[PATCH v4 1/5] firmware: scmi: voltage regulator

[Jaehoon Chung <jh80.chung@samsung.com>]

On 3/9/21 6:38 AM, Etienne Carriere wrote:
> Implement voltage regulators interfaced by the SCMI voltage domain
> protocol. The DT bindings are defined in the Linux kernel since
> SCMI voltage domain and regulators patches [1] and [2] integration
> in v5.11-rc7.
> 
> Link: [1] https://protect2.fireeye.com/v1/url?k=4762535a-18f96b93-4763d815-0cc47a336fae-3c00cacbc555f86e&q=1&e=d232145a-df26-46c6-b2ed-fd2b665c4b71&u=https%3A%2F%2Fgithub.com%2Ftorvalds%2Flinux%2Fcommit%2F0f80fcec08e9c50b8d2992cf26495673765ebaba
> Link: [2] https://protect2.fireeye.com/v1/url?k=3da6e589-623ddd40-3da76ec6-0cc47a336fae-8f68d44282000af5&q=1&e=d232145a-df26-46c6-b2ed-fd2b665c4b71&u=https%3A%2F%2Fgithub.com%2Ftorvalds%2Flinux%2Fcommit%2F2add5cacff3531e54c50b0832128299faa9f0563
> Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung

> ---
> Changes in v4:
> - define a device for SCMI voltage protocol that binds the SCMI regulators
>   as suggested by Patrick.
> - removed Simon and Jaehoon tags since changes.
> 
> Changes in v3:
> - applied review tags
> 
> Changes in v2:
> - no change
> ---
>  doc/device-tree-bindings/arm/arm,scmi.txt |  34 ++++
>  drivers/firmware/scmi/scmi_agent-uclass.c |  10 ++
>  drivers/power/regulator/Kconfig           |   8 +
>  drivers/power/regulator/Makefile          |   1 +
>  drivers/power/regulator/scmi_regulator.c  | 195 ++++++++++++++++++++++
>  include/scmi_protocols.h                  | 113 +++++++++++++
>  6 files changed, 361 insertions(+)
>  create mode 100644 drivers/power/regulator/scmi_regulator.c
> 
> diff --git a/doc/device-tree-bindings/arm/arm,scmi.txt b/doc/device-tree-bindings/arm/arm,scmi.txt
> index 1f293ea24..a76124f4a 100644
> --- a/doc/device-tree-bindings/arm/arm,scmi.txt
> +++ b/doc/device-tree-bindings/arm/arm,scmi.txt
> @@ -62,6 +62,20 @@ Required properties:
>   - #power-domain-cells : Should be 1. Contains the device or the power
>  			 domain ID value used by SCMI commands.
>  
> +Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
> +------------------------------------------------------------
> +An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
> +and should be always positioned as a root regulator.
> +It does not support any current operation.
> +
> +SCMI Regulators are grouped under a 'regulators' node which in turn is a child
> +of the SCMI Voltage protocol node inside the desired SCMI instance node.
> +
> +This binding uses the common regulator binding[6].
> +
> +Required properties:
> + - reg : shall identify an existent SCMI Voltage Domain.
> +
>  Sensor bindings for the sensors based on SCMI Message Protocol
>  --------------------------------------------------------------
>  SCMI provides an API to access the various sensors on the SoC.
> @@ -105,6 +119,7 @@ Required sub-node properties:
>  [3] Documentation/devicetree/bindings/thermal/thermal.txt
>  [4] Documentation/devicetree/bindings/sram/sram.yaml
>  [5] Documentation/devicetree/bindings/reset/reset.txt
> +[6] Documentation/devicetree/bindings/regulator/regulator.yaml
>  
>  Example:
>  
> @@ -169,6 +184,25 @@ firmware {
>  			reg = <0x16>;
>  			#reset-cells = <1>;
>  		};
> +
> +		scmi_voltage: protocol at 17 {
> +			reg = <0x17>;
> +
> +			regulators {
> +				regulator_devX: regulator at 0 {
> +					reg = <0x0>;
> +					regulator-max-microvolt = <3300000>;
> +				};
> +
> +				regulator_devY: regulator at 9 {
> +					reg = <0x9>;
> +					regulator-min-microvolt = <500000>;
> +					regulator-max-microvolt = <4200000>;
> +				};
> +
> +				...
