Merge series "Add support for voltage regulator on ChromeOS EC." from Pi-Hsun Shih <pihsun@chromium.org>:

Add support for controlling voltage regulator that is connected and
controlled by ChromeOS EC. Kernel controls these regulators through
newly added EC host commands.

Changes from v5:
* Move new host command to a separate patch.
* Use devm_regulator_register.
* Address review comments.

Changes from v4:
* Change compatible name from regulator-cros-ec to cros-ec-regulator.

Changes from v3:
* Fix dt bindings file name.
* Remove check around CONFIG_OF in driver.
* Add new host commands to cros_ec_trace.
* Address review comments.

Changes from v2:
* Add 'depends on OF' to Kconfig.
* Add Kconfig description about compiling as module.

Changes from v1:
* Change compatible string to google,regulator-cros-ec.
* Use reg property in device tree.
* Change license for dt binding according to checkpatch.pl.
* Address comments on code styles.

Pi-Hsun Shih (3):
  dt-bindings: regulator: Add DT binding for cros-ec-regulator
  platform/chrome: cros_ec: Add command for regulator control.
  regulator: Add driver for cros-ec-regulator

 .../regulator/google,cros-ec-regulator.yaml   |  51 ++++
 drivers/platform/chrome/cros_ec_trace.c       |   5 +
 drivers/regulator/Kconfig                     |  10 +
 drivers/regulator/Makefile                    |   1 +
 drivers/regulator/cros-ec-regulator.c         | 257 ++++++++++++++++++
 .../linux/platform_data/cros_ec_commands.h    |  82 ++++++
 6 files changed, 406 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/regulator/google,cros-ec-regulator.yaml
 create mode 100644 drivers/regulator/cros-ec-regulator.c

base-commit: b791d1bdf9212d944d749a5c7ff6febdba241771
--
2.27.0.290.gba653c62da-goog

6 files changed, 406 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/regulator/google,cros-ec-regulator.yaml b/Documentation/devicetree/bindings/regulator/google,cros-ec-regulator.yaml
new file mode 100644
index 000000000000..c9453d7ce227
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/google,cros-ec-regulator.yaml
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/google,cros-ec-regulator.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ChromeOS EC controlled voltage regulators
+
+maintainers:
+  - Pi-Hsun Shih <pihsun@chromium.org>
+
+description:
+  Any property defined as part of the core regulator binding, defined in
+  regulator.yaml, can also be used.
+
+allOf:
+  - $ref: "regulator.yaml#"
+
+properties:
+  compatible:
+    const: google,cros-ec-regulator
+
+  reg:
+    maxItems: 1
+    description: Identifier for the voltage regulator to ChromeOS EC.
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        cros_ec: ec@0 {
+            compatible = "google,cros-ec-spi";
+            reg = <0>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            regulator@0 {
+                compatible = "google,cros-ec-regulator";
+                regulator-min-microvolt = <1800000>;
+                regulator-max-microvolt = <3300000>;
+                reg = <0>;
+            };
+        };
+    };
+...
diff --git a/drivers/platform/chrome/cros_ec_trace.c b/drivers/platform/chrome/cros_ec_trace.c
index 523a39bd0ff6..425e9441b7ca 100644
--- a/drivers/platform/chrome/cros_ec_trace.c
+++ b/drivers/platform/chrome/cros_ec_trace.c
@@ -161,6 +161,11 @@
 	TRACE_SYMBOL(EC_CMD_ADC_READ), \
 	TRACE_SYMBOL(EC_CMD_ROLLBACK_INFO), \
 	TRACE_SYMBOL(EC_CMD_AP_RESET), \
+	TRACE_SYMBOL(EC_CMD_REGULATOR_GET_INFO), \
+	TRACE_SYMBOL(EC_CMD_REGULATOR_ENABLE), \
+	TRACE_SYMBOL(EC_CMD_REGULATOR_IS_ENABLED), \
+	TRACE_SYMBOL(EC_CMD_REGULATOR_SET_VOLTAGE), \
+	TRACE_SYMBOL(EC_CMD_REGULATOR_GET_VOLTAGE), \
 	TRACE_SYMBOL(EC_CMD_CR51_BASE), \
 	TRACE_SYMBOL(EC_CMD_CR51_LAST), \
 	TRACE_SYMBOL(EC_CMD_FP_PASSTHRU), \
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 8f677f5d79b4..c398e90e0e73 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -238,6 +238,16 @@ config REGULATOR_CPCAP
 	  Say y here for CPCAP regulator found on some Motorola phones
 	  and tablets such as Droid 4.
 
