[PATCH v7 4/4] HID: hid-msi: Add Rumble Intensity Attributes

["Derek J. Clark" <derekjohn.clark@gmail.com>]

Adds intensity adjustment for the left and right rumble motors.

Claude was used during the reverse-engineering data gathering for this
feature done by Zhouwang Huang. As the code had already been affected,
I used Claude to create the initial framing for the feature, then did
manual cleanup of the _show and _store functions afterwards to fix bugs
and keep the coding style consistent. Claude was also used as an initial
reviewer of this patch.

Assisted-by: Claude:claude-sonnet-4-6
Co-developed-by: Zhouwang Huang <honjow311@gmail.com>
Signed-off-by: Zhouwang Huang <honjow311@gmail.com>
Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
---
v7:
  - Match on write address for rumble reports to prevent late ACK
    from causing synchronization errors.
  - Use spinlock for read/write profile_pending.
  - Use smp_[store_release|load_acquire] pattern for checking
    gamepad_registered to avoid possible races during teardown.
  - Use struct for rumble reports.
v6:
  - Make all timeouts 25ms to ensure at least 2 jiffies in a 100Hz
    config.
  - Add spinlock_irqsave for read/write access on rumble_intensity
    variables.
  - Gate all attribute show/store functions with gamepad_registered.
v5:
  - Remove mkey related changes.
v2:
  - Use pending_profile and sync to rom mutexes.
---
 drivers/hid/hid-msi.c | 192 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 192 insertions(+)

diff --git a/drivers/hid/hid-msi.c b/drivers/hid/hid-msi.c
index 61917902e38d3..4adc5588618df 100644
--- a/drivers/hid/hid-msi.c
+++ b/drivers/hid/hid-msi.c
@@ -79,6 +79,8 @@ enum claw_profile_ack_pending {
 	CLAW_M1_PENDING,
 	CLAW_M2_PENDING,
 	CLAW_RGB_PENDING,
+	CLAW_RUMBLE_LEFT_PENDING,
+	CLAW_RUMBLE_RIGHT_PENDING,
 };
 
 enum claw_key_index {
@@ -266,6 +268,11 @@ static const u16 button_mapping_addr_new[] = {
 static const u16 rgb_addr_old = 0x01fa;
 static const u16 rgb_addr_new = 0x024a;
 
+static const u16 rumble_addr[] = {
+	0x0022,  /* left  */
+	0x0023,  /* right */
+};
+
 struct claw_command_report {
 	u8 report_id;
 	u8 padding[2];
@@ -308,6 +315,12 @@ struct claw_rgb_report {
 	struct rgb_frame zone_data;
 } __packed;
 
+struct claw_rumble_report {
+	struct claw_profile_report;
+	u8 padding;
+	u8 intensity;
+} __packed;
+
 struct claw_drvdata {
 	/* MCU General Variables */
 	enum claw_profile_ack_pending profile_pending;
@@ -331,9 +344,13 @@ struct claw_drvdata {
 	enum claw_gamepad_mode_index gamepad_mode;
 	u8 m1_codes[CLAW_KEYS_MAX];
 	u8 m2_codes[CLAW_KEYS_MAX];
+	u8 rumble_intensity_right;
+	u8 rumble_intensity_left;
 	bool gamepad_registered;
+	spinlock_t rumble_lock; /* lock for rumble_intensity read/write */
 	spinlock_t mode_lock; /* Lock for mode data read/write */
 	const u16 *bmap_addr;
+	bool rumble_support;
 	bool bmap_support;
 
 	/* RGB Variables */
@@ -381,6 +398,7 @@ static int claw_gamepad_mode_event(struct claw_drvdata *drvdata,
 static int claw_profile_event(struct claw_drvdata *drvdata, struct claw_command_report *cmd_rep)
 {
 	enum claw_profile_ack_pending profile;
+	struct claw_rumble_report *rumble;
 	struct claw_mkey_report *mkeys;
 	struct claw_rgb_report *frame;
 	u16 rgb_addr, read_addr;
@@ -430,6 +448,20 @@ static int claw_profile_event(struct claw_drvdata *drvdata, struct claw_command_
 		}
 
