Add 'led' command

This patch allows any board implementing the coloured LED API
to control the LEDs from the console.

led [green | yellow | red | all ]  [ on | off ]

or

led [ 1 | 2 | 3 | all ]  [ on | off ]

Adds configuration item CONFIG_CMD_LED enabling the command.

Partially based on patch from Ulf Samuelsson:
http://www.mail-archive.com/u-boot@lists.denx.de/msg09593.html.

Updated based on feedback:
http://www.mail-archive.com/u-boot@lists.denx.de/msg41847.html
https://groups.google.com/d/topic/beagleboard/8Wf1HiK_QBo/discussion


* Fixed a handful of style issues.
* Significantly reduced the number of #ifdefs and redundant code
* Converted redundant code into loops test against a structure
* Made use of cmd_usage()
* Introduced a str_onoff() function, but haven't yet put it in common
* Eliminated trailing newline

Signed-off-by: Jason Kridner <jkridner@beagleboard.org>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

common/cmd_led.c

+/*
+ * (C) Copyright 2010
+ * Jason Kridner <jkridner@beagleboard.org>
+ *
+ * Based on cmd_led.c patch from:
+ * http://www.mail-archive.com/u-boot@lists.denx.de/msg06873.html
+ * (C) Copyright 2008
+ * Ulf Samuelsson <ulf.samuelsson@atmel.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <config.h>
+#include <command.h>
+#include <status_led.h>
+
+struct led_tbl_s {
+	char		*string;	/* String for use in the command */
+	led_id_t	mask;		/* Mask used for calling __led_set() */
+	void		(*on)(void);	/* Optional fucntion for turning LED on */
+	void		(*off)(void);	/* Optional fucntion for turning LED on */
+};
+
+typedef struct led_tbl_s led_tbl_t;
+
+static const led_tbl_t led_commands[] = {
+#ifdef CONFIG_BOARD_SPECIFIC_LED
+#ifdef STATUS_LED_BIT
+	{ "0", STATUS_LED_BIT, NULL, NULL },
+#endif
+#ifdef STATUS_LED_BIT1
+	{ "1", STATUS_LED_BIT1, NULL, NULL },
+#endif
+#ifdef STATUS_LED_BIT2
+	{ "2", STATUS_LED_BIT2, NULL, NULL },
+#endif
+#ifdef STATUS_LED_BIT3
+	{ "3", STATUS_LED_BIT3, NULL, NULL },
+#endif
+#endif
+#ifdef STATUS_LED_GREEN
+	{ "green", STATUS_LED_GREEN, green_LED_off, green_LED_on },
+#endif
+#ifdef STATUS_LED_YELLOW
+	{ "yellow", STATUS_LED_YELLOW, yellow_LED_off, yellow_LED_on },
+#endif
+#ifdef STATUS_LED_RED
+	{ "red", STATUS_LED_RED, red_LED_off, red_LED_on },
+#endif
+#ifdef STATUS_LED_BLUE
+	{ "blue", STATUS_LED_BLUE, blue_LED_off, blue_LED_on },
+#endif
+	{ NULL, 0, NULL, NULL }
+};
+
+int str_onoff (char *var)
+{
+	if (strcmp(var, "off") == 0) {
+		return 0;
+	}
+	if (strcmp(var, "on") == 0) {
+		return 1;
+	}
+	return -1;
+}
+
+int do_led (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	int state, i;
+
+	/* Validate arguments */
+	if ((argc != 3)) {
+		return cmd_usage(cmdtp);
+	}
+
+	state = str_onoff(argv[2]);
+	if (state < 0) {
+		return cmd_usage(cmdtp);
+	}
+
+	for (i = 0; led_commands[i].string; i++) {
+		if ((strcmp("all", argv[1]) == 0) || 
+		    (strcmp(led_commands[i].string, argv[1]) == 0)) {
+			if (led_commands[i].on) {
+				if (state) {
+					led_commands[i].on();
+				} else {
+					led_commands[i].off();
+				}
+			} else {
+				__led_set(led_commands[i].mask, state);
+			}
+			break;
+		}
+	}
+
+	/* If we ran out of matches, print Usage */
+	if (!led_commands[i].string && !(strcmp("all", argv[1]) == 0)) {
+		return cmd_usage(cmdtp);
+	}
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	led, 3, 1, do_led,
+	"led\t- ["
+#ifdef CONFIG_BOARD_SPECIFIC_LED
+#ifdef STATUS_LED_BIT
+	"0|"
+#endif
+#ifdef STATUS_LED_BIT1
+	"1|"
+#endif
+#ifdef STATUS_LED_BIT2
+	"2|"
+#endif
+#ifdef STATUS_LED_BIT3
+	"3|"
+#endif
+#endif
+#ifdef STATUS_LED_GREEN
+	"green|"
+#endif
+#ifdef STATUS_LED_YELLOW
+	"yellow|"
+#endif
+#ifdef STATUS_LED_RED
+	"red|"
+#endif
+#ifdef STATUS_LED_BLUE
+	"blue|"
+#endif
+	"all] [on|off]\n",
+	"led [led_name] [on|off] sets or clears led(s)\n"
+);