ab3100-otp.c revision 5a0e3ad6af8660be21ca98a971cd00f331318c05 
1/*
2 * drivers/mfd/ab3100_otp.c
3 *
4 * Copyright (C) 2007-2009 ST-Ericsson AB
5 * License terms: GNU General Public License (GPL) version 2
6 * Driver to read out OTP from the AB3100 Mixed-signal circuit
7 * Author: Linus Walleij <linus.walleij@stericsson.com>
8 */
9
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/init.h>
14#include <linux/platform_device.h>
15#include <linux/mfd/ab3100.h>
16#include <linux/debugfs.h>
17#include <linux/seq_file.h>
18
19/* The OTP registers */
20#define AB3100_OTP0		0xb0
21#define AB3100_OTP1		0xb1
22#define AB3100_OTP2		0xb2
23#define AB3100_OTP3		0xb3
24#define AB3100_OTP4		0xb4
25#define AB3100_OTP5		0xb5
26#define AB3100_OTP6		0xb6
27#define AB3100_OTP7		0xb7
28#define AB3100_OTPP		0xbf
29
30/**
31 * struct ab3100_otp
32 * @dev containing device
33 * @ab3100 a pointer to the parent ab3100 device struct
34 * @locked whether the OTP is locked, after locking, no more bits
35 *       can be changed but before locking it is still possible
36 *       to change bits from 1->0.
37 * @freq clocking frequency for the OTP, this frequency is either
38 *       32768Hz or 1MHz/30
39 * @paf product activation flag, indicates whether this is a real
40 *       product (paf true) or a lab board etc (paf false)
41 * @imeich if this is set it is possible to override the
42 *       IMEI number found in the tac, fac and svn fields with
43 *       (secured) software
44 * @cid customer ID
45 * @tac type allocation code of the IMEI
46 * @fac final assembly code of the IMEI
47 * @svn software version number of the IMEI
48 * @debugfs a debugfs file used when dumping to file
49 */
50struct ab3100_otp {
51	struct device *dev;
52	struct ab3100 *ab3100;
53	bool locked;
54	u32 freq;
55	bool paf;
56	bool imeich;
57	u16 cid:14;
58	u32 tac:20;
59	u8 fac;
60	u32 svn:20;
61	struct dentry *debugfs;
62};
63
64static int __init ab3100_otp_read(struct ab3100_otp *otp)
65{
66	struct ab3100 *ab = otp->ab3100;
67	u8 otpval[8];
68	u8 otpp;
69	int err;
70
71	err = ab3100_get_register_interruptible(ab, AB3100_OTPP, &otpp);
72	if (err) {
73		dev_err(otp->dev, "unable to read OTPP register\n");
74		return err;
75	}
76
77	err = ab3100_get_register_page_interruptible(ab, AB3100_OTP0,
78						     otpval, 8);
79	if (err) {
80		dev_err(otp->dev, "unable to read OTP register page\n");
81		return err;
82	}
83
84	/* Cache OTP properties, they never change by nature */
85	otp->locked = (otpp & 0x80);
86	otp->freq = (otpp & 0x40) ? 32768 : 34100;
87	otp->paf = (otpval[1] & 0x80);
88	otp->imeich = (otpval[1] & 0x40);
89	otp->cid = ((otpval[1] << 8) | otpval[0]) & 0x3fff;
90	otp->tac = ((otpval[4] & 0x0f) << 16) | (otpval[3] << 8) | otpval[2];
91	otp->fac = ((otpval[5] & 0x0f) << 4) | (otpval[4] >> 4);
92	otp->svn = (otpval[7] << 12) | (otpval[6] << 4) | (otpval[5] >> 4);
93	return 0;
94}
95
96/*
97 * This is a simple debugfs human-readable file that dumps out
98 * the contents of the OTP.
99 */
100#ifdef CONFIG_DEBUG_FS
101static int ab3100_show_otp(struct seq_file *s, void *v)
102{
103	struct ab3100_otp *otp = s->private;
104
105	seq_printf(s, "OTP is %s\n", otp->locked ? "LOCKED" : "UNLOCKED");
106	seq_printf(s, "OTP clock switch startup is %uHz\n", otp->freq);
107	seq_printf(s, "PAF is %s\n", otp->paf ? "SET" : "NOT SET");
108	seq_printf(s, "IMEI is %s\n", otp->imeich ?
