>
> I think this could be `dev_info()`, but definitely not `dev_err()`. Although
> I'd
> personally move the logging from here to the probe function if you want to log
> which features are available. `ret` is necessarily 1 here, so I don't think
> printing it
> provides additional information.
To the layman I would say dev_info is too noisy actually. I think debugging
(dev_dbg) would be just fine. If there is a function not working, adding dynamic
debugging on kernel command line of modprobe line will be plenty sufficient to get
this information.
>
>
> > +
> > +out:
> > + mutex_unlock(&list_mutex);
> > + return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(dell_privacy_has_micmute);
> > +
> > +/*
> > + * The flow of privacy event:
> > + * 1) User presses key. HW does stuff with this key (timeout is started)
> > + * 2) WMI event is emitted from BIOS
> > + * 3) WMI event is received by dell-privacy
> > + * 4) KEY_MICMUTE emitted from dell-privacy
> > + * 5) Userland picks up key and modifies kcontrol for SW mute
> > + * 6) Codec kernel driver catches and calls ledtrig_audio_set defined by
> > + * dell-privacy-acpi driver. Codec driver will call like this to switch
> micmute led state.
> > + * ledtrig_audio_set(LED_AUDIO_MICMUTE, micmute_led ? LED_ON :LED_OFF);
> > + * 7) If "LED" is set to on dell-privacy notifies EC,and timeout is
> cancelled,
> > + * HW mic mute activated.
> > + */
> > +bool dell_privacy_process_event(int type, int code, int status)
> > +{
> > + struct privacy_wmi_data *priv;
> > + const struct key_entry *key;
> > + bool ret = false;
> > +
> > + mutex_lock(&list_mutex);
> > + priv = list_first_entry_or_null(&wmi_list,
> > + struct privacy_wmi_data,
> > + list);
> > + if (!priv) {
> > + dev_err(&priv->wdev->dev, "priv data is NULL\n");
> > + goto error;
> > + }
> > +
>
> I think the rest of the function could be replaced with:
>
> ret = sparse_keymap_report_event(priv->input_dev, DELL_SCAN_CODE(type,
> code), 1, true)
>
> if (ret)
> priv->last_status = status;
>
> error:
> [...]
>
> (see later a comment for the definition of DELL_SCAN_CODE())
>
>
> > + key = sparse_keymap_entry_from_scancode(priv->input_dev, (type << 16) |
> code);
> > + if (!key) {
> > + dev_warn(&priv->wdev->dev, "Unknown key with type 0x%04x and code
> 0x%04x pressed\n",
> > + type, code);
> > + goto error;
> > + }
> > + dev_dbg(&priv->wdev->dev, "Key with type 0x%04x and code 0x%04x
> pressed\n", type, code);
> > +
> > + switch (code) {
> > + case DELL_PRIVACY_AUDIO_EVENT: /* Mic mute */
> > + case DELL_PRIVACY_CAMERA_EVENT: /* Camera mute */
> > + priv->last_status = status;
> > + sparse_keymap_report_entry(priv->input_dev, key, 1, true);
> > + ret = true;
> > + break;
> > + default:
> > + dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x 0x%04x", type,
> code);
>
> The capitalization is inconsistent. Please either make all messages lowercase
> or
> make them all start with an uppercase letter. (And a newline character is
> missing.)
>
>
> > + }
> > +
> > +error:
> > + mutex_unlock(&list_mutex);
> > + return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(dell_privacy_process_event);
> > +
> > +static ssize_t dell_privacy_supported_type_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + enum dell_hardware_privacy_type type;
> > + struct privacy_wmi_data *priv = dev_get_drvdata(dev);
> > + char *s = buf;
> > + u32 privacy_list;
> > +
> > + privacy_list = priv->features_present;
> > + for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX;
> type++) {
> > + if (privacy_types[type]) {
>
> Is this check necessary?
