vibrator hal: add loop mode control and update waveform

This patch updates the click waveform to use 6 ms full amplitude as well
as switching to open-loop mode for any duration that's less than 20 ms.
The medium and strong now shares the same strength to provide a stronger
default feedback.

Bug: 37952639
Test: keyboard and home key taps
Change-Id: I00086e47e41d97ce8363ba4032eeab320ad1b765
Signed-off-by: David Lin <dtwlin@google.com>

vibrator/Vibrator.cpp

@@ -43,27 +43,39 @@ static constexpr char WAVEFORM_MODE[] = "waveform";
 
 // Use effect #1 in the waveform library
 static constexpr char WAVEFORM_CLICK_EFFECT_SEQ[] = "1 0";
-static constexpr uint32_t WAVEFORM_CLICK_EFFECT_MS = 45;
+static constexpr uint32_t WAVEFORM_CLICK_EFFECT_MS = 6;
 
 // Make double click a single click and loop once
 static constexpr char WAVEFORM_DOUBLE_CLICK_EFFECT_SEQ[] = "1 1";
 static constexpr uint32_t WAVEFORM_DOUBLE_CLICK_EFFECT_MS = WAVEFORM_CLICK_EFFECT_MS * 2;
 
+// Timeout threshold for selecting open or closed loop mode
+static constexpr int8_t LOOP_MODE_THRESHOLD_MS = 20;
+
 Vibrator::Vibrator(std::ofstream&& activate, std::ofstream&& duration,
         std::ofstream&& state, std::ofstream&& rtpinput,
         std::ofstream&& mode, std::ofstream&& sequencer,
-        std::ofstream&& scale) :
+        std::ofstream&& scale, std::ofstream&& ctrlloop) :
     mActivate(std::move(activate)),
     mDuration(std::move(duration)),
     mState(std::move(state)),
     mRtpInput(std::move(rtpinput)),
     mMode(std::move(mode)),
     mSequencer(std::move(sequencer)),
-    mScale(std::move(scale)) {}
+    mScale(std::move(scale)),
+    mCtrlLoop(std::move(ctrlloop)) {}
 
 // Methods from ::android::hardware::vibrator::V1_0::IVibrator follow.
 Return<Status> Vibrator::on(uint32_t timeout_ms) {
+    uint32_t loop_mode = 1;
 
+    // Open-loop mode is used for short click for over-drive
+    // Close-loop mode is used for long notification for stability
+    if (timeout_ms > LOOP_MODE_THRESHOLD_MS) {
+        loop_mode = 0;
+    }
+
+    mCtrlLoop <<  loop_mode << std::endl;
     mDuration << timeout_ms << std::endl;
     if (!mDuration) {
         ALOGE("Failed to set duration (%d): %s", errno, strerror(errno));
@@ -109,7 +121,7 @@ Return<Status> Vibrator::setAmplitude(uint8_t amplitude) {
             std::round((amplitude - 1) / 254.0 * (MAX_RTP_INPUT - MIN_RTP_INPUT) +
             MIN_RTP_INPUT);
 
-    mRtpInput << rtp_input;
+    mRtpInput << rtp_input << std::endl;
     if (!mRtpInput) {
         ALOGE("Failed to set amplitude (%d): %s", errno, strerror(errno));
         return Status::UNKNOWN_ERROR;
@@ -123,12 +135,9 @@ static uint8_t convertEffectStrength(EffectStrength strength) {
 
     switch (strength) {
     case EffectStrength::LIGHT:
-        scale = 2; // 50%
+        scale = 1; // 50%
         break;
     case EffectStrength::MEDIUM:
-        scale = 1; // 75%
-        break;
-    default:
     case EffectStrength::STRONG:
         scale = 0; // 100%
         break;

vibrator/Vibrator.h

@@ -32,7 +32,7 @@ public:
     Vibrator(std::ofstream&& activate, std::ofstream&& duration,
             std::ofstream&& state, std::ofstream&& rtpinput,
             std::ofstream&& mode, std::ofstream&& sequencer,
-            std::ofstream&& scale);
+            std::ofstream&& scale, std::ofstream&& ctrlloop);
 
     // Methods from ::android::hardware::vibrator::V1_0::IVibrator follow.
     Return<Status> on(uint32_t timeoutMs)  override;
@@ -49,6 +49,7 @@ private:
     std::ofstream mMode;
     std::ofstream mSequencer;
     std::ofstream mScale;
+    std::ofstream mCtrlLoop;
 };
 }  // namespace implementation
 }  // namespace V1_0

vibrator/service.cpp

@@ -38,6 +38,7 @@ static const char *RTP_INPUT_PATH = "/sys/class/leds/vibrator/device/rtp_input";
 static const char *MODE_PATH = "/sys/class/leds/vibrator/device/mode";
 static const char *SEQUENCER_PATH = "/sys/class/leds/vibrator/device/set_sequencer";
 static const char *SCALE_PATH = "/sys/class/leds/vibrator/device/scale";
+static const char *CTRL_LOOP_PATH = "/sys/class/leds/vibrator/device/ctrl_loop";
 
 status_t registerVibratorService() {
     // ostreams below are required
@@ -94,9 +95,15 @@ status_t registerVibratorService() {
         ALOGW("Failed to open %s (%d): %s", SCALE_PATH, error, strerror(error));
     }
 
+    std::ofstream ctrlloop{CTRL_LOOP_PATH};
+    if (!state) {
+        int error = errno;
+        ALOGW("Failed to open %s (%d): %s", CTRL_LOOP_PATH, error, strerror(error));
+    }
+
     sp<IVibrator> vibrator = new Vibrator(std::move(activate), std::move(duration),
             std::move(state), std::move(rtpinput), std::move(mode),
-            std::move(sequencer), std::move(scale));
+            std::move(sequencer), std::move(scale), std::move(ctrlloop));
 
     vibrator->registerAsService();