power: supply: axp288_fuel_gauge: Do not register our psy on (some) H…

…DMI sticks

The Intel Compute Stick (Cherry Trail version) and the Meegopad T08 HDMI
stick, both use an axp288 PMIC.  They also both have this wired up in such
a way that the detection logic in the PMIC claims that a valid battery is
present, resuling in GNOME and KDE showing a full-battery in their status
bar and power-settings, while these devices do not have a battery.

For lack of a better fix add a DMI blacklist and do not register the
axp288_fuel_gauge psy on devices on the blacklist.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

drivers/power/supply/axp288_fuel_gauge.c

@@ -17,6 +17,7 @@
  *
  */
 
+#include <linux/dmi.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
@@ -679,6 +680,37 @@ static void fuel_gauge_init_irq(struct axp288_fg_info *info)
 	}
 }
 
+/*
+ * Some devices have no battery (HDMI sticks) and the axp288 battery's
+ * detection reports one despite it not being there.
+ */
+static const struct dmi_system_id axp288_fuel_gauge_blacklist[] = {
+	{
+		/* Intel Cherry Trail Compute Stick, Windows version */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "STK1AW32SC"),
+		},
+	},
+	{
+		/* Intel Cherry Trail Compute Stick, version without an OS */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "STK1A32SC"),
+		},
+	},
+	{
+		/* Meegopad T08 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Default string"),
+			DMI_MATCH(DMI_BOARD_VENDOR, "To be filled by OEM."),
+			DMI_MATCH(DMI_BOARD_NAME, "T3 MRD"),
+			DMI_MATCH(DMI_BOARD_VERSION, "V1.1"),
+		},
+	},
+	{}
+};
+
 static int axp288_fuel_gauge_probe(struct platform_device *pdev)
 {
 	int i, ret = 0;
@@ -694,6 +726,9 @@ static int axp288_fuel_gauge_probe(struct platform_device *pdev)
 		[BAT_VOLT] = "axp288-batt-volt",
 	};
 
+	if (dmi_check_system(axp288_fuel_gauge_blacklist))
+		return -ENODEV;
+
 	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;