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linux/drivers/mfd/ab3100-otp.c
Linus Walleij 12992dd89c mfd: AB3100 OTP readout 
This adds the ability to read out OTP (One-Time Programmable)
registers in the AB3100 MFD ASIC. It's a simple sysfs file you
can cat to prompt. The OTP registers of the AB3100 are used to
store various device-unique information such as customer ID,
product flags and the 3GPP standard IMEI (International Mobile
Equipment Indentity) number.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2009-09-17 09:47:21 +02:00

269 lines
6.9 KiB
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/*
* 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/init.h>
#include <linux/platform_device.h>
#include <linux/mfd/ab3100.h>
#include <linux/debugfs.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
* @ab3100 a pointer to the parent ab3100 device struct
* @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;
struct ab3100 *ab3100;
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)
{
struct ab3100 *ab = otp->ab3100;
u8 otpval[8];
u8 otpp;
int err;
err = ab3100_get_register_interruptible(ab, AB3100_OTPP, &otpp);
if (err) {
dev_err(otp->dev, "unable to read OTPP register\n");
return err;
}
err = ab3100_get_register_page_interruptible(ab, AB3100_OTP0,
otpval, 8);
if (err) {
dev_err(otp->dev, "unable to read OTP register page\n");
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_DEBUGFS
static int show_otp(struct seq_file *s, void *v)
{
struct ab3100_otp *otp = s->private;
int err;
seq_printf(s, "OTP is %s\n", otp->locked ? "LOCKED" : "UNLOCKED");
seq_printf(s, "OTP clock switch startup is %uHz\n", otp->freq);
seq_printf(s, "PAF is %s\n", otp->paf ? "SET" : "NOT SET");
seq_printf(s, "IMEI is %s\n", otp->imeich ?
"CHANGEABLE" : "NOT CHANGEABLE");
seq_printf(s, "CID: 0x%04x (decimal: %d)\n", otp->cid, otp->cid);
seq_printf(s, "IMEI: %u-%u-%u\n", otp->tac, otp->fac, otp->svn);
return 0;
}
static int ab3100_otp_open(struct inode *inode, struct file *file)
{
return single_open(file, ab3100_otp_show, 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!\n");
return err;
}
}
static void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
{
debugfs_remove_file(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\n", 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 = kzalloc(sizeof(struct ab3100_otp), GFP_KERNEL);
if (!otp) {
dev_err(&pdev->dev, "could not allocate AB3100 OTP device\n");
return -ENOMEM;
}
otp->dev = &pdev->dev;
/* Replace platform data coming in with a local struct */
otp->ab3100 = platform_get_drvdata(pdev);
platform_set_drvdata(pdev, otp);
err = ab3100_otp_read(otp);
if (err)
return err;
dev_info(&pdev->dev, "AB3100 OTP readout registered\n");
/* 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 out_no_sysfs;
}
/* debugfs entries */
err = ab3100_otp_init_debugfs(&pdev->dev, otp);
if (err)
goto out_no_debugfs;
return 0;
out_no_sysfs:
for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
device_remove_file(&pdev->dev,
&ab3100_otp_attrs[i]);
out_no_debugfs:
kfree(otp);
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);
kfree(otp);
return 0;
}
static struct platform_driver ab3100_otp_driver = {
.driver = {
.name = "ab3100-otp",
.owner = THIS_MODULE,
},
.remove = __exit_p(ab3100_otp_remove),
};
static int __init ab3100_otp_init(void)
{
return platform_driver_probe(&ab3100_otp_driver,
ab3100_otp_probe);
}
static void __exit ab3100_otp_exit(void)
{
platform_driver_unregister(&ab3100_otp_driver);
}
module_init(ab3100_otp_init);
module_exit(ab3100_otp_exit);
MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
MODULE_LICENSE("GPL");
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