[PATCH v9 04/12] HID: asus: add vibration strength configuration

[Denis Benato <denis.benato@linux.dev>]

ASUS ROG Ally handhelds support the vibration strength to be configured:
add sysfs attributes to allow userspace configure motors vibration
intensity.

Assisted-by: opencode:glm-5.2
Signed-off-by: Denis Benato <denis.benato@linux.dev>
Signed-off-by: Luke Jones <luke@ljones.dev>
---
 drivers/hid/hid-asus.c | 199 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 199 insertions(+)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index bf6b7c70b370..c7c5be576297 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -206,6 +206,10 @@ struct ally_config {
 	u8 left_trigger_max;
 	u8 right_trigger_min;
 	u8 right_trigger_max;
+
+	/* Vibration settings */
+	u8 vibration_intensity_left;
+	u8 vibration_intensity_right;
 };
 
 /*
@@ -864,15 +868,197 @@ static ssize_t xbox_controller_store(struct device *dev,
 
 static DEVICE_ATTR_RW(xbox_controller);
 
+/**
+ * ally_set_vibration_intensity() - Set vibration intensity values
+ * @ally: ally handheld structure
+ * @hdev: HID device
+ * @left: Left motor intensity (0-100)
+ * @right: Right motor intensity (0-100)
+ *
+ * Return: 0 on success, negative errno on failure
+ */
+static int ally_set_vibration_intensity(struct ally_handheld *ally,
+					struct hid_device *hdev, u8 left, u8 right)
+{
+	const u8 data[] = { left, right };
+	int ret;
+
+	u8 *buf __free(kfree) = ally_alloc_cmd(CMD_SET_VIBRATION_INTENSITY, data, sizeof(data));
+	if (!buf)
+		return -ENOMEM;
+
+	ret = ally_gamepad_send_packet(ally, hdev, buf, ROG_ALLY_REPORT_SIZE);
+	if (ret < 0) {
+		hid_err(hdev, "Failed to set vibration intensity: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static ssize_t left_vibration_intensity_show(struct device *dev, struct device_attribute *attr,
+					     char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct ally_handheld *ally = drvdata->rog_ally;
+	struct ally_config *cfg;
+
+	if (!ally)
+		return -ENODEV;
+
+	cfg = ally_get_config(ally);
+	if (!cfg)
+		return -ENODEV;
+
+	guard(mutex)(&cfg->config_mutex);
+
+	return sysfs_emit(buf, "%u\n", cfg->vibration_intensity_left);
+}
+
+static ssize_t left_vibration_intensity_store(struct device *dev, struct device_attribute *attr,
+					      const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct ally_handheld *ally = drvdata->rog_ally;
+	struct ally_config *cfg;
+	u8 value;
+	int ret;
+
+	if (!ally)
+		return -ENODEV;
+
+	cfg = ally_get_config(ally);
+	if (!cfg)
+		return -ENODEV;
+
+	ret = kstrtou8(buf, 10, &value);
+	if (ret || value > 100)
+		return -EINVAL;
+
+	guard(mutex)(&cfg->config_mutex);
+
+	ret = ally_set_vibration_intensity(ally, hdev, value,
+					   cfg->vibration_intensity_right);
+	if (ret < 0)
+		return ret;
+
+	cfg->vibration_intensity_left = value;
+
+	sysfs_notify(&dev->kobj, "left_vibration", "intensity");
+
+	return count;
+}
+
+static ssize_t left_vibration_intensity_range_show(struct device *dev,
+						   struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "0 100\n");
+}
+
+static ssize_t right_vibration_intensity_show(struct device *dev, struct device_attribute *attr,
+					      char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct ally_handheld *ally = drvdata->rog_ally;
+	struct ally_config *cfg;
+
+	if (!ally)
+		return -ENODEV;
+
+	cfg = ally_get_config(ally);
+	if (!cfg)
+		return -ENODEV;
+
+	guard(mutex)(&cfg->config_mutex);
+
+	return sysfs_emit(buf, "%u\n", cfg->vibration_intensity_right);
+}
+
+static ssize_t right_vibration_intensity_store(struct device *dev, struct device_attribute *attr,
+					       const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct ally_handheld *ally = drvdata->rog_ally;
+	struct ally_config *cfg;
+	u8 value;
+	int ret;
+
+	if (!ally)
+		return -ENODEV;
+
+	cfg = ally_get_config(ally);
+	if (!cfg)
+		return -ENODEV;
+
+	ret = kstrtou8(buf, 10, &value);
+	if (ret || value > 100)
+		return -EINVAL;
+
+	guard(mutex)(&cfg->config_mutex);
+
+	ret = ally_set_vibration_intensity(ally, hdev,
+					   cfg->vibration_intensity_left, value);
+	if (ret < 0)
+		return ret;
+
+	cfg->vibration_intensity_right = value;
+
+	sysfs_notify(&dev->kobj, "right_vibration", "intensity");
+
+	return count;
+}
+
+static ssize_t right_vibration_intensity_range_show(struct device *dev,
+						    struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "0 100\n");
+}
+
+static struct device_attribute dev_attr_left_vibration_intensity =
+	__ATTR(intensity, 0644, left_vibration_intensity_show, left_vibration_intensity_store);
+
+static struct device_attribute dev_attr_left_vibration_intensity_range =
+	__ATTR(intensity_range, 0444, left_vibration_intensity_range_show, NULL);
+
+static struct device_attribute dev_attr_right_vibration_intensity =
+	__ATTR(intensity, 0644, right_vibration_intensity_show, right_vibration_intensity_store);
+
+static struct device_attribute dev_attr_right_vibration_intensity_range =
+	__ATTR(intensity_range, 0444, right_vibration_intensity_range_show, NULL);
+
 static struct attribute *ally_config_attrs[] = {
 	&dev_attr_xbox_controller.attr,
 	NULL
 };
 
