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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* wm831x-otp.c -- OTP for Wolfson WM831x PMICs
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*
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* Copyright 2009 Wolfson Microelectronics PLC.
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*
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* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/delay.h>
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#include <linux/mfd/core.h>
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#include <linux/random.h>
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#include <linux/mfd/wm831x/core.h>
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#include <linux/mfd/wm831x/otp.h>
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/* In bytes */
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#define WM831X_UNIQUE_ID_LEN 16
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/* Read the unique ID from the chip into id */
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static int wm831x_unique_id_read(struct wm831x *wm831x, char *id)
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{
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int i, val;
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for (i = 0; i < WM831X_UNIQUE_ID_LEN / 2; i++) {
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val = wm831x_reg_read(wm831x, WM831X_UNIQUE_ID_1 + i);
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if (val < 0)
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return val;
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id[i * 2] = (val >> 8) & 0xff;
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id[(i * 2) + 1] = val & 0xff;
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}
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return 0;
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}
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static ssize_t wm831x_unique_id_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct wm831x *wm831x = dev_get_drvdata(dev);
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int rval;
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char id[WM831X_UNIQUE_ID_LEN];
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rval = wm831x_unique_id_read(wm831x, id);
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if (rval < 0)
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return 0;
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return sprintf(buf, "%*phN\n", WM831X_UNIQUE_ID_LEN, id);
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}
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static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);
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int wm831x_otp_init(struct wm831x *wm831x)
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{
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char uuid[WM831X_UNIQUE_ID_LEN];
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int ret;
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ret = device_create_file(wm831x->dev, &dev_attr_unique_id);
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if (ret != 0)
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dev_err(wm831x->dev, "Unique ID attribute not created: %d\n",
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ret);
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ret = wm831x_unique_id_read(wm831x, uuid);
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if (ret == 0)
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add_device_randomness(uuid, sizeof(uuid));
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else
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dev_err(wm831x->dev, "Failed to read UUID: %d\n", ret);
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return ret;
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}
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void wm831x_otp_exit(struct wm831x *wm831x)
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{
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device_remove_file(wm831x->dev, &dev_attr_unique_id);
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}
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