[PATCH v3 3/4] regulator: add SCMI driver
Cristian Marussi
cristian.marussi at arm.com
Mon Oct 26 16:31:47 EDT 2020
Add a simple regulator based on SCMI Voltage Domain Protocol.
Signed-off-by: Cristian Marussi <cristian.marussi at arm.com>
----
v2 --> v3
- remove multiple linear mappings support
- removed duplicated voltage name printout
- added a few comments
- simplified return path in scmi_reg_set_voltage_sel()
v1 --> v2
- removed duplicate regulator naming
- removed redundant .get/set_voltage ops: only _sel variants implemented
- removed condexpr on fail path to increase readability
v0 --> v1
- fixed init_data constraint parsing
- fixes for v5.8 (linear_range.h)
- fixed commit message content and subject line format
- factored out SCMI core specific changes to distinct patch
- reworked Kconfig and Makefile to keep proper alphabetic order
- fixed SPDX comment style
- removed unneeded inline functions
- reworked conditionals for legibility
- fixed some return paths to properly report SCMI original errors codes
- added some more descriptive error messages when fw returns invalid ranges
- removed unneeded explicit devm_regulator_unregister from .remove()
---
drivers/regulator/Kconfig | 9 +
drivers/regulator/Makefile | 1 +
drivers/regulator/scmi-regulator.c | 403 +++++++++++++++++++++++++++++
3 files changed, 413 insertions(+)
create mode 100644 drivers/regulator/scmi-regulator.c
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index de17ef7e18f0..6d3a10cb9833 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -155,6 +155,15 @@ config REGULATOR_ARIZONA_MICSUPP
and Wolfson Microelectronic Arizona codecs
devices.
+config REGULATOR_ARM_SCMI
+ tristate "SCMI based regulator driver"
+ depends on ARM_SCMI_PROTOCOL && OF
+ help
+ This adds the regulator driver support for ARM platforms using SCMI
+ protocol for device voltage management.
+ This driver uses SCMI Message Protocol driver to interact with the
+ firmware providing the device Voltage functionality.
+
config REGULATOR_AS3711
tristate "AS3711 PMIC"
depends on MFD_AS3711
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index d8d3ecf526a8..0532a7393d5d 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_REGULATOR_AD5398) += ad5398.o
obj-$(CONFIG_REGULATOR_ANATOP) += anatop-regulator.o
obj-$(CONFIG_REGULATOR_ARIZONA_LDO1) += arizona-ldo1.o
obj-$(CONFIG_REGULATOR_ARIZONA_MICSUPP) += arizona-micsupp.o
+obj-$(CONFIG_REGULATOR_ARM_SCMI) += scmi-regulator.o
obj-$(CONFIG_REGULATOR_AS3711) += as3711-regulator.o
obj-$(CONFIG_REGULATOR_AS3722) += as3722-regulator.o
obj-$(CONFIG_REGULATOR_AXP20X) += axp20x-regulator.o
diff --git a/drivers/regulator/scmi-regulator.c b/drivers/regulator/scmi-regulator.c
new file mode 100644
index 000000000000..e8d75e737bae
--- /dev/null
+++ b/drivers/regulator/scmi-regulator.c
@@ -0,0 +1,403 @@
+// 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 0;
+ }
+
+ 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, "Skipping invalid 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 = sreg->of_node->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;
+
+ sreg->conf.dev = dev;
+ 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(rinfo->sregv), 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 at arm.com>");
+MODULE_DESCRIPTION("ARM SCMI regulator driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1
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