diff options
Diffstat (limited to 'drivers/regulator/scmi-regulator.c')
| -rw-r--r-- | drivers/regulator/scmi-regulator.c | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/drivers/regulator/scmi-regulator.c b/drivers/regulator/scmi-regulator.c new file mode 100644 index 000000000000..0e8b3caa8146 --- /dev/null +++ b/drivers/regulator/scmi-regulator.c @@ -0,0 +1,417 @@ +// 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"); |