altos/stmf0: Compute serial baud rate registers at runtime

This allows the system clock to vary at runtime, instead of requiring
a fixed value.

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

diff --git a/src/stmf0/ao_serial_stm.c b/src/stmf0/ao_serial_stm.c
index 30b0dbd26cde52af8a5a1405cbce34e700a99c2c..06fc054ae9879153e8ce43a0d393d7da1f3f28ed 100644 (file)
--- a/src/stmf0/ao_serial_stm.c
+++ b/src/stmf0/ao_serial_stm.c
@@ -163,24 +163,12 @@ ao_usart_drain(struct ao_stm_usart *usart)
        ao_arch_release_interrupts();
 }
 
-static const struct {
-       uint32_t brr;
-} ao_usart_speeds[] = {
-       [AO_SERIAL_SPEED_4800] = {
-               AO_PCLK / 4800
-       },
-       [AO_SERIAL_SPEED_9600] = {
-               AO_PCLK / 9600
-       },
-       [AO_SERIAL_SPEED_19200] = {
-               AO_PCLK / 19200
-       },
-       [AO_SERIAL_SPEED_57600] = {
-               AO_PCLK / 57600
-       },
-       [AO_SERIAL_SPEED_115200] = {
-               AO_PCLK / 115200
-       },
+static const uint32_t ao_usart_speeds[] = {
+       [AO_SERIAL_SPEED_4800] = 4800,
+       [AO_SERIAL_SPEED_9600] = 9600,
+       [AO_SERIAL_SPEED_19200] = 19200,
+       [AO_SERIAL_SPEED_57600] = 57600,
+       [AO_SERIAL_SPEED_115200] = 115200,
 };
 
 static void
@@ -188,7 +176,7 @@ ao_usart_set_speed(struct ao_stm_usart *usart, uint8_t speed)
 {
        if (speed > AO_SERIAL_SPEED_115200)
                return;
-       usart->reg->brr = ao_usart_speeds[speed].brr;
+       usart->reg->brr = AO_PCLK / ao_usart_speeds[speed];
 }
 
 static void