Use dentry_path() to create full path to inode object
[pohmelfs.git] / drivers / mfd / wm831x-otp.c
blobf742745ff354ec2bc485d533805f02340a11d2fd
1 /*
2 * wm831x-otp.c -- OTP for Wolfson WM831x PMICs
4 * Copyright 2009 Wolfson Microelectronics PLC.
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/i2c.h>
18 #include <linux/bcd.h>
19 #include <linux/delay.h>
20 #include <linux/mfd/core.h>
22 #include <linux/mfd/wm831x/core.h>
23 #include <linux/mfd/wm831x/otp.h>
25 /* In bytes */
26 #define WM831X_UNIQUE_ID_LEN 16
28 /* Read the unique ID from the chip into id */
29 static int wm831x_unique_id_read(struct wm831x *wm831x, char *id)
31 int i, val;
33 for (i = 0; i < WM831X_UNIQUE_ID_LEN / 2; i++) {
34 val = wm831x_reg_read(wm831x, WM831X_UNIQUE_ID_1 + i);
35 if (val < 0)
36 return val;
38 id[i * 2] = (val >> 8) & 0xff;
39 id[(i * 2) + 1] = val & 0xff;
42 return 0;
45 static ssize_t wm831x_unique_id_show(struct device *dev,
46 struct device_attribute *attr, char *buf)
48 struct wm831x *wm831x = dev_get_drvdata(dev);
49 int i, rval;
50 char id[WM831X_UNIQUE_ID_LEN];
51 ssize_t ret = 0;
53 rval = wm831x_unique_id_read(wm831x, id);
54 if (rval < 0)
55 return 0;
57 for (i = 0; i < WM831X_UNIQUE_ID_LEN; i++)
58 ret += sprintf(&buf[ret], "%02x", buf[i]);
60 ret += sprintf(&buf[ret], "\n");
62 return ret;
65 static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);
67 int wm831x_otp_init(struct wm831x *wm831x)
69 int ret;
71 ret = device_create_file(wm831x->dev, &dev_attr_unique_id);
72 if (ret != 0)
73 dev_err(wm831x->dev, "Unique ID attribute not created: %d\n",
74 ret);
76 return ret;
79 void wm831x_otp_exit(struct wm831x *wm831x)
81 device_remove_file(wm831x->dev, &dev_attr_unique_id);