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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans de Goede <hdegoede@redhat.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 301/846] ACPI: scan: Create platform device for BCM4752 and LNV4752 ACPI nodes
Date:   Mon, 24 Jan 2022 19:36:58 +0100
Message-Id: <20220124184111.291619529@linuxfoundation.org>
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From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit f85196bdd5a50da74670250564740fc852b3c239 ]

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")
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/scan.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 5b54c80b9d32a..6e9cd41c5f9b1 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1690,6 +1690,7 @@ 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.
@@ -1698,11 +1699,18 @@ 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", },
 		{}
 	};
 
@@ -1716,8 +1724,7 @@ 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);
-- 
2.34.1