ARM: cfa10036: Retrieve the board variant from the AT24

The AT24 found on the expansion boards store the variant of the board it
is soldered onto.

That means that we are that way able to determine what expansion board
is currently plugged in if any. If we can't communicate with the EEPROM,
we just assume that only the CFA-10036 is there.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/boards/crystalfontz-cfa10036/Makefile

@@ -1 +1 @@
-obj-y += cfa10036.o
+obj-y += cfa10036.o hwdetect.o

arch/arm/boards/crystalfontz-cfa10036/cfa10036.c

@@ -42,6 +42,8 @@
 
 #include <generated/mach-types.h>
 
+#include "hwdetect.h"
+
 /* setup the CPU card internal signals */
 static const uint32_t cfa10036_pads[] = {
 	/* duart */
@@ -120,6 +122,8 @@ static int cfa10036_devices_init(void)
 	i2c_register_board_info(0, cfa10036_i2c_devices, ARRAY_SIZE(cfa10036_i2c_devices));
 	add_generic_device_res("i2c-gpio", 0, NULL, 0, &i2c_gpio_pdata);
 
+	cfa10036_detect_hw();
+
 	return 0;
 }
 device_initcall(cfa10036_devices_init);

arch/arm/boards/crystalfontz-cfa10036/hwdetect.c

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2012 Free Electrons
+ *
+ * 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.
+ *
+ *
+ */
+
+#include <common.h>
+
+#include <environment.h>
+#include <fcntl.h>
+#include <fs.h>
+#include <globalvar.h>
+#include <libbb.h>
+#include <magicvar.h>
+
+#include <asm/armlinux.h>
+
+enum board_type {
+	BOARD_ID_CFA10036 = 0,
+	BOARD_ID_CFA10037 = 1,
+	BOARD_ID_CFA10049 = 2,
+};
+
+struct cfa_eeprom_info {
+	u8 board_id;
+}__attribute__ ((packed));
+
+static int cfa10036_read_eeprom(const char *file, struct cfa_eeprom_info *info)
+{
+	int fd;
+	int ret;
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0) {
+		ret = fd;
+		goto err;
+	}
+
+	ret = read_full(fd, info, sizeof(*info));
+	if (ret < 0)
+		goto err_open;
+
+	ret = 0;
+
+err_open:
+	close(fd);
+err:
+	if (ret)
+		pr_err("can not read eeprom %s (%s)\n", file, strerror(ret));
+	return ret;
+}
+
+void cfa10036_detect_hw(void)
+{
+	enum board_type cfa_type;
+	struct cfa_eeprom_info info;
+	char *board_name;
+	int ret;
+
+	ret = cfa10036_read_eeprom("/dev/eeprom0", &info);
+	if (ret)
+		cfa_type = BOARD_ID_CFA10036;
+	else
+		cfa_type = info.board_id;
+
+	switch (cfa_type) {
+	case BOARD_ID_CFA10036:
+		board_name = "cfa10036";
+		break;
+	case BOARD_ID_CFA10037:
+		board_name = "cfa10037";
+		break;
+	case BOARD_ID_CFA10049:
+		board_name = "cfa10049";
+		break;
+	default:
+		pr_err("Board ID not supported\n");
+		return;
+	}
+
+	globalvar_add_simple("board.variant");
+	setenv("global.board.variant", board_name);
+	pr_info("Booting on a CFA10036 with %s\n", board_name);
+}
+
+BAREBOX_MAGICVAR_NAMED(global_board_variant, global.board.variant, "The board variant");

arch/arm/boards/crystalfontz-cfa10036/hwdetect.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 Free Electrons
+ *
+ * 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.
+ *
+ *
+ */
+
+#ifndef __HWDETECT_H__
+#define __HWDETECT_H__
+
+void cfa10036_detect_hw(void);
+
+#endif /* __HWDETECT_H__ */