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 */
49 struct 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
ab3100_otp_read(struct ab3100_otp * otp)62 static 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
ab3100_show_otp(struct seq_file * s,void * v)99 static 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
ab3100_otp_open(struct inode * inode,struct file * file)113 static int ab3100_otp_open(struct inode *inode, struct file *file)
114 {
115 return single_open(file, ab3100_show_otp, inode->i_private);
116 }
117
118 static 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
ab3100_otp_init_debugfs(struct device * dev,struct ab3100_otp * otp)125 static 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
ab3100_otp_exit_debugfs(struct ab3100_otp * otp)132 static 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 */
ab3100_otp_init_debugfs(struct device * dev,struct ab3100_otp * otp)138 static inline void __init ab3100_otp_init_debugfs(struct device *dev,
139 struct ab3100_otp *otp)
140 {
141 }
142
ab3100_otp_exit_debugfs(struct ab3100_otp * otp)143 static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
144 {
145 }
146 #endif
147
148 #define SHOW_AB3100_ATTR(name) \
149 static 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
157 SHOW_AB3100_ATTR(locked)
158 SHOW_AB3100_ATTR(freq)
159 SHOW_AB3100_ATTR(paf)
160 SHOW_AB3100_ATTR(imeich)
161 SHOW_AB3100_ATTR(cid)
162 SHOW_AB3100_ATTR(fac)
163 SHOW_AB3100_ATTR(tac)
164 SHOW_AB3100_ATTR(svn)
165
166 static 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
ab3100_otp_probe(struct platform_device * pdev)177 static 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
211 err:
212 while (--i >= 0)
213 device_remove_file(&pdev->dev, &ab3100_otp_attrs[i]);
214 return err;
215 }
216
ab3100_otp_remove(struct platform_device * pdev)217 static 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
229 static struct platform_driver ab3100_otp_driver = {
230 .driver = {
231 .name = "ab3100-otp",
232 },
233 .remove = __exit_p(ab3100_otp_remove),
234 };
235
236 module_platform_driver_probe(ab3100_otp_driver, ab3100_otp_probe);
237
238 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
239 MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
240 MODULE_LICENSE("GPL");
241