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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * SCPI Generic power domain support.4 *5 * Copyright (C) 2016 ARM Ltd.6 */7 8#include <linux/err.h>9#include <linux/io.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/pm_domain.h>14#include <linux/scpi_protocol.h>15 16struct scpi_pm_domain {17 struct generic_pm_domain genpd;18 struct scpi_ops *ops;19 u32 domain;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 these25 * specific to compatibles rather than getting these values from device tree.26 */27enum 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 34static 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 else42 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 51static 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 58static 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 65static 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;113 scpi_pd->genpd.name = devm_kasprintf(dev, GFP_KERNEL,114 "%pOFn.%d", np, i);115 if (!scpi_pd->genpd.name) {116 dev_err(dev, "Failed to allocate genpd name:%pOFn.%d\n",117 np, i);118 continue;119 }120 scpi_pd->genpd.power_off = scpi_pd_power_off;121 scpi_pd->genpd.power_on = scpi_pd_power_on;122 123 /*124 * Treat all power domains as off at boot.125 *126 * The SCP firmware itself may have switched on some domains,127 * but for reference counting purpose, keep it this way.128 */129 pm_genpd_init(&scpi_pd->genpd, NULL, true);130 }131 132 scpi_pd_data->domains = domains;133 scpi_pd_data->num_domains = num_domains;134 135 of_genpd_add_provider_onecell(np, scpi_pd_data);136 137 return 0;138}139 140static const struct of_device_id scpi_power_domain_ids[] = {141 { .compatible = "arm,scpi-power-domains", },142 { /* sentinel */ }143};144MODULE_DEVICE_TABLE(of, scpi_power_domain_ids);145 146static struct platform_driver scpi_power_domain_driver = {147 .driver = {148 .name = "scpi_power_domain",149 .of_match_table = scpi_power_domain_ids,150 },151 .probe = scpi_pm_domain_probe,152};153module_platform_driver(scpi_power_domain_driver);154 155MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");156MODULE_DESCRIPTION("ARM SCPI power domain driver");157MODULE_LICENSE("GPL v2");158