>
>
> > + if (privacy_list & BIT(type))
> > + s += sprintf(s, "[%s] [supported]\n",
> privacy_types[type]);
> > + else
> > + s += sprintf(s, "[%s] [unsupport]\n",
> privacy_types[type]);
>
> You can use `sysfs_emit_at()` here.
>
>
> > + }
> > + }
> > +
> > + if (s != buf)
> > + /* convert the last space to a newline */
> > + *(s-1) = '\n';
>
> I believe this is not needed?
>
>
> > + return (s - buf);
> > +}
> > +
> > +static ssize_t dell_privacy_current_state_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct privacy_wmi_data *priv = dev_get_drvdata(dev);
> > + enum dell_hardware_privacy_type type;
> > + u32 privacy_state = priv->last_status;
> > + u32 privacy_supported = priv->features_present;
> > + char *s = buf;
> > +
> > + for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX;
> type++) {
> > + if (privacy_supported & BIT(type)) {
> > + if (privacy_state & BIT(type))
> > + s += sprintf(s, "[%s] [unmuted]\n",
> privacy_types[type]);
> > + else
> > + s += sprintf(s, "[%s] [muted]\n", privacy_types[type]);
>
> sysfs_emit_at
>
>
> > + }
> > + }
> > +
> > + if (s != buf)
> > + /* convert the last space to a newline */
> > + *(s-1) = '\n';
>
> not needed?
>
>
> > + return (s - buf);
> > +}
> > +
> > +static DEVICE_ATTR_RO(dell_privacy_supported_type);
> > +static DEVICE_ATTR_RO(dell_privacy_current_state);
> > +
> > +static struct attribute *privacy_attributes[] = {
> > + &dev_attr_dell_privacy_supported_type.attr,
> > + &dev_attr_dell_privacy_current_state.attr,
> > + NULL,
> > +};
> > +
> > +static const struct attribute_group privacy_attribute_group = {
> > + .attrs = privacy_attributes
> > +};
> > +
> > +/*
> > + * Describes the Device State class exposed by BIOS which can be consumed
> by
> > + * various applications interested in knowing the Privacy feature
> capabilities.
> > + * class DeviceState
> > + * {
> > + * [key, read] string InstanceName;
> > + * [read] boolean ReadOnly;
> > + * [WmiDataId(1), read] uint32 DevicesSupported;
> > + * 0 – None, 0x1 – Microphone, 0x2 – Camera, 0x4 -ePrivacy Screen
> ^ ^ ^ ^ ^^
> Please use a single type of hyphen/dash consistently. One space is enough.
>
>
> > + * [WmiDataId(2), read] uint32 CurrentState;
> > + * 0:Off; 1:On. Bit0 – Microphone, Bit1 – Camera, Bit2 - ePrivacyScreen
> ^ ^ ^
> Same here.
>
>
> > + * };
> > + */
> > +static int get_current_status(struct wmi_device *wdev)
> > +{
> > + struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
> > + union acpi_object *obj_present;
> > + u32 *buffer;
> > + int ret = 0;
> > +
> > + if (!priv) {
> > + pr_err("dell privacy priv is NULL\n");
>
> dev_err?
>
>
> > + return -EINVAL;
> > + }
> > + /* check privacy support features and device states */
> > + obj_present = wmidev_block_query(wdev, 0);
> > + if (!obj_present) {
> > + dev_err(&wdev->dev, "failed to read Binary MOF\n");
> > + ret = -EIO;
> > + return ret;
>
> return -EIO ?
>
>
> > + }
> > +
> > + if (obj_present->type != ACPI_TYPE_BUFFER) {
> > + dev_err(&wdev->dev, "Binary MOF is not a buffer!\n");
> > + ret = -EIO;
> > + goto obj_free;
> > + }
> > + /* Although it's not technically a failure, this would lead to
> > + * unexpected behavior
> > + */
> > + if (obj_present->buffer.length != 8) {
> > + dev_err(&wdev->dev, "Dell privacy buffer has unexpected length
> (%d)!\n",
> > + obj_present->buffer.length);
> > + ret = -EINVAL;
> > + goto obj_free;
> > + }
> > + buffer = (u32 *)obj_present->buffer.pointer;
> > + priv->features_present = buffer[0];
> > + priv->last_status = buffer[1];
>
> It's a minor thing, but I still think it'd more explicit and somewhat better
> to
> use `get_unaligned_le32()` (or `get_unaligned_cpu32()`).
