1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/mfd/ab3100_otp.c
4 *
5 * Copyright (C) 2007-2009 ST-Ericsson AB
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/abx500.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 * @locked: whether the OTP is locked, after locking, no more bits
34 *       can be changed but before locking it is still possible
35 *       to change bits from 1->0.
36 * @freq: clocking frequency for the OTP, this frequency is either
37 *       32768Hz or 1MHz/30
38 * @paf: product activation flag, indicates whether this is a real
39 *       product (paf true) or a lab board etc (paf false)
40 * @imeich: if this is set it is possible to override the
41 *       IMEI number found in the tac, fac and svn fields with
42 *       (secured) software
43 * @cid: customer ID
44 * @tac: type allocation code of the IMEI
45 * @fac: final assembly code of the IMEI
46 * @svn: software version number of the IMEI
47 * @debugfs: a debugfs file used when dumping to file
48 */
49struct ab3100_otp {
50	struct device *dev;
51	bool locked;
52	u32 freq;
53	bool paf;
54	bool imeich;
55	u16 cid:14;
56	u32 tac:20;
57	u8 fac;
58	u32 svn:20;
59	struct dentry *debugfs;
60};
61
62static int __init ab3100_otp_read(struct ab3100_otp *otp)
63{
64	u8 otpval[8];
65	u8 otpp;
66	int err;
67
68	err = abx500_get_register_interruptible(otp->dev, 0,
69		AB3100_OTPP, &otpp);
70	if (err) {
71		dev_err(otp->dev, "unable to read OTPP register\n");
72		return err;
73	}
74
75	err = abx500_get_register_page_interruptible(otp->dev, 0,
76		AB3100_OTP0, otpval, 8);
77	if (err) {
78		dev_err(otp->dev, "unable to read OTP register page\n");
79		return err;
80	}
81
82	/* Cache OTP properties, they never change by nature */
83	otp->locked = (otpp & 0x80);
84	otp->freq = (otpp & 0x40) ? 32768 : 34100;
85	otp->paf = (otpval[1] & 0x80);
86	otp->imeich = (otpval[1] & 0x40);
87	otp->cid = ((otpval[1] << 8) | otpval[0]) & 0x3fff;
88	otp->tac = ((otpval[4] & 0x0f) << 16) | (otpval[3] << 8) | otpval[2];
89	otp->fac = ((otpval[5] & 0x0f) << 4) | (otpval[4] >> 4);
90	otp->svn = (otpval[7] << 12) | (otpval[6] << 4) | (otpval[5] >> 4);
91	return 0;
92}
93
94/*
95 * This is a simple debugfs human-readable file that dumps out
96 * the contents of the OTP.
97 */
98#ifdef CONFIG_DEBUG_FS
99static int ab3100_show_otp(struct seq_file *s, void *v)
100{
101	struct ab3100_otp *otp = s->private;
102
103	seq_printf(s, "OTP is %s\n", otp->locked ? "LOCKED" : "UNLOCKED");
104	seq_printf(s, "OTP clock switch startup is %uHz\n", otp->freq);
105	seq_printf(s, "PAF is %s\n", otp->paf ? "SET" : "NOT SET");
106	seq_printf(s, "IMEI is %s\n", otp->imeich ?
