Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / mfd / wm831x-otp.c

diff --git a/kernel/drivers/mfd/wm831x-otp.c b/kernel/drivers/mfd/wm831x-otp.c
new file mode 100644 (file)
index 0000000..b90f3e0
--- /dev/null
+++ b/kernel/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);
+}
+