Blackfin char driver for Blackfin on-chip OTP memory (v3)
initial char driver for otp memory (only read supported atm ... needs real examples/docs for write support) v2-v3: - fixup __initdata with __initconst, as we are heading for 2.6.26 Signed-off-by: Mike Frysinger <vapier.adi@gmail.com> Signed-off-by: Bryan Wu <cooloney@kernel.org> Acked-by: Jiri Slaby <jirislaby@gmail.com>
This commit is contained in:
Mike Frysinger
Bryan Wu
Родитель
0a27842337
Коммит
2dc63a84b2
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@ -481,6 +481,34 @@ config BRIQ_PANEL
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It's safe to say N here.
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config BFIN_OTP
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tristate "Blackfin On-Chip OTP Memory Support"
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depends on BLACKFIN && (BF52x || BF54x)
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default y
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help
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If you say Y here, you will get support for a character device
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interface into the One Time Programmable memory pages that are
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stored on the Blackfin processor. This will not get you access
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to the secure memory pages however. You will need to write your
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own secure code and reader for that.
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To compile this driver as a module, choose M here: the module
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will be called bfin-otp.
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If unsure, it is safe to say Y.
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config BFIN_OTP_WRITE_ENABLE
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bool "Enable writing support of OTP pages"
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depends on BFIN_OTP
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default n
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help
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If you say Y here, you will enable support for writing of the
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OTP pages. This is dangerous by nature as you can only program
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the pages once, so only enable this option when you actually
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need it so as to not inadvertently clobber data.
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If unsure, say N.
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config PRINTER
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tristate "Parallel printer support"
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depends on PARPORT
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@ -59,6 +59,7 @@ obj-$(CONFIG_VIOTAPE) += viotape.o
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obj-$(CONFIG_HVCS) += hvcs.o
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obj-$(CONFIG_SGI_MBCS) += mbcs.o
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obj-$(CONFIG_BRIQ_PANEL) += briq_panel.o
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obj-$(CONFIG_BFIN_OTP) += bfin-otp.o
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obj-$(CONFIG_PRINTER) += lp.o
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obj-$(CONFIG_TIPAR) += tipar.o
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@ -0,0 +1,189 @@
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/*
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* Blackfin On-Chip OTP Memory Interface
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* Supports BF52x/BF54x
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*
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* Copyright 2007-2008 Analog Devices Inc.
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*
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* Enter bugs at http://blackfin.uclinux.org/
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/types.h>
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#include <asm/blackfin.h>
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#include <asm/uaccess.h>
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#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
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#define stampit() stamp("here i am")
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#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
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#define DRIVER_NAME "bfin-otp"
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#define PFX DRIVER_NAME ": "
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static DEFINE_MUTEX(bfin_otp_lock);
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/* OTP Boot ROM functions */
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#define _BOOTROM_OTP_COMMAND 0xEF000018
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#define _BOOTROM_OTP_READ 0xEF00001A
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#define _BOOTROM_OTP_WRITE 0xEF00001C
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static u32 (* const otp_command)(u32 command, u32 value) = (void *)_BOOTROM_OTP_COMMAND;
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static u32 (* const otp_read)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_READ;
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static u32 (* const otp_write)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_WRITE;
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/* otp_command(): defines for "command" */
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#define OTP_INIT 0x00000001
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#define OTP_CLOSE 0x00000002
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/* otp_{read,write}(): defines for "flags" */
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#define OTP_LOWER_HALF 0x00000000 /* select upper/lower 64-bit half (bit 0) */
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#define OTP_UPPER_HALF 0x00000001
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#define OTP_NO_ECC 0x00000010 /* do not use ECC */
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#define OTP_LOCK 0x00000020 /* sets page protection bit for page */
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#define OTP_ACCESS_READ 0x00001000
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#define OTP_ACCESS_READWRITE 0x00002000
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/* Return values for all functions */
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#define OTP_SUCCESS 0x00000000
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#define OTP_MASTER_ERROR 0x001
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#define OTP_WRITE_ERROR 0x003
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#define OTP_READ_ERROR 0x005
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#define OTP_ACC_VIO_ERROR 0x009
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#define OTP_DATA_MULT_ERROR 0x011
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#define OTP_ECC_MULT_ERROR 0x021
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#define OTP_PREV_WR_ERROR 0x041
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#define OTP_DATA_SB_WARN 0x100
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#define OTP_ECC_SB_WARN 0x200
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/**
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* bfin_otp_read - Read OTP pages
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*
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* All reads must be in half page chunks (half page == 64 bits).
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*/
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static ssize_t bfin_otp_read(struct file *file, char __user *buff, size_t count, loff_t *pos)
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{
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ssize_t bytes_done;
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u32 page, flags, ret;
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u64 content;
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stampit();
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if (count % sizeof(u64))
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return -EMSGSIZE;
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if (mutex_lock_interruptible(&bfin_otp_lock))
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return -ERESTARTSYS;
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bytes_done = 0;
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page = *pos / (sizeof(u64) * 2);
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while (bytes_done < count) {
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flags = (*pos % (sizeof(u64) * 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
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stamp("processing page %i (%s)", page, (flags == OTP_UPPER_HALF ? "upper" : "lower"));
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ret = otp_read(page, flags, &content);
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if (ret & OTP_MASTER_ERROR) {
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bytes_done = -EIO;
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break;
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}
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if (copy_to_user(buff + bytes_done, &content, sizeof(content))) {
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bytes_done = -EFAULT;
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break;
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}
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if (flags == OTP_UPPER_HALF)
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++page;
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bytes_done += sizeof(content);
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*pos += sizeof(content);
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}
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mutex_unlock(&bfin_otp_lock);
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return bytes_done;
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}
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#ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
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/**
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* bfin_otp_write - Write OTP pages
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*
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* All writes must be in half page chunks (half page == 64 bits).
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*/
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static ssize_t bfin_otp_write(struct file *filp, const char __user *buff, size_t count, loff_t *pos)
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{
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stampit();
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if (count % sizeof(u64))
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return -EMSGSIZE;
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if (mutex_lock_interruptible(&bfin_otp_lock))
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return -ERESTARTSYS;
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/* need otp_init() documentation before this can be implemented */
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mutex_unlock(&bfin_otp_lock);
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return -EINVAL;
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}
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#else
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# define bfin_otp_write NULL
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#endif
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static struct file_operations bfin_otp_fops = {
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.owner = THIS_MODULE,
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.read = bfin_otp_read,
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.write = bfin_otp_write,
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};
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static struct miscdevice bfin_otp_misc_device = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = DRIVER_NAME,
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.fops = &bfin_otp_fops,
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};
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/**
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* bfin_otp_init - Initialize module
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*
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* Registers the device and notifier handler. Actual device
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* initialization is handled by bfin_otp_open().
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*/
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static int __init bfin_otp_init(void)
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{
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int ret;
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stampit();
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ret = misc_register(&bfin_otp_misc_device);
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if (ret) {
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pr_init(KERN_ERR PFX "unable to register a misc device\n");
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return ret;
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}
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pr_init(KERN_INFO PFX "initialized\n");
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return 0;
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}
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/**
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* bfin_otp_exit - Deinitialize module
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*
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* Unregisters the device and notifier handler. Actual device
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* deinitialization is handled by bfin_otp_close().
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*/
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static void __exit bfin_otp_exit(void)
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{
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stampit();
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misc_deregister(&bfin_otp_misc_device);
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}
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module_init(bfin_otp_init);
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module_exit(bfin_otp_exit);
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MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
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MODULE_DESCRIPTION("Blackfin OTP Memory Interface");
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MODULE_LICENSE("GPL");
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