ec/lenovo/h8: Implement ACPI methods to set battery thresholds

There are two known reverse-engineered ways to manage battery
thresholds.
This patch implements them and adds a way to enable them for
different mainboards.

Tested on W530 with 4.18.3-gentoo kernel and X220 with 4.20.11.
Works fine with new Linux userspace API for controlling battery
thresholds, available since 4.17.
(/sys/class/power_supply/BAT0/charge_(start|stop)_threshold).

The new API is supported by TLP (you might need to set NATACPI_ENABLE=1
in /etc/tlp.conf).

tpacpi-bat works fine too.

Signed-off-by: Alexey Kharlamov <der@2-47.ru>
Signed-off-by: Evgeny Zinoviev <me@ch1p.com>

Change-Id: I2a90f9e9b32462b8a5e9bc8d3087ae0fea563ea5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/23178
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/src/ec/lenovo/h8/acpi/thinkpad_bat_thresholds_24.asl b/src/ec/lenovo/h8/acpi/thinkpad_bat_thresholds_24.asl
new file mode 100644
index 0000000000..52176490f4
--- /dev/null
+++ b/src/ec/lenovo/h8/acpi/thinkpad_bat_thresholds_24.asl
@@ -0,0 +1,117 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (c) 2017 Arthur Heymans <arthur@aheymans.xyz>
+ * Copyright (c) 2018 Evgeny Zinoviev <me@ch1p.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of
+ * the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+
+Scope(\_SB.PCI0.LPCB.EC)
+{
+	Field (ERAM, ByteAcc, NoLock, Preserve)
+	{
+		Offset (0x03),
+				, 2,
+				BSTP, 1, /* Battery start/stop threshold */
+		Offset (0x24),
+				TSH0, 8, /* Battery0 threshold */
+		Offset (0x25),
+				TSH1, 8, /* Battery1 threshold */
+	}
+}
+
+Scope(\_SB.PCI0.LPCB.EC.BAT0)
+{
+	/*
+	 * Set threshold on battery0,
+	 *
+	 * Arg0: 0: Start threshold
+	 *       1: Stop threshold
+	 * Arg1: Percentage
+	 */
+	Method (SETT, 2, NotSerialized)
+	{
+		if (Arg0 <= 1 && Arg1 <= 100)
+		{
+			BSTP = Arg0
+#if defined(H8_BAT_THRESHOLDS_BIT7)
+			TSH0 = Arg1
+#else
+			TSH0 = Arg1 | 0x80
+#endif
+		}
+	}
+
+	/**
+	 * Get threshold on battery0
+	 *
+	 * Arg0: 0: Start threshold
+	 *       1: Stop threshold
+	 */
+	Method (GETT, 1, NotSerialized)
+	{
+		if (Arg0 <= 1)
+		{
+			BSTP = Arg0
+#if defined(H8_BAT_THRESHOLDS_BIT7)
+			Return (TSH0)
+#else
+			Return (TSH0 & ~0x80)
+#endif
+		}
+		Return (0)
+	}
+}
+
+Scope(\_SB.PCI0.LPCB.EC.BAT1)
+{
+	/*
+	 * Set threshold on battery1
+	 *
+	 * Arg0: 0: Start threshold
+	 *       1: Stop threshold
+	 * Arg1: Percentage
+	 */
+	Method (SETT, 2, NotSerialized)
+	{
+		if (Arg0 <= 1 && Arg1 <= 100)
+		{
+			BSTP = Arg0
+#if defined(H8_BAT_THRESHOLDS_BIT7)
+			TSH1 = Arg1
+#else
+			TSH1 = Arg1 | 0x80
+#endif
+		}
+	}
+
+	/**
+	 * Get threshold on battery1
+	 *
+	 * Arg0: 0: Start threshold
+	 *       1: Stop threshold
+	 */
+	Method (GETT, 1, NotSerialized)
+	{
+		if (Arg0 <= 1)
+		{
+			BSTP = Arg0
+#if defined(H8_BAT_THRESHOLDS_BIT7)
+			Return (TSH1)
+#else
+			Return (TSH1 & ~0x80)
+#endif
+		}
+		Return (0)
+	}
+}