Hi 2022. szeptember 11., vasárnap 21:49 keltezéssel, Arvid Norlander írta: > This is loosly 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> > [...] > +#define QUICKSTART_VERSION "1.04" > + > +#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/input.h> > +#include <linux/input/sparse-keymap.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_CLASS "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 acpi_device *acpi_dev; > + struct input_dev *input_device; > + struct quickstart_button *button; > + /* Name of button for debug messages */ > + char *name; > + /* ID of button as returned by GHID */ > + u32 id; > + /* Flags for cleanup */ > + unsigned int input_registered : 1; This member is set, but never read. > + unsigned int sysfs_created : 1; > + /* Track if a wakeup event was received */ > + unsigned int wakeup_cause : 1; > + /* Name of input device */ > + char input_name[32]; > + /* Physical path for the input device */ > + char phys[32]; > +}; > + > +/* > + * 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 scnprintf(buf, PAGE_SIZE, "%s\n", > + (quickstart->wakeup_cause ? "true" : "false")); Please use `sysfs_emit()` preferably. And I think it would be easier to use 0/1 instead of true/false. And you could use `kstrtobool()` in the _store() function. > +} > + > +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; > + > + 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 scnprintf(buf, PAGE_SIZE, "%d\n", quickstart->id); Since it is unsigned `%u` would probably be better. > +} > +static DEVICE_ATTR_RO(button_id); > + > +/* ACPI Driver functions */ > +static void quickstart_acpi_notify(struct acpi_device *acpi_dev, u32 event) > +{ > + struct quickstart_acpi *quickstart = acpi_driver_data(acpi_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"); > + } > + break; > + default: > + pr_err("Unexpected ACPI event notify (%u)\n", event); > + 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_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(quickstart->acpi_dev->handle, "GHID", > + NULL, &buffer); > + if (ACPI_FAILURE(status)) { > + pr_err("%s GHID method failed\n", quickstart->name); > + return -EINVAL; > + } > + obj = buffer.pointer; > + > + /* > + * GHID returns buffers, sanity check that is the case. > + */ > + if (obj->type != ACPI_TYPE_BUFFER) { > + pr_err("%s GHID did not return buffer\n", quickstart->name); > + return -EINVAL; `buffer.pointer` is not freed here. Since you know the maximum size, you could consider using an on-stack buffer. > + } > + > + /* > + * 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 = le16_to_cpu(*(u16 *)obj->buffer.pointer); Probably does not matter here, but I personally like to use `get_unaligned_leN()` because those functions just always work. > + break; > + case 4: > + quickstart->id = le32_to_cpu(*(u32 *)obj->buffer.pointer); > + break; > + case 8: > + quickstart->id = le64_to_cpu(*(u64 *)obj->buffer.pointer); > + break; > + default: > + pr_err("%s GHID method returned buffer of unexpected length %lu\n", > + quickstart->name, (unsigned long)obj->buffer.length); > + ret = -EINVAL; > + break; > + } > + > + kfree(buffer.pointer); > + > + return ret; > +} > + > +static int quickstart_acpi_config(struct quickstart_acpi *quickstart) > +{ > + char *bid = acpi_device_bid(quickstart->acpi_dev); > + char *name; > + > + name = kmalloc(strlen(bid) + 1, GFP_KERNEL); > + if (!name) > + return -ENOMEM; > + > + quickstart->name = name; > + strcpy(quickstart->name, bid); You could use `kstrdup()` here, but you could probably even use `devm_kstrdup()` and then this function could be entirely removed. > + > + return 0; > +} > + > +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_acpi_remove(struct acpi_device *acpi_dev) > +{ > + struct quickstart_acpi *quickstart; > + > + if (!acpi_dev) > + return -EINVAL; > + > + quickstart = acpi_driver_data(acpi_dev); > + if (!quickstart) > + return -EINVAL; > + > + if (quickstart->sysfs_created) > + sysfs_remove_group(&quickstart->acpi_dev->dev.kobj, > + &quickstart_attr_group); > + > + kfree(quickstart->name); > + quickstart->name = NULL; > + > + kfree(quickstart); > + > + return 0; > +} > + > +static int quickstart_acpi_add(struct acpi_device *acpi_dev) > +{ > + int ret; > + struct quickstart_acpi *quickstart; > + > + if (!acpi_dev) > + return -EINVAL; > + > + quickstart = kzalloc(sizeof(*quickstart), GFP_KERNEL); Have you considered `devm_kzalloc()`? > + 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. > + */ > + acpi_dev->driver_data = quickstart; > + quickstart->acpi_dev = acpi_dev; > + dev_set_drvdata(&acpi_dev->dev, quickstart); > + > + strcpy(acpi_device_name(acpi_dev), QUICKSTART_ACPI_DEVICE_NAME); > + strcpy(acpi_device_class(acpi_dev), QUICKSTART_ACPI_CLASS); > + > + /* Initialize device name */ > + ret = quickstart_acpi_config(quickstart); > + if (ret < 0) > + goto error; > + > + /* Retrieve the GHID ID */ > + ret = quickstart_acpi_ghid(quickstart); > + if (ret < 0) > + goto error; > + > + /* Set up sysfs entries */ > + ret = sysfs_create_group(&quickstart->acpi_dev->dev.kobj, > + &quickstart_attr_group); You could use `devm_device_add_group()`. And then the `sysfs_created` member could be removed. > + if (ret) { > + quickstart->sysfs_created = 0; > + pr_err("Unable to setup sysfs entries\n"); > + goto error; > + } > + quickstart->sysfs_created = !ret; > + > + /* Set up input device */ > + quickstart->input_device = > + devm_input_allocate_device(&quickstart->acpi_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); > + if (ret) { > + quickstart->input_registered = 0; > + pr_err("Unable to register input device\n"); > + goto error; > + } > + quickstart->input_registered = !ret; > + > + return 0; > +error: > + quickstart_acpi_remove(acpi_dev); > + return ret; > +} > + > +static const struct acpi_device_id quickstart_device_ids[] = { > + { QUICKSTART_ACPI_HID, 0 }, > + { "", 0 }, > +}; > +MODULE_DEVICE_TABLE(acpi, quickstart_device_ids); > + > +static struct acpi_driver quickstart_acpi_driver = { > + .name = "quickstart", > + .owner = THIS_MODULE, > + .class = QUICKSTART_ACPI_CLASS, > + .ids = quickstart_device_ids, > + .flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS, > + .ops = { > + .add = quickstart_acpi_add, > + .remove = quickstart_acpi_remove, > + .notify = quickstart_acpi_notify > + }, > +}; > + > +/* Module functions */ > +static void quickstart_exit(void) > +{ > + acpi_bus_unregister_driver(&quickstart_acpi_driver); > +} > + > +static int __init quickstart_init(void) > +{ > + int ret; > + > + /* ACPI driver register */ > + ret = acpi_bus_register_driver(&quickstart_acpi_driver); > + if (ret) > + return ret; > + > + pr_info("ACPI Direct App Launch ver %s\n", QUICKSTART_VERSION); > + > + return 0; > +} > + > +module_init(quickstart_init); > +module_exit(quickstart_exit); You could use the `module_acpi_driver()` macro to generate the init/exit methods. > -- > 2.37.3 Regards, Barnabás Pőcze
