drivers/mfd/ab3100-otp.c

   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/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 int __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,
 130                                            &ab3100_otp_operations);
 131         if (!otp->debugfs) {
 132                 dev_err(dev, "AB3100 debugfs OTP file registration failed!\n");
 133                 return -ENOENT;
 134         }
 135         return 0;
 136 }
 137
 138 static void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
 139 {
 140         debugfs_remove(otp->debugfs);
 141 }
 142 #else
 143 /* Compile this out if debugfs not selected */
 144 static inline int __init ab3100_otp_init_debugfs(struct device *dev,
 145                                                  struct ab3100_otp *otp)
 146 {
 147         return 0;
 148 }
 149
 150 static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
 151 {
 152 }
 153 #endif
 154
 155 #define SHOW_AB3100_ATTR(name) \
 156 static ssize_t ab3100_otp_##name##_show(struct device *dev, \
 157                                struct device_attribute *attr, \
 158                                char *buf) \
 159 {\
 160         struct ab3100_otp *otp = dev_get_drvdata(dev); \
 161         return sprintf(buf, "%u\n", otp->name); \
 162 }
 163
 164 SHOW_AB3100_ATTR(locked)
 165 SHOW_AB3100_ATTR(freq)
 166 SHOW_AB3100_ATTR(paf)
 167 SHOW_AB3100_ATTR(imeich)
 168 SHOW_AB3100_ATTR(cid)
 169 SHOW_AB3100_ATTR(fac)
 170 SHOW_AB3100_ATTR(tac)
 171 SHOW_AB3100_ATTR(svn)
 172
 173 static struct device_attribute ab3100_otp_attrs[] = {
 174         __ATTR(locked, S_IRUGO, ab3100_otp_locked_show, NULL),
 175         __ATTR(freq, S_IRUGO, ab3100_otp_freq_show, NULL),
 176         __ATTR(paf, S_IRUGO, ab3100_otp_paf_show, NULL),
 177         __ATTR(imeich, S_IRUGO, ab3100_otp_imeich_show, NULL),
 178         __ATTR(cid, S_IRUGO, ab3100_otp_cid_show, NULL),
 179         __ATTR(fac, S_IRUGO, ab3100_otp_fac_show, NULL),
 180         __ATTR(tac, S_IRUGO, ab3100_otp_tac_show, NULL),
 181         __ATTR(svn, S_IRUGO, ab3100_otp_svn_show, NULL),
 182 };
 183
 184 static int __init ab3100_otp_probe(struct platform_device *pdev)
 185 {
 186         struct ab3100_otp *otp;
 187         int err = 0;
 188         int i;
 189
 190         otp = devm_kzalloc(&pdev->dev, sizeof(struct ab3100_otp), GFP_KERNEL);
 191         if (!otp) {
 192                 dev_err(&pdev->dev, "could not allocate AB3100 OTP device\n");
 193                 return -ENOMEM;
 194         }
 195         otp->dev = &pdev->dev;
 196
 197         /* Replace platform data coming in with a local struct */
 198         platform_set_drvdata(pdev, otp);
 199
 200         err = ab3100_otp_read(otp);
 201         if (err)
 202                 return err;
 203
 204         dev_info(&pdev->dev, "AB3100 OTP readout registered\n");
 205
 206         /* sysfs entries */
 207         for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++) {
 208                 err = device_create_file(&pdev->dev,
 209                                          &ab3100_otp_attrs[i]);
 210                 if (err)
 211                         goto err;
 212         }
 213
 214         /* debugfs entries */
 215         err = ab3100_otp_init_debugfs(&pdev->dev, otp);
 216         if (err)
 217                 goto err;
 218
 219         return 0;
 220
 221 err:
 222         while (--i >= 0)
 223                 device_remove_file(&pdev->dev, &ab3100_otp_attrs[i]);
 224         return err;
 225 }
 226
 227 static int __exit ab3100_otp_remove(struct platform_device *pdev)
 228 {
 229         struct ab3100_otp *otp = platform_get_drvdata(pdev);
 230         int i;
 231
 232         for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
 233                 device_remove_file(&pdev->dev,
 234                                    &ab3100_otp_attrs[i]);
 235         ab3100_otp_exit_debugfs(otp);
 236         return 0;
 237 }
 238
 239 static struct platform_driver ab3100_otp_driver = {
 240         .driver = {
 241                 .name = "ab3100-otp",
 242         },
 243         .remove  = __exit_p(ab3100_otp_remove),
 244 };
 245
 246 module_platform_driver_probe(ab3100_otp_driver, ab3100_otp_probe);
 247
 248 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 249 MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
 250 MODULE_LICENSE("GPL");