regulator: Regulator driver for the Mediatek DVFSRC

Driver for regulators exposed by the DVFSRC (dynamic voltage and
frequency scaling resource collector) found in devices based on
mt8183 and newer platforms.

Signed-off-by: Henry Chen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/Kconfig

···
 	  This driver supports the control of different power rails of device
 	  through regulator interface.
 
+config REGULATOR_MTK_DVFSRC
+	tristate "MediaTek DVFSRC regulator driver"
+	depends on MTK_DVFSRC
+	help
+	  Say y here to control regulator by DVFSRC (dynamic voltage
+	  and frequency scaling resource collector).
+	  This driver supports to control regulators via the DVFSRC
+	  of Mediatek. It allows for voting on regulator state
+	  between multiple users.
+
 config REGULATOR_PALMAS
 	tristate "TI Palmas PMIC Regulators"
 	depends on MFD_PALMAS

drivers/regulator/Makefile

···
 obj-$(CONFIG_REGULATOR_MT6360) += mt6360-regulator.o
 obj-$(CONFIG_REGULATOR_MT6380)	+= mt6380-regulator.o
 obj-$(CONFIG_REGULATOR_MT6397)	+= mt6397-regulator.o
+obj-$(CONFIG_REGULATOR_MTK_DVFSRC) += mtk-dvfsrc-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_LABIBB) += qcom-labibb-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o

