[PATCH] platform/x86: hp-wmi: add support for thermal policy

[Elia Devito <eliadevito@gmail.com>]

HP Spectre notebooks (and probabily other model as well)
support at least 3 thermal policy:
 - Default
 - Performance
 - Cool

the correct thermal policy configuration make the firmware to correctly
set OEM variables for Intel DPTF and optimize fan management to reach
the best performance.

Signed-off-by: Elia Devito <eliadevito@gmail.com>
---
 drivers/platform/x86/hp-wmi.c | 80 +++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c
index 1762f335bac9..14ee176f5588 100644
--- a/drivers/platform/x86/hp-wmi.c
+++ b/drivers/platform/x86/hp-wmi.c
@@ -81,6 +81,7 @@ enum hp_wmi_commandtype {
 	HPWMI_FEATURE2_QUERY		= 0x0d,
 	HPWMI_WIRELESS2_QUERY		= 0x1b,
 	HPWMI_POSTCODEERROR_QUERY	= 0x2a,
+	HPWMI_THERMAL_POLICY_QUERY	= 0x4c
 };
 
 enum hp_wmi_command {
@@ -114,6 +115,12 @@ enum hp_wireless2_bits {
 	HPWMI_POWER_FW_OR_HW	= HPWMI_POWER_BIOS | HPWMI_POWER_HARD,
 };
 
+enum hp_thermal_policy {
+	HP_THERMAL_POLICY_PERFORMANCE	= 0x00,
+	HP_THERMAL_POLICY_DEFAULT		= 0x01,
+	HP_THERMAL_POLICY_COOL			= 0x02
+};
+
 #define IS_HWBLOCKED(x) ((x & HPWMI_POWER_FW_OR_HW) != HPWMI_POWER_FW_OR_HW)
 #define IS_SWBLOCKED(x) !(x & HPWMI_POWER_SOFT)
 
@@ -458,6 +465,28 @@ static ssize_t postcode_show(struct device *dev, struct device_attribute *attr,
 	return sprintf(buf, "0x%x\n", value);
 }
 
+static ssize_t thermal_policy_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	int value;
+
+	/* Get the current thermal policy */
+	value = hp_wmi_read_int(HPWMI_THERMAL_POLICY_QUERY);
+	if (value < 0)
+		return value;
+
+	switch (value) {
+	case HP_THERMAL_POLICY_PERFORMANCE:
+		return sprintf(buf, "Performance (%x)\n", value);
+	case HP_THERMAL_POLICY_DEFAULT:
+		return sprintf(buf, "Default (%x)\n", value);
+	case HP_THERMAL_POLICY_COOL:
+		return sprintf(buf, "Cool (%x)\n", value);
+	default:
+		return sprintf(buf, "Unknown (%x)\n", value);
+	}
+}
+
 static ssize_t als_store(struct device *dev, struct device_attribute *attr,
 			 const char *buf, size_t count)
 {
@@ -499,12 +528,35 @@ static ssize_t postcode_store(struct device *dev, struct device_attribute *attr,
 	return count;
 }
 
+static ssize_t thermal_policy_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	u32 tmp;
+	int ret;
+
+	ret = kstrtou32(buf, 10, &tmp);
+	if (ret)
+		return ret;
+
+	if (tmp < HP_THERMAL_POLICY_PERFORMANCE || tmp > HP_THERMAL_POLICY_COOL)
+		return -EINVAL;
+
+	/* Set thermal policy */
+	ret = hp_wmi_perform_query(HPWMI_THERMAL_POLICY_QUERY, HPWMI_WRITE, &tmp,
+				       sizeof(tmp), sizeof(tmp));
+	if (ret)
+		return ret < 0 ? ret : -EINVAL;
+
+	return count;
+}
+
 static DEVICE_ATTR_RO(display);
 static DEVICE_ATTR_RO(hddtemp);
 static DEVICE_ATTR_RW(als);
 static DEVICE_ATTR_RO(dock);
 static DEVICE_ATTR_RO(tablet);
 static DEVICE_ATTR_RW(postcode);
+static DEVICE_ATTR_RW(thermal_policy);
 
 static struct attribute *hp_wmi_attrs[] = {
 	&dev_attr_display.attr,
@@ -861,6 +913,30 @@ static int __init hp_wmi_rfkill2_setup(struct platform_device *device)
 	return err;
 }
 
+static int thermal_policy_setup(struct platform_device *device)
+{
+	int err, tp;
+
+	tp = hp_wmi_read_int(HPWMI_THERMAL_POLICY_QUERY);
+	if (tp < 0)
+		return tp;
+
+	/*
+	 * set thermal policy to ensure that the firmware correctly
+	 * sets the OEM variables for the DPTF
+	 */
+	err = hp_wmi_perform_query(HPWMI_THERMAL_POLICY_QUERY, HPWMI_WRITE, &tp,
+							   sizeof(tp), 0);
+	if (err)
+		return err;
+
+	err = device_create_file(&device->dev, &dev_attr_thermal_policy);
+	if (err)
+		return err;
+
+	return 0;
+}
+
 static int __init hp_wmi_bios_setup(struct platform_device *device)
 {
 	/* clear detected rfkill devices */
@@ -872,6 +948,8 @@ static int __init hp_wmi_bios_setup(struct platform_device *device)
 	if (hp_wmi_rfkill_setup(device))
 		hp_wmi_rfkill2_setup(device);
 
+	thermal_policy_setup(device);
+
 	return 0;
 }
 
@@ -879,6 +957,8 @@ static int __exit hp_wmi_bios_remove(struct platform_device *device)
 {
 	int i;
 
+	device_remove_file(&device->dev, &dev_attr_thermal_policy);
+
 	for (i = 0; i < rfkill2_count; i++) {
 		rfkill_unregister(rfkill2[i].rfkill);
 		rfkill_destroy(rfkill2[i].rfkill);
-- 
2.26.2