+static struct attribute *ally_left_vibration_attrs[] = {
+	&dev_attr_left_vibration_intensity.attr,
+	&dev_attr_left_vibration_intensity_range.attr,
+	NULL
+};
+
+static struct attribute *ally_right_vibration_attrs[] = {
+	&dev_attr_right_vibration_intensity.attr,
+	&dev_attr_right_vibration_intensity_range.attr,
+	NULL
+};
+
 static const struct attribute_group ally_attr_groups[] = {
 	{
 		.attrs = ally_config_attrs,
 	},
+	{
+		.name = "left_vibration",
+		.attrs = ally_left_vibration_attrs,
+	},
+	{
+		.name = "right_vibration",
+		.attrs = ally_right_vibration_attrs,
+	},
 };
 
 /**
@@ -917,6 +1103,8 @@ static struct ally_config *ally_config_create(struct hid_device *hdev, struct al
 		cfg->left_outer_threshold = 90;
 		cfg->right_deadzone = 10;
 		cfg->right_outer_threshold = 90;
+		cfg->vibration_intensity_left = 100;
+		cfg->vibration_intensity_right = 100;
 	}
 
 	spin_lock_irqsave(&ally_data_lock, flags);
@@ -1250,6 +1438,17 @@ static int hid_asus_ally_init(struct hid_device *hdev, struct ally_handheld *all
 				 ret);
 	}
 
+	/*
+	 * The MCU does not keep the vibration intensity across a reset:
+	 * send the recorded values again, whichever interface probed.
+	 */
+	ret = ally_set_vibration_intensity(ally, hdev,
+					   cfg->vibration_intensity_left,
+					   cfg->vibration_intensity_right);
+	if (ret < 0)
+		hid_warn(hdev, "Failed to restore vibration intensity: %d\n",
+			 ret);
+
 	return 0;
 }
 
-- 
2.47.3