| 1 |
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| 2 | |
| 3 | * In some cases UART attached devices which require an in kernel driver,
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| 4 | * e.g. UART attached Bluetooth HCIs are described in the ACPI tables
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| 5 | * by an ACPI device with a broken or missing UartSerialBusV2() resource.
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| 6 | *
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| 7 | * This causes the kernel to create a /dev/ttyS# char-device for the UART
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| 8 | * instead of creating an in kernel serdev-controller + serdev-device pair
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| 9 | * for the in kernel driver.
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| 10 | *
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| 11 | * The quirk handling in acpi_quirk_skip_serdev_enumeration() makes the kernel
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| 12 | * create a serdev-controller device for these UARTs instead of a /dev/ttyS#.
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| 13 | *
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| 14 | * Instantiating the actual serdev-device to bind to is up to pdx86 code,
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| 15 | * this header provides a helper for getting the serdev-controller device.
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| 16 |
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| 17 | #include <linux/acpi.h>
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| 18 | #include <linux/device.h>
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| 19 | #include <linux/err.h>
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| 20 | #include <linux/printk.h>
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| 21 | #include <linux/sprintf.h>
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| 22 | #include <linux/string.h>
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| 23 |
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| 24 | static inline struct device *
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| 25 | get_serdev_controller_from_parent(struct device *ctrl_dev,
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| 26 | int serial_ctrl_port,
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| 27 | const char *serdev_ctrl_name)
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| 28 | {
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| 29 | struct device *child;
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| 30 | char name[32];
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| 31 | int i;
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| 32 |
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| 33 |
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| 34 | for (i = 0; i < 3; i++) {
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| 35 | switch (i) {
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| 36 | case 0:
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| 37 | snprintf(name, sizeof(name), "%s:0", dev_name(ctrl_dev));
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| 38 | break;
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| 39 | case 1:
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| 40 | snprintf(name, sizeof(name), "%s.%d",
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| 41 | dev_name(ctrl_dev), serial_ctrl_port);
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| 42 | break;
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| 43 | case 2:
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| 44 | strscpy(name, serdev_ctrl_name, sizeof(name));
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| 45 | break;
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| 46 | }
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| 47 |
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| 48 | child = device_find_child_by_name(ctrl_dev, name);
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| 49 | put_device(ctrl_dev);
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| 50 | if (!child) {
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| 51 | pr_err("error could not find '%s' device\n", name);
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| 52 | return ERR_PTR(-ENODEV);
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| 53 | }
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| 54 |
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| 55 | ctrl_dev = child;
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| 56 | }
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| 57 |
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| 58 | return ctrl_dev;
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| 59 | }
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| 60 |
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| 61 | static inline struct device *
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| 62 | get_serdev_controller(const char *serial_ctrl_hid,
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| 63 | const char *serial_ctrl_uid,
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| 64 | int serial_ctrl_port,
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| 65 | const char *serdev_ctrl_name)
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| 66 | {
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| 67 | struct acpi_device *adev;
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| 68 | struct device *parent;
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| 69 |
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| 70 | adev = acpi_dev_get_first_match_dev(serial_ctrl_hid, serial_ctrl_uid, -1);
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| 71 | if (!adev) {
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| 72 | pr_err("error could not get %s/%s serial-ctrl adev\n",
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| 73 | serial_ctrl_hid, serial_ctrl_uid ?: "*");
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| 74 | return ERR_PTR(-ENODEV);
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| 75 | }
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| 76 |
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| 77 |
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| 78 | parent = get_device(acpi_get_first_physical_node(adev));
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| 79 | acpi_dev_put(adev);
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| 80 | if (!parent) {
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| 81 | pr_err("error could not get %s/%s serial-ctrl physical node\n",
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| 82 | serial_ctrl_hid, serial_ctrl_uid ?: "*");
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| 83 | return ERR_PTR(-ENODEV);
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| 84 | }
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| 85 |
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| 86 |
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| 87 | return get_serdev_controller_from_parent(parent, serial_ctrl_port, serdev_ctrl_name);
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| 88 | }
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