drivers/mfd/ab3100-otp.c

   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
  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
  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
 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
 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
 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 */
 138 static inline void __init ab3100_otp_init_debugfs(struct device *dev,
 139                                                   struct ab3100_otp *otp)
 140 {
 141 }
 142
 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
 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
 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");