// SPDX-License-Identifier: GPL-2.0-only /* * SCPI Generic power domain support. * * Copyright (C) 2016 ARM Ltd. */ #include <linux/err.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of_platform.h> #include <linux/pm_domain.h> #include <linux/scpi_protocol.h> struct scpi_pm_domain { struct generic_pm_domain genpd; struct scpi_ops *ops; u32 domain; char name[30]; }; /* * These device power state values are not well-defined in the specification. * In case, different implementations use different values, we can make these * specific to compatibles rather than getting these values from device tree. */ enum scpi_power_domain_state { SCPI_PD_STATE_ON = 0, SCPI_PD_STATE_OFF = 3, }; #define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd) static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on) { int ret; enum scpi_power_domain_state state; if (power_on) state = SCPI_PD_STATE_ON; else state = SCPI_PD_STATE_OFF; ret = pd->ops->device_set_power_state(pd->domain, state); if (ret) return ret; return !(state == pd->ops->device_get_power_state(pd->domain)); } static int scpi_pd_power_on(struct generic_pm_domain *domain) { struct scpi_pm_domain *pd = to_scpi_pd(domain); return scpi_pd_power(pd, true); } static int scpi_pd_power_off(struct generic_pm_domain *domain) { struct scpi_pm_domain *pd = to_scpi_pd(domain); return scpi_pd_power(pd, false); } static int scpi_pm_domain_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct scpi_pm_domain *scpi_pd; struct genpd_onecell_data *scpi_pd_data; struct generic_pm_domain **domains; struct scpi_ops *scpi_ops; int ret, num_domains, i; scpi_ops = get_scpi_ops(); if (!scpi_ops) return -EPROBE_DEFER; if (!np) { dev_err(dev, "device tree node not found\n"); return -ENODEV; } if (!scpi_ops->device_set_power_state || !scpi_ops->device_get_power_state) { dev_err(dev, "power domains not supported in the firmware\n"); return -ENODEV; } ret = of_property_read_u32(np, "num-domains", &num_domains); if (ret) { dev_err(dev, "number of domains not found\n"); return -EINVAL; } scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL); if (!scpi_pd) return -ENOMEM; scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL); if (!scpi_pd_data) return -ENOMEM; domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL); if (!domains) return -ENOMEM; for (i = 0; i < num_domains; i++, scpi_pd++) { domains[i] = &scpi_pd->genpd; scpi_pd->domain = i; scpi_pd->ops = scpi_ops; sprintf(scpi_pd->name, "%pOFn.%d", np, i); scpi_pd->genpd.name = scpi_pd->name; scpi_pd->genpd.power_off = scpi_pd_power_off; scpi_pd->genpd.power_on = scpi_pd_power_on; /* * Treat all power domains as off at boot. * * The SCP firmware itself may have switched on some domains, * but for reference counting purpose, keep it this way. */ pm_genpd_init(&scpi_pd->genpd, NULL, true); } scpi_pd_data->domains = domains; scpi_pd_data->num_domains = num_domains; of_genpd_add_provider_onecell(np, scpi_pd_data); return 0; } static const struct of_device_id scpi_power_domain_ids[] = { { .compatible = "arm,scpi-power-domains", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, scpi_power_domain_ids); static struct platform_driver scpi_power_domain_driver = { .driver = { .name = "scpi_power_domain", .of_match_table = scpi_power_domain_ids, }, .probe = scpi_pm_domain_probe, }; module_platform_driver(scpi_power_domain_driver); MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); MODULE_DESCRIPTION("ARM SCPI power domain driver"); MODULE_LICENSE("GPL v2");