> +			};
> +		};
>  	};
>  };
>  
> diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
> index 516e690ac..f13e46c36 100644
> --- a/drivers/firmware/scmi/scmi_agent-uclass.c
> +++ b/drivers/firmware/scmi/scmi_agent-uclass.c
> @@ -79,6 +79,16 @@ static int scmi_bind_protocols(struct udevice *dev)
>  			if (IS_ENABLED(CONFIG_RESET_SCMI))
>  				drv = DM_DRIVER_GET(scmi_reset_domain);
>  			break;
> +		case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
> +			if (IS_ENABLED(CONFIG_DM_REGULATOR_SCMI)) {
> +				node = ofnode_find_subnode(node, "regulators");
> +				if (!ofnode_valid(node)) {
> +					dev_err(dev, "no regulators node\n");
> +					return -ENXIO;
> +				}
> +				drv = DM_DRIVER_GET(scmi_voltage_domain);
> +			}
> +			break;
>  		default:
>  			break;
>  		}
> diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
> index fbbea18c7..5d6180229 100644
> --- a/drivers/power/regulator/Kconfig
> +++ b/drivers/power/regulator/Kconfig
> @@ -353,3 +353,11 @@ config DM_REGULATOR_TPS65941
>  	TPS65941 series of PMICs have 5 single phase BUCKs that can also
>  	be configured in multi phase modes & 4 LDOs. The driver implements
>  	get/set api for value and enable.
> +
> +config DM_REGULATOR_SCMI
> +	bool "Enable driver for SCMI voltage domain regulators"
> +	depends on DM_REGULATOR
> +	select SCMI_AGENT
> +        help
> +          Enable this option if you want to support regulators exposed through
> +	  the SCMI voltage domain protocol by a SCMI server.
> diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
> index 9d58112dc..b2f5972ea 100644
> --- a/drivers/power/regulator/Makefile
> +++ b/drivers/power/regulator/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_DM_REGULATOR_TPS65910) += tps65910_regulator.o
>  obj-$(CONFIG_DM_REGULATOR_TPS62360) += tps62360_regulator.o
>  obj-$(CONFIG_$(SPL_)DM_REGULATOR_STPMIC1) += stpmic1.o
>  obj-$(CONFIG_DM_REGULATOR_TPS65941) += tps65941_regulator.o
> +obj-$(CONFIG_DM_REGULATOR_SCMI) += scmi_regulator.o
> diff --git a/drivers/power/regulator/scmi_regulator.c b/drivers/power/regulator/scmi_regulator.c
> new file mode 100644
> index 000000000..b3142bf4e
> --- /dev/null
> +++ b/drivers/power/regulator/scmi_regulator.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2020-2021 Linaro Limited
> + */
> +#include <common.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <scmi_agent.h>
> +#include <scmi_protocols.h>
> +#include <asm/types.h>
> +#include <dm/device.h>
> +#include <dm/device_compat.h>
> +#include <dm/device-internal.h>
> +#include <linux/kernel.h>
> +#include <power/regulator.h>
> +
> +/**
> + * struct scmi_regulator_platdata - Platform data for a scmi voltage domain regulator
> + * @domain_id: ID representing the regulator for the related SCMI agent
> + */
> +struct scmi_regulator_platdata {
> +	u32 domain_id;
> +};
> +
> +static int scmi_voltd_set_enable(struct udevice *dev, bool enable)
> +{
> +	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> +	struct scmi_voltd_config_set_in in = {
> +		.domain_id = pdata->domain_id,
> +		.config = enable ? SCMI_VOLTD_CONFIG_ON : SCMI_VOLTD_CONFIG_OFF,
> +	};
> +	struct scmi_voltd_config_set_out out;
> +	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
> +					  SCMI_VOLTAGE_DOMAIN_CONFIG_SET,
> +					  in, out);
> +	int ret;
> +
> +	ret = devm_scmi_process_msg(dev->parent->parent, &msg);
> +	if (ret)
> +		return ret;
> +
> +	ret = scmi_to_linux_errno(out.status);
> +	if (ret)
> +		return ret;
> +
> +	return ret;
> +}
> +
> +static int scmi_voltd_get_enable(struct udevice *dev)
> +{
> +	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> +	struct scmi_voltd_config_get_in in = {
