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/*
* SCPI Generic power domain support.
*
* Copyright (C) 2016 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#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");
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