+config REGULATOR_CROS_EC
+	tristate "ChromeOS EC regulators"
+	depends on CROS_EC && OF
+	help
+	  This driver supports voltage regulators that is connected to ChromeOS
+	  EC and controlled through EC host commands.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called cros-ec-regulator.
+
 config REGULATOR_DA903X
 	tristate "Dialog Semiconductor DA9030/DA9034 regulators"
 	depends on PMIC_DA903X
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index e8f163371071..46592c160d22 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o
 obj-$(CONFIG_REGULATOR_88PG86X) += 88pg86x.o
 obj-$(CONFIG_REGULATOR_88PM800) += 88pm800-regulator.o
 obj-$(CONFIG_REGULATOR_88PM8607) += 88pm8607.o
+obj-$(CONFIG_REGULATOR_CROS_EC) += cros-ec-regulator.o
 obj-$(CONFIG_REGULATOR_CPCAP) += cpcap-regulator.o
 obj-$(CONFIG_REGULATOR_AAT2870) += aat2870-regulator.o
 obj-$(CONFIG_REGULATOR_AB3100) += ab3100.o
diff --git a/drivers/regulator/cros-ec-regulator.c b/drivers/regulator/cros-ec-regulator.c
new file mode 100644
index 000000000000..35f97246bc48
--- /dev/null
+++ b/drivers/regulator/cros-ec-regulator.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright 2020 Google LLC.
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/slab.h>
+
+struct cros_ec_regulator_data {
+	struct regulator_desc desc;
+	struct regulator_dev *dev;
+	struct cros_ec_device *ec_dev;
+
+	u32 index;
+
+	u16 *voltages_mV;
+	u16 num_voltages;
+};
+
+static int cros_ec_cmd(struct cros_ec_device *ec, u32 version, u32 command,
+		       void *outdata, u32 outsize, void *indata, u32 insize)
+{
+	struct cros_ec_command *msg;
+	int ret;
+
+	msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->version = version;
+	msg->command = command;
+	msg->outsize = outsize;
+	msg->insize = insize;
+
+	if (outdata && outsize > 0)
+		memcpy(msg->data, outdata, outsize);
+
+	ret = cros_ec_cmd_xfer_status(ec, msg);
+	if (ret < 0)
+		goto cleanup;
+
+	if (insize)
+		memcpy(indata, msg->data, insize);
+
+cleanup:
+	kfree(msg);
+	return ret;
+}
+
+static int cros_ec_regulator_enable(struct regulator_dev *dev)
+{
+	struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+	struct ec_params_regulator_enable cmd = {
+		.index = data->index,
+		.enable = 1,
+	};
+
+	return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
+			  sizeof(cmd), NULL, 0);
+}
+
+static int cros_ec_regulator_disable(struct regulator_dev *dev)
+{
+	struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+	struct ec_params_regulator_enable cmd = {
+		.index = data->index,
+		.enable = 0,
+	};
+
+	return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
+			  sizeof(cmd), NULL, 0);
+}
+
+static int cros_ec_regulator_is_enabled(struct regulator_dev *dev)
+{
+	struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+	struct ec_params_regulator_is_enabled cmd = {
+		.index = data->index,
+	};
+	struct ec_response_regulator_is_enabled resp;
+	int ret;
+
+	ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_IS_ENABLED, &cmd,
+			  sizeof(cmd), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+	return resp.enabled;
+}
+
+static int cros_ec_regulator_list_voltage(struct regulator_dev *dev,
+					  unsigned int selector)
+{
+	struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+
+	if (selector >= data->num_voltages)
+		return -EINVAL;
+
+	return data->voltages_mV[selector] * 1000;
+}
+
+static int cros_ec_regulator_get_voltage(struct regulator_dev *dev)
+{
+	struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+	struct ec_params_regulator_get_voltage cmd = {
+		.index = data->index,
+	};
+	struct ec_response_regulator_get_voltage resp;
+	int ret;
+
+	ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_VOLTAGE, &cmd,
+			  sizeof(cmd), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+	return resp.voltage_mv * 1000;
+}
+
+static int cros_ec_regulator_set_voltage(struct regulator_dev *dev, int min_uV,
+					 int max_uV, unsigned int *selector)
