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alistair23-linux/drivers/mfd/ab3100-otp.c
Greg Kroah-Hartman 45640a383a mfd: ab3100: no need to check return value of debugfs_create functions 
When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20190706164722.18766-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-01 08:06:59 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/mfd/ab3100_otp.c
*
* Copyright (C) 2007-2009 ST-Ericsson AB
* 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\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 void __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);
}
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 void __init ab3100_otp_init_debugfs(struct device *dev,
struct ab3100_otp *otp)
{
}
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 = devm_kzalloc(&pdev->dev, sizeof(struct ab3100_otp), GFP_KERNEL);
if (!otp)
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\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;
}
/* debugfs entries */
ab3100_otp_init_debugfs(&pdev->dev, otp);
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",
},
.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");
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