mach-ux500: dynamic UIB (user interface boards) detection

Add support for dynamic detection of the UIB used (at the cost of one i2c error
on the lesser-used UIB) and also provide an override via a command line
parameter if needed.

Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Sundar Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 135 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/board-mop500-uib.c b/arch/arm/mach-ux500/board-mop500-uib.c
new file mode 100644
index 000000000000..69cce41f602a
--- /dev/null
+++ b/arch/arm/mach-ux500/board-mop500-uib.c
@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
+ * License terms: GNU General Public License (GPL), version 2
+ */
+
+#define pr_fmt(fmt)	"mop500-uib: " fmt
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+
+#include <mach/hardware.h>
+#include "board-mop500.h"
+
+enum mop500_uib {
+	STUIB,
+	U8500UIB,
+};
+
+struct uib {
+	const char *name;
+	const char *option;
+	void (*init)(void);
+};
+
+static struct __initdata uib mop500_uibs[] = {
+	[STUIB] = {
+		.name	= "ST-UIB",
+		.option	= "stuib",
+		.init	= mop500_stuib_init,
+	},
+	[U8500UIB] = {
+		.name	= "U8500-UIB",
+		.option	= "u8500uib",
+		.init	= mop500_u8500uib_init,
+	},
+};
+
+static struct uib *mop500_uib;
+
+static int __init mop500_uib_setup(char *str)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mop500_uibs); i++) {
+		struct uib *uib = &mop500_uibs[i];
+
+		if (!strcmp(str, uib->option)) {
+			mop500_uib = uib;
+			break;
+		}
+	}
+
+	if (i == ARRAY_SIZE(mop500_uibs))
+		pr_err("invalid uib= option (%s)\n", str);
+
+	return 1;
+}
+__setup("uib=", mop500_uib_setup);
+
+/*
+ * The UIBs are detected after the I2C host controllers are registered, so
+ * i2c_register_board_info() can't be used.
+ */
+void mop500_uib_i2c_add(int busnum, struct i2c_board_info *info,
+		unsigned n)
+{
+	struct i2c_adapter *adap;
+	struct i2c_client *client;
+	int i;
+
+	adap = i2c_get_adapter(busnum);
+	if (!adap) {
+		pr_err("failed to get adapter i2c%d\n", busnum);
+		return;
+	}
+
+	for (i = 0; i < n; i++) {
+		client = i2c_new_device(adap, &info[i]);
+		if (!client)
+			pr_err("failed to register %s to i2c%d\n",
+					info[i].type, busnum);
+	}
+
+	i2c_put_adapter(adap);
+}
+
+static void __init __mop500_uib_init(struct uib *uib, const char *why)
+{
+	pr_info("%s (%s)\n", uib->name, why);
+	uib->init();
+}
+
+/*
+ * Detect the UIB attached based on the presence or absence of i2c devices.
+ */
+static int __init mop500_uib_init(void)
+{
+	struct uib *uib = mop500_uib;
+	struct i2c_adapter *i2c0;
+	int ret;
+
+	if (!cpu_is_u8500())
+		return -ENODEV;
+
+	if (uib) {
+		__mop500_uib_init(uib, "from uib= boot argument");
+		return 0;
+	}
+
+	i2c0 = i2c_get_adapter(0);
+	if (!i2c0) {
+		__mop500_uib_init(&mop500_uibs[STUIB],
+				"fallback, could not get i2c0");
+		return -ENODEV;
+	}
+
+	/* U8500-UIB has the TC35893 at 0x44 on I2C0, the ST-UIB doesn't. */
+	ret = i2c_smbus_xfer(i2c0, 0x44, 0, I2C_SMBUS_WRITE, 0,
+			I2C_SMBUS_QUICK, NULL);
+	i2c_put_adapter(i2c0);
+
+	if (ret == 0)
+		uib = &mop500_uibs[U8500UIB];
+	else
+		uib = &mop500_uibs[STUIB];
+
+	__mop500_uib_init(uib, "detected");
+
+	return 0;
+}
+
+module_init(mop500_uib_init);