altos: Use alt_t for all Pascal-based altitude data

This allows alt_t to be overridden for systems using the MS5607/MS5611
sensors

Signed-off-by: Keith Packard <keithp@keithp.com>

4 files changed, 18 insertions, 6 deletions

diff --git a/src/core/ao.h b/src/core/ao.h
index 200d4bc4..e559e876 100644
--- a/src/core/ao.h
+++ b/src/core/ao.h
@@ -272,11 +272,13 @@ ao_temp_to_dC(int16_t temp) __reentrant;
  * Convert between pressure in Pa and altitude in meters
  */
 
-int32_t
+#include <ao_data.h>
+
+alt_t
 ao_pa_to_altitude(int32_t pa);
 
 int32_t
-ao_altitude_to_pa(int32_t alt);
+ao_altitude_to_pa(alt_t alt);
 
 #if HAS_DBG
 #include <ao_dbg.h>
diff --git a/src/core/ao_convert_pa.c b/src/core/ao_convert_pa.c
index 0c93caea..1413681d 100644
--- a/src/core/ao_convert_pa.c
+++ b/src/core/ao_convert_pa.c
@@ -26,7 +26,7 @@ static const int32_t altitude_table[] = {
 #define ALT_SCALE	(1 << ALT_SHIFT)
 #define ALT_MASK	(ALT_SCALE - 1)
 
-int32_t
+alt_t
 ao_pa_to_altitude(int32_t pa)
 {
 	int16_t	o;
@@ -40,8 +40,8 @@ ao_pa_to_altitude(int32_t pa)
 	o = pa >> ALT_SHIFT;
 	part = pa & ALT_MASK;
 
-	low = (int32_t) altitude_table[o] * (ALT_SCALE - part);
-	high = (int32_t) altitude_table[o+1] * part + (ALT_SCALE >> 1);
+	low = (alt_t) FETCH_ALT(o) * (ALT_SCALE - part);
+	high = (alt_t) FETCH_ALT(o+1) * part + (ALT_SCALE >> 1);
 	return (low + high) >> ALT_SHIFT;
 }
 
diff --git a/src/core/ao_convert_pa_test.c b/src/core/ao_convert_pa_test.c
index 972a4d4c..143ce958 100644
--- a/src/core/ao_convert_pa_test.c
+++ b/src/core/ao_convert_pa_test.c
@@ -17,6 +17,7 @@
 
 #include <stdint.h>
 #define AO_CONVERT_TEST
+typedef int32_t alt_t;
 #include "ao_host.h"
 #include "ao_convert_pa.c"
 
diff --git a/src/core/ao_data.h b/src/core/ao_data.h
index 2b9ef5ac..90182b12 100644
--- a/src/core/ao_data.h
+++ b/src/core/ao_data.h
@@ -110,7 +110,12 @@ extern volatile __data uint8_t		ao_data_count;
 #define HAS_BARO	1
 
 typedef int32_t	pres_t;
-typedef int32_t alt_t;
+
+#ifndef AO_ALT_TYPE
+#define AO_ALT_TYPE	int32_t
+#endif
+
+typedef AO_ALT_TYPE	alt_t;
 
 #define ao_data_pres_cook(packet)	ao_ms5607_convert(&packet->ms5607_raw, &packet->ms5607_cooked)
 
@@ -135,6 +140,10 @@ typedef int16_t alt_t;
 
 #endif
 
+#if !HAS_BARO
+typedef int16_t alt_t;
+#endif
+
 /*
  * Need a few macros to pull data from the sensors:
  *