107		   "CHANGEABLE" : "NOT CHANGEABLE");
108	seq_printf(s, "CID: 0x%04x (decimal: %d)\n", otp->cid, otp->cid);
109	seq_printf(s, "IMEI: %u-%u-%u\n", otp->tac, otp->fac, otp->svn);
110	return 0;
111}
112
113static int ab3100_otp_open(struct inode *inode, struct file *file)
114{
115	return single_open(file, ab3100_show_otp, inode->i_private);
116}
117
118static const struct file_operations ab3100_otp_operations = {
119	.open		= ab3100_otp_open,
120	.read		= seq_read,
121	.llseek		= seq_lseek,
122	.release	= single_release,
123};
124
125static void __init ab3100_otp_init_debugfs(struct device *dev,
126					   struct ab3100_otp *otp)
127{
128	otp->debugfs = debugfs_create_file("ab3100_otp", S_IFREG | S_IRUGO,
129					   NULL, otp, &ab3100_otp_operations);
130}
131
132static void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
133{
134	debugfs_remove(otp->debugfs);
135}
136#else
137/* Compile this out if debugfs not selected */
138static inline void __init ab3100_otp_init_debugfs(struct device *dev,
139						  struct ab3100_otp *otp)
140{
141}
142
143static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
144{
145}
146#endif
147
148#define SHOW_AB3100_ATTR(name) \
149static ssize_t ab3100_otp_##name##_show(struct device *dev, \
150			       struct device_attribute *attr, \
151			       char *buf) \
152{\
153	struct ab3100_otp *otp = dev_get_drvdata(dev); \
154	return sprintf(buf, "%u\n", otp->name); \
155}
156
157SHOW_AB3100_ATTR(locked)
158SHOW_AB3100_ATTR(freq)
159SHOW_AB3100_ATTR(paf)
160SHOW_AB3100_ATTR(imeich)
161SHOW_AB3100_ATTR(cid)
162SHOW_AB3100_ATTR(fac)
163SHOW_AB3100_ATTR(tac)
164SHOW_AB3100_ATTR(svn)
165
166static struct device_attribute ab3100_otp_attrs[] = {
167	__ATTR(locked, S_IRUGO, ab3100_otp_locked_show, NULL),
168	__ATTR(freq, S_IRUGO, ab3100_otp_freq_show, NULL),
169	__ATTR(paf, S_IRUGO, ab3100_otp_paf_show, NULL),
170	__ATTR(imeich, S_IRUGO, ab3100_otp_imeich_show, NULL),
171	__ATTR(cid, S_IRUGO, ab3100_otp_cid_show, NULL),
172	__ATTR(fac, S_IRUGO, ab3100_otp_fac_show, NULL),
173	__ATTR(tac, S_IRUGO, ab3100_otp_tac_show, NULL),
174	__ATTR(svn, S_IRUGO, ab3100_otp_svn_show, NULL),
175};
176
177static int __init ab3100_otp_probe(struct platform_device *pdev)
178{
179	struct ab3100_otp *otp;
180	int err = 0;
181	int i;
182
183	otp = devm_kzalloc(&pdev->dev, sizeof(struct ab3100_otp), GFP_KERNEL);
184	if (!otp)
185		return -ENOMEM;
186
187	otp->dev = &pdev->dev;
188
189	/* Replace platform data coming in with a local struct */
190	platform_set_drvdata(pdev, otp);
191
192	err = ab3100_otp_read(otp);
193	if (err)
194		return err;
195
196	dev_info(&pdev->dev, "AB3100 OTP readout registered\n");
197
198	/* sysfs entries */
199	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++) {
200		err = device_create_file(&pdev->dev,
201					 &ab3100_otp_attrs[i]);
202		if (err)
203			goto err;
204	}
205
206	/* debugfs entries */
207	ab3100_otp_init_debugfs(&pdev->dev, otp);
208
209	return 0;
210
211err:
212	while (--i >= 0)
213		device_remove_file(&pdev->dev, &ab3100_otp_attrs[i]);
214	return err;
215}
216
217static int __exit ab3100_otp_remove(struct platform_device *pdev)
218{
219	struct ab3100_otp *otp = platform_get_drvdata(pdev);
220	int i;
221
222	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
223		device_remove_file(&pdev->dev,
224				   &ab3100_otp_attrs[i]);
225	ab3100_otp_exit_debugfs(otp);
226	return 0;
227}
228
229static struct platform_driver ab3100_otp_driver = {
230	.driver = {
231		.name = "ab3100-otp",
232	},
233	.remove	 = __exit_p(ab3100_otp_remove),
234};
235
236module_platform_driver_probe(ab3100_otp_driver, ab3100_otp_probe);
237
238MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
239MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
240MODULE_LICENSE("GPL");
241