From 3f5dc472965e6a5b8efe60e33c7b6c2d18d92008 Mon Sep 17 00:00:00 2001
From: Stefan Kerkmann <karlk90@pm.me>
Date: Mon, 11 Jul 2022 15:17:05 +0200
Subject: [Core] Use polled waiting on ChibiOS platforms that support it
 (#17607)

* Use polled waiting on platforms that support it

Due to context switching overhead waiting a very short amount of time on
a sleeping thread is often not accurate and in fact not usable for timing
critical usage i.e. in a driver. Thus we use polled waiting for ranges
in the us range on platforms that support it instead. The fallback is
the thread sleeping mechanism.

This includes:

* ARM platforms with CYCCNT register (ARMv7, ARMv8) this is
  incremented at CPU clock frequency
* GD32VF103 RISC-V port with CSR_MCYCLE register this is incremented at
  CPU clock frequency
* RP2040 ARMv6 port which uses the integrated timer peripheral which is
  incremented with a fixed 1MHz frequency

* Use wait_us() instead of chSysPolledDelayX

...as it is powered by busy waiting now.

* Add chibios waiting methods test bench
---
 keyboards/preonic/rev3_drop/matrix.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

(limited to 'keyboards/preonic')

diff --git a/keyboards/preonic/rev3_drop/matrix.c b/keyboards/preonic/rev3_drop/matrix.c
index 07171a39e9..82214e03d9 100644
--- a/keyboards/preonic/rev3_drop/matrix.c
+++ b/keyboards/preonic/rev3_drop/matrix.c
@@ -15,14 +15,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <stdint.h>
-#include <stdbool.h>
-#include <string.h>
-#include "hal.h"
-#include "timer.h"
-#include "wait.h"
-#include "debug.h"
-#include "matrix.h"
+#include "quantum.h"
 
 typedef uint16_t matrix_col_t;
 
@@ -40,9 +33,13 @@ __attribute__((weak)) void matrix_init_user(void) {}
 
 __attribute__((weak)) void matrix_scan_user(void) {}
 
-__attribute__((weak)) void matrix_init_kb(void) { matrix_init_user(); }
+__attribute__((weak)) void matrix_init_kb(void) {
+    matrix_init_user();
+}
 
-__attribute__((weak)) void matrix_scan_kb(void) { matrix_scan_user(); }
+__attribute__((weak)) void matrix_scan_kb(void) {
+    matrix_scan_user();
+}
 
 void matrix_init(void) {
     dprintf("matrix init\n");
@@ -150,9 +147,13 @@ uint8_t matrix_scan(void) {
     return 1;
 }
 
-bool matrix_is_on(uint8_t row, uint8_t col) { return (matrix[row] & (1 << col)); }
+bool matrix_is_on(uint8_t row, uint8_t col) {
+    return (matrix[row] & (1 << col));
+}
 
-matrix_row_t matrix_get_row(uint8_t row) { return matrix[row]; }
+matrix_row_t matrix_get_row(uint8_t row) {
+    return matrix[row];
+}
 
 void matrix_print(void) {
     dprintf("\nr/c 01234567\n");
-- 
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