/*
   * drivers/mfd/ab3100_otp.c
   *
   * Copyright (C) 2007-2009 ST-Ericsson AB
   * License terms: GNU General Public License (GPL) version 2
   * Driver to read out OTP from the AB3100 Mixed-signal circuit
   * Author: Linus Walleij <linus.walleij@stericsson.com>
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/mfd/abx500.h>
  #include <linux/debugfs.h>
  #include <linux/seq_file.h>
  
  /* The OTP registers */
  #define AB3100_OTP0		0xb0
  #define AB3100_OTP1		0xb1
  #define AB3100_OTP2		0xb2
  #define AB3100_OTP3		0xb3
  #define AB3100_OTP4		0xb4
  #define AB3100_OTP5		0xb5
  #define AB3100_OTP6		0xb6
  #define AB3100_OTP7		0xb7
  #define AB3100_OTPP		0xbf
  
  /**
   * struct ab3100_otp
   * @dev containing device
   * @locked whether the OTP is locked, after locking, no more bits
   *       can be changed but before locking it is still possible
   *       to change bits from 1->0.
   * @freq clocking frequency for the OTP, this frequency is either
   *       32768Hz or 1MHz/30
   * @paf product activation flag, indicates whether this is a real
   *       product (paf true) or a lab board etc (paf false)
   * @imeich if this is set it is possible to override the
   *       IMEI number found in the tac, fac and svn fields with
   *       (secured) software
   * @cid customer ID
   * @tac type allocation code of the IMEI
   * @fac final assembly code of the IMEI
   * @svn software version number of the IMEI
   * @debugfs a debugfs file used when dumping to file
   */
  struct ab3100_otp {
  	struct device *dev;
  	bool locked;
  	u32 freq;
  	bool paf;
  	bool imeich;
  	u16 cid:14;
  	u32 tac:20;
  	u8 fac;
  	u32 svn:20;
  	struct dentry *debugfs;
  };
  
  static int __init ab3100_otp_read(struct ab3100_otp *otp)
  {
  	u8 otpval[8];
  	u8 otpp;
  	int err;
  
  	err = abx500_get_register_interruptible(otp->dev, 0,
  		AB3100_OTPP, &otpp);
  	if (err) {
  		dev_err(otp->dev, "unable to read OTPP register
  ");
  		return err;
  	}
  
  	err = abx500_get_register_page_interruptible(otp->dev, 0,
  		AB3100_OTP0, otpval, 8);
  	if (err) {
  		dev_err(otp->dev, "unable to read OTP register page
  ");
  		return err;
  	}
  
  	/* Cache OTP properties, they never change by nature */
  	otp->locked = (otpp & 0x80);
  	otp->freq = (otpp & 0x40) ? 32768 : 34100;
  	otp->paf = (otpval[1] & 0x80);
  	otp->imeich = (otpval[1] & 0x40);
  	otp->cid = ((otpval[1] << 8) | otpval[0]) & 0x3fff;
  	otp->tac = ((otpval[4] & 0x0f) << 16) | (otpval[3] << 8) | otpval[2];
  	otp->fac = ((otpval[5] & 0x0f) << 4) | (otpval[4] >> 4);
  	otp->svn = (otpval[7] << 12) | (otpval[6] << 4) | (otpval[5] >> 4);
  	return 0;
  }
  
  /*
   * This is a simple debugfs human-readable file that dumps out
   * the contents of the OTP.
   */
  #ifdef CONFIG_DEBUG_FS
  static int ab3100_show_otp(struct seq_file *s, void *v)
  {
  	struct ab3100_otp *otp = s->private;
  
  	seq_printf(s, "OTP is %s
  ", otp->locked ? "LOCKED" : "UNLOCKED");
  	seq_printf(s, "OTP clock switch startup is %uHz
  ", otp->freq);
  	seq_printf(s, "PAF is %s
  ", otp->paf ? "SET" : "NOT SET");
  	seq_printf(s, "IMEI is %s
  ", otp->imeich ?
  		   "CHANGEABLE" : "NOT CHANGEABLE");
  	seq_printf(s, "CID: 0x%04x (decimal: %d)
  ", otp->cid, otp->cid);
  	seq_printf(s, "IMEI: %u-%u-%u
  ", otp->tac, otp->fac, otp->svn);
  	return 0;
  }
  
  static int ab3100_otp_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, ab3100_show_otp, inode->i_private);
  }
  
