2 files changed, 40 insertions, 12 deletions

diff --git a/src/drivers/Cst816s.cpp b/src/drivers/Cst816s.cpp
index 1ff163b0..49d6ed0e 100644
--- a/src/drivers/Cst816s.cpp
+++ b/src/drivers/Cst816s.cpp
@@ -18,7 +18,7 @@ using namespace Pinetime::Drivers;
 Cst816S::Cst816S(TwiMaster& twiMaster, uint8_t twiAddress) : twiMaster {twiMaster}, twiAddress {twiAddress} {
 }
 
-void Cst816S::Init() {
+bool Cst816S::Init() {
   nrf_gpio_cfg_output(PinMap::Cst816sReset);
   nrf_gpio_pin_set(PinMap::Cst816sReset);
   vTaskDelay(50);
@@ -51,10 +51,27 @@ void Cst816S::Init() {
   */
   static constexpr uint8_t irqCtl = 0b01110000;
   twiMaster.Write(twiAddress, 0xFA, &irqCtl, 1);
+
+  // There's mixed information about which register contains which information
+  if (twiMaster.Read(twiAddress, 0xA7, &chipId, 1) == TwiMaster::ErrorCodes::TransactionFailed) {
+    chipId = 0xFF;
+    return false;
+  }
+  if (twiMaster.Read(twiAddress, 0xA8, &vendorId, 1) == TwiMaster::ErrorCodes::TransactionFailed) {
+    vendorId = 0xFF;
+    return false;
+  }
+  if (twiMaster.Read(twiAddress, 0xA9, &fwVersion, 1) == TwiMaster::ErrorCodes::TransactionFailed) {
+    fwVersion = 0xFF;
+    return false;
+  }
+
+  return chipId == 0xb4 && vendorId == 0 && fwVersion == 1;
 }
 
 Cst816S::TouchInfos Cst816S::GetTouchInfo() {
   Cst816S::TouchInfos info;
+  uint8_t touchData[7];
 
   auto ret = twiMaster.Read(twiAddress, 0, touchData, sizeof(touchData));
   if (ret != TwiMaster::ErrorCodes::NoError) {
@@ -62,18 +79,17 @@ Cst816S::TouchInfos Cst816S::GetTouchInfo() {
     return info;
   }
 
-  auto nbTouchPoints = touchData[2] & 0x0f;
+  // This can only be 0 or 1
+  uint8_t nbTouchPoints = touchData[touchPointNumIndex] & 0x0f;
 
-  auto xHigh = touchData[touchXHighIndex] & 0x0f;
-  auto xLow = touchData[touchXLowIndex];
-  uint16_t x = (xHigh << 8) | xLow;
+  uint8_t xHigh = touchData[touchXHighIndex] & 0x0f;
+  uint8_t xLow = touchData[touchXLowIndex];
+  info.x = (xHigh << 8) | xLow;
 
-  auto yHigh = touchData[touchYHighIndex] & 0x0f;
-  auto yLow = touchData[touchYLowIndex];
-  uint16_t y = (yHigh << 8) | yLow;
+  uint8_t yHigh = touchData[touchYHighIndex] & 0x0f;
+  uint8_t yLow = touchData[touchYLowIndex];
+  info.y = (yHigh << 8) | yLow;
 
-  info.x = x;
-  info.y = y;
   info.touching = (nbTouchPoints > 0);
   info.gesture = static_cast<Gestures>(touchData[gestureIndex]);
 
diff --git a/src/drivers/Cst816s.h b/src/drivers/Cst816s.h
index 7b46c5d5..0fec8419 100644
--- a/src/drivers/Cst816s.h
+++ b/src/drivers/Cst816s.h
@@ -30,11 +30,20 @@ namespace Pinetime {
       Cst816S(Cst816S&&) = delete;
       Cst816S& operator=(Cst816S&&) = delete;
 
-      void Init();
+      bool Init();
       TouchInfos GetTouchInfo();
       void Sleep();
       void Wakeup();
 
+      uint8_t GetChipId() const {
+        return chipId;
+      }
+      uint8_t GetVendorId() const {
+        return vendorId;
+      }
+      uint8_t GetFwVersion() const {
+        return fwVersion;
+      }
     private:
       // Unused/Unavailable commented out
       static constexpr uint8_t gestureIndex = 1;
@@ -49,9 +58,12 @@ namespace Pinetime {
       //static constexpr uint8_t touchXYIndex = 7;
       //static constexpr uint8_t touchMiscIndex = 8;
 
-      uint8_t touchData[7];
       TwiMaster& twiMaster;
       uint8_t twiAddress;
+
+      uint8_t chipId;
+      uint8_t vendorId;
+      uint8_t fwVersion;
     };
 
   }