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Diffstat (limited to 'drivers/mfd/wm831x-otp.c')
-rw-r--r--drivers/mfd/wm831x-otp.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/mfd/wm831x-otp.c b/drivers/mfd/wm831x-otp.c
new file mode 100644
index 000000000000..f742745ff354
--- /dev/null
+++ b/drivers/mfd/wm831x-otp.c
@@ -0,0 +1,83 @@
1/*
2 * wm831x-otp.c -- OTP for Wolfson WM831x PMICs
3 *
4 * Copyright 2009 Wolfson Microelectronics PLC.
5 *
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7 *
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.
12 *
13 */
14
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>
21
22#include <linux/mfd/wm831x/core.h>
23#include <linux/mfd/wm831x/otp.h>
24
25/* In bytes */
26#define WM831X_UNIQUE_ID_LEN 16
27
28/* Read the unique ID from the chip into id */
29static int wm831x_unique_id_read(struct wm831x *wm831x, char *id)
30{
31 int i, val;
32
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;
37
38 id[i * 2] = (val >> 8) & 0xff;
39 id[(i * 2) + 1] = val & 0xff;
40 }
41
42 return 0;
43}
44
45static ssize_t wm831x_unique_id_show(struct device *dev,
46 struct device_attribute *attr, char *buf)
47{
48 struct wm831x *wm831x = dev_get_drvdata(dev);
49 int i, rval;
50 char id[WM831X_UNIQUE_ID_LEN];
51 ssize_t ret = 0;
52
53 rval = wm831x_unique_id_read(wm831x, id);
54 if (rval < 0)
55 return 0;
56
57 for (i = 0; i < WM831X_UNIQUE_ID_LEN; i++)
58 ret += sprintf(&buf[ret], "%02x", buf[i]);
59
60 ret += sprintf(&buf[ret], "\n");
61
62 return ret;
63}
64
65static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);
66
67int wm831x_otp_init(struct wm831x *wm831x)
68{
69 int ret;
70
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);
75
76 return ret;
77}
78
79void wm831x_otp_exit(struct wm831x *wm831x)
80{
81 device_remove_file(wm831x->dev, &dev_attr_unique_id);
82}
83