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// SPDX-License-Identifier: GPL-2.0
//
// System Control and Management Interface (SCMI) based regulator driver
//
// Copyright (C) 2020 ARM Ltd.
//
// Implements a regulator driver on top of the SCMI Voltage Protocol.
//
// The ARM SCMI Protocol aims in general to hide as much as possible all the
// underlying operational details while providing an abstracted interface for
// its users to operate upon: as a consequence the resulting operational
// capabilities and configurability of this regulator device are much more
// limited than the ones usually available on a standard physical regulator.
//
// The supported SCMI regulator ops are restricted to the bare minimum:
//
// - 'status_ops': enable/disable/is_enabled
// - 'voltage_ops': get_voltage_sel/set_voltage_sel
// list_voltage/map_voltage
//
// Each SCMI regulator instance is associated, through the means of a proper DT
// entry description, to a specific SCMI Voltage Domain.
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/linear_range.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/scmi_protocol.h>
#include <linux/slab.h>
#include <linux/types.h>
struct scmi_regulator {
u32 id;
struct scmi_device *sdev;
struct regulator_dev *rdev;
struct device_node *of_node;
struct regulator_desc desc;
struct regulator_config conf;
};
struct scmi_regulator_info {
int num_doms;
struct scmi_regulator **sregv;
};
static int scmi_reg_enable(struct regulator_dev *rdev)
{
struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
const struct scmi_handle *handle = sreg->sdev->handle;
return handle->voltage_ops->config_set(handle, sreg->id,
SCMI_VOLTAGE_ARCH_STATE_ON);
}
static int scmi_reg_disable(struct regulator_dev *rdev)
{
struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
const struct scmi_handle *handle = sreg->sdev->handle;
return handle->voltage_ops->config_set(handle, sreg->id,
SCMI_VOLTAGE_ARCH_STATE_OFF);
}
static int scmi_reg_is_enabled(struct regulator_dev *rdev)
{
int ret;
u32 config;
struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
const struct scmi_handle *handle = sreg->sdev->handle;
ret = handle->voltage_ops->config_get(handle, sreg->id,
&config);
if (ret) {
dev_err(&sreg->sdev->dev,
"Error %d reading regulator %s status.\n",
ret, sreg->desc.name);
return ret;
}
return config & SCMI_VOLTAGE_ARCH_STATE_ON;
}
static int scmi_reg_get_voltage_sel(struct regulator_dev *rdev)
{
int ret;
s32 volt_uV;
struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
const struct scmi_handle *handle = sreg->sdev->handle;
ret = handle->voltage_ops->level_get(handle, sreg->id, &volt_uV);
if (ret)
return ret;
return sreg->desc.ops->map_voltage(rdev, volt_uV, volt_uV);
}
static int scmi_reg_set_voltage_sel(struct regulator_dev *rdev,
unsigned int selector)
{
s32 volt_uV;
struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
const struct scmi_handle *handle = sreg->sdev->handle;
volt_uV = sreg->desc.ops->list_voltage(rdev, selector);
if (volt_uV <= 0)
return -EINVAL;
return handle->voltage_ops->level_set(handle, sreg->id, 0x0, volt_uV);
}
static const struct regulator_ops scmi_reg_fixed_ops = {
.enable = scmi_reg_enable,
.disable = scmi_reg_disable,
.is_enabled = scmi_reg_is_enabled,
};
static const struct regulator_ops scmi_reg_linear_ops = {
.enable = scmi_reg_enable,
.disable = scmi_reg_disable,
.is_enabled = scmi_reg_is_enabled,
.get_voltage_sel = scmi_reg_get_voltage_sel,
.set_voltage_sel = scmi_reg_set_voltage_sel,
.list_voltage = regulator_list_voltage_linear,
.map_voltage = regulator_map_voltage_linear,
};
static const struct regulator_ops scmi_reg_discrete_ops = {
.enable = scmi_reg_enable,
.disable = scmi_reg_disable,
.is_enabled = scmi_reg_is_enabled,
.get_voltage_sel = scmi_reg_get_voltage_sel,
.set_voltage_sel = scmi_reg_set_voltage_sel,
.list_voltage = regulator_list_voltage_table,
.map_voltage = regulator_map_voltage_iterate,
};
static int
scmi_config_linear_regulator_mappings(struct scmi_regulator *sreg,
const struct scmi_voltage_info *vinfo)
{
s32 delta_uV;
/*
* Note that SCMI voltage domains describable by linear ranges
* (segments) {low, high, step} are guaranteed to come in one single
* triplet by the SCMI Voltage Domain protocol support itself.
