Hi, On 9/23/22 21:24, Barnabás Pőcze wrote: > 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. True, might just as well drop the if and simply call sparse_keymap_report_event() without checking the result. > > >> + } >> + 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) Ack yes please, using .dev_groups is greatly preferred. > > >> + 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 > Regards, Hans