 		break;
+	case CLAW_RUMBLE_LEFT_PENDING:
+		rumble = (struct claw_rumble_report *)cmd_rep->data;
+		if (be16_to_cpu(rumble->read_addr) != rumble_addr[0])
+			return -EINVAL;
+		scoped_guard(spinlock, &drvdata->rumble_lock)
+			drvdata->rumble_intensity_left = rumble->intensity;
+		break;
+	case CLAW_RUMBLE_RIGHT_PENDING:
+		rumble = (struct claw_rumble_report *)cmd_rep->data;
+		if (be16_to_cpu(rumble->read_addr) != rumble_addr[1])
+			return -EINVAL;
+		scoped_guard(spinlock, &drvdata->rumble_lock)
+			drvdata->rumble_intensity_right = rumble->intensity;
+		break;
 	default:
 		dev_dbg(&drvdata->hdev->dev,
 			"Got profile event without changes pending from command: %x\n",
@@ -919,6 +951,154 @@ static ssize_t button_mapping_options_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(button_mapping_options);
 
+static ssize_t rumble_intensity_left_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t count)
+{
+	struct claw_rumble_report report = { {0x01, cpu_to_be16(rumble_addr[0])}, 0x01 };
+	struct hid_device *hdev = to_hid_device(dev);
+	struct claw_drvdata *drvdata = hid_get_drvdata(hdev);
+	u8 val;
+	int ret;
+
+	/* Pairs with smp_store_release from cfg_setup_fn in system_wq context */
+	if (!smp_load_acquire(&drvdata->gamepad_registered))
+		return -ENODEV;
+
+	ret = kstrtou8(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val > 100)
+		return -EINVAL;
+
+	report.intensity = val;
+
+	guard(mutex)(&drvdata->rom_mutex);
+	ret = claw_hw_output_report(hdev, CLAW_COMMAND_TYPE_WRITE_PROFILE_DATA,
+				    (u8 *)&report, sizeof(report), 25);
+	if (ret)
+		return ret;
+
+	/* MCU will not send ACK until the USB transaction completes. ACK is sent
+	 * immediately after and will hit the stale state machine, before the next
+	 * command re-arms the state machine. Timeout 0 ensures no deadlock waiting
+	 * for ACK that ill never come.
+	 */
+	ret = claw_hw_output_report(hdev, CLAW_COMMAND_TYPE_SYNC_TO_ROM, NULL, 0, 0);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t rumble_intensity_left_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct claw_rumble_report report = { {0x01, cpu_to_be16(rumble_addr[0])}, 0x01 };
+	struct hid_device *hdev = to_hid_device(dev);
+	struct claw_drvdata *drvdata = hid_get_drvdata(hdev);
+	int ret;
+	u8 val;
+
+	/* Pairs with smp_store_release from cfg_setup_fn in system_wq context */
+	if (!smp_load_acquire(&drvdata->gamepad_registered))
+		return -ENODEV;
+
+	guard(mutex)(&drvdata->profile_mutex);
+	scoped_guard(spinlock_irqsave, &drvdata->profile_lock)
+		drvdata->profile_pending = CLAW_RUMBLE_LEFT_PENDING;
+	ret = claw_hw_output_report(hdev, CLAW_COMMAND_TYPE_READ_PROFILE,
+				    (u8 *)&report, sizeof(report), 25);
+	if (ret)
+		return ret;
+
+	scoped_guard(spinlock_irqsave, &drvdata->rumble_lock)
+		val = drvdata->rumble_intensity_left;
+
+	return sysfs_emit(buf, "%u\n", val);
+}
+static DEVICE_ATTR_RW(rumble_intensity_left);
+
+static ssize_t rumble_intensity_right_store(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t count)
+{
+	struct claw_rumble_report report = { {0x01, cpu_to_be16(rumble_addr[1])}, 0x01 };
+	struct hid_device *hdev = to_hid_device(dev);
+	struct claw_drvdata *drvdata = hid_get_drvdata(hdev);
+	u8 val;
+	int ret;
+
+	/* Pairs with smp_store_release from cfg_setup_fn in system_wq context */
+	if (!smp_load_acquire(&drvdata->gamepad_registered))
+		return -ENODEV;
+
+	ret = kstrtou8(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val > 100)
+		return -EINVAL;
+
+	report.intensity = val;
+
+	guard(mutex)(&drvdata->rom_mutex);
+	ret = claw_hw_output_report(hdev, CLAW_COMMAND_TYPE_WRITE_PROFILE_DATA,
+				    (u8 *)&report, sizeof(report), 25);
+	if (ret)
+		return ret;
+
+	/* MCU will not send ACK until the USB transaction completes. ACK is sent
+	 * immediately after and will hit the stale state machine, before the next
+	 * command re-arms the state machine. Timeout 0 ensures no deadlock waiting
+	 * for ACK that ill never come.
+	 */
+	ret = claw_hw_output_report(hdev, CLAW_COMMAND_TYPE_SYNC_TO_ROM, NULL, 0, 0);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t rumble_intensity_right_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct claw_rumble_report report = { {0x01, cpu_to_be16(rumble_addr[1])}, 0x01 };
+	struct hid_device *hdev = to_hid_device(dev);
+	struct claw_drvdata *drvdata = hid_get_drvdata(hdev);
+	int ret;
+	u8 val;
+
+	/* Pairs with smp_store_release from cfg_setup_fn in system_wq context */
+	if (!smp_load_acquire(&drvdata->gamepad_registered))
+		return -ENODEV;
+
+	guard(mutex)(&drvdata->profile_mutex);
+	scoped_guard(spinlock_irqsave, &drvdata->profile_lock)
+		drvdata->profile_pending = CLAW_RUMBLE_RIGHT_PENDING;
+	ret = claw_hw_output_report(hdev, CLAW_COMMAND_TYPE_READ_PROFILE,
+				    (u8 *)&report, sizeof(report), 25);
+	if (ret)
+		return ret;
+
+	scoped_guard(spinlock_irqsave, &drvdata->rumble_lock)
+		val = drvdata->rumble_intensity_right;
+
+	return sysfs_emit(buf, "%u\n", val);
+}
+static DEVICE_ATTR_RW(rumble_intensity_right);
+
+static ssize_t rumble_intensity_range_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	return sysfs_emit(buf, "0-100\n");
+}
+static DEVICE_ATTR_RO(rumble_intensity_range);
+
 static umode_t claw_gamepad_attr_is_visible(struct kobject *kobj, struct attribute *attr,
 					    int n)
 {
@@ -939,6 +1119,12 @@ static umode_t claw_gamepad_attr_is_visible(struct kobject *kobj, struct attribu
 	    attr == &dev_attr_reset.attr)
 		return attr->mode;
 
