1 // SPDX-License-Identifier: GPL-2.0+
2 // (C) 2022 Pali Rohár <pali@kernel.org>
3
4 #include <asm/io.h>
5 #include <asm-generic/gpio.h>
6 #include <dm.h>
7 #include <linux/delay.h>
8 #include <wdt.h>
9
10 #define MAX6370_SET_MASK 0x7
11 #define MAX6370_SET_1MS 0x0
12 #define MAX6370_SET_10MS 0x1
13 #define MAX6370_SET_30MS 0x2
14 #define MAX6370_SET_DISABLE 0x3
15 #define MAX6370_SET_100MS 0x4
16 #define MAX6370_SET_1S 0x5
17 #define MAX6370_SET_10S 0x6
18 #define MAX6370_SET_60S 0x7
19
20 #define MAX6370_WDI 0x8
21
22 struct max6370_wdt {
23 void __iomem *reg;
24 struct gpio_desc gpio_wdi;
25 };
26
max6370_wdt_start(struct udevice * dev,u64 ms,ulong flags)27 static int max6370_wdt_start(struct udevice *dev, u64 ms, ulong flags)
28 {
29 struct max6370_wdt *wdt = dev_get_priv(dev);
30 u8 val;
31
32 val = readb(wdt->reg);
33 val &= ~MAX6370_SET_MASK;
34
35 if (ms <= 1)
36 val |= MAX6370_SET_1MS;
37 else if (ms <= 10)
38 val |= MAX6370_SET_10MS;
39 else if (ms <= 30)
40 val |= MAX6370_SET_30MS;
41 else if (ms <= 100)
42 val |= MAX6370_SET_100MS;
43 else if (ms <= 1000)
44 val |= MAX6370_SET_1S;
45 else if (ms <= 10000)
46 val |= MAX6370_SET_10S;
47 else
48 val |= MAX6370_SET_60S;
49
50 writeb(val, wdt->reg);
51
52 return 0;
53 }
54
max6370_wdt_stop(struct udevice * dev)55 static int max6370_wdt_stop(struct udevice *dev)
56 {
57 struct max6370_wdt *wdt = dev_get_priv(dev);
58 u8 val;
59
60 val = readb(wdt->reg);
61 val &= ~MAX6370_SET_MASK;
62 val |= MAX6370_SET_DISABLE;
63 writeb(val, wdt->reg);
64
65 return 0;
66 }
67
max6370_wdt_reset(struct udevice * dev)68 static int max6370_wdt_reset(struct udevice *dev)
69 {
70 struct max6370_wdt *wdt = dev_get_priv(dev);
71 u8 val;
72
73 if (dm_gpio_is_valid(&wdt->gpio_wdi)) {
74 dm_gpio_set_value(&wdt->gpio_wdi, 1);
75 __udelay(1);
76 dm_gpio_set_value(&wdt->gpio_wdi, 0);
77 } else {
78 val = readb(wdt->reg);
79 writeb(val | MAX6370_WDI, wdt->reg);
80 writeb(val & ~MAX6370_WDI, wdt->reg);
81 }
82
83 return 0;
84 }
85
max6370_wdt_probe(struct udevice * dev)86 static int max6370_wdt_probe(struct udevice *dev)
87 {
88 struct max6370_wdt *wdt = dev_get_priv(dev);
89
90 wdt->reg = dev_read_addr_ptr(dev);
91 if (!wdt->reg)
92 return -EINVAL;
93
94 /* WDI gpio is optional */
95 gpio_request_by_name(dev, "gpios", 0, &wdt->gpio_wdi, GPIOD_IS_OUT);
96
97 return 0;
98 }
99
100 static const struct wdt_ops max6370_wdt_ops = {
101 .start = max6370_wdt_start,
102 .stop = max6370_wdt_stop,
103 .reset = max6370_wdt_reset,
104 };
105
106 static const struct udevice_id max6370_wdt_ids[] = {
107 { .compatible = "maxim,max6370" },
108 {}
109 };
110
111 U_BOOT_DRIVER(max6370_wdt) = {
112 .name = "max6370_wdt",
113 .id = UCLASS_WDT,
114 .of_match = max6370_wdt_ids,
115 .probe = max6370_wdt_probe,
116 .priv_auto = sizeof(struct max6370_wdt),
117 .ops = &max6370_wdt_ops,
118 };
119