projects / mirror_ubuntu-focal-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 6704e517 MB |
2 | /* |
| 3 | * wm831x-otp.c -- OTP for Wolfson WM831x PMICs | |
| 4 | * | |
| 5 | * Copyright 2009 Wolfson Microelectronics PLC. | |
| 6 | * | |
| 7 | * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> | |
| 6704e517 MB |
8 | */ |
| 9 | ||
| 10 | #include <linux/kernel.h> | |
| 11 | #include <linux/module.h> | |
| 12 | #include <linux/i2c.h> | |
| 13 | #include <linux/bcd.h> | |
| 14 | #include <linux/delay.h> | |
| 15 | #include <linux/mfd/core.h> | |
| 27130f0c | 16 | #include <linux/random.h> |
| 6704e517 MB |
17 | |
| 18 | #include <linux/mfd/wm831x/core.h> | |
| 19 | #include <linux/mfd/wm831x/otp.h> | |
| 20 | ||
| 21 | /* In bytes */ | |
| 22 | #define WM831X_UNIQUE_ID_LEN 16 | |
| 23 | ||
| 24 | /* Read the unique ID from the chip into id */ | |
| 25 | static int wm831x_unique_id_read(struct wm831x *wm831x, char *id) | |
| 26 | { | |
| 27 | int i, val; | |
| 28 | ||
| 29 | for (i = 0; i < WM831X_UNIQUE_ID_LEN / 2; i++) { | |
| 30 | val = wm831x_reg_read(wm831x, WM831X_UNIQUE_ID_1 + i); | |
| 31 | if (val < 0) | |
| 32 | return val; | |
| 33 | ||
| 34 | id[i * 2] = (val >> 8) & 0xff; | |
| 35 | id[(i * 2) + 1] = val & 0xff; | |
| 36 | } | |
| 37 | ||
| 38 | return 0; | |
| 39 | } | |
| 40 | ||
| 41 | static ssize_t wm831x_unique_id_show(struct device *dev, | |
| 42 | struct device_attribute *attr, char *buf) | |
| 43 | { | |
| 44 | struct wm831x *wm831x = dev_get_drvdata(dev); | |
| a5656a70 | 45 | int rval; |
| 6704e517 | 46 | char id[WM831X_UNIQUE_ID_LEN]; |
| 6704e517 MB |
47 | |
| 48 | rval = wm831x_unique_id_read(wm831x, id); | |
| 49 | if (rval < 0) | |
| 50 | return 0; | |
| 51 | ||
| a5656a70 | 52 | return sprintf(buf, "%*phN\n", WM831X_UNIQUE_ID_LEN, id); |
| 6704e517 MB |
53 | } |
| 54 | ||
| 55 | static DEVICE_ATTR(unique_id, 0444, wm831x_unique_id_show, NULL); | |
| 56 | ||
| 57 | int wm831x_otp_init(struct wm831x *wm831x) | |
| 58 | { | |
| 27130f0c | 59 | char uuid[WM831X_UNIQUE_ID_LEN]; |
| 6704e517 MB |
60 | int ret; |
| 61 | ||
| 62 | ret = device_create_file(wm831x->dev, &dev_attr_unique_id); | |
| 63 | if (ret != 0) | |
| 64 | dev_err(wm831x->dev, "Unique ID attribute not created: %d\n", | |
| 65 | ret); | |
| 66 | ||
| 27130f0c MB |
67 | ret = wm831x_unique_id_read(wm831x, uuid); |
| 68 | if (ret == 0) | |
| 69 | add_device_randomness(uuid, sizeof(uuid)); | |
| 70 | else | |
| 71 | dev_err(wm831x->dev, "Failed to read UUID: %d\n", ret); | |
| 72 | ||
| 6704e517 MB |
73 | return ret; |
| 74 | } | |
| 75 | ||
| 76 | void wm831x_otp_exit(struct wm831x *wm831x) | |
| 77 | { | |
| 78 | device_remove_file(wm831x->dev, &dev_attr_unique_id); | |
| 79 | } | |
| 80 |