Hi 2022. szeptember 22., csütörtök 20:24 keltezéssel, Arvid Norlander írta: > This is loosely based on a previous staging driver that was removed. See > links below for more info on that driver. The original commit ID was > 0be013e3dc2ee79ffab8a438bbb4e216837e3d52. > > However, here a completely different approach is taken to the user space > API (which should solve the issues the original driver had). Each PNP0C32 > device is a button, and each such button gets a separate input device > associated with it (instead of a shared platform input device). > > The button ID (as read from ACPI method GHID) is provided via a sysfs file > "button_id". > > If the button caused a wakeup it will "latch" the "wakeup_cause" sysfs file > to true. This can be reset by a user space process. > > Link: https://marc.info/?l=linux-acpi&m=120550727131007 > Link: https://lkml.org/lkml/2010/5/28/327 > Signed-off-by: Arvid Norlander <lkml@xxxxxxxxx> > --- > [...] > diff --git a/drivers/platform/x86/quickstart.c b/drivers/platform/x86/quickstart.c > new file mode 100644 > index 000000000000..ce51abe012f7 > --- /dev/null > +++ b/drivers/platform/x86/quickstart.c > @@ -0,0 +1,320 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * quickstart.c - ACPI Direct App Launch driver > + * > + * Copyright (C) 2022 Arvid Norlander <lkml@xxxxxxxxxx> > + * Copyright (C) 2007-2010 Angelo Arrifano <miknix@xxxxxxxxx> > + * > + * Information gathered from disassembled dsdt and from here: > + * <https://archive.org/details/microsoft-acpi-dirapplaunch> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/types.h> > +#include <linux/acpi.h> > +#include <linux/platform_device.h> > +#include <linux/input.h> > +#include <linux/input/sparse-keymap.h> > +#include <asm/unaligned.h> > + > +MODULE_AUTHOR("Arvid Norlander <lkml@xxxxxxxxx>"); > +MODULE_AUTHOR("Angelo Arrifano"); > +MODULE_DESCRIPTION("ACPI Direct App Launch driver"); > +MODULE_LICENSE("GPL"); > + > +#define QUICKSTART_ACPI_DEVICE_NAME "quickstart" > +#define QUICKSTART_ACPI_HID "PNP0C32" > + > +/* > + * There will be two events: > + * 0x02 - A hot button was pressed while device was off/sleeping. > + * 0x80 - A hot button was pressed while device was up. > + */ > +#define QUICKSTART_EVENT_WAKE 0x02 > +#define QUICKSTART_EVENT_RUNTIME 0x80 > + > +/* > + * Each PNP0C32 device is an individual button. This structure > + * keeps track of data associated with said device. > + */ > +struct quickstart_acpi { > + struct platform_device *platform_dev; > + struct input_dev *input_device; > + struct quickstart_button *button; > + /* ID of button as returned by GHID */ > + u32 id; > + /* Name of input device */ > + char input_name[32]; > + /* Physical path for the input device */ > + char phys[32]; > + /* Track if a wakeup event was received */ > + bool wakeup_cause; > +}; > + > +#define quickstart_name(dev) acpi_device_bid(dev->acpi_dev) This does not seem to be used. > + > +/* > + * Knowing what these buttons do require system specific knowledge. > + * This could be done by matching on DMI data in a long quirk table. > + * However, it is easier to leave it up to user space to figure this out. > + * > + * Using for example udev hwdb the scancode 0x1 can be remapped suitably. > + */ > +static const struct key_entry quickstart_keymap[] = { > + { KE_KEY, 0x1, { KEY_UNKNOWN } }, > + { KE_END, 0 }, > +}; > + > +static ssize_t wakeup_cause_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct quickstart_acpi *quickstart = dev_get_drvdata(dev); > + > + return sysfs_emit(buf, "%s\n", > + (quickstart->wakeup_cause ? "true" : "false")); > +} > + > +static ssize_t wakeup_cause_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct quickstart_acpi *quickstart = dev_get_drvdata(dev); > + > + if (count < 2) > + return -EINVAL; > + > + if (strncasecmp(buf, "false", 4) != 0) > + return -EINVAL; > + If "true"/"false" will be used in the final version, then I think this check currently is too lax. You could use `sysfs_streq()`. And I think the `count < 2` check is not needed. > + quickstart->wakeup_cause = false; > + return count; > +} > +static DEVICE_ATTR_RW(wakeup_cause); > + > +static ssize_t button_id_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct quickstart_acpi *quickstart = dev_get_drvdata(dev); > + > + return sysfs_emit(buf, "%u\n", quickstart->id); > +} > +static DEVICE_ATTR_RO(button_id); > + > +/* ACPI Driver functions */ > +static void quickstart_acpi_notify(acpi_handle handle, u32 event, void *context) > +{ > + struct platform_device *device = context; > + struct quickstart_acpi *quickstart = dev_get_drvdata(&device->dev); > + > + if (!quickstart) > + return; > + > + switch (event) { > + case QUICKSTART_EVENT_WAKE: > + quickstart->wakeup_cause = true; > + break; > + case QUICKSTART_EVENT_RUNTIME: > + if (!sparse_keymap_report_event(quickstart->input_device, 0x1, > + 1, true)) { > + pr_info("Key handling error\n"); I don't think this branch can ever be taken. > + } > + break; > + default: > + pr_err("Unexpected ACPI event notify (%u)\n", event); I think `dev_{err,info}()` should be preferred. > + break; > + } > +} > + > +/* > + * The GHID ACPI method is used to indicate the "role" of the button. > + * However, all the meanings of these values are vendor defined. > + * > + * We do however expose this value to user space. > + */ > +static int quickstart_acpi_ghid(struct quickstart_acpi *quickstart) > +{ > + acpi_handle handle = ACPI_HANDLE(&quickstart->platform_dev->dev); > + acpi_status status; > + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; > + int ret = 0; > + union acpi_object *obj = NULL; > + > + /* > + * This returns a buffer telling the button usage ID, > + * and triggers pending notify events (The ones before booting). > + */ > + status = acpi_evaluate_object(handle, "GHID", NULL, &buffer); > + if (ACPI_FAILURE(status)) { > + dev_err(&quickstart->platform_dev->dev, > + "GHID method failed, ACPI status %u\n", status); > + return -EINVAL; > + } > + obj = buffer.pointer; > + > + /* > + * GHID returns buffers, sanity check that is the case. > + */ > + if (obj->type != ACPI_TYPE_BUFFER) { > + dev_err(&quickstart->platform_dev->dev, > + "GHID did not return buffer\n"); > + ret = -EINVAL; > + goto free_and_return; > + } > + > + /* > + * Quoting the specification: > + * "The GHID method can return a BYTE, WORD, or DWORD. > + * The value must be encoded in little-endian byte > + * order (least significant byte first)." > + */ > + switch (obj->buffer.length) { > + case 1: > + quickstart->id = *(u8 *)obj->buffer.pointer; > + break; > + case 2: > + quickstart->id = get_unaligned_le16(obj->buffer.pointer); > + break; > + case 4: > + quickstart->id = get_unaligned_le32(obj->buffer.pointer); > + break; > + case 8: > + quickstart->id = get_unaligned_le64(obj->buffer.pointer); > + break; > + default: > + dev_err(&quickstart->platform_dev->dev, > + "GHID method returned buffer of unexpected length %lu\n", > + (unsigned long)obj->buffer.length); > + ret = -EINVAL; > + break; > + } > + > +free_and_return: > + kfree(buffer.pointer); > + > + return ret; > +} > + > +static struct attribute *quickstart_attributes[] = { > + &dev_attr_wakeup_cause.attr, > + &dev_attr_button_id.attr, > + NULL, > +}; > + > +static const struct attribute_group quickstart_attr_group = { > + .attrs = quickstart_attributes, > +}; > + > +static int quickstart_remove(struct platform_device *device) > +{ > + acpi_handle handle = ACPI_HANDLE(&device->dev); > + > + acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, > + quickstart_acpi_notify); > + > + return 0; > +} > + > +static int quickstart_probe(struct platform_device *device) > +{ > + int ret; > + acpi_handle handle = ACPI_HANDLE(&device->dev); > + acpi_status status; > + struct quickstart_acpi *quickstart; > + > + if (!device) > + return -EINVAL; > + > + quickstart = > + devm_kzalloc(&device->dev, sizeof(*quickstart), GFP_KERNEL); > + if (!quickstart) > + return -ENOMEM; > + > + /* > + * This must be set early for proper cleanup on error handling path. > + * After this point generic error handling can be used. > + */ > + quickstart->platform_dev = device; > + dev_set_drvdata(&device->dev, quickstart); > + > + /* Retrieve the GHID ID */ > + ret = quickstart_acpi_ghid(quickstart); > + if (ret < 0) > + goto error; You can replace all `goto`s in this function with `return`s. In fact, you should because `quickstart_remove()` does not do useful work until the ACPI notify handler is registered, but if that succeeds, this function can no longer fail. > + > + /* Set up sysfs entries */ > + ret = devm_device_add_group(&quickstart->platform_dev->dev, > + &quickstart_attr_group); In the meantime I realized there is a simpler solution. Use the `ATTRIBUTE_GROUPS()` macro and then simply set the `.dev_groups` member of `quickstart_platform_driver.driver`. (see drivers/platform/x86/hp-wmi.c) > + if (ret) { > + dev_err(&device->dev, "Unable to setup sysfs entries\n"); > + goto error; > + } > + > + /* Set up input device */ > + quickstart->input_device = > + devm_input_allocate_device(&quickstart->platform_dev->dev); > + if (!quickstart->input_device) { > + ret = -ENOMEM; > + goto error; > + } > + ret = sparse_keymap_setup(quickstart->input_device, quickstart_keymap, > + NULL); > + if (ret) > + goto error; > + > + snprintf(quickstart->input_name, sizeof(quickstart->phys), > + "Quickstart Button %u", quickstart->id); > + snprintf(quickstart->phys, sizeof(quickstart->phys), > + QUICKSTART_ACPI_DEVICE_NAME "/input%u", quickstart->id); > + > + quickstart->input_device->name = quickstart->input_name; > + quickstart->input_device->phys = quickstart->phys; > + quickstart->input_device->id.bustype = BUS_HOST; > + > + ret = input_register_device(quickstart->input_device); > + > + /* Set up notify handler */ > + status = acpi_install_notify_handler(handle, ACPI_DEVICE_NOTIFY, > + quickstart_acpi_notify, device); > + if (ACPI_FAILURE(status)) { > + dev_err(&device->dev, "Error installing notify handler\n"); > + return -EIO; > + } > + > + return 0; > +error: > + quickstart_remove(device); > + return ret; > +} > + > +static const struct acpi_device_id quickstart_device_ids[] = { > + { QUICKSTART_ACPI_HID, 0 }, > + { "", 0 }, Small thing, but usually the comma after the sentinel entry is omitted. (see quickstart_keymap, quickstart_attributes as well) > +}; > +MODULE_DEVICE_TABLE(acpi, quickstart_device_ids); > + > +static struct platform_driver quickstart_platform_driver = { > + .probe = quickstart_probe, > + .remove = quickstart_remove, > + .driver = { > + .name = QUICKSTART_ACPI_DEVICE_NAME, > + .acpi_match_table = quickstart_device_ids, > + .owner = THIS_MODULE, > + } > +}; > + > +module_platform_driver(quickstart_platform_driver); > -- > 2.37.3 Regards, Barnabás Pőcze