>
>
> > +
> > +obj_free:
> > + kfree(obj_present);
> > + return ret;
> > +}
> > +
> > +static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
> > + enum led_brightness brightness)
> > +{
> > + struct privacy_wmi_data *priv = cdev_to_led(led_cdev);
> > + static char *acpi_method = (char *)"ECAK";
> > + acpi_status status;
> > + acpi_handle handle;
> > +
> > + handle = ec_get_handle();
> > + if (!handle)
> > + return -EIO;
> > +
> > + if (!acpi_has_method(handle, acpi_method))
> > + return -EIO;
> > +
> > + status = acpi_evaluate_object(handle, acpi_method, NULL, NULL);
> > + if (ACPI_FAILURE(status)) {
> > + dev_err(&priv->wdev->dev, "Error setting privacy EC ack value:
> %s\n",
> > + acpi_format_exception(status));
> > + return -EIO;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * Pressing the mute key activates a time delayed circuit to physically cut
> > + * off the mute. The LED is in the same circuit, so it reflects the true
> > + * state of the HW mute. The reason for the EC "ack" is so that software
> > + * can first invoke a SW mute before the HW circuit is cut off. Without SW
> > + * cutting this off first does not affect the time delayed muting or status
> > + * of the LED but there is a possibility of a "popping" noise.
> > + *
> > + * If the EC receives the SW ack, the circuit will be activated before the
> > + * delay completed.
> > + *
> > + * Exposing as an LED device allows the codec drivers notification path to
> > + * EC ACK to work
> > + */
> > +static int dell_privacy_leds_setup(struct device *dev)
> > +{
> > + struct privacy_wmi_data *priv = dev_get_drvdata(dev);
> > + int ret;
> > +
> > + priv->cdev.name = "dell-privacy::micmute";
> > + priv->cdev.max_brightness = 1;
> > + priv->cdev.brightness_set_blocking = dell_privacy_micmute_led_set;
> > + priv->cdev.default_trigger = "audio-micmute";
> > + priv->cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
> > + ret = devm_led_classdev_register(dev, &priv->cdev);
> > + if (ret)
> > + return ret;
> > + return 0;
>
> You can replace the last four lines with:
>
> return devm_led_classdev_register(...);
>
>
> > +}
> > +
> > +static int dell_privacy_wmi_probe(struct wmi_device *wdev, const void
> *context)
> > +{
> > + struct privacy_wmi_data *priv;
> > + struct key_entry *keymap;
> > + int ret, i;
> > +
> > + ret = wmi_has_guid(DELL_PRIVACY_GUID);
> > + if (!ret)
> > + pr_debug("Unable to detect available Dell privacy devices: %d\n",
> ret);
>
> When this branch is taken, `ret` is necessarily zero, so I don't think
> printing it
> provides useful information.
>
> And I believe this `wmi_has_guid()` check is unnecessary since the probe
> method
> would not be called if the device didn't have such WMI guid if I'm not
> mistaken.
>
>
> > +
> > + priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + dev_set_drvdata(&wdev->dev, priv);
> > + priv->wdev = wdev;
> > + /* create evdev passing interface */
> > + priv->input_dev = devm_input_allocate_device(&wdev->dev);
> > + if (!priv->input_dev)
> > + return -ENOMEM;
> > +
> > + /* remap the wmi keymap event to new keymap */
> > + keymap = kcalloc(ARRAY_SIZE(dell_wmi_keymap_type_0012),
> > + sizeof(struct key_entry), GFP_KERNEL);
> > + if (!keymap)
> > + return -ENOMEM;
> > +
> > + /* remap the keymap code with Dell privacy key type 0x12 as prefix
> > + * KEY_MICMUTE scancode will be reported as 0x120001
> > + */
> > + for (i = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
> > + keymap[i] = dell_wmi_keymap_type_0012[i];
> > + keymap[i].code |= (0x0012 << 16);
> > + }
>
> I still don't see the need for allocating and copying the keymap. Wouldn't the
> following be sufficient?
