shell: implement buzzer command

source/shell/buzzer.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <buzzer.h>
+#include <console.h>
+
+extern struct buzzer buzzers[];
+extern size_t nbuzzers;
+
+int shell_buzzer(struct console *con, size_t argc, const char **argv)
+{
+	struct buzzer *buzzer;
+	size_t buzzer_id = 0;
+	uint32_t freq = 0;
+	int state = 0;
+
+	if (argc >= 3)
+		freq = strtoul(argv[2], NULL, 0);
+
+	if (argc >= 2)
+		state = (strcmp(argv[1], "on") == 0);
+
+	if (argc >= 1)
+		buzzer_id = strtoul(argv[0], NULL, 0);
+
+	fprintf(con->fp, "%u %d %u\n", buzzer_id, state, freq);
+
+	if (buzzer_id > nbuzzers) {
+		fprintf(con->fp, "error: invalid buzzer ID %d\n", buzzer_id);
+		return -1;
+	}
+
+	buzzer = buzzers + buzzer_id;
+
+	if (!state) {
+		buzzer_disable(buzzer);
+		return 0;
+	}
+
+	if (freq)
+		buzzer_set_freq(buzzer, freq);
+
+	buzzer_enable(buzzer);
+
+	return 0;
+}