From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 drivers/mfd/wm831x-otp.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 drivers/mfd/wm831x-otp.c

(limited to 'drivers/mfd/wm831x-otp.c')

diff --git a/drivers/mfd/wm831x-otp.c b/drivers/mfd/wm831x-otp.c
new file mode 100644
index 000000000..b90f3e06b
--- /dev/null
+++ b/drivers/mfd/wm831x-otp.c
@@ -0,0 +1,91 @@
+/*
+ * wm831x-otp.c  --  OTP for Wolfson WM831x PMICs
+ *
+ * Copyright 2009 Wolfson Microelectronics PLC.
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ *  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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/delay.h>
+#include <linux/mfd/core.h>
+#include <linux/random.h>
+
+#include <linux/mfd/wm831x/core.h>
+#include <linux/mfd/wm831x/otp.h>
+
+/* In bytes */
+#define WM831X_UNIQUE_ID_LEN 16
+
+/* Read the unique ID from the chip into id */
+static int wm831x_unique_id_read(struct wm831x *wm831x, char *id)
+{
+	int i, val;
+
+	for (i = 0; i < WM831X_UNIQUE_ID_LEN / 2; i++) {
+		val = wm831x_reg_read(wm831x, WM831X_UNIQUE_ID_1 + i);
+		if (val < 0)
+			return val;
+
+		id[i * 2]       = (val >> 8) & 0xff;
+		id[(i * 2) + 1] = val & 0xff;
+	}
+
+	return 0;
+}
+
+static ssize_t wm831x_unique_id_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct wm831x *wm831x = dev_get_drvdata(dev);
+	int i, rval;
+	char id[WM831X_UNIQUE_ID_LEN];
+	ssize_t ret = 0;
+
+	rval = wm831x_unique_id_read(wm831x, id);
+	if (rval < 0)
+		return 0;
+
+	for (i = 0; i < WM831X_UNIQUE_ID_LEN; i++)
+		ret += sprintf(&buf[ret], "%02x", buf[i]);
+
+	ret += sprintf(&buf[ret], "\n");
+
+	return ret;
+}
+
+static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);
+
+int wm831x_otp_init(struct wm831x *wm831x)
+{
+	char uuid[WM831X_UNIQUE_ID_LEN];
+	int ret;
+
+	ret = device_create_file(wm831x->dev, &dev_attr_unique_id);
+	if (ret != 0)
+		dev_err(wm831x->dev, "Unique ID attribute not created: %d\n",
+			ret);
+
+	ret = wm831x_unique_id_read(wm831x, uuid);
+	if (ret == 0)
+		add_device_randomness(uuid, sizeof(uuid));
+	else
+		dev_err(wm831x->dev, "Failed to read UUID: %d\n", ret);
+
+	return ret;
+}
+
+void wm831x_otp_exit(struct wm831x *wm831x)
+{
+	device_remove_file(wm831x->dev, &dev_attr_unique_id);
+}
+
-- 
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