+{
+	struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+	int min_mV = DIV_ROUND_UP(min_uV, 1000);
+	int max_mV = max_uV / 1000;
+	struct ec_params_regulator_set_voltage cmd = {
+		.index = data->index,
+		.min_mv = min_mV,
+		.max_mv = max_mV,
+	};
+
+	/*
+	 * This can happen when the given range [min_uV, max_uV] doesn't
+	 * contain any voltage that can be represented exactly in mV.
+	 */
+	if (min_mV > max_mV)
+		return -EINVAL;
+
+	return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_SET_VOLTAGE, &cmd,
+			   sizeof(cmd), NULL, 0);
+}
+
+static struct regulator_ops cros_ec_regulator_voltage_ops = {
+	.enable = cros_ec_regulator_enable,
+	.disable = cros_ec_regulator_disable,
+	.is_enabled = cros_ec_regulator_is_enabled,
+	.list_voltage = cros_ec_regulator_list_voltage,
+	.get_voltage = cros_ec_regulator_get_voltage,
+	.set_voltage = cros_ec_regulator_set_voltage,
+};
+
+static int cros_ec_regulator_init_info(struct device *dev,
+				       struct cros_ec_regulator_data *data)
+{
+	struct ec_params_regulator_get_info cmd = {
+		.index = data->index,
+	};
+	struct ec_response_regulator_get_info resp;
+	int ret;
+
+	ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_INFO, &cmd,
+			   sizeof(cmd), &resp, sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	data->num_voltages =
+		min_t(u16, ARRAY_SIZE(resp.voltages_mv), resp.num_voltages);
+	data->voltages_mV =
+		devm_kmemdup(dev, resp.voltages_mv,
+			     sizeof(u16) * data->num_voltages, GFP_KERNEL);
+	data->desc.n_voltages = data->num_voltages;
+
+	/* Make sure the returned name is always a valid string */
+	resp.name[ARRAY_SIZE(resp.name) - 1] = '\0';
+	data->desc.name = devm_kstrdup(dev, resp.name, GFP_KERNEL);
+	if (!data->desc.name)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int cros_ec_regulator_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct cros_ec_regulator_data *drvdata;
+	struct regulator_init_data *init_data;
+	struct regulator_config cfg = {};
+	struct regulator_desc *desc;
+	int ret;
+
+	drvdata = devm_kzalloc(
+		&pdev->dev, sizeof(struct cros_ec_regulator_data), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	drvdata->ec_dev = dev_get_drvdata(dev->parent);
+	desc = &drvdata->desc;
+
+	init_data = of_get_regulator_init_data(dev, np, desc);
+	if (!init_data)
+		return -EINVAL;
+
+	ret = of_property_read_u32(np, "reg", &drvdata->index);
+	if (ret < 0)
+		return ret;
+
+	desc->owner = THIS_MODULE;
+	desc->type = REGULATOR_VOLTAGE;
+	desc->ops = &cros_ec_regulator_voltage_ops;
+
+	ret = cros_ec_regulator_init_info(dev, drvdata);
+	if (ret < 0)
+		return ret;
+
+	cfg.dev = &pdev->dev;
+	cfg.init_data = init_data;
+	cfg.driver_data = drvdata;
+	cfg.of_node = np;
+
+	drvdata->dev = devm_regulator_register(dev, &drvdata->desc, &cfg);
+	if (IS_ERR(drvdata->dev)) {
+		ret = PTR_ERR(drvdata->dev);
+		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
+		goto free_name;
+	}
+
+	platform_set_drvdata(pdev, drvdata);
+
+	return 0;
+
+free_name:
+	kfree(desc->name);
+	return ret;
+}
+
+static const struct of_device_id regulator_cros_ec_of_match[] = {
+	{ .compatible = "google,cros-ec-regulator", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, regulator_cros_ec_of_match);
+
+static struct platform_driver cros_ec_regulator_driver = {
+	.probe		= cros_ec_regulator_probe,
+	.driver		= {
+		.name		= "cros-ec-regulator",
+		.of_match_table = regulator_cros_ec_of_match,
+	},
+};
+
+module_platform_driver(cros_ec_regulator_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChromeOS EC controlled regulator");
+MODULE_AUTHOR("Pi-Hsun Shih <pihsun@chromium.org>");
diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
index 69210881ebac..a417b51b5764 100644
--- a/include/linux/platform_data/cros_ec_commands.h
+++ b/include/linux/platform_data/cros_ec_commands.h
@@ -5431,6 +5431,88 @@ struct ec_response_rollback_info {
 #define EC_CMD_AP_RESET 0x0125
 