> +		.domain_id = pdata->domain_id,
> +	};
> +	struct scmi_voltd_config_get_out out;
> +	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
> +					  SCMI_VOLTAGE_DOMAIN_CONFIG_GET,
> +					  in, out);
> +	int ret;
> +
> +	ret = devm_scmi_process_msg(dev->parent->parent, &msg);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = scmi_to_linux_errno(out.status);
> +	if (ret < 0)
> +		return ret;
> +
> +	return out.config == SCMI_VOLTD_CONFIG_ON;
> +}
> +
> +static int scmi_voltd_set_voltage_level(struct udevice *dev, int uV)
> +{
> +	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> +	struct scmi_voltd_level_set_in in = {
> +		.domain_id = pdata->domain_id,
> +		.voltage_level = uV,
> +	};
> +	struct scmi_voltd_level_set_out out;
> +	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
> +					  SCMI_VOLTAGE_DOMAIN_LEVEL_SET,
> +					  in, out);
> +	int ret;
> +
> +	ret = devm_scmi_process_msg(dev->parent->parent, &msg);
> +	if (ret < 0)
> +		return ret;
> +
> +	return scmi_to_linux_errno(out.status);
> +}
> +
> +static int scmi_voltd_get_voltage_level(struct udevice *dev)
> +{
> +	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> +	struct scmi_voltd_level_get_in in = {
> +		.domain_id = pdata->domain_id,
> +	};
> +	struct scmi_voltd_level_get_out out;
> +	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
> +					  SCMI_VOLTAGE_DOMAIN_LEVEL_GET,
> +					  in, out);
> +	int ret;
> +
> +	ret = devm_scmi_process_msg(dev->parent->parent, &msg);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = scmi_to_linux_errno(out.status);
> +	if (ret < 0)
> +		return ret;
> +
> +	return out.voltage_level;
> +}
> +
> +static int scmi_regulator_of_to_plat(struct udevice *dev)
> +{
> +	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> +	fdt_addr_t reg;
> +
> +	reg = dev_read_addr(dev);
> +	if (reg == FDT_ADDR_T_NONE)
> +		return -EINVAL;
> +
> +	pdata->domain_id = (u32)reg;
> +
> +	return 0;
> +}
> +
> +static int scmi_regulator_probe(struct udevice *dev)
> +{
> +	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
> +	struct scmi_voltd_attr_in in = { 0 };
> +	struct scmi_voltd_attr_out out = { 0 };
> +	struct scmi_msg scmi_msg = {
> +		.protocol_id = SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
> +		.message_id = SCMI_VOLTAGE_DOMAIN_ATTRIBUTES,
> +		.in_msg = (u8 *)&in,
> +		.in_msg_sz = sizeof(in),
> +		.out_msg = (u8 *)&out,
> +		.out_msg_sz = sizeof(out),
> +	};
> +	int ret;
> +
> +	/* Check voltage domain is known from SCMI server */
> +	in.domain_id = pdata->domain_id;
> +
> +	ret = devm_scmi_process_msg(dev->parent->parent, &scmi_msg);
> +	if (ret) {
> +		dev_err(dev, "Failed to query voltage domain %u: %d\n",
> +			pdata->domain_id, ret);
> +		return -ENXIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dm_regulator_ops scmi_voltd_ops = {
> +	.get_value = scmi_voltd_get_voltage_level,
> +	.set_value = scmi_voltd_set_voltage_level,
> +	.get_enable = scmi_voltd_get_enable,
> +	.set_enable = scmi_voltd_set_enable,
> +};
> +
> +U_BOOT_DRIVER(scmi_regulator) = {
> +	.name = "scmi_regulator",
> +	.id = UCLASS_REGULATOR,
> +	.ops = &scmi_voltd_ops,
> +	.probe = scmi_regulator_probe,
> +	.of_to_plat = scmi_regulator_of_to_plat,
> +	.plat_auto = sizeof(struct scmi_regulator_platdata),
> +};
> +
> +static int scmi_regulator_bind(struct udevice *dev)
> +{
> +	struct driver *drv;
> +	ofnode node;
> +	int ret;
> +
> +	drv = DM_DRIVER_GET(scmi_regulator);
> +
> +	ofnode_for_each_subnode(node, dev_ofnode(dev)) {
> +		ret = device_bind(dev, drv, ofnode_get_name(node),
> +				  NULL, node, NULL);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +U_BOOT_DRIVER(scmi_voltage_domain) = {