>
> #define DELL_SCAN_CODE(type, code) ((type) << 16 | (code))
> static const struct key_entry dell_wmi_keymap_type_0012[] = {
> { KE_KEY, DELL_SCAN_CODE(0x0012, 0x0001), { KEY_MICMUTE } },
> { KE_SW, DELL_SCAN_CODE(0x0012, 0x0002), { SW_CAMERA_LENS_COVER } },
> { KE_END, 0},
> };
>
> Other Dell drivers potentially merge multiple keymaps, so dynamically
> allocating
> the key_entry array is justified. Here I see no such need. Can you explain why
> this copying is done?
>
>
> > + ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
> > + if (ret)
> > + return ret;
>
> `keymap` is leaked if this or any of the later early-returns are taken.
>
>
> > +
> > + priv->input_dev->dev.parent = &wdev->dev;
> > + priv->input_dev->name = "Dell Privacy Driver";
> > + priv->input_dev->id.bustype = BUS_HOST;
> > +
> > + ret = input_register_device(priv->input_dev);
> > + if (ret)
> > + return ret;
> > +
> > + ret = get_current_status(priv->wdev);
> > + if (ret)
> > + return ret;
> > +
> > + ret = devm_device_add_group(&wdev->dev, &privacy_attribute_group);
> > + if (ret)
> > + return ret;
> > +
> > + ret = dell_privacy_leds_setup(&priv->wdev->dev);
> > + if (ret)
> > + return ret;
> > +
> > + mutex_lock(&list_mutex);
> > + list_add_tail(&priv->list, &wmi_list);
> > + mutex_unlock(&list_mutex);
> > + kfree(keymap);
> > + return 0;
> > +}
> > +
> > +static int dell_privacy_wmi_remove(struct wmi_device *wdev)
> > +{
> > + struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
> > +
> > + mutex_lock(&list_mutex);
> > + list_del(&priv->list);
> > + mutex_unlock(&list_mutex);
> > + return 0;
> > +}
> > +
> > +static const struct wmi_device_id dell_wmi_privacy_wmi_id_table[] = {
> > + { .guid_string = DELL_PRIVACY_GUID },
> > + { },
> > +};
> > +
> > +static struct wmi_driver dell_privacy_wmi_driver = {
> > + .driver = {
> > + .name = "dell-privacy",
> > + },
> > + .probe = dell_privacy_wmi_probe,
> > + .remove = dell_privacy_wmi_remove,
> > + .id_table = dell_wmi_privacy_wmi_id_table,
> > +};
> > +
> > +module_wmi_driver(dell_privacy_wmi_driver);
> > +
> > +MODULE_DEVICE_TABLE(wmi, dell_wmi_privacy_wmi_id_table);
> > +MODULE_AUTHOR("Perry Yuan <perry_yuan@xxxxxxxx>");
> > +MODULE_DESCRIPTION("Dell Privacy WMI Driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/platform/x86/dell/dell-privacy-wmi.h
> b/drivers/platform/x86/dell/dell-privacy-wmi.h
> > new file mode 100644
> > index 000000000000..a24893754286
> > --- /dev/null
> > +++ b/drivers/platform/x86/dell/dell-privacy-wmi.h
> > @@ -0,0 +1,32 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Dell privacy notification driver
> > + *
> > + * Copyright (C) 2021 Dell Inc. All Rights Reserved.