drivers/regulator/mtk-dvfsrc-regulator.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 MediaTek Inc.
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/soc/mediatek/mtk_dvfsrc.h>
+
+#define DVFSRC_ID_VCORE		0
+#define DVFSRC_ID_VSCP		1
+
+#define MT_DVFSRC_REGULAR(match, _name,	_volt_table)	\
+[DVFSRC_ID_##_name] = {					\
+	.desc = {					\
+		.name = match,				\
+		.of_match = of_match_ptr(match),	\
+		.ops = &dvfsrc_vcore_ops,		\
+		.type = REGULATOR_VOLTAGE,		\
+		.id = DVFSRC_ID_##_name,		\
+		.owner = THIS_MODULE,			\
+		.n_voltages = ARRAY_SIZE(_volt_table),	\
+		.volt_table = _volt_table,		\
+	},	\
+}
+
+/*
+ * DVFSRC regulators' information
+ *
+ * @desc: standard fields of regulator description.
+ * @voltage_selector:  Selector used for get_voltage_sel() and
+ *			   set_voltage_sel() callbacks
+ */
+
+struct dvfsrc_regulator {
+	struct regulator_desc	desc;
+};
+
+/*
+ * MTK DVFSRC regulators' init data
+ *
+ * @size: num of regulators
+ * @regulator_info: regulator info.
+ */
+struct dvfsrc_regulator_init_data {
+	u32 size;
+	struct dvfsrc_regulator *regulator_info;
+};
+
+static inline struct device *to_dvfsrc_dev(struct regulator_dev *rdev)
+{
+	return rdev_get_dev(rdev)->parent;
+}
+
+static int dvfsrc_set_voltage_sel(struct regulator_dev *rdev,
+				  unsigned int selector)
+{
+	struct device *dvfsrc_dev = to_dvfsrc_dev(rdev);
+	int id = rdev_get_id(rdev);
+
+	if (id == DVFSRC_ID_VCORE)
+		mtk_dvfsrc_send_request(dvfsrc_dev,
+					MTK_DVFSRC_CMD_VCORE_REQUEST,
+					selector);
+	else if (id == DVFSRC_ID_VSCP)
+		mtk_dvfsrc_send_request(dvfsrc_dev,
+					MTK_DVFSRC_CMD_VSCP_REQUEST,
+					selector);
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int dvfsrc_get_voltage_sel(struct regulator_dev *rdev)
+{
+	struct device *dvfsrc_dev = to_dvfsrc_dev(rdev);
+	int id = rdev_get_id(rdev);
+	int val, ret;
+
+	if (id == DVFSRC_ID_VCORE)
+		ret = mtk_dvfsrc_query_info(dvfsrc_dev,
+					    MTK_DVFSRC_CMD_VCORE_LEVEL_QUERY,
+					    &val);
+	else if (id == DVFSRC_ID_VSCP)
+		ret = mtk_dvfsrc_query_info(dvfsrc_dev,
+					    MTK_DVFSRC_CMD_VSCP_LEVEL_QUERY,
+					    &val);
+	else
+		return -EINVAL;
+
+	if (ret != 0)
+		return ret;
+
+	return val;
+}
+
+static const struct regulator_ops dvfsrc_vcore_ops = {
+	.list_voltage = regulator_list_voltage_table,
+	.get_voltage_sel = dvfsrc_get_voltage_sel,
+	.set_voltage_sel = dvfsrc_set_voltage_sel,
+};
+
+static const unsigned int mt8183_voltages[] = {
+	725000,
+	800000,
+};
+
+static struct dvfsrc_regulator mt8183_regulators[] = {
+	MT_DVFSRC_REGULAR("dvfsrc-vcore", VCORE,
+			  mt8183_voltages),
+};
+
+static const struct dvfsrc_regulator_init_data regulator_mt8183_data = {
+	.size = ARRAY_SIZE(mt8183_regulators),
+	.regulator_info = &mt8183_regulators[0],
+};
+
+static const unsigned int mt6873_voltages[] = {
+	575000,
+	600000,
+	650000,
+	725000,
+};
+
+static struct dvfsrc_regulator mt6873_regulators[] = {
+	MT_DVFSRC_REGULAR("dvfsrc-vcore", VCORE,
+			  mt6873_voltages),
+	MT_DVFSRC_REGULAR("dvfsrc-vscp", VSCP,
+			  mt6873_voltages),
+};
+
+static const struct dvfsrc_regulator_init_data regulator_mt6873_data = {
+	.size = ARRAY_SIZE(mt6873_regulators),
+	.regulator_info = &mt6873_regulators[0],
+};
+
+static const struct of_device_id mtk_dvfsrc_regulator_match[] = {
+	{
+		.compatible = "mediatek,mt8183-dvfsrc",
+		.data = &regulator_mt8183_data,
+	}, {
+		.compatible = "mediatek,mt8192-dvfsrc",
+		.data = &regulator_mt6873_data,
+	}, {
+		.compatible = "mediatek,mt6873-dvfsrc",
+		.data = &regulator_mt6873_data,
+	}, {
+		/* sentinel */
+	},
+};
+MODULE_DEVICE_TABLE(of, mtk_dvfsrc_regulator_match);
+
+static int dvfsrc_vcore_regulator_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	struct device *dev = &pdev->dev;
+	struct regulator_config config = { };
+	struct regulator_dev *rdev;
+	const struct dvfsrc_regulator_init_data *regulator_init_data;
+	struct dvfsrc_regulator *mt_regulators;
+	int i;
+
+	match = of_match_node(mtk_dvfsrc_regulator_match, dev->parent->of_node);
+
+	if (!match) {
+		dev_err(dev, "invalid compatible string\n");
+		return -ENODEV;
+	}
+
+	regulator_init_data = match->data;
+
+	mt_regulators = regulator_init_data->regulator_info;
+	for (i = 0; i < regulator_init_data->size; i++) {
+		config.dev = dev->parent;
+		config.driver_data = (mt_regulators + i);
+		rdev = devm_regulator_register(dev->parent,
+					       &(mt_regulators + i)->desc,
+					       &config);
+		if (IS_ERR(rdev)) {
+			dev_err(dev, "failed to register %s\n",
+				(mt_regulators + i)->desc.name);
+			return PTR_ERR(rdev);
+		}
+	}
+
+	return 0;
+}
+
+static struct platform_driver mtk_dvfsrc_regulator_driver = {
+	.driver = {
+		.name  = "mtk-dvfsrc-regulator",
+	},
+	.probe = dvfsrc_vcore_regulator_probe,
+};
+
+static int __init mtk_dvfsrc_regulator_init(void)
+{
+	return platform_driver_register(&mtk_dvfsrc_regulator_driver);
+}
+subsys_initcall(mtk_dvfsrc_regulator_init);
+
+static void __exit mtk_dvfsrc_regulator_exit(void)
+{
+	platform_driver_unregister(&mtk_dvfsrc_regulator_driver);
+}
+module_exit(mtk_dvfsrc_regulator_exit);
+
+MODULE_AUTHOR("Arvin wang <[e-mail]>");
+MODULE_LICENSE("GPL v2");