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

[Vishnu Sankar <vishnuocv@gmail.com>]

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@gmail.com>
Signed-off-by: Vishnu Sankar <vsankar@lenovo.com>
Suggested-by: Mark Pearson <mpearson-lenovo@squebb.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