 /*****************************************************************************/
+/* Voltage regulator controls */
+
+/*
+ * Get basic info of voltage regulator for given index.
+ *
+ * Returns the regulator name and supported voltage list in mV.
+ */
+#define EC_CMD_REGULATOR_GET_INFO 0x012B
+
+/* Maximum length of regulator name */
+#define EC_REGULATOR_NAME_MAX_LEN 16
+
+/* Maximum length of the supported voltage list. */
+#define EC_REGULATOR_VOLTAGE_MAX_COUNT 16
+
+struct ec_params_regulator_get_info {
+	uint32_t index;
+} __ec_align4;
+
+struct ec_response_regulator_get_info {
+	char name[EC_REGULATOR_NAME_MAX_LEN];
+	uint16_t num_voltages;
+	uint16_t voltages_mv[EC_REGULATOR_VOLTAGE_MAX_COUNT];
+} __ec_align1;
+
+/*
+ * Configure the regulator as enabled / disabled.
+ */
+#define EC_CMD_REGULATOR_ENABLE 0x012C
+
+struct ec_params_regulator_enable {
+	uint32_t index;
+	uint8_t enable;
+} __ec_align4;
+
+/*
+ * Query if the regulator is enabled.
+ *
+ * Returns 1 if the regulator is enabled, 0 if not.
+ */
+#define EC_CMD_REGULATOR_IS_ENABLED 0x012D
+
+struct ec_params_regulator_is_enabled {
+	uint32_t index;
+} __ec_align4;
+
+struct ec_response_regulator_is_enabled {
+	uint8_t enabled;
+} __ec_align1;
+
+/*
+ * Set voltage for the voltage regulator within the range specified.
+ *
+ * The driver should select the voltage in range closest to min_mv.
+ *
+ * Also note that this might be called before the regulator is enabled, and the
+ * setting should be in effect after the regulator is enabled.
+ */
+#define EC_CMD_REGULATOR_SET_VOLTAGE 0x012E
+
+struct ec_params_regulator_set_voltage {
+	uint32_t index;
+	uint32_t min_mv;
+	uint32_t max_mv;
+} __ec_align4;
+
+/*
+ * Get the currently configured voltage for the voltage regulator.
+ *
+ * Note that this might be called before the regulator is enabled.
+ */
+#define EC_CMD_REGULATOR_GET_VOLTAGE 0x012F
+
+struct ec_params_regulator_get_voltage {
+	uint32_t index;
+} __ec_align4;
+
+struct ec_response_regulator_get_voltage {
+	uint32_t voltage_mv;
+} __ec_align4;
+
+/*****************************************************************************/
 /* The command range 0x200-0x2FF is reserved for Rotor. */
 
 /*****************************************************************************/