platform/x86: thinkpad_acpi: Fix errors reading battery thresholds

Check whether the battery supports the relevant charge threshold before
reading the value to silence these errors:

thinkpad_acpi: acpi_evalf(BCTG, dd, ...) failed: AE_NOT_FOUND
ACPI: \_SB_.PCI0.LPC_.EC__.HKEY: BCTG: evaluate failed
thinkpad_acpi: acpi_evalf(BCSG, dd, ...) failed: AE_NOT_FOUND
ACPI: \_SB_.PCI0.LPC_.EC__.HKEY: BCSG: evaluate failed

when reading the charge thresholds via sysfs on platforms that do not
support them such as the ThinkPad T400.

Fixes: 2801b96 ("thinkpad_acpi: Add support for battery thresholds")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=202619
Signed-off-by: Jonathan Teh <jonathan.teh@outlook.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/MI0P293MB01967B206E1CA6F337EBFB12926CA@MI0P293MB0196.ITAP293.PROD.OUTLOOK.COM
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: jonathan-teh

drivers/platform/x86/lenovo/thinkpad_acpi.c

@@ -9525,14 +9525,16 @@ static int tpacpi_battery_get(int what, int battery, int *ret)
 {
 	switch (what) {
 	case THRESHOLD_START:
-		if ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_START, ret, battery))
+		if (!battery_info.batteries[battery].start_support ||
+		    ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_START, ret, battery)))
 			return -ENODEV;
 
 		/* The value is in the low 8 bits of the response */
 		*ret = *ret & 0xFF;
 		return 0;
 	case THRESHOLD_STOP:
-		if ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_STOP, ret, battery))
+		if (!battery_info.batteries[battery].stop_support ||
+		    ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_STOP, ret, battery)))
 			return -ENODEV;
 		/* Value is in lower 8 bits */
 		*ret = *ret & 0xFF;