platform/x86: 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 speed stored in the EC registers.
For example the rpm register will have 0x4200 instead of 0x1068, here
the actual RPM is "4200" in decimal.

Add a quirk to handle this.

Signed-off-by: Vishnu Sankar <[e-mail]>
Suggested-by: Mark Pearson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Hans de Goede <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>

drivers/platform/x86/thinkpad_acpi.c

···
 static int fan_watchdog_maxinterval;
 
 static bool fan_with_ns_addr;
+static bool ecfw_with_fan_dec_rpm;
 
 static struct mutex fan_mutex;
 
···
 	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);
···
 	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);
···
 #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),
···
 	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)
···
 		pr_info("ECFW with non-standard fan reg control found\n");
 		fan_with_ns_addr = 1;
 		/* Fan ctrl support from host is undefined for now */
+		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 (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) {
 			/*