From 867df82ced7b8aecba30eb4f68f864d5613d601b Mon Sep 17 00:00:00 2001
From: MrKevinWeiss <weiss.kevin604@gmail.com>
Date: Tue, 19 May 2020 17:07:11 +0200
Subject: [PATCH] tests/periph_spi: Expose default SPI CS pins

Expose the option to use default cs pins defined as DEFAULT_SPI_CS_PORT and DEFAULT_SPI_CS_PIN.
This is used if a wiring environment is already defined.
CFLAGS can be used to define the CS pin from the environment provided allowing easier automation of tests.
---
 tests/periph_spi/README.md |  6 ++++++
 tests/periph_spi/main.c    | 34 ++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/tests/periph_spi/README.md b/tests/periph_spi/README.md
index 543b51d09b..102adee3a5 100644
--- a/tests/periph_spi/README.md
+++ b/tests/periph_spi/README.md
@@ -6,3 +6,9 @@ as master or slave, and to send and receive data via SPI.
 Background
 ==========
 Test for the low-level SPI driver.
+
+## Default SPI CS pin
+
+To overwrite the optional default cs pin CFLAGS can be used:
+
+`CFLAGS="-DDEFAULT_SPI_CS_PORT=<my_port_int> -DDEFAULT_SPI_CS_PIN=<my_pin_int>" BOARD=<my_board> make flash term`
diff --git a/tests/periph_spi/main.c b/tests/periph_spi/main.c
index 98f6b15930..d5163eaaf8 100644
--- a/tests/periph_spi/main.c
+++ b/tests/periph_spi/main.c
@@ -28,6 +28,20 @@
 #include "shell.h"
 #include "periph/spi.h"
 
+/**
+ * @brief   Default port number used for the CS pin if unassigned
+ */
+#ifndef DEFAULT_SPI_CS_PORT
+#define DEFAULT_SPI_CS_PORT 0
+#endif
+
+/**
+ * @brief   Default port number used for the CS pin if unassigned
+ */
+#ifndef DEFAULT_SPI_CS_PIN
+#define DEFAULT_SPI_CS_PIN 0
+#endif
+
 /**
  * @brief   Some parameters used for benchmarking
  */
@@ -83,8 +97,8 @@ int cmd_init(int argc, char **argv)
 {
     int dev, mode, clk, port, pin, tmp;
 
-    if (argc < 5) {
-        printf("usage: %s <dev> <mode> <clk> <cs port> <cs pin>\n", argv[0]);
+    if (argc < 4) {
+        printf("usage: %s <dev> <mode> <clk> [cs port] [cs pin]\n", argv[0]);
         puts("\tdev:");
         for (int i = 0; i < (int)SPI_NUMOF; i++) {
             printf("\t\t%i: SPI_DEV(%i)\n", i, i);
@@ -142,8 +156,20 @@ int cmd_init(int argc, char **argv)
     }
 
     /* parse chip select port and pin */
-    port = atoi(argv[4]);
-    pin = atoi(argv[5]);
+    if (argc > 5) {
+        pin = atoi(argv[5]);
+    }
+    else {
+        pin = DEFAULT_SPI_CS_PIN;
+    }
+
+    if (argc > 4) {
+        port = atoi(argv[4]);
+    }
+    else {
+        port = DEFAULT_SPI_CS_PORT;
+    }
+
     if (pin < 0 || port < -1) {
         puts("error: invalid CS port/pin combination specified");
     }