421 lines
11 KiB
C
421 lines
11 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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//
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// System Control and Management Interface (SCMI) based regulator driver
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//
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// Copyright (C) 2020-2021 ARM Ltd.
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//
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// Implements a regulator driver on top of the SCMI Voltage Protocol.
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//
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// The ARM SCMI Protocol aims in general to hide as much as possible all the
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// underlying operational details while providing an abstracted interface for
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// its users to operate upon: as a consequence the resulting operational
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// capabilities and configurability of this regulator device are much more
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// limited than the ones usually available on a standard physical regulator.
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//
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// The supported SCMI regulator ops are restricted to the bare minimum:
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//
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// - 'status_ops': enable/disable/is_enabled
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// - 'voltage_ops': get_voltage_sel/set_voltage_sel
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// list_voltage/map_voltage
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//
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// Each SCMI regulator instance is associated, through the means of a proper DT
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// entry description, to a specific SCMI Voltage Domain.
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/linear_range.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/machine.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/scmi_protocol.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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static const struct scmi_voltage_proto_ops *voltage_ops;
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struct scmi_regulator {
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u32 id;
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struct scmi_device *sdev;
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struct scmi_protocol_handle *ph;
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struct regulator_dev *rdev;
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struct device_node *of_node;
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struct regulator_desc desc;
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struct regulator_config conf;
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};
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struct scmi_regulator_info {
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int num_doms;
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struct scmi_regulator **sregv;
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};
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static int scmi_reg_enable(struct regulator_dev *rdev)
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{
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struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
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return voltage_ops->config_set(sreg->ph, sreg->id,
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SCMI_VOLTAGE_ARCH_STATE_ON);
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}
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static int scmi_reg_disable(struct regulator_dev *rdev)
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{
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struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
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return voltage_ops->config_set(sreg->ph, sreg->id,
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SCMI_VOLTAGE_ARCH_STATE_OFF);
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}
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static int scmi_reg_is_enabled(struct regulator_dev *rdev)
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{
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int ret;
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u32 config;
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struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
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ret = voltage_ops->config_get(sreg->ph, sreg->id, &config);
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if (ret) {
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dev_err(&sreg->sdev->dev,
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"Error %d reading regulator %s status.\n",
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ret, sreg->desc.name);
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return ret;
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}
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return config & SCMI_VOLTAGE_ARCH_STATE_ON;
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}
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static int scmi_reg_get_voltage_sel(struct regulator_dev *rdev)
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{
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int ret;
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s32 volt_uV;
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struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
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ret = voltage_ops->level_get(sreg->ph, sreg->id, &volt_uV);
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if (ret)
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return ret;
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return sreg->desc.ops->map_voltage(rdev, volt_uV, volt_uV);
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}
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static int scmi_reg_set_voltage_sel(struct regulator_dev *rdev,
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unsigned int selector)
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{
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s32 volt_uV;
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struct scmi_regulator *sreg = rdev_get_drvdata(rdev);
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volt_uV = sreg->desc.ops->list_voltage(rdev, selector);
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if (volt_uV <= 0)
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return -EINVAL;
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return voltage_ops->level_set(sreg->ph, sreg->id, 0x0, volt_uV);
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}
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static const struct regulator_ops scmi_reg_fixed_ops = {
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.enable = scmi_reg_enable,
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.disable = scmi_reg_disable,
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.is_enabled = scmi_reg_is_enabled,
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};
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static const struct regulator_ops scmi_reg_linear_ops = {
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.enable = scmi_reg_enable,
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.disable = scmi_reg_disable,
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.is_enabled = scmi_reg_is_enabled,
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.get_voltage_sel = scmi_reg_get_voltage_sel,
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.set_voltage_sel = scmi_reg_set_voltage_sel,
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.list_voltage = regulator_list_voltage_linear,
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.map_voltage = regulator_map_voltage_linear,
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};
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static const struct regulator_ops scmi_reg_discrete_ops = {
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.enable = scmi_reg_enable,
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.disable = scmi_reg_disable,
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.is_enabled = scmi_reg_is_enabled,
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.get_voltage_sel = scmi_reg_get_voltage_sel,
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.set_voltage_sel = scmi_reg_set_voltage_sel,
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.list_voltage = regulator_list_voltage_table,
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.map_voltage = regulator_map_voltage_iterate,
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};
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static int
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scmi_config_linear_regulator_mappings(struct scmi_regulator *sreg,
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const struct scmi_voltage_info *vinfo)
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{
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s32 delta_uV;
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/*
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* Note that SCMI voltage domains describable by linear ranges
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* (segments) {low, high, step} are guaranteed to come in one single
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* triplet by the SCMI Voltage Domain protocol support itself.
