Fix SPI Transfer rx code

TEST: Read SPI data from a sensor

Change-Id: I4a853d89f177fd281c0cb29d64bc57d82d7a0478

2 files changed, 15 insertions, 11 deletions

diff --git a/client/spi_device_impl.cc b/client/spi_device_impl.cc
index 81d863c..e21ca5a 100644
--- a/client/spi_device_impl.cc
+++ b/client/spi_device_impl.cc
@@ -22,6 +22,7 @@
 
 using android::sp;
 using android::os::IPeripheralManagerClient;
+using android::binder::Status;
 
 SpiDeviceImpl::SpiDeviceImpl(const std::string& name,
                              sp<IPeripheralManagerClient> client)
@@ -43,15 +44,18 @@ int SpiDeviceImpl::WriteBuffer(const uint8_t* data, size_t len) {
 int SpiDeviceImpl::Transfer(const uint8_t* tx_data,
                             uint8_t* rx_data,
                             size_t len) {
-  std::unique_ptr<std::vector<uint8_t>> sent(nullptr);
-  std::unique_ptr<std::vector<uint8_t>> received(
-      rx_data ? new std::vector<uint8_t> : nullptr);
+  std::unique_ptr<std::vector<uint8_t>> sent;
+  std::unique_ptr<std::vector<uint8_t>> received;
 
-  if (tx_data != nullptr)
-    sent.reset(new std::vector<uint8_t>(tx_data, tx_data + len));
+  if (tx_data == nullptr)
+    return EINVAL;
 
-  return client_->SpiDeviceTransfer(name_, sent, &received, len)
-      .serviceSpecificErrorCode();
+  sent.reset(new std::vector<uint8_t>(tx_data, tx_data + len));
+
+  Status status = client_->SpiDeviceTransfer(name_, sent, &received, len);
+  if (status.isOk() && rx_data)
+    memcpy(rx_data, received->data(), len);
+  return status.serviceSpecificErrorCode();
 }
 
 int SpiDeviceImpl::SetFrequency(uint32_t freq_hz) {
diff --git a/daemon/peripheral_manager_client.cc b/daemon/peripheral_manager_client.cc
index 5bffd6f..5eaa2e5 100644
--- a/daemon/peripheral_manager_client.cc
+++ b/daemon/peripheral_manager_client.cc
@@ -173,15 +173,15 @@ Status PeripheralManagerClient::SpiDeviceTransfer(
   if (!spi_devices_.count(name))
     return Status::fromServiceSpecificError(EPERM);
 
-  uint8_t* data_sent = tx_data ? tx_data->data() : nullptr;
   if (!rx_data) {
-    if (spi_devices_.find(name)->second->Transfer(data_sent, nullptr, size)) {
+    if (spi_devices_.find(name)->second->Transfer(tx_data->data(), nullptr,
+                                                  size)) {
       return Status::ok();
     }
   } else {
     rx_data->reset(new std::vector<uint8_t>(size));
-    if (spi_devices_.find(name)->second->Transfer(data_sent, (*rx_data)->data(),
-                                                  size)) {
+    if (spi_devices_.find(name)->second->Transfer(tx_data->data(),
+                                                  (*rx_data)->data(), size)) {
       return Status::ok();
     }
   }