From cc450aa9fb0792ca0c5ae05f648e04dba0fc19d1 Mon Sep 17 00:00:00 2001
From: Fredrik Tolf <fredrik@dolda2000.com>
Date: Fri, 14 Sep 2018 20:44:29 +0200
Subject: [PATCH] gpio: Added port-number mapping.

---
 gpio.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 59 insertions(+), 7 deletions(-)

diff --git a/gpio.c b/gpio.c
index babc061..1d8b322 100644
--- a/gpio.c
+++ b/gpio.c
@@ -6,13 +6,36 @@
 #include <errno.h>
 #include <err.h>
 
+static const int bmap[] = {
+    -1,
+    -1, -1,  2, -1,  3, -1,  4, 14, -1, 15, 17, 18, 27, -1, 22, 23, -1, 24, 10, -1,
+     9, 25, 11,  8, -1,  7, -1, -1,  5, -1,  6, 12, 13, -1, 19, 16, 21, 20, -1, 21,
+};
+static const int imap[] = {
+    -1, -1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13,
+    14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, 27,
+};
+static const int *umap = bmap;
+static int mapn = sizeof(bmap) / sizeof(*bmap);
+
+static int mappin(int num)
+{
+    if((num < 0) || (num >= mapn))
+	return(-1);
+    return(umap[num]);
+}
+
 static void setport(int p, int v)
 {
     char path[256], line[256];
     FILE *fp;
-    int rv;
+    int rv, rp;
     
-    sprintf(path, "/sys/class/gpio/gpio%i/direction", p);
+    if((rp = mappin(p)) < 0) {
+	fprintf(stderr, "gpio: %i: no such port\n", p);
+	exit(1);
+    }
+    sprintf(path, "/sys/class/gpio/gpio%i/direction", rp);
     if((fp = fopen(path, "r")) == NULL)
 	err(1, "%s", path);
     rv = !!fgets(line, sizeof(line), fp);
@@ -22,24 +45,47 @@ static void setport(int p, int v)
 	    err(1, "%s", path);
 	fprintf(fp, "out\n"); fflush(fp);
 	if(ferror(fp))
-	    errx(1, "gpio%i: could not set to output", p);
+	    errx(1, "gpio%i: could not set to output", rp);
 	fclose(fp);
     }
-    sprintf(path, "/sys/class/gpio/gpio%i/value", p);
+    sprintf(path, "/sys/class/gpio/gpio%i/value", rp);
     if((fp = fopen(path, "w")) == NULL)
 	err(1, "%s", path);
     fprintf(fp, "%i\n", v); fflush(fp);
     if(ferror(fp))
-	errx(1, "gpio%i: could not set value", p);
+	errx(1, "gpio%i: could not set value", rp);
     fclose(fp);
 }
 
+static void usage(FILE *out)
+{
+    fprintf(out, "usage: gpio [-hi] PORT=VAL...\n");
+}
+
 int main(int argc, char **argv)
 {
-    int i, port, val;
+    int c, i, port, val;
     char *p, *e;
     
-    for(i = 1; i < argc; i++) {
+    while((c = getopt(argc, argv, "hi")) >= 0) {
+	switch(c) {
+	case 'h':
+	    usage(stdout);
+	    return(0);
+	case 'i':
+	    umap = imap;
+	    mapn = sizeof(imap) / sizeof(*imap);
+	    break;
+	default:
+	    usage(stderr);
+	    return(1);
+	}
+    }
+    if(optind >= argc) {
+	usage(stderr);
+	return(1);
+    }
+    for(i = optind; i < argc; i++) {
 	if((p = strchr(argv[i], '=')) == NULL) {
 	    fprintf(stderr, "gpio: %s: not of the form PORT=VAL\n", argv[i]);
 	    exit(1);
@@ -58,3 +104,9 @@ int main(int argc, char **argv)
     }
     return(0);
 }
+
+/*
+ * Local Variables:
+ * compile-command: "gcc -Wall -g -O2 -march=native -o gpio gpio.c"
+ * End:
+ */
-- 
2.11.0