[PATCH AUTOSEL 6.8 09/30] ACPI: x86: Add PNP_UART1_SKIP quirk for Lenovo Blade2 tablets

Sasha Levin
2024-05-27T14:14:36Z

From: Hans de Goede <hdegoede@redhat.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@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.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