[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / mfd / wm831x-otp.c

/*
 * wm831x-otp.c  --  OTP for Wolfson WM831x PMICs
 *
 * Copyright 2009 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/delay.h>
#include <linux/mfd/core.h>
#include <linux/random.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/otp.h>

/* In bytes */
#define WM831X_UNIQUE_ID_LEN 16

/* Read the unique ID from the chip into id */
static int wm831x_unique_id_read(struct wm831x *wm831x, char *id)
{
	int i, val;

	for (i = 0; i < WM831X_UNIQUE_ID_LEN / 2; i++) {
		val = wm831x_reg_read(wm831x, WM831X_UNIQUE_ID_1 + i);
		if (val < 0)
			return val;

		id[i * 2]       = (val >> 8) & 0xff;
		id[(i * 2) + 1] = val & 0xff;
	}

	return 0;
}

static ssize_t wm831x_unique_id_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct wm831x *wm831x = dev_get_drvdata(dev);
	int i, rval;
	char id[WM831X_UNIQUE_ID_LEN];
	ssize_t ret = 0;

	rval = wm831x_unique_id_read(wm831x, id);
	if (rval < 0)
		return 0;

	for (i = 0; i < WM831X_UNIQUE_ID_LEN; i++)
		ret += sprintf(&buf[ret], "%02x", buf[i]);

	ret += sprintf(&buf[ret], "\n");

	return ret;
}

static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);

int wm831x_otp_init(struct wm831x *wm831x)
{
	char uuid[WM831X_UNIQUE_ID_LEN];
	int ret;

	ret = device_create_file(wm831x->dev, &dev_attr_unique_id);
	if (ret != 0)
		dev_err(wm831x->dev, "Unique ID attribute not created: %d\n",
			ret);

	ret = wm831x_unique_id_read(wm831x, uuid);
	if (ret == 0)
		add_device_randomness(uuid, sizeof(uuid));
	else
		dev_err(wm831x->dev, "Failed to read UUID: %d\n", ret);

	return ret;
}

void wm831x_otp_exit(struct wm831x *wm831x)
{
	device_remove_file(wm831x->dev, &dev_attr_unique_id);
}
Commit	Line	Data
6704e517 MB	1	/*
	2	* wm831x-otp.c -- OTP for Wolfson WM831x PMICs
	3	*
	4	* Copyright 2009 Wolfson Microelectronics PLC.
	5	*
	6	* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License as published by the
	10	* Free Software Foundation; either version 2 of the License, or (at your
	11	* option) any later version.
	12	*
	13	*/
	14
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/i2c.h>
	18	#include <linux/bcd.h>
	19	#include <linux/delay.h>
	20	#include <linux/mfd/core.h>
27130f0c	21	#include <linux/random.h>
6704e517 MB	22
	23	#include <linux/mfd/wm831x/core.h>
	24	#include <linux/mfd/wm831x/otp.h>
	25
	26	/* In bytes */
	27	#define WM831X_UNIQUE_ID_LEN 16
	28
	29	/* Read the unique ID from the chip into id */
	30	static int wm831x_unique_id_read(struct wm831x wm831x, char id)
	31	{
	32	int i, val;
	33
	34	for (i = 0; i < WM831X_UNIQUE_ID_LEN / 2; i++) {
	35	val = wm831x_reg_read(wm831x, WM831X_UNIQUE_ID_1 + i);
	36	if (val < 0)
	37	return val;
	38
	39	id[i * 2] = (val >> 8) & 0xff;
	40	id[(i * 2) + 1] = val & 0xff;
	41	}
	42
	43	return 0;
	44	}
	45
	46	static ssize_t wm831x_unique_id_show(struct device *dev,
	47	struct device_attribute attr, char buf)
	48	{
	49	struct wm831x *wm831x = dev_get_drvdata(dev);
	50	int i, rval;
	51	char id[WM831X_UNIQUE_ID_LEN];
	52	ssize_t ret = 0;
	53
	54	rval = wm831x_unique_id_read(wm831x, id);
	55	if (rval < 0)
	56	return 0;
	57
	58	for (i = 0; i < WM831X_UNIQUE_ID_LEN; i++)
	59	ret += sprintf(&buf[ret], "%02x", buf[i]);
	60
	61	ret += sprintf(&buf[ret], "\n");
	62
	63	return ret;
	64	}
	65
	66	static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL);
	67
	68	int wm831x_otp_init(struct wm831x *wm831x)
	69	{
27130f0c	70	char uuid[WM831X_UNIQUE_ID_LEN];
6704e517 MB	71	int ret;
	72
	73	ret = device_create_file(wm831x->dev, &dev_attr_unique_id);
	74	if (ret != 0)
	75	dev_err(wm831x->dev, "Unique ID attribute not created: %d\n",
	76	ret);
	77
27130f0c MB	78	ret = wm831x_unique_id_read(wm831x, uuid);
	79	if (ret == 0)
	80	add_device_randomness(uuid, sizeof(uuid));
	81	else
	82	dev_err(wm831x->dev, "Failed to read UUID: %d\n", ret);
	83
6704e517 MB	84	return ret;
	85	}
	86
	87	void wm831x_otp_exit(struct wm831x *wm831x)
	88	{
	89	device_remove_file(wm831x->dev, &dev_attr_unique_id);
	90	}
	91