commit eb3029c6697007eac7a76a8bd34452cedbd2c526
author Jonathan Hogg <me@jonathanhogg.com> Mon Jul 12 11:35:25 2021 +0100
committer Damien George <damien@micropython.org> Fri Jul 16 23:05:30 2021 +1000
tree e048e4dc73128e0e2bbb8ad981f062cdb0964484
parent 98c5703027e7db9a030f747f4dd1684407230656

esp32/machine_spi: Calculate actual attained baudrate.

Calculate the actual baudrate that the hardware is capable of achieving 
and remember it so that printing the SPI object will show this. Fixes 
#7530.

ports/esp32/machine_hw_spi.c

diff --git a/ports/esp32/machine_hw_spi.c b/ports/esp32/machine_hw_spi.c
index 98c0aba..2792216 100644
--- a/ports/esp32/machine_hw_spi.c
+++ b/ports/esp32/machine_hw_spi.c
@@ -144,9 +144,13 @@
         changed = true;
     }
 
-    if (baudrate != -1 && baudrate != self->baudrate) {
-        self->baudrate = baudrate;
-        changed = true;
+    if (baudrate != -1) {
+        // calculate the actual clock frequency that the SPI peripheral can produce
+        baudrate = spi_get_actual_clock(APB_CLK_FREQ, baudrate, 0);
+        if (baudrate != self->baudrate) {
+            self->baudrate = baudrate;
+            changed = true;
+        }
     }
 
     if (polarity != -1 && polarity != self->polarity) {