> > + */
> > +
> > +#ifndef _DELL_PRIVACY_WMI_H_
> > +#define _DELL_PRIVACY_WMI_H_
> > +
> > +#if IS_ENABLED(CONFIG_DELL_PRIVACY)
> > +int dell_privacy_has_micmute(void);
> > +bool dell_privacy_present(void);
> > +bool dell_privacy_process_event(int type, int code, int status);
> > +#else /* CONFIG_DELL_PRIVACY */
> > +static inline int dell_privacy_has_micmute(void)
> > +{
> > + return -ENODEV;
> > +}
> > +
> > +static inline int dell_privacy_present(void)
> ^^^
> It's declared with `bool` return type a couple lines above.
>
>
> > +{
> > + return -ENODEV;
> > +}
> > +
> > +static inline void dell_privacy_process_event(int type, int code, int
> status)
> ^^^^
> It's declared with `bool` return type a couple lines above.
>
>
> > +{}
> > +#endif /* CONFIG_DELL_PRIVACY */
> > +
> > +int dell_privacy_acpi_init(void);
> > +void dell_privacy_acpi_exit(void);
>
> These two don't seem to be referenced anywhere?
>
>
> > +#endif
> > diff --git a/drivers/platform/x86/dell/dell-wmi.c
> b/drivers/platform/x86/dell/dell-wmi.c
> > index bbdb3e860892..8ef9e22a538f 100644
> > --- a/drivers/platform/x86/dell/dell-wmi.c
> > +++ b/drivers/platform/x86/dell/dell-wmi.c
> > @@ -27,6 +27,7 @@
> > #include <acpi/video.h>
> > #include "dell-smbios.h"
> > #include "dell-wmi-descriptor.h"
> > +#include "dell-privacy-wmi.h"
> >
> > MODULE_AUTHOR("Matthew Garrett <mjg@xxxxxxxxxx>");
> > MODULE_AUTHOR("Pali Rohár <pali@xxxxxxxxxx>");
> > @@ -381,6 +382,7 @@ static void dell_wmi_notify(struct wmi_device *wdev,
> > u16 *buffer_entry, *buffer_end;
> > acpi_size buffer_size;
> > int len, i;
> > + int ret;
> >
> > if (obj->type != ACPI_TYPE_BUFFER) {
> > pr_warn("bad response type %x\n", obj->type);
> > @@ -427,7 +429,6 @@ static void dell_wmi_notify(struct wmi_device *wdev,
> >
> > switch (buffer_entry[1]) {
> > case 0x0000: /* One key pressed or event occurred */
> > - case 0x0012: /* Event with extended data occurred */
> > if (len > 2)
> > dell_wmi_process_key(wdev, buffer_entry[1],
> > buffer_entry[2]);
> > @@ -439,6 +440,16 @@ static void dell_wmi_notify(struct wmi_device *wdev,
> > dell_wmi_process_key(wdev, buffer_entry[1],
> > buffer_entry[i]);
> > break;
> > + case 0x0012:
> > + ret = dell_privacy_present();
> > + if ((ret) && (len > 2)) {
>
> Is the `len > 2` check correct?
>
> Moreover, I personally don't see any reason to use a new variable here
> (`ret`).
>
> If you incorporate the `dell_privacy_present()` check into
> `dell_privacy_process_event()`, then even
>
> if (len > ?? && dell_privacy_process_event(...))
> /* nothing */ ;
> else if (len > 2)
> dell_wmi_process_key(...);
>
> would work as Hans has already pointed it out. And there'd be no need for
> `dell_privacy_present()` anymore.
>
>
> > + dell_privacy_process_event(buffer_entry[1],
> > + buffer_entry[3], buffer_entry[4]);
> > + } else if (len > 2) {
> > + dell_wmi_process_key(wdev, buffer_entry[1],
> > + buffer_entry[2]);
> > + }
> > + break;
> > default: /* Unknown event */
> > pr_info("Unknown WMI event type 0x%x\n",
> > (int)buffer_entry[1]);
> > --
> > 2.25.1
> >
>
>
> Regards,
> Barnabás Pőcze
