linux-kernel - [PATCH AUTOSEL 6.8 09/30] ACPI: x86: Add PNP_UART1

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Date: Mon, 27 May 2024 10:13:18 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Hans de Goede <hdegoede@...hat.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Sasha Levin <sashal@...nel.org>,
	rafael@...nel.org,
	mika.westerberg@...ux.intel.com,
	raag.jadav@...el.com,
	michal.wilczynski@...el.com,
	linux-acpi@...r.kernel.org
Subject: [PATCH AUTOSEL 6.8 09/30] ACPI: x86: Add PNP_UART1_SKIP quirk for Lenovo Blade2 tablets

From: Hans de Goede <hdegoede@...hat.com>

[ Upstream commit d8f20383a2fc3a3844b08a4999cf0e81164a0e56 ]

The x86 Android tablets on which quirks to skip looking for a matching
UartSerialBus resource and instead unconditionally create a serial bus
device (serdev) are necessary there are 2 sorts of serialports:

ACPI enumerated highspeed designware UARTs, these are the ones which
typcially need to be skipped since they need a serdev for the attached
BT HCI.

A PNP enumerated UART which is part of the PCU. So far the existing
quirks have ignored this. But on the Lenovo Yoga Tablet 2 Pro 1380
models this is used for a custom fastcharging protocol. There is
a Micro USB switch which can switch the USB data lines to this uart
and then a 600 baud protocol is used to configure the charger for
a voltage higher then 5V.

Add a new ACPI_QUIRK_PNP_UART1_SKIP quirk type and set this for
the existing entry for the Lenovo Yoga Tablet 2 830 / 1050 models.
Note this will lead to unnecessarily also creating a serdev for
the PCU UART on the 830 / 1050 which don't need this, but the UART
is not used otherwise there so that is not a problem.

Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/acpi/x86/utils.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/x86/utils.c b/drivers/acpi/x86/utils.c
index 90c3d2eab9e99..e5612067ccac8 100644
--- a/drivers/acpi/x86/utils.c
+++ b/drivers/acpi/x86/utils.c
@@ -260,9 +260,10 @@ bool force_storage_d3(void)
 #define ACPI_QUIRK_SKIP_I2C_CLIENTS				BIT(0)
 #define ACPI_QUIRK_UART1_SKIP					BIT(1)
 #define ACPI_QUIRK_UART1_TTY_UART2_SKIP				BIT(2)
-#define ACPI_QUIRK_SKIP_ACPI_AC_AND_BATTERY			BIT(3)
-#define ACPI_QUIRK_USE_ACPI_AC_AND_BATTERY			BIT(4)
-#define ACPI_QUIRK_SKIP_GPIO_EVENT_HANDLERS			BIT(5)
+#define ACPI_QUIRK_PNP_UART1_SKIP				BIT(3)
+#define ACPI_QUIRK_SKIP_ACPI_AC_AND_BATTERY			BIT(4)
+#define ACPI_QUIRK_USE_ACPI_AC_AND_BATTERY			BIT(5)
+#define ACPI_QUIRK_SKIP_GPIO_EVENT_HANDLERS			BIT(6)
 
 static const struct dmi_system_id acpi_quirk_skip_dmi_ids[] = {
 	/*
@@ -342,6 +343,7 @@ static const struct dmi_system_id acpi_quirk_skip_dmi_ids[] = {
 			DMI_MATCH(DMI_BIOS_VERSION, "BLADE_21"),
 		},
 		.driver_data = (void *)(ACPI_QUIRK_SKIP_I2C_CLIENTS |
+					ACPI_QUIRK_PNP_UART1_SKIP |
 					ACPI_QUIRK_SKIP_ACPI_AC_AND_BATTERY),
 	},
 	{
@@ -440,14 +442,18 @@ static int acpi_dmi_skip_serdev_enumeration(struct device *controller_parent, bo
 	if (ret)
 		return 0;
 
-	/* to not match on PNP enumerated debug UARTs */
-	if (!dev_is_platform(controller_parent))
-		return 0;
-
 	dmi_id = dmi_first_match(acpi_quirk_skip_dmi_ids);
 	if (dmi_id)
 		quirks = (unsigned long)dmi_id->driver_data;
 
+	if (!dev_is_platform(controller_parent)) {
+		/* PNP enumerated UARTs */
+		if ((quirks & ACPI_QUIRK_PNP_UART1_SKIP) && uid == 1)
+			*skip = true;
+
+		return 0;
+	}
+
 	if ((quirks & ACPI_QUIRK_UART1_SKIP) && uid == 1)
 		*skip = true;
 
-- 
2.43.0