linux/drivers/mfd/ab3100-otp.c
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   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 */
  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 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
 138static 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 */
 144static inline int __init ab3100_otp_init_debugfs(struct device *dev,
 145                                                 struct ab3100_otp *otp)
 146{
 147        return 0;
 148}
 149
 150static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
 151{
 152}
 153#endif
 154
 155#define SHOW_AB3100_ATTR(name) \
 156static 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
 164SHOW_AB3100_ATTR(locked)
 165SHOW_AB3100_ATTR(freq)
 166SHOW_AB3100_ATTR(paf)
 167SHOW_AB3100_ATTR(imeich)
 168SHOW_AB3100_ATTR(cid)
 169SHOW_AB3100_ATTR(fac)
 170SHOW_AB3100_ATTR(tac)
 171SHOW_AB3100_ATTR(svn)
 172
 173static 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
 184static 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 = kzalloc(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                goto err_otp_read;
 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_create_file;
 212        }
 213
 214        /* debugfs entries */
 215        err = ab3100_otp_init_debugfs(&pdev->dev, otp);
 216        if (err)
 217                goto err_init_debugfs;
 218
 219        return 0;
 220
 221err_init_debugfs:
 222err_create_file:
 223        while (--i >= 0)
 224                device_remove_file(&pdev->dev, &ab3100_otp_attrs[i]);
 225err_otp_read:
 226        kfree(otp);
 227        return err;
 228}
 229
 230static int __exit ab3100_otp_remove(struct platform_device *pdev)
 231{
 232        struct ab3100_otp *otp = platform_get_drvdata(pdev);
 233        int i;
 234
 235        for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
 236                device_remove_file(&pdev->dev,
 237                                   &ab3100_otp_attrs[i]);
 238        ab3100_otp_exit_debugfs(otp);
 239        kfree(otp);
 240        return 0;
 241}
 242
 243static struct platform_driver ab3100_otp_driver = {
 244        .driver = {
 245                .name = "ab3100-otp",
 246                .owner = THIS_MODULE,
 247        },
 248        .remove  = __exit_p(ab3100_otp_remove),
 249};
 250
 251static int __init ab3100_otp_init(void)
 252{
 253        return platform_driver_probe(&ab3100_otp_driver,
 254                                     ab3100_otp_probe);
 255}
 256
 257static void __exit ab3100_otp_exit(void)
 258{
 259        platform_driver_unregister(&ab3100_otp_driver);
 260}
 261
 262module_init(ab3100_otp_init);
 263module_exit(ab3100_otp_exit);
 264
 265MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 266MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
 267MODULE_LICENSE("GPL");
 268
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