From 100f06614c70b9f8e2259fccef4597c4e414e9cf Mon Sep 17 00:00:00 2001
From: Jeremy Feltracco <jpfeltracco@gmail.com>
Date: Thu, 11 Apr 2019 10:26:35 -0400
Subject: [PATCH] AP_HAL_Linux: Add support for setting uart parity on Linux
 boards

Pass set_parity down through UART class so that set_parity actually
works for Linux boards.
---
 libraries/AP_HAL_Linux/SerialDevice.h |  3 +++
 libraries/AP_HAL_Linux/UARTDevice.cpp | 20 ++++++++++++++++++++
 libraries/AP_HAL_Linux/UARTDevice.h   |  1 +
 libraries/AP_HAL_Linux/UARTDriver.cpp |  4 ++++
 libraries/AP_HAL_Linux/UARTDriver.h   |  2 ++
 5 files changed, 30 insertions(+)

diff --git a/libraries/AP_HAL_Linux/SerialDevice.h b/libraries/AP_HAL_Linux/SerialDevice.h
index 59b62c00cd..ad10a3774d 100644
--- a/libraries/AP_HAL_Linux/SerialDevice.h
+++ b/libraries/AP_HAL_Linux/SerialDevice.h
@@ -20,4 +20,7 @@ public:
     {
         /* most devices simply ignore this setting */
     };
+
+    /* Depends on lower level to implement, most devices are fine with defaults */
+    virtual void set_parity(int v) { }
 };
diff --git a/libraries/AP_HAL_Linux/UARTDevice.cpp b/libraries/AP_HAL_Linux/UARTDevice.cpp
index d4eda6cca5..77b3a38fbf 100644
--- a/libraries/AP_HAL_Linux/UARTDevice.cpp
+++ b/libraries/AP_HAL_Linux/UARTDevice.cpp
@@ -130,3 +130,23 @@ void UARTDevice::set_flow_control(AP_HAL::UARTDriver::flow_control flow_control_
 
     _flow_control = flow_control_setting;
 }
+
+void UARTDevice::set_parity(int v)
+{
+    struct termios t;
+    tcgetattr(_fd, &t);
+    if (v != 0) {
+        // enable parity
+        t.c_cflag |= PARENB;
+        if (v == 1) {
+            t.c_cflag |= PARODD;
+        } else {
+            t.c_cflag &= ~PARODD;
+        }
+    }
+    else {
+        // disable parity
+        t.c_cflag &= ~PARENB;
+    }
+    tcsetattr(_fd, TCSANOW, &t);
+}
diff --git a/libraries/AP_HAL_Linux/UARTDevice.h b/libraries/AP_HAL_Linux/UARTDevice.h
index abb1d76dfc..b6dcae6ed6 100644
--- a/libraries/AP_HAL_Linux/UARTDevice.h
+++ b/libraries/AP_HAL_Linux/UARTDevice.h
@@ -19,6 +19,7 @@ public:
     {
         return _flow_control;
     }
+    virtual void set_parity(int v) override;
 
 private:
     void _disable_crlf();
diff --git a/libraries/AP_HAL_Linux/UARTDriver.cpp b/libraries/AP_HAL_Linux/UARTDriver.cpp
index 8e22326f1c..a7e19ba953 100644
--- a/libraries/AP_HAL_Linux/UARTDriver.cpp
+++ b/libraries/AP_HAL_Linux/UARTDriver.cpp
@@ -457,6 +457,10 @@ void UARTDriver::_timer_tick(void)
     _in_timer = false;
 }
 
+void UARTDriver::configure_parity(uint8_t v) {
+    _device->set_parity(v);
+}
+
 /*
   return timestamp estimate in microseconds for when the start of
   a nbytes packet arrived on the uart. This should be treated as a
diff --git a/libraries/AP_HAL_Linux/UARTDriver.h b/libraries/AP_HAL_Linux/UARTDriver.h
index 775baadf66..1083844191 100644
--- a/libraries/AP_HAL_Linux/UARTDriver.h
+++ b/libraries/AP_HAL_Linux/UARTDriver.h
@@ -45,6 +45,8 @@ public:
         return _device->get_flow_control();
     }
 
+    virtual void configure_parity(uint8_t v);
+
     virtual void set_flow_control(enum flow_control flow_control_setting) override
    {
        _device->set_flow_control(flow_control_setting);