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9952f691 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
8bec4337 SH |
2 | /* |
3 | * SCPI Generic power domain support. | |
4 | * | |
5 | * Copyright (C) 2016 ARM Ltd. | |
8bec4337 SH |
6 | */ |
7 | ||
8 | #include <linux/err.h> | |
9 | #include <linux/io.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/of_platform.h> | |
12 | #include <linux/pm_domain.h> | |
13 | #include <linux/scpi_protocol.h> | |
14 | ||
15 | struct scpi_pm_domain { | |
16 | struct generic_pm_domain genpd; | |
17 | struct scpi_ops *ops; | |
18 | u32 domain; | |
19 | char name[30]; | |
20 | }; | |
21 | ||
22 | /* | |
23 | * These device power state values are not well-defined in the specification. | |
24 | * In case, different implementations use different values, we can make these | |
25 | * specific to compatibles rather than getting these values from device tree. | |
26 | */ | |
27 | enum scpi_power_domain_state { | |
28 | SCPI_PD_STATE_ON = 0, | |
29 | SCPI_PD_STATE_OFF = 3, | |
30 | }; | |
31 | ||
32 | #define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd) | |
33 | ||
34 | static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on) | |
35 | { | |
36 | int ret; | |
37 | enum scpi_power_domain_state state; | |
38 | ||
39 | if (power_on) | |
40 | state = SCPI_PD_STATE_ON; | |
41 | else | |
42 | state = SCPI_PD_STATE_OFF; | |
43 | ||
44 | ret = pd->ops->device_set_power_state(pd->domain, state); | |
45 | if (ret) | |
46 | return ret; | |
47 | ||
48 | return !(state == pd->ops->device_get_power_state(pd->domain)); | |
49 | } | |
50 | ||
51 | static int scpi_pd_power_on(struct generic_pm_domain *domain) | |
52 | { | |
53 | struct scpi_pm_domain *pd = to_scpi_pd(domain); | |
54 | ||
55 | return scpi_pd_power(pd, true); | |
56 | } | |
57 | ||
58 | static int scpi_pd_power_off(struct generic_pm_domain *domain) | |
59 | { | |
60 | struct scpi_pm_domain *pd = to_scpi_pd(domain); | |
61 | ||
62 | return scpi_pd_power(pd, false); | |
63 | } | |
64 | ||
65 | static int scpi_pm_domain_probe(struct platform_device *pdev) | |
66 | { | |
67 | struct device *dev = &pdev->dev; | |
68 | struct device_node *np = dev->of_node; | |
69 | struct scpi_pm_domain *scpi_pd; | |
70 | struct genpd_onecell_data *scpi_pd_data; | |
71 | struct generic_pm_domain **domains; | |
72 | struct scpi_ops *scpi_ops; | |
73 | int ret, num_domains, i; | |
74 | ||
75 | scpi_ops = get_scpi_ops(); | |
76 | if (!scpi_ops) | |
77 | return -EPROBE_DEFER; | |
78 | ||
79 | if (!np) { | |
80 | dev_err(dev, "device tree node not found\n"); | |
81 | return -ENODEV; | |
82 | } | |
83 | ||
84 | if (!scpi_ops->device_set_power_state || | |
85 | !scpi_ops->device_get_power_state) { | |
86 | dev_err(dev, "power domains not supported in the firmware\n"); | |
87 | return -ENODEV; | |
88 | } | |
89 | ||
90 | ret = of_property_read_u32(np, "num-domains", &num_domains); | |
91 | if (ret) { | |
92 | dev_err(dev, "number of domains not found\n"); | |
93 | return -EINVAL; | |
94 | } | |
95 | ||
96 | scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL); | |
97 | if (!scpi_pd) | |
98 | return -ENOMEM; | |
99 | ||
100 | scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL); | |
101 | if (!scpi_pd_data) | |
102 | return -ENOMEM; | |
103 | ||
104 | domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL); | |
105 | if (!domains) | |
106 | return -ENOMEM; | |
107 | ||
108 | for (i = 0; i < num_domains; i++, scpi_pd++) { | |
109 | domains[i] = &scpi_pd->genpd; | |
110 | ||
111 | scpi_pd->domain = i; | |
112 | scpi_pd->ops = scpi_ops; | |
75afbfc1 | 113 | sprintf(scpi_pd->name, "%pOFn.%d", np, i); |
8bec4337 SH |
114 | scpi_pd->genpd.name = scpi_pd->name; |
115 | scpi_pd->genpd.power_off = scpi_pd_power_off; | |
116 | scpi_pd->genpd.power_on = scpi_pd_power_on; | |
117 | ||
118 | /* | |
119 | * Treat all power domains as off at boot. | |
120 | * | |
121 | * The SCP firmware itself may have switched on some domains, | |
122 | * but for reference counting purpose, keep it this way. | |
123 | */ | |
124 | pm_genpd_init(&scpi_pd->genpd, NULL, true); | |
125 | } | |
126 | ||
127 | scpi_pd_data->domains = domains; | |
128 | scpi_pd_data->num_domains = num_domains; | |
129 | ||
130 | of_genpd_add_provider_onecell(np, scpi_pd_data); | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | static const struct of_device_id scpi_power_domain_ids[] = { | |
136 | { .compatible = "arm,scpi-power-domains", }, | |
137 | { /* sentinel */ } | |
138 | }; | |
139 | MODULE_DEVICE_TABLE(of, scpi_power_domain_ids); | |
140 | ||
141 | static struct platform_driver scpi_power_domain_driver = { | |
142 | .driver = { | |
143 | .name = "scpi_power_domain", | |
144 | .of_match_table = scpi_power_domain_ids, | |
145 | }, | |
146 | .probe = scpi_pm_domain_probe, | |
147 | }; | |
148 | module_platform_driver(scpi_power_domain_driver); | |
149 | ||
150 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); | |
151 | MODULE_DESCRIPTION("ARM SCPI power domain driver"); | |
152 | MODULE_LICENSE("GPL v2"); |