  static const struct file_operations ab3100_otp_operations = {
  	.open		= ab3100_otp_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static int __init ab3100_otp_init_debugfs(struct device *dev,
  					  struct ab3100_otp *otp)
  {
  	otp->debugfs = debugfs_create_file("ab3100_otp", S_IFREG | S_IRUGO,
  					   NULL, otp,
  					   &ab3100_otp_operations);
  	if (!otp->debugfs) {
  		dev_err(dev, "AB3100 debugfs OTP file registration failed!
  ");
  		return -ENOENT;
  	}
  	return 0;
  }
  
  static void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
  {
  	debugfs_remove(otp->debugfs);
  }
  #else
  /* Compile this out if debugfs not selected */
  static inline int __init ab3100_otp_init_debugfs(struct device *dev,
  						 struct ab3100_otp *otp)
  {
  	return 0;
  }
  
  static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
  {
  }
  #endif
  
  #define SHOW_AB3100_ATTR(name) \
  static ssize_t ab3100_otp_##name##_show(struct device *dev, \
  			       struct device_attribute *attr, \
  			       char *buf) \
  {\
  	struct ab3100_otp *otp = dev_get_drvdata(dev); \
  	return sprintf(buf, "%u
  ", otp->name); \
  }
  
  SHOW_AB3100_ATTR(locked)
  SHOW_AB3100_ATTR(freq)
  SHOW_AB3100_ATTR(paf)
  SHOW_AB3100_ATTR(imeich)
  SHOW_AB3100_ATTR(cid)
  SHOW_AB3100_ATTR(fac)
  SHOW_AB3100_ATTR(tac)
  SHOW_AB3100_ATTR(svn)
  
  static struct device_attribute ab3100_otp_attrs[] = {
  	__ATTR(locked, S_IRUGO, ab3100_otp_locked_show, NULL),
  	__ATTR(freq, S_IRUGO, ab3100_otp_freq_show, NULL),
  	__ATTR(paf, S_IRUGO, ab3100_otp_paf_show, NULL),
  	__ATTR(imeich, S_IRUGO, ab3100_otp_imeich_show, NULL),
  	__ATTR(cid, S_IRUGO, ab3100_otp_cid_show, NULL),
  	__ATTR(fac, S_IRUGO, ab3100_otp_fac_show, NULL),
  	__ATTR(tac, S_IRUGO, ab3100_otp_tac_show, NULL),
  	__ATTR(svn, S_IRUGO, ab3100_otp_svn_show, NULL),
  };
  
  static int __init ab3100_otp_probe(struct platform_device *pdev)
  {
  	struct ab3100_otp *otp;
  	int err = 0;
  	int i;
  
  	otp = devm_kzalloc(&pdev->dev, sizeof(struct ab3100_otp), GFP_KERNEL);
  	if (!otp) {
  		dev_err(&pdev->dev, "could not allocate AB3100 OTP device
  ");
  		return -ENOMEM;
  	}
  	otp->dev = &pdev->dev;
  
  	/* Replace platform data coming in with a local struct */
  	platform_set_drvdata(pdev, otp);
  
  	err = ab3100_otp_read(otp);
  	if (err)
  		return err;
  
  	dev_info(&pdev->dev, "AB3100 OTP readout registered
  ");
  
  	/* sysfs entries */
  	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++) {
  		err = device_create_file(&pdev->dev,
  					 &ab3100_otp_attrs[i]);
  		if (err)
  			goto err;
  	}
  
  	/* debugfs entries */
  	err = ab3100_otp_init_debugfs(&pdev->dev, otp);
  	if (err)
  		goto err;
  
  	return 0;
  
  err:
  	while (--i >= 0)
  		device_remove_file(&pdev->dev, &ab3100_otp_attrs[i]);
  	return err;
  }
  
  static int __exit ab3100_otp_remove(struct platform_device *pdev)
  {
  	struct ab3100_otp *otp = platform_get_drvdata(pdev);
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
  		device_remove_file(&pdev->dev,
  				   &ab3100_otp_attrs[i]);
  	ab3100_otp_exit_debugfs(otp);
  	return 0;
  }
  
  static struct platform_driver ab3100_otp_driver = {
  	.driver = {
  		.name = "ab3100-otp",
  		.owner = THIS_MODULE,
  	},
  	.remove	 = __exit_p(ab3100_otp_remove),
  };
  
  module_platform_driver_probe(ab3100_otp_driver, ab3100_otp_probe);
  
  MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
  MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
  MODULE_LICENSE("GPL");