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*/
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delta_uV = (vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_HIGH] -
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vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW]);
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/* Rule out buggy negative-intervals answers from fw */
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if (delta_uV < 0) {
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dev_err(&sreg->sdev->dev,
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"Invalid volt-range %d-%duV for domain %d\n",
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vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW],
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vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_HIGH],
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sreg->id);
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return -EINVAL;
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}
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if (!delta_uV) {
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/* Just one fixed voltage exposed by SCMI */
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sreg->desc.fixed_uV =
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vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW];
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sreg->desc.n_voltages = 1;
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sreg->desc.ops = &scmi_reg_fixed_ops;
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} else {
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/* One simple linear mapping. */
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sreg->desc.min_uV =
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vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_LOW];
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sreg->desc.uV_step =
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vinfo->levels_uv[SCMI_VOLTAGE_SEGMENT_STEP];
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sreg->desc.linear_min_sel = 0;
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sreg->desc.n_voltages = (delta_uV / sreg->desc.uV_step) + 1;
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sreg->desc.ops = &scmi_reg_linear_ops;
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}
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return 0;
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}
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static int
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scmi_config_discrete_regulator_mappings(struct scmi_regulator *sreg,
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const struct scmi_voltage_info *vinfo)
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{
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/* Discrete non linear levels are mapped to volt_table */
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sreg->desc.n_voltages = vinfo->num_levels;
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if (sreg->desc.n_voltages > 1) {
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sreg->desc.volt_table = (const unsigned int *)vinfo->levels_uv;
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sreg->desc.ops = &scmi_reg_discrete_ops;
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} else {
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sreg->desc.fixed_uV = vinfo->levels_uv[0];
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sreg->desc.ops = &scmi_reg_fixed_ops;
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}
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return 0;
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}
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static int scmi_regulator_common_init(struct scmi_regulator *sreg)
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{
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int ret;
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struct device *dev = &sreg->sdev->dev;
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const struct scmi_voltage_info *vinfo;
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vinfo = voltage_ops->info_get(sreg->ph, sreg->id);
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if (!vinfo) {
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dev_warn(dev, "Failure to get voltage domain %d\n",
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sreg->id);
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return -ENODEV;
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}
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/*
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* Regulator framework does not fully support negative voltages
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* so we discard any voltage domain reported as supporting negative
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* voltages: as a consequence each levels_uv entry is guaranteed to
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* be non-negative from here on.
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*/
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if (vinfo->negative_volts_allowed) {
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dev_warn(dev, "Negative voltages NOT supported...skip %s\n",
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sreg->of_node->full_name);
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return -EOPNOTSUPP;
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}
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sreg->desc.name = devm_kasprintf(dev, GFP_KERNEL, "%s", vinfo->name);
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if (!sreg->desc.name)
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return -ENOMEM;
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sreg->desc.id = sreg->id;
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sreg->desc.type = REGULATOR_VOLTAGE;
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sreg->desc.owner = THIS_MODULE;
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sreg->desc.of_match_full_name = true;
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sreg->desc.of_match = sreg->of_node->full_name;
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sreg->desc.regulators_node = "regulators";
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if (vinfo->segmented)
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ret = scmi_config_linear_regulator_mappings(sreg, vinfo);
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else
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ret = scmi_config_discrete_regulator_mappings(sreg, vinfo);
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if (ret)
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return ret;
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/*
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* Using the scmi device here to have DT searched from Voltage
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* protocol node down.
