+		 * firmware just reports what PD negotiation resulted
+		 * in.
+		 */
+	case hwmon_curr:
+		*str = "PD Contract Current";
+		break;
+	case hwmon_in:
+		*str = "PD Contract Voltage";
+		break;
+	case hwmon_temp:
+		*str = "Battery Temp";
+		break;
+	case hwmon_fan:
+		*str = "System Fan";
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int
+steamdeck_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+		      u32 attr, int channel, long val)
+{
+	struct steamdeck_hwmon *sd = dev_get_drvdata(dev);
+
+	if (type != hwmon_fan ||
+	    attr != hwmon_fan_target)
+		return -EOPNOTSUPP;
+
+	val = clamp_val(val, 0, 7300);
+
+	if (ACPI_FAILURE(acpi_execute_simple_method(sd->adev->handle,
+						    "FANS", val)))
+		return -EIO;
+
+	return 0;
+}
+
+static umode_t
+steamdeck_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+			   u32 attr, int channel)
+{
+	if (type == hwmon_fan &&
+	    attr == hwmon_fan_target)
+		return 0644;
+
+	return 0444;
+}
+
+static const struct hwmon_channel_info *steamdeck_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL),
+	HWMON_CHANNEL_INFO(curr,
+			   HWMON_C_INPUT | HWMON_C_LABEL),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL |
+			   HWMON_F_TARGET | HWMON_F_FAULT),
+	NULL
+};
+
+static const struct hwmon_ops steamdeck_hwmon_ops = {
+	.is_visible = steamdeck_hwmon_is_visible,
+	.read = steamdeck_hwmon_read,
+	.read_string = steamdeck_hwmon_read_string,
+	.write = steamdeck_hwmon_write,
+};
+
+static const struct hwmon_chip_info steamdeck_hwmon_chip_info = {
+	.ops = &steamdeck_hwmon_ops,
+	.info = steamdeck_hwmon_info,
+};
+
+static int steamdeck_hwmon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct steamdeck_hwmon *sd;
+	struct device *hwmon;
+
+	sd = devm_kzalloc(dev, sizeof(*sd), GFP_KERNEL);
+	if (!sd)
+		return -ENOMEM;
+
+	sd->adev = ACPI_COMPANION(dev->parent);
+	hwmon = devm_hwmon_device_register_with_info(dev,
+						     "steamdeck_hwmon",
+						     sd,
+						     &steamdeck_hwmon_chip_info,
+						     NULL);
+	if (IS_ERR(hwmon)) {
+		dev_err(dev, "Failed to register HWMON device");
+		return PTR_ERR(hwmon);
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id steamdeck_hwmon_id_table[] = {
+	{ .name = STEAMDECK_HWMON_NAME },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, steamdeck_hwmon_id_table);
+
+static struct platform_driver steamdeck_hwmon_driver = {
+	.probe = steamdeck_hwmon_probe,
+	.driver = {
+		.name = STEAMDECK_HWMON_NAME,
+	},
+	.id_table = steamdeck_hwmon_id_table,
+};
+module_platform_driver(steamdeck_hwmon_driver);
+
+MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
+MODULE_DESCRIPTION("Steam Deck EC sensors driver");
+MODULE_LICENSE("GPL");
-- 
2.45.2

