1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Reset driver for Axxia devices |
4 | * |
5 | * Copyright (C) 2014 LSI |
6 | */ |
7 | #include <linux/init.h> |
8 | #include <linux/err.h> |
9 | #include <linux/io.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/mfd/syscon.h> |
12 | #include <linux/module.h> |
13 | #include <linux/notifier.h> |
14 | #include <linux/of.h> |
15 | #include <linux/platform_device.h> |
16 | #include <linux/reboot.h> |
17 | #include <linux/regmap.h> |
18 | |
19 | #define SC_CRIT_WRITE_KEY 0x1000 |
20 | #define SC_LATCH_ON_RESET 0x1004 |
21 | #define SC_RESET_CONTROL 0x1008 |
22 | #define RSTCTL_RST_ZERO (1<<3) |
23 | #define RSTCTL_RST_FAB (1<<2) |
24 | #define RSTCTL_RST_CHIP (1<<1) |
25 | #define RSTCTL_RST_SYS (1<<0) |
26 | #define SC_EFUSE_INT_STATUS 0x180c |
27 | #define EFUSE_READ_DONE (1<<31) |
28 | |
29 | static int axxia_restart_handler(struct sys_off_data *data) |
30 | { |
31 | struct regmap *syscon = data->cb_data; |
32 | |
33 | /* Access Key (0xab) */ |
34 | regmap_write(map: syscon, SC_CRIT_WRITE_KEY, val: 0xab); |
35 | /* Select internal boot from 0xffff0000 */ |
36 | regmap_write(map: syscon, SC_LATCH_ON_RESET, val: 0x00000040); |
37 | /* Assert ResetReadDone (to avoid hanging in boot ROM) */ |
38 | regmap_write(map: syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE); |
39 | /* Assert chip reset */ |
40 | regmap_update_bits(map: syscon, SC_RESET_CONTROL, |
41 | RSTCTL_RST_CHIP, RSTCTL_RST_CHIP); |
42 | |
43 | return NOTIFY_DONE; |
44 | } |
45 | |
46 | static int axxia_reset_probe(struct platform_device *pdev) |
47 | { |
48 | struct device *dev = &pdev->dev; |
49 | struct regmap *syscon; |
50 | int err; |
51 | |
52 | syscon = syscon_regmap_lookup_by_phandle(np: dev->of_node, property: "syscon" ); |
53 | if (IS_ERR(ptr: syscon)) { |
54 | pr_err("%pOFn: syscon lookup failed\n" , dev->of_node); |
55 | return PTR_ERR(ptr: syscon); |
56 | } |
57 | |
58 | err = devm_register_sys_off_handler(dev: &pdev->dev, mode: SYS_OFF_MODE_RESTART, |
59 | priority: 128, callback: axxia_restart_handler, cb_data: syscon); |
60 | if (err) |
61 | dev_err(dev, "cannot register restart handler (err=%d)\n" , err); |
62 | |
63 | return err; |
64 | } |
65 | |
66 | static const struct of_device_id of_axxia_reset_match[] = { |
67 | { .compatible = "lsi,axm55xx-reset" , }, |
68 | {}, |
69 | }; |
70 | MODULE_DEVICE_TABLE(of, of_axxia_reset_match); |
71 | |
72 | static struct platform_driver axxia_reset_driver = { |
73 | .probe = axxia_reset_probe, |
74 | .driver = { |
75 | .name = "axxia-reset" , |
76 | .of_match_table = of_match_ptr(of_axxia_reset_match), |
77 | }, |
78 | }; |
79 | builtin_platform_driver(axxia_reset_driver); |
80 | |