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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
commit | 50ba0232fd5312410f1b65247e774244f89a628e (patch) | |
tree | fd8f2fc78e9e548af0ff9590276602ee6125be00 /drivers/platform/x86/serdev_helpers.h | |
parent | Releasing progress-linux version 6.7.12-1~progress7.99u1. (diff) | |
download | linux-50ba0232fd5312410f1b65247e774244f89a628e.tar.xz linux-50ba0232fd5312410f1b65247e774244f89a628e.zip |
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/platform/x86/serdev_helpers.h')
-rw-r--r-- | drivers/platform/x86/serdev_helpers.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/drivers/platform/x86/serdev_helpers.h b/drivers/platform/x86/serdev_helpers.h new file mode 100644 index 0000000000..bcf3a0c356 --- /dev/null +++ b/drivers/platform/x86/serdev_helpers.h @@ -0,0 +1,80 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * In some cases UART attached devices which require an in kernel driver, + * e.g. UART attached Bluetooth HCIs are described in the ACPI tables + * by an ACPI device with a broken or missing UartSerialBusV2() resource. + * + * This causes the kernel to create a /dev/ttyS# char-device for the UART + * instead of creating an in kernel serdev-controller + serdev-device pair + * for the in kernel driver. + * + * The quirk handling in acpi_quirk_skip_serdev_enumeration() makes the kernel + * create a serdev-controller device for these UARTs instead of a /dev/ttyS#. + * + * Instantiating the actual serdev-device to bind to is up to pdx86 code, + * this header provides a helper for getting the serdev-controller device. + */ +#include <linux/acpi.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/printk.h> +#include <linux/sprintf.h> +#include <linux/string.h> + +static inline struct device * +get_serdev_controller(const char *serial_ctrl_hid, + const char *serial_ctrl_uid, + int serial_ctrl_port, + const char *serdev_ctrl_name) +{ + struct device *ctrl_dev, *child; + struct acpi_device *ctrl_adev; + char name[32]; + int i; + + ctrl_adev = acpi_dev_get_first_match_dev(serial_ctrl_hid, serial_ctrl_uid, -1); + if (!ctrl_adev) { + pr_err("error could not get %s/%s serial-ctrl adev\n", + serial_ctrl_hid, serial_ctrl_uid); + return ERR_PTR(-ENODEV); + } + + /* get_first_physical_node() returns a weak ref */ + ctrl_dev = get_device(acpi_get_first_physical_node(ctrl_adev)); + if (!ctrl_dev) { + pr_err("error could not get %s/%s serial-ctrl physical node\n", + serial_ctrl_hid, serial_ctrl_uid); + ctrl_dev = ERR_PTR(-ENODEV); + goto put_ctrl_adev; + } + + /* Walk host -> uart-ctrl -> port -> serdev-ctrl */ + for (i = 0; i < 3; i++) { + switch (i) { + case 0: + snprintf(name, sizeof(name), "%s:0", dev_name(ctrl_dev)); + break; + case 1: + snprintf(name, sizeof(name), "%s.%d", + dev_name(ctrl_dev), serial_ctrl_port); + break; + case 2: + strscpy(name, serdev_ctrl_name, sizeof(name)); + break; + } + + child = device_find_child_by_name(ctrl_dev, name); + put_device(ctrl_dev); + if (!child) { + pr_err("error could not find '%s' device\n", name); + ctrl_dev = ERR_PTR(-ENODEV); + goto put_ctrl_adev; + } + + ctrl_dev = child; + } + +put_ctrl_adev: + acpi_dev_put(ctrl_adev); + return ctrl_dev; +} |