linux-kernel - [PATCH] Thinkpad_acpi: Fix for ThinkPad's with ECFW showing incorrect fan speed

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Message-ID: <20241105235505.8493-1-vishnuocv@gmail.com>
Date: Wed,  6 Nov 2024 08:55:05 +0900
From: Vishnu Sankar <vishnuocv@...il.com>
To: hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com,
	ibm-acpi-devel@...ts.sourceforge.net,
	platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Vishnu Sankar <vishnuocv@...il.com>,
	Vishnu Sankar <vsankar@...ovo.com>,
	Mark Pearson <mpearson-lenovo@...ebb.ca>
Subject: [PATCH] Thinkpad_acpi: Fix for ThinkPad's with ECFW showing incorrect fan speed

Fix for Thinkpad's with ECFW showing incorrect fan speed.
Some models use decimal instead of hexadecimal for the fan speed stored
in the EC registers.
for eg: the rpm register will have 0x4200 instead of 0x1068.
Here the actual RPM is "4200" in decimal.

A quirk added to handle this.

Signed-off-by: Vishnu Sankar <vishnuocv@...il.com>
Signed-off-by: Vishnu Sankar <vsankar@...ovo.com>
Suggested-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
---
 drivers/platform/x86/thinkpad_acpi.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 4c1b0553f872..6371a9f765c1 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -7936,6 +7936,7 @@ static u8 fan_control_resume_level;
 static int fan_watchdog_maxinterval;
 
 static bool fan_with_ns_addr;
+static bool ecfw_with_fan_dec_rpm;
 
 static struct mutex fan_mutex;
 
@@ -8682,7 +8683,11 @@ static ssize_t fan_fan1_input_show(struct device *dev,
 	if (res < 0)
 		return res;
 
-	return sysfs_emit(buf, "%u\n", speed);
+	/* Check for fan speeds displayed in hexadecimal */
+	if (!ecfw_with_fan_dec_rpm)
+		return sysfs_emit(buf, "%u\n", speed);
+	else
+		return sysfs_emit(buf, "%x\n", speed);
 }
 
 static DEVICE_ATTR(fan1_input, S_IRUGO, fan_fan1_input_show, NULL);
@@ -8699,7 +8704,11 @@ static ssize_t fan_fan2_input_show(struct device *dev,
 	if (res < 0)
 		return res;
 
-	return sysfs_emit(buf, "%u\n", speed);
+	/* Check for fan speeds displayed in hexadecimal */
+	if (!ecfw_with_fan_dec_rpm)
+		return sysfs_emit(buf, "%u\n", speed);
+	else
+		return sysfs_emit(buf, "%x\n", speed);
 }
 
 static DEVICE_ATTR(fan2_input, S_IRUGO, fan_fan2_input_show, NULL);
@@ -8775,6 +8784,7 @@ static const struct attribute_group fan_driver_attr_group = {
 #define TPACPI_FAN_2CTL		0x0004		/* selects fan2 control */
 #define TPACPI_FAN_NOFAN	0x0008		/* no fan available */
 #define TPACPI_FAN_NS		0x0010		/* For EC with non-Standard register addresses */
+#define TPACPI_FAN_DECRPM	0x0020		/* For ECFW's with RPM in register as decimal */
 
 static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
 	TPACPI_QEC_IBM('1', 'Y', TPACPI_FAN_Q1),
@@ -8803,6 +8813,7 @@ static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
 	TPACPI_Q_LNV3('R', '1', 'D', TPACPI_FAN_NS),	/* 11e Gen5 GL-R */
 	TPACPI_Q_LNV3('R', '0', 'V', TPACPI_FAN_NS),	/* 11e Gen5 KL-Y */
 	TPACPI_Q_LNV3('N', '1', 'O', TPACPI_FAN_NOFAN),	/* X1 Tablet (2nd gen) */
+	TPACPI_Q_LNV3('R', '0', 'Q', TPACPI_FAN_DECRPM),/* L480 */
 };
 
 static int __init fan_init(struct ibm_init_struct *iibm)
@@ -8847,6 +8858,13 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 		tp_features.fan_ctrl_status_undef = 1;
 	}
 
+	/* Check for the EC/BIOS with RPM reported in decimal*/
+	if (quirks & TPACPI_FAN_DECRPM) {
+		pr_info("ECFW with fan RPM as decimal in EC register\n");
+		ecfw_with_fan_dec_rpm = 1;
+		tp_features.fan_ctrl_status_undef = 1;
+	}
+
 	if (gfan_handle) {
 		/* 570, 600e/x, 770e, 770x */
 		fan_status_access_mode = TPACPI_FAN_RD_ACPI_GFAN;
@@ -9067,7 +9085,11 @@ static int fan_read(struct seq_file *m)
 		if (rc < 0)
 			return rc;
 
-		seq_printf(m, "speed:\t\t%d\n", speed);
+		/* Check for fan speeds displayed in hexadecimal */
+		if (!ecfw_with_fan_dec_rpm)
+			seq_printf(m, "speed:\t\t%d\n", speed);
+		else
+			seq_printf(m, "speed:\t\t%x\n", speed);
 
 		if (fan_status_access_mode == TPACPI_FAN_RD_TPEC_NS) {
 			/*
-- 
2.43.0