*/
delta_uV = (vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_HIGH] -
vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW]);
/* Rule out buggy negative-intervals answers from fw */
if (delta_uV < 0) {
dev_err(&sreg->sdev->dev,
"Invalid volt-range %d-%duV for domain %d\n",
vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW],
vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_HIGH],
sreg->id);
return -EINVAL;
}
if (!delta_uV) {
/* Just one fixed voltage exposed by SCMI */
sreg->desc.fixed_uV =
vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW];
sreg->desc.n_voltages = 1;
sreg->desc.ops = &scmi_reg_fixed_ops;
} else {
/* One simple linear mapping. */
sreg->desc.min_uV =
vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW];
sreg->desc.uV_step =
vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_STEP];
sreg->desc.linear_min_sel = 0;
sreg->desc.n_voltages = delta_uV / sreg->desc.uV_step;
sreg->desc.ops = &scmi_reg_linear_ops;
}
return 0;
}
static int
scmi_config_discrete_regulator_mappings(struct scmi_regulator *sreg,
const struct scmi_voltage_info *vinfo)
{
/* Discrete non linear levels are mapped to volt_table */
sreg->desc.n_voltages = vinfo->num_levels;
if (sreg->desc.n_voltages > 1) {
sreg->desc.volt_table = (const unsigned int *)vinfo->levels_uv;
sreg->desc.ops = &scmi_reg_discrete_ops;
} else {
sreg->desc.fixed_uV = vinfo->levels_uv[0];
sreg->desc.ops = &scmi_reg_fixed_ops;
}
return 0;
}
static int scmi_regulator_common_init(struct scmi_regulator *sreg)
{
int ret;
const struct scmi_handle *handle = sreg->sdev->handle;
struct device *dev = &sreg->sdev->dev;
const struct scmi_voltage_info *vinfo;
vinfo = handle->voltage_ops->info_get(handle, sreg->id);
if (!vinfo) {
dev_warn(dev, "Failure to get voltage domain %d\n",
sreg->id);
return -ENODEV;
}
/*
* Regulator framework does not fully support negative voltages
* so we discard any voltage domain reported as supporting negative
* voltages: as a consequence each levels_uv entry is guaranteed to
* be non-negative from here on.
*/
if (vinfo->negative_volts_allowed) {
dev_warn(dev, "Negative voltages NOT supported...skip %s\n",
sreg->of_node->full_name);
return -EOPNOTSUPP;
}
sreg->desc.name = devm_kasprintf(dev, GFP_KERNEL, "%s", vinfo->name);
if (!sreg->desc.name)
return -ENOMEM;
sreg->desc.id = sreg->id;
sreg->desc.type = REGULATOR_VOLTAGE;
sreg->desc.owner = THIS_MODULE;
sreg->desc.of_match_full_name = true;
sreg->desc.of_match = sreg->of_node->full_name;
sreg->desc.regulators_node = "regulators";
if (vinfo->segmented)
ret = scmi_config_linear_regulator_mappings(sreg, vinfo);
else
ret = scmi_config_discrete_regulator_mappings(sreg, vinfo);
if (ret)
return ret;
/*
* Using the scmi device here to have DT searched from Voltage
* protocol node down.
