1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * LinkStation power off restart driver
4  * Copyright (C) 2020 Daniel González Cabanelas <dgcbueu@gmail.com>
5  */
6 
7 #include <linux/module.h>
8 #include <linux/notifier.h>
9 #include <linux/of.h>
10 #include <linux/of_mdio.h>
11 #include <linux/of_platform.h>
12 #include <linux/reboot.h>
13 #include <linux/phy.h>
14 
15 /* Defines from the eth phy Marvell driver */
16 #define MII_MARVELL_COPPER_PAGE		0
17 #define MII_MARVELL_LED_PAGE		3
18 #define MII_MARVELL_WOL_PAGE		17
19 #define MII_MARVELL_PHY_PAGE		22
20 
21 #define MII_PHY_LED_CTRL		16
22 #define MII_88E1318S_PHY_LED_TCR	18
23 #define MII_88E1318S_PHY_WOL_CTRL	16
24 #define MII_M1011_IEVENT		19
25 
26 #define MII_88E1318S_PHY_LED_TCR_INTn_ENABLE		BIT(7)
27 #define MII_88E1318S_PHY_LED_TCR_FORCE_INT		BIT(15)
28 #define MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS	BIT(12)
29 #define LED2_FORCE_ON					(0x8 << 8)
30 #define LEDMASK						GENMASK(11,8)
31 
32 static struct phy_device *phydev;
33 
34 static void mvphy_reg_intn(u16 data)
35 {
36 	int rc = 0, saved_page;
37 
38 	saved_page = phy_select_page(phydev, MII_MARVELL_LED_PAGE);
39 	if (saved_page < 0)
40 		goto err;
41 
42 	/* Force manual LED2 control to let INTn work */
43 	__phy_modify(phydev, MII_PHY_LED_CTRL, LEDMASK, LED2_FORCE_ON);
44 
45 	/* Set the LED[2]/INTn pin to the required state */
46 	__phy_modify(phydev, MII_88E1318S_PHY_LED_TCR,
47 		     MII_88E1318S_PHY_LED_TCR_FORCE_INT,
48 		     MII_88E1318S_PHY_LED_TCR_INTn_ENABLE | data);
49 
50 	if (!data) {
51 		/* Clear interrupts to ensure INTn won't be holded in high state */
52 		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_COPPER_PAGE);
53 		__phy_read(phydev, MII_M1011_IEVENT);
54 
55 		/* If WOL was enabled and a magic packet was received before powering
56 		 * off, we won't be able to wake up by sending another magic packet.
57 		 * Clear WOL status.
58 		 */
59 		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_WOL_PAGE);
60 		__phy_set_bits(phydev, MII_88E1318S_PHY_WOL_CTRL,
61 			       MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS);
62 	}
63 err:
64 	rc = phy_restore_page(phydev, saved_page, rc);
65 	if (rc < 0)
66 		dev_err(&phydev->mdio.dev, "Write register failed, %d\n", rc);
67 }
68 
69 static int linkstation_reboot_notifier(struct notifier_block *nb,
70 				       unsigned long action, void *unused)
71 {
72 	if (action == SYS_RESTART)
73 		mvphy_reg_intn(MII_88E1318S_PHY_LED_TCR_FORCE_INT);
74 
75 	return NOTIFY_DONE;
76 }
77 
78 static struct notifier_block linkstation_reboot_nb = {
79 	.notifier_call = linkstation_reboot_notifier,
80 };
81 
82 static void linkstation_poweroff(void)
83 {
84 	unregister_reboot_notifier(&linkstation_reboot_nb);
85 	mvphy_reg_intn(0);
86 
87 	kernel_restart("Power off");
88 }
89 
90 static const struct of_device_id ls_poweroff_of_match[] = {
91 	{ .compatible = "buffalo,ls421d" },
92 	{ .compatible = "buffalo,ls421de" },
93 	{ },
94 };
95 
96 static int __init linkstation_poweroff_init(void)
97 {
98 	struct mii_bus *bus;
99 	struct device_node *dn;
100 
101 	dn = of_find_matching_node(NULL, ls_poweroff_of_match);
102 	if (!dn)
103 		return -ENODEV;
104 	of_node_put(dn);
105 
106 	dn = of_find_node_by_name(NULL, "mdio");
107 	if (!dn)
108 		return -ENODEV;
109 
110 	bus = of_mdio_find_bus(dn);
111 	of_node_put(dn);
112 	if (!bus)
113 		return -EPROBE_DEFER;
114 
115 	phydev = phy_find_first(bus);
116 	put_device(&bus->dev);
117 	if (!phydev)
118 		return -EPROBE_DEFER;
119 
120 	register_reboot_notifier(&linkstation_reboot_nb);
121 	pm_power_off = linkstation_poweroff;
122 
123 	return 0;
124 }
125 
126 static void __exit linkstation_poweroff_exit(void)
127 {
128 	pm_power_off = NULL;
129 	unregister_reboot_notifier(&linkstation_reboot_nb);
130 }
131 
132 module_init(linkstation_poweroff_init);
133 module_exit(linkstation_poweroff_exit);
134 
135 MODULE_AUTHOR("Daniel González Cabanelas <dgcbueu@gmail.com>");
136 MODULE_DESCRIPTION("LinkStation power off driver");
137 MODULE_LICENSE("GPL v2");
138