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"Das U-Boot" Source Tree
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for a PMIC watchdog timer controlled via Siemens SCU firmware
4 * extensions. Only useful on some Siemens i.MX8-based platforms as
5 * special NXP SCFW is needed which provides the needed SCU API.
6 *
7 * Copyright (C) 2024 Siemens AG
8 */
9
10#include <dm.h>
11#include <wdt.h>
12#include <firmware/imx/sci/sci.h>
13
14/* watchdog commands */
15#define CMD_START_WDT 0x55
16#define CMD_STOP_WDT 0x45
17#define CMD_PING_WDT 0x35
18
19static int scu_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
20{
21 /* start external watchdog via Timer API */
22 return sc_timer_control_siemens_pmic_wdog(-1, CMD_START_WDT);
23}
24
25static int scu_wdt_stop(struct udevice *dev)
26{
27 /* stop external watchdog via Timer API */
28 return sc_timer_control_siemens_pmic_wdog(-1, CMD_STOP_WDT);
29}
30
31static int scu_wdt_reset(struct udevice *dev)
32{
33 return sc_timer_control_siemens_pmic_wdog(-1, CMD_PING_WDT);
34}
35
36static int scu_wdt_probe(struct udevice *dev)
37{
38 debug("%s(dev=%p)\n", __func__, dev);
39 return 0;
40}
41
42static const struct wdt_ops scu_wdt_ops = {
43 .reset = scu_wdt_reset,
44 .start = scu_wdt_start,
45 .stop = scu_wdt_stop,
46};
47
48static const struct udevice_id scu_wdt_ids[] = {
49 { .compatible = "siemens,scu-wdt" },
50 { }
51};
52
53U_BOOT_DRIVER(scu_wdt) = {
54 .name = "scu_wdt",
55 .id = UCLASS_WDT,
56 .of_match = scu_wdt_ids,
57 .probe = scu_wdt_probe,
58 .ops = &scu_wdt_ops,
59};