*/
sreg->conf.dev = dev;
/* Store for later retrieval via rdev_get_drvdata() */
sreg->conf.driver_data = sreg;
return 0;
}
static int process_scmi_regulator_of_node(struct scmi_device *sdev,
struct device_node *np,
struct scmi_regulator_info *rinfo)
{
u32 dom, ret;
ret = of_property_read_u32(np, "reg", &dom);
if (ret)
return ret;
if (dom >= rinfo->num_doms)
return -ENODEV;
if (rinfo->sregv[dom]) {
dev_err(&sdev->dev,
"SCMI Voltage Domain %d already in use. Skipping: %s\n",
dom, np->full_name);
return -EINVAL;
}
rinfo->sregv[dom] = devm_kzalloc(&sdev->dev,
sizeof(struct scmi_regulator),
GFP_KERNEL);
if (!rinfo->sregv[dom])
return -ENOMEM;
rinfo->sregv[dom]->id = dom;
rinfo->sregv[dom]->sdev = sdev;
/* get hold of good nodes */
of_node_get(np);
rinfo->sregv[dom]->of_node = np;
dev_dbg(&sdev->dev,
"Found SCMI Regulator entry -- OF node [%d] -> %s\n",
dom, np->full_name);
return 0;
}
static int scmi_regulator_probe(struct scmi_device *sdev)
{
int d, ret, num_doms;
struct device_node *np, *child;
const struct scmi_handle *handle = sdev->handle;
struct scmi_regulator_info *rinfo;
if (!handle || !handle->voltage_ops)
return -ENODEV;
num_doms = handle->voltage_ops->num_domains_get(handle);
if (num_doms <= 0) {
if (!num_doms) {
dev_err(&sdev->dev,
"number of voltage domains invalid\n");
num_doms = -EINVAL;
} else {
dev_err(&sdev->dev,
"failed to get voltage domains - err:%d\n",
num_doms);
}
return num_doms;
}
rinfo = devm_kzalloc(&sdev->dev, sizeof(*rinfo), GFP_KERNEL);
if (!rinfo)
return -ENOMEM;
/* Allocate pointers array for all possible domains */
rinfo->sregv = devm_kcalloc(&sdev->dev, num_doms,
sizeof(void *), GFP_KERNEL);
if (!rinfo->sregv)
return -ENOMEM;
rinfo->num_doms = num_doms;
/*
* Start collecting into rinfo->sregv possibly good SCMI Regulators as
* described by a well-formed DT entry and associated with an existing
* plausible SCMI Voltage Domain number, all belonging to this SCMI
* platform instance node (handle->dev->of_node).
*/
np = of_find_node_by_name(handle->dev->of_node, "regulators");
for_each_child_of_node(np, child) {
ret = process_scmi_regulator_of_node(sdev, child, rinfo);
/* abort on any mem issue */
if (ret == -ENOMEM)
return ret;
}
/*
* Register a regulator for each valid regulator-DT-entry that we
* can successfully reach via SCMI and has a valid associated voltage
* domain.
*/
for (d = 0; d < num_doms; d++) {
struct scmi_regulator *sreg = rinfo->sregv[d];
/* Skip empty slots */
if (!sreg)
continue;
ret = scmi_regulator_common_init(sreg);
/* Skip invalid voltage domains */
if (ret)
continue;
sreg->rdev = devm_regulator_register(&sdev->dev, &sreg->desc,
&sreg->conf);
if (IS_ERR(sreg->rdev)) {
sreg->rdev = NULL;
continue;
}
dev_info(&sdev->dev,
"Regulator %s registered for domain [%d]\n",
sreg->desc.name, sreg->id);
}
dev_set_drvdata(&sdev->dev, rinfo);
return 0;
}
static void scmi_regulator_remove(struct scmi_device *sdev)
{
int d;
struct scmi_regulator_info *rinfo;
rinfo = dev_get_drvdata(&sdev->dev);
if (!rinfo)
return;
for (d = 0; d < rinfo->num_doms; d++) {
if (!rinfo->sregv[d])
continue;
of_node_put(rinfo->sregv[d]->of_node);
}
}
static const struct scmi_device_id scmi_regulator_id_table[] = {
{ SCMI_PROTOCOL_VOLTAGE, "regulator" },
{ },
};
MODULE_DEVICE_TABLE(scmi, scmi_regulator_id_table);
static struct scmi_driver scmi_drv = {
.name = "scmi-regulator",
.probe = scmi_regulator_probe,
.remove = scmi_regulator_remove,
.id_table = scmi_regulator_id_table,
};
module_scmi_driver(scmi_drv);
MODULE_AUTHOR("Cristian Marussi <cristian.marussi@arm.com>");
MODULE_DESCRIPTION("ARM SCMI regulator driver");
MODULE_LICENSE("GPL v2");