1 /* SPDX-License-Identifier:	GPL-2.0+
2  *
3  * Copyright (c) 2018 Microchip Technology, Inc.
4  *
5  */
6 
7 #include <common.h>
8 #include <linux/err.h>
9 #include <dm.h>
10 #include <w1-eeprom.h>
11 #include <w1.h>
12 
13 #define W1_F2D_READ_EEPROM      0xf0
14 
15 #define EEP_SANDBOX_SAMPLE_MEM "this is a sample EEPROM memory string."
16 
17 static int eep_sandbox_read_buf(struct udevice *dev, unsigned int offset,
18 				u8 *buf, unsigned int count)
19 {
20 	/* do not allow to copy more than our maximum sample string */
21 	if (offset + count < strlen(EEP_SANDBOX_SAMPLE_MEM)) {
22 		offset = 0;
23 		count = strlen(EEP_SANDBOX_SAMPLE_MEM);
24 	}
25 	strncpy((char *)buf, EEP_SANDBOX_SAMPLE_MEM, count);
26 
27 	/*
28 	 * in case the w1 subsystem uses some different kind of sandbox testing,
29 	 * like randomized gpio values , we take the buffer from there
30 	 */
31 
32 	w1_reset_select(dev);
33 
34 	w1_write_byte(dev, W1_F2D_READ_EEPROM);
35 	w1_write_byte(dev, offset & 0xff);
36 	w1_write_byte(dev, offset >> 8);
37 
38 	w1_read_buf(dev, buf, count);
39 
40 	/*
41 	 * even if read buf from w1 fails, return success as we hardcoded
42 	 * the buffer.
43 	 */
44 	return 0;
45 }
46 
47 static const struct w1_eeprom_ops eep_sandbox_ops = {
48 	.read_buf	= eep_sandbox_read_buf,
49 };
50 
51 static const struct udevice_id eep_sandbox_id[] = {
52 	{ .compatible = "sandbox,w1-eeprom", .data = W1_FAMILY_EEP_SANDBOX },
53 	{ },
54 };
55 
56 U_BOOT_DRIVER(eep_sandbox) = {
57 	.name		= "eep_sandbox",
58 	.id		= UCLASS_W1_EEPROM,
59 	.of_match	= eep_sandbox_id,
60 	.ops		= &eep_sandbox_ops,
61 };
62