linux_kernel/include/linux/scpi_protocol.h

/*
 * SCPI Message Protocol driver header
 *
 * Copyright (C) 2014 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/types.h>

struct scpi_opp {
	u32 freq;
	u32 m_volt;
} __packed;

struct scpi_dvfs_info {
	unsigned int count;
	unsigned int latency; /* in nanoseconds */
	struct scpi_opp *opps;
};

/**
 * struct scpi_ops - represents the various operations provided
 *	by SCP through SCPI message protocol
 * @get_version: returns the major and minor revision on the SCPI
 *	message protocol
 * @clk_get_range: gets clock range limit(min - max in Hz)
 * @clk_get_val: gets clock value(in Hz)
 * @clk_set_val: sets the clock value, setting to 0 will disable the
 *	clock (if supported)
 * @dvfs_get_idx: gets the Operating Point of the given power domain.
 *	OPP is an index to the list return by @dvfs_get_info
 * @dvfs_set_idx: sets the Operating Point of the given power domain.
 *	OPP is an index to the list return by @dvfs_get_info
 * @dvfs_get_info: returns the DVFS capabilities of the given power
 *	domain. It includes the OPP list and the latency information
 */
struct scpi_ops {
	u32 (*get_version)(void);
	int (*clk_get_range)(u16, unsigned long *, unsigned long *);
	unsigned long (*clk_get_val)(u16);
	int (*clk_set_val)(u16, unsigned long);
	int (*dvfs_get_idx)(u8);
	int (*dvfs_set_idx)(u8, u8);
	struct scpi_dvfs_info *(*dvfs_get_info)(u8);
};

#if IS_ENABLED(CONFIG_ARM_SCPI_PROTOCOL)
struct scpi_ops *get_scpi_ops(void);
#else
static inline struct scpi_ops *get_scpi_ops(void) { return NULL; }
#endif