ab3100-otp.c

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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 <[email protected]>
 */

#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 {
    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\n");
        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\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_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\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_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!\n");
        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\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 */
    platform_set_drvdata(pdev, otp);

    err = ab3100_otp_read(otp);
    if (err)
        goto err_otp_read;

    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 err_create_file;
    }

    /* debugfs entries */
    err = ab3100_otp_init_debugfs(&pdev->dev, otp);
    if (err)
        goto err_init_debugfs;

    return 0;

err_init_debugfs:
err_create_file:
    while (--i >= 0)
        device_remove_file(&pdev->dev, &ab3100_otp_attrs[i]);
err_otp_read:
    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 <[email protected]>");
MODULE_DESCRIPTION("AB3100 OTP Readout Driver");
MODULE_LICENSE("GPL");