109		   "CHANGEABLE" : "NOT CHANGEABLE");
110	seq_printf(s, "CID: 0x%04x (decimal: %d)\n", otp->cid, otp->cid);
111	seq_printf(s, "IMEI: %u-%u-%u\n", otp->tac, otp->fac, otp->svn);
112	return 0;
113}
114
115static int ab3100_otp_open(struct inode *inode, struct file *file)
116{
117	return single_open(file, ab3100_show_otp, inode->i_private);
118}
119
120static const struct file_operations ab3100_otp_operations = {
121	.open		= ab3100_otp_open,
122	.read		= seq_read,
123	.llseek		= seq_lseek,
124	.release	= single_release,
125};
126
127static int __init ab3100_otp_init_debugfs(struct device *dev,
128					  struct ab3100_otp *otp)
129{
130	otp->debugfs = debugfs_create_file("ab3100_otp", S_IFREG | S_IRUGO,
131					   NULL, otp,
132					   &ab3100_otp_operations);
133	if (!otp->debugfs) {
134		dev_err(dev, "AB3100 debugfs OTP file registration failed!\n");
135		return -ENOENT;
136	}
137	return 0;
138}
139
140static void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
141{
142	debugfs_remove(otp->debugfs);
143}
144#else
145/* Compile this out if debugfs not selected */
146static inline int __init ab3100_otp_init_debugfs(struct device *dev,
147						 struct ab3100_otp *otp)
148{
149	return 0;
150}
151
152static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
153{
154}
155#endif
156
157#define SHOW_AB3100_ATTR(name) \
158static ssize_t ab3100_otp_##name##_show(struct device *dev, \
159			       struct device_attribute *attr, \
160			       char *buf) \
161{\
162	struct ab3100_otp *otp = dev_get_drvdata(dev); \
163	return sprintf(buf, "%u\n", otp->name); \
164}
165
166SHOW_AB3100_ATTR(locked)
167SHOW_AB3100_ATTR(freq)
168SHOW_AB3100_ATTR(paf)
169SHOW_AB3100_ATTR(imeich)
170SHOW_AB3100_ATTR(cid)
171SHOW_AB3100_ATTR(fac)
172SHOW_AB3100_ATTR(tac)
173SHOW_AB3100_ATTR(svn)
174
175static struct device_attribute ab3100_otp_attrs[] = {
176	__ATTR(locked, S_IRUGO, ab3100_otp_locked_show, NULL),
177	__ATTR(freq, S_IRUGO, ab3100_otp_freq_show, NULL),
178	__ATTR(paf, S_IRUGO, ab3100_otp_paf_show, NULL),
179	__ATTR(imeich, S_IRUGO, ab3100_otp_imeich_show, NULL),
180	__ATTR(cid, S_IRUGO, ab3100_otp_cid_show, NULL),
181	__ATTR(fac, S_IRUGO, ab3100_otp_fac_show, NULL),
182	__ATTR(tac, S_IRUGO, ab3100_otp_tac_show, NULL),
183	__ATTR(svn, S_IRUGO, ab3100_otp_svn_show, NULL),
184};
185
186static int __init ab3100_otp_probe(struct platform_device *pdev)
187{
188	struct ab3100_otp *otp;
189	int err = 0;
190	int i;
191
192	otp = kzalloc(sizeof(struct ab3100_otp), GFP_KERNEL);
193	if (!otp) {
194		dev_err(&pdev->dev, "could not allocate AB3100 OTP device\n");
195		return -ENOMEM;
196	}
197	otp->dev = &pdev->dev;
198
199	/* Replace platform data coming in with a local struct */
200	otp->ab3100 = platform_get_drvdata(pdev);
201	platform_set_drvdata(pdev, otp);
202
203	err = ab3100_otp_read(otp);
204	if (err)
205		return err;
206
207	dev_info(&pdev->dev, "AB3100 OTP readout registered\n");
208
209	/* sysfs entries */
210	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++) {
211		err = device_create_file(&pdev->dev,
212					 &ab3100_otp_attrs[i]);
213		if (err)
214			goto out_no_sysfs;
215	}
216
217	/* debugfs entries */
218	err = ab3100_otp_init_debugfs(&pdev->dev, otp);
219	if (err)
220		goto out_no_debugfs;
221
222	return 0;
223
224out_no_sysfs:
225	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
226		device_remove_file(&pdev->dev,
227				   &ab3100_otp_attrs[i]);
228out_no_debugfs:
229	kfree(otp);
230	return err;
231}
232
233static int __exit ab3100_otp_remove(struct platform_device *pdev)
234{
235	struct ab3100_otp *otp = platform_get_drvdata(pdev);
236	int i;
237
238	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
239		device_remove_file(&pdev->dev,
240				   &ab3100_otp_attrs[i]);
241	ab3100_otp_exit_debugfs(otp);
242	kfree(otp);
243	return 0;
244}
245
246static struct platform_driver ab3100_otp_driver = {
247	.driver = {
248		.name = "ab3100-otp",
249		.owner = THIS_MODULE,
250	},
251	.remove	 = __exit_p(ab3100_otp_remove),
252};
253
254static int __init ab3100_otp_init(void)
255{
256	return platform_driver_probe(&ab3100_otp_driver,
257				     ab3100_otp_probe);
258}
259
260static void __exit ab3100_otp_exit(void)
261{
262	platform_driver_unregister(&ab3100_otp_driver);
263}
264
265module_init(ab3100_otp_init);
266module_exit(ab3100_otp_exit);
267
268MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
269MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
270MODULE_LICENSE("GPL");
271