BCM4752 and LNV4752 ACPI nodes describe a Broadcom 4752 GPS module
attached to an UART of the system.
The GPS modules talk a custom protocol which only works with a closed-
source Android gpsd daemon which knows this protocol.
The ACPI nodes also describe GPIOs to turn the GPS on/off these are
handled by the net/rfkill/rfkill-gpio.c code. This handling predates the
addition of enumeration of ACPI instantiated serdevs to the kernel and
was broken by that addition, because the ACPI scan code now no longer
instantiates platform_device-s for these nodes.
Rename the i2c_multi_instantiate_ids HID list to ignore_serial_bus_ids
and add the BCM4752 and LNV4752 HIDs, so that rfkill-gpio gets
a platform_device to bind to again; and so that a tty cdev for gpsd
gets created for these.
Fixes: e361d1f85855 ("ACPI / scan: Fix enumeration for special UART devices")
Cc: Frédéric Danis <frederic.danis.oss@xxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Note there is some work on reverse-engineering the protocol for these
GPS modules here, but this is not complete:
https://redmine.replicant.us/projects/replicant/wiki/BCM4751
https://git.replicant.us/contrib/PaulK/bcm4751/
---
drivers/acpi/scan.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 526e823a33fb..c5dfbe26a0cb 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1701,6 +1701,7 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
{
struct list_head resource_list;
bool is_serial_bus_slave = false;
+ static const struct acpi_device_id ignore_serial_bus_ids[] = {
/*
* These devices have multiple I2cSerialBus resources and an i2c-client
* must be instantiated for each, each with its own i2c_device_id.
@@ -1709,11 +1710,18 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
* drivers/platform/x86/i2c-multi-instantiate.c driver, which knows
* which i2c_device_id to use for each resource.
*/
- static const struct acpi_device_id i2c_multi_instantiate_ids[] = {
{"BSG1160", },
{"BSG2150", },
{"INT33FE", },
{"INT3515", },
+ /*
+ * HIDs of device with an UartSerialBusV2 resource for which userspace
+ * expects a regular tty cdev to be created (instead of the in kernel
+ * serdev) and which have a kernel driver which expects a platform_dev
+ * such as the rfkill-gpio driver.
+ */
+ {"BCM4752", },
+ {"LNV4752", },
{}
};
@@ -1727,8 +1735,7 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
fwnode_property_present(&device->fwnode, "baud")))
return true;
- /* Instantiate a pdev for the i2c-multi-instantiate drv to bind to */
- if (!acpi_match_device_ids(device, i2c_multi_instantiate_ids))
+ if (!acpi_match_device_ids(device, ignore_serial_bus_ids))
return false;
INIT_LIST_HEAD(&resource_list);
--
2.33.1
