[PATCH 11/12] HID: wiimote: Cache wiimote led state

[David Herrmann <dh.herrmann@googlemail.com>]

Save the current state of the leds in the wiimote data structure. This
allows us to discard new led requests that wouldn't change anything.
Protect the whole state structure by a spinlock. Every wiiproto_*
function expects this spinlock to be held when called.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
---
 drivers/hid/hid-wiimote.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/hid/hid-wiimote.c b/drivers/hid/hid-wiimote.c
index 3fb18fb..f9a3bcb 100644
--- a/drivers/hid/hid-wiimote.c
+++ b/drivers/hid/hid-wiimote.c
@@ -27,6 +27,11 @@ struct wiimote_buf {
 	size_t size;
 };
 
+struct wiimote_state {
+	spinlock_t lock;
+	__u8 flags;
+};
+
 struct wiimote_data {
 	atomic_t ready;
 	struct hid_device *hdev;
@@ -37,12 +42,16 @@ struct wiimote_data {
 	__u8 tail;
 	struct wiimote_buf outq[WIIMOTE_BUFSIZE];
 	struct work_struct worker;
+
+	struct wiimote_state state;
 };
 
 #define WIIPROTO_FLAG_LED1 0x01
 #define WIIPROTO_FLAG_LED2 0x02
 #define WIIPROTO_FLAG_LED3 0x04
 #define WIIPROTO_FLAG_LED4 0x08
+#define WIIPROTO_FLAGS_LEDS (WIIPROTO_FLAG_LED1 | WIIPROTO_FLAG_LED2 | \
+					WIIPROTO_FLAG_LED3 | WIIPROTO_FLAG_LED4)
 
 enum wiiproto_reqs {
 	WIIPROTO_REQ_LED = 0x11,
@@ -160,6 +169,11 @@ static void wiiproto_req_leds(struct wiimote_data *wdata, int leds)
 {
 	__u8 cmd[2];
 
+	leds &= WIIPROTO_FLAGS_LEDS;
+	if ((wdata->state.flags & WIIPROTO_FLAGS_LEDS) == leds)
+		return;
+	wdata->state.flags = (wdata->state.flags & ~WIIPROTO_FLAGS_LEDS) | leds;
+
 	cmd[0] = WIIPROTO_REQ_LED;
 	cmd[1] = 0;
 
@@ -232,6 +246,7 @@ static int wiimote_hid_event(struct hid_device *hdev, struct hid_report *report,
 	struct wiimote_data *wdata = hid_get_drvdata(hdev);
 	struct wiiproto_handler *h;
 	int i;
+	unsigned long flags;
 
 	if (!atomic_read(&wdata->ready))
 		return -EBUSY;
@@ -241,12 +256,16 @@ static int wiimote_hid_event(struct hid_device *hdev, struct hid_report *report,
 	if (size < 1)
 		return -EINVAL;
 
+	spin_lock_irqsave(&wdata->state.lock, flags);
+
 	for (i = 0; handlers[i].id; ++i) {
 		h = &handlers[i];
 		if (h->id == raw_data[0] && h->size < size)
 			h->func(wdata, &raw_data[1]);
 	}
 
+	spin_unlock_irqrestore(&wdata->state.lock, flags);
+
 	return 0;
 }
 
@@ -284,6 +303,8 @@ static struct wiimote_data *wiimote_create(struct hid_device *hdev)
 	spin_lock_init(&wdata->qlock);
 	INIT_WORK(&wdata->worker, wiimote_worker);
 
+	spin_lock_init(&wdata->state.lock);
+
 	return wdata;
 }
 
@@ -326,7 +347,12 @@ static int wiimote_hid_probe(struct hid_device *hdev,
 	smp_wmb();
 	atomic_set(&wdata->ready, 1);
 	hid_info(hdev, "New device registered\n");
+
+	/* by default set led1 after device initialization */
+	spin_lock_irq(&wdata->state.lock);
 	wiiproto_req_leds(wdata, WIIPROTO_FLAG_LED1);
+	spin_unlock_irq(&wdata->state.lock);
+
 	return 0;
 
 err_stop:
-- 
1.7.6