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*/
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sreg->conf.dev = dev;
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/* Store for later retrieval via rdev_get_drvdata() */
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sreg->conf.driver_data = sreg;
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return 0;
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}
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static int process_scmi_regulator_of_node(struct scmi_device *sdev,
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struct scmi_protocol_handle *ph,
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struct device_node *np,
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struct scmi_regulator_info *rinfo)
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{
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u32 dom, ret;
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ret = of_property_read_u32(np, "reg", &dom);
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if (ret)
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return ret;
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if (dom >= rinfo->num_doms)
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return -ENODEV;
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if (rinfo->sregv[dom]) {
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dev_err(&sdev->dev,
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"SCMI Voltage Domain %d already in use. Skipping: %s\n",
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dom, np->full_name);
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return -EINVAL;
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}
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rinfo->sregv[dom] = devm_kzalloc(&sdev->dev,
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sizeof(struct scmi_regulator),
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GFP_KERNEL);
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if (!rinfo->sregv[dom])
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return -ENOMEM;
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rinfo->sregv[dom]->id = dom;
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rinfo->sregv[dom]->sdev = sdev;
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rinfo->sregv[dom]->ph = ph;
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/* get hold of good nodes */
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of_node_get(np);
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rinfo->sregv[dom]->of_node = np;
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dev_dbg(&sdev->dev,
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"Found SCMI Regulator entry -- OF node [%d] -> %s\n",
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dom, np->full_name);
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return 0;
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}
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static int scmi_regulator_probe(struct scmi_device *sdev)
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{
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int d, ret, num_doms;
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struct device_node *np, *child;
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const struct scmi_handle *handle = sdev->handle;
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struct scmi_regulator_info *rinfo;
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struct scmi_protocol_handle *ph;
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if (!handle)
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return -ENODEV;
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voltage_ops = handle->devm_protocol_get(sdev,
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SCMI_PROTOCOL_VOLTAGE, &ph);
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if (IS_ERR(voltage_ops))
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return PTR_ERR(voltage_ops);
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num_doms = voltage_ops->num_domains_get(ph);
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if (!num_doms)
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return 0;
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if (num_doms < 0) {
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dev_err(&sdev->dev, "failed to get voltage domains - err:%d\n",
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num_doms);
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return num_doms;
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}
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rinfo = devm_kzalloc(&sdev->dev, sizeof(*rinfo), GFP_KERNEL);
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if (!rinfo)
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return -ENOMEM;
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/* Allocate pointers array for all possible domains */
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rinfo->sregv = devm_kcalloc(&sdev->dev, num_doms,
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sizeof(void *), GFP_KERNEL);
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if (!rinfo->sregv)
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return -ENOMEM;
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rinfo->num_doms = num_doms;
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/*
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* Start collecting into rinfo->sregv possibly good SCMI Regulators as
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* described by a well-formed DT entry and associated with an existing
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* plausible SCMI Voltage Domain number, all belonging to this SCMI
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* platform instance node (handle->dev->of_node).
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*/
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of_node_get(handle->dev->of_node);
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np = of_find_node_by_name(handle->dev->of_node, "regulators");
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for_each_child_of_node(np, child) {
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ret = process_scmi_regulator_of_node(sdev, ph, child, rinfo);
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/* abort on any mem issue */
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if (ret == -ENOMEM) {
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of_node_put(child);
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return ret;
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}
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}
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of_node_put(np);
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/*
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* Register a regulator for each valid regulator-DT-entry that we
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* can successfully reach via SCMI and has a valid associated voltage
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* domain.
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*/
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for (d = 0; d < num_doms; d++) {
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struct scmi_regulator *sreg = rinfo->sregv[d];
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/* Skip empty slots */
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if (!sreg)
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continue;
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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");
|