+	/* Hide rumble attrs if not supported */
+	if (attr == &dev_attr_rumble_intensity_left.attr ||
+	    attr == &dev_attr_rumble_intensity_right.attr ||
+	    attr == &dev_attr_rumble_intensity_range.attr)
+		return drvdata->rumble_support ? attr->mode : 0;
+
 	/* Hide button mapping attrs if it isn't supported */
 	return drvdata->bmap_support ? attr->mode : 0;
 }
@@ -952,6 +1138,9 @@ static struct attribute *claw_gamepad_attrs[] = {
 	&dev_attr_mkeys_function.attr,
 	&dev_attr_mkeys_function_index.attr,
 	&dev_attr_reset.attr,
+	&dev_attr_rumble_intensity_left.attr,
+	&dev_attr_rumble_intensity_right.attr,
+	&dev_attr_rumble_intensity_range.attr,
 	NULL,
 };
 
@@ -1498,6 +1687,7 @@ static void claw_features_supported(struct claw_drvdata *drvdata)
 		drvdata->bmap_support = true;
 		if (minor >= 0x66) {
 			drvdata->bmap_addr = button_mapping_addr_new;
+			drvdata->rumble_support = true;
 			drvdata->rgb_addr = rgb_addr_new;
 		} else {
 			drvdata->bmap_addr = button_mapping_addr_old;
@@ -1509,6 +1699,7 @@ static void claw_features_supported(struct claw_drvdata *drvdata)
 	if ((major == 0x02 && minor >= 0x17) || major >= 0x03) {
 		drvdata->bmap_support = true;
 		drvdata->bmap_addr = button_mapping_addr_new;
+		drvdata->rumble_support = true;
 		drvdata->rgb_addr = rgb_addr_new;
 		return;
 	}
@@ -1557,6 +1748,7 @@ static int claw_probe(struct hid_device *hdev, u8 ep)
 	spin_lock_init(&drvdata->mode_lock);
 	spin_lock_init(&drvdata->profile_lock);
 	spin_lock_init(&drvdata->frame_lock);
+	spin_lock_init(&drvdata->rumble_lock);
 	init_completion(&drvdata->send_cmd_complete);
 	INIT_DELAYED_WORK(&drvdata->cfg_resume, &cfg_resume_fn);
 	INIT_DELAYED_WORK(&drvdata->cfg_setup, &cfg_setup_fn);
-- 
2.53.0