> +	.name = "scmi_voltage_domain",
> +	.id = UCLASS_NOP,
> +	.bind = scmi_regulator_bind,
> +};
> diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
> index ccab97c96..2db71697e 100644
> --- a/include/scmi_protocols.h
> +++ b/include/scmi_protocols.h
> @@ -23,6 +23,7 @@ enum scmi_std_protocol {
>  	SCMI_PROTOCOL_ID_CLOCK = 0x14,
>  	SCMI_PROTOCOL_ID_SENSOR = 0x15,
>  	SCMI_PROTOCOL_ID_RESET_DOMAIN = 0x16,
> +	SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN = 0x17,
>  };
>  
>  enum scmi_status_code {
> @@ -176,4 +177,116 @@ struct scmi_rd_reset_out {
>  	s32 status;
>  };
>  
> +/*
> + * SCMI Voltage Domain Protocol
> + */
> +
> +enum scmi_voltage_domain_message_id {
> +	SCMI_VOLTAGE_DOMAIN_ATTRIBUTES = 0x3,
> +	SCMI_VOLTAGE_DOMAIN_CONFIG_SET = 0x5,
> +	SCMI_VOLTAGE_DOMAIN_CONFIG_GET = 0x6,
> +	SCMI_VOLTAGE_DOMAIN_LEVEL_SET = 0x7,
> +	SCMI_VOLTAGE_DOMAIN_LEVEL_GET = 0x8,
> +};
> +
> +#define SCMI_VOLTD_NAME_LEN		16
> +
> +#define SCMI_VOLTD_CONFIG_MASK		GENMASK(3, 0)
> +#define SCMI_VOLTD_CONFIG_OFF		0
> +#define SCMI_VOLTD_CONFIG_ON		0x7
> +
> +/**
> + * struct scmi_voltd_attr_in - Payload for VOLTAGE_DOMAIN_ATTRIBUTES message
> + * @domain_id:	SCMI voltage domain ID
> + */
> +struct scmi_voltd_attr_in {
> +	u32 domain_id;
> +};
> +
> +/**
> + * struct scmi_voltd_attr_out - Payload for VOLTAGE_DOMAIN_ATTRIBUTES response
> + * @status:	SCMI command status
> + * @attributes:	Retrieved attributes of the voltage domain
> + * @name:	Voltage domain name
> + */
> +struct scmi_voltd_attr_out {
> +	s32 status;
> +	u32 attributes;
> +	char name[SCMI_VOLTD_NAME_LEN];
> +};
> +
> +/**
> + * struct scmi_voltd_config_set_in - Message payload for VOLTAGE_CONFIG_SET cmd
> + * @domain_id:	SCMI voltage domain ID
> + * @config:	Configuration data of the voltage domain
> + */
> +struct scmi_voltd_config_set_in {
> +	u32 domain_id;
> +	u32 config;
> +};
> +
> +/**
> + * struct scmi_voltd_config_set_out - Response for VOLTAGE_CONFIG_SET command
> + * @status:	SCMI command status
> + */
> +struct scmi_voltd_config_set_out {
> +	s32 status;
> +};
> +
> +/**
> + * struct scmi_voltd_config_get_in - Message payload for VOLTAGE_CONFIG_GET cmd
> + * @domain_id:	SCMI voltage domain ID
> + */
> +struct scmi_voltd_config_get_in {
> +	u32 domain_id;
> +};
> +
> +/**
> + * struct scmi_voltd_config_get_out - Response for VOLTAGE_CONFIG_GET command
> + * @status:	SCMI command status
> + * @config:	Configuration data of the voltage domain
> + */
> +struct scmi_voltd_config_get_out {
> +	s32 status;
> +	u32 config;
> +};
> +
> +/**
> + * struct scmi_voltd_level_set_in - Message payload for VOLTAGE_LEVEL_SET cmd
> + * @domain_id:		SCMI voltage domain ID
> + * @flags:		Parameter flags for configuring target level
> + * @voltage_level:	Target voltage level in microvolts (uV)
> + */
> +struct scmi_voltd_level_set_in {
> +	u32 domain_id;
> +	u32 flags;
> +	s32 voltage_level;
> +};
> +
> +/**
> + * struct scmi_voltd_level_set_out - Response for VOLTAGE_LEVEL_SET command
> + * @status:	SCMI	command status
> + */
> +struct scmi_voltd_level_set_out {
> +	s32 status;
> +};
> +
> +/**
> + * struct scmi_voltd_level_get_in - Message payload for VOLTAGE_LEVEL_GET cmd
> + * @domain_id:		SCMI voltage domain ID
> + */
> +struct scmi_voltd_level_get_in {
> +	u32 domain_id;
> +};
> +
> +/**
> + * struct scmi_voltd_level_get_out - Response for VOLTAGE_LEVEL_GET command
> + * @status:		SCMI command status
> + * @voltage_level:	Voltage level in microvolts (uV)
> + */
> +struct scmi_voltd_level_get_out {
> +	s32 status;
> +	s32 voltage_level;
> +};
> +
>  #endif /* _SCMI_PROTOCOLS_H */
>