nmhw24: configure com/io shield gpios in dtb

when a COM/IO shield is detected, its two IOs
are given names in the gpio section so that they
are accessible from Linux gpio chardev.

BugzId: 60150

board/nm/nrhw24/board.c

@@ -889,7 +889,7 @@ static void blink_led(int pulses)
 {
 	const int pulse_width = 400*1000; /* 400ms */
 
-	/* Assumed status led on, indicator off */
+	/* Assumes status led on, indicator off */
 	set_status_led(0, 0);
 
 	while (pulses) {
@@ -1142,6 +1142,54 @@ static void ft_enable_node(void* blob, const char* name)
 	}
 }
 
+/*
+ * Modify the name of a gpio in a gpio-line-names string list.
+ */
+static void ft_set_gpio_name(void *blob, const char* gpio, int pin, const char* name)
+{
+	int node_ofs = fdt_path_offset(blob, gpio);
+	if (node_ofs != -1) {
+		const struct fdt_property* prop = fdt_get_property(blob, node_ofs, "gpio-line-names", NULL);
+		if (prop != NULL) {
+			const char* text;
+			int pos = 0;
+			int i;
+			char buffer[512];
+
+			/* TODO: Determine number of entries from ngpios field */
+
+			for (i=0; i<32; i++) {
+				if (i == pin) {
+					/* Take provided name if GPIO pin is matched */
+					text = name;
+				}
+				else {
+					/* Take existing name from strin list */
+					(void)fdt_get_string_index(blob, node_ofs, "gpio-line-names", i, &text);
+				}
+				/* Add name to new string list */
+				strncpy(buffer+pos, text, sizeof(buffer)-pos);
+				pos += strlen(text) + 1;
+				printf(" %d %d %s\n", i, pos, text);
+			}
+
+			(void)fdt_setprop(blob, node_ofs, "gpio-line-names", buffer, pos);
+		}
+	}
+}
+
+/*
+ * Enable digital IOs provided by COM/IO shield in gpio nodes
+ */
+static void ft_comio_gpios(void *blob)
+{
+	/* gpio0_7: COM/IO relay output */
+	ft_set_gpio_name(blob, "/ocp/gpio@44e07000", 7, "COMIO_OUT0");
+
+	/* gpio1_8: COM/IO digital input */
+	ft_set_gpio_name(blob, "/ocp/gpio@4804c000", 8, "COMIO_IN0");
+}
+
 static void ft_shields(void* blob)
 {
 	int shield_type = -1;
@@ -1149,6 +1197,7 @@ static void ft_shields(void* blob)
 	shield_type = bd_get_shield(0);
 	switch (shield_type) {
 		case SHIELD_COM_IO:
+			ft_comio_gpios(blob);
 			ft_enable_node(blob, "/netbox_dio_comio");
 			/* TODO: Should use alias serial0 */
 			ft_enable_node(blob, "/ocp/serial@44e09000");