linux/drivers/staging/media/atomisp/pci/sh_css_frac.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Support for Intel Camera Imaging ISP subsystem.
 * Copyright (c) 2015, Intel Corporation.
 *
 * 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.
 */

#ifndef __SH_CSS_FRAC_H
#define __SH_CSS_FRAC_H

#include <linux/minmax.h>

#include "mamoiada_params.h"

#define sISP_REG_BIT		      ISP_VEC_ELEMBITS
#define uISP_REG_BIT		      ((unsigned int)(sISP_REG_BIT - 1))
#define sSHIFT				    (16 - sISP_REG_BIT)
#define uSHIFT				    ((unsigned int)(16 - uISP_REG_BIT))
#define sFRACTION_BITS_FITTING(a) (a - sSHIFT)
#define uFRACTION_BITS_FITTING(a) ((unsigned int)(a - uSHIFT))
#define sISP_VAL_MIN		      (-(1 << uISP_REG_BIT))
#define sISP_VAL_MAX		      ((1 << uISP_REG_BIT) - 1)
#define uISP_VAL_MIN		      (0U)
#define uISP_VAL_MAX		      ((unsigned int)((1 << uISP_REG_BIT) - 1))

/* a:fraction bits for 16bit precision, b:fraction bits for ISP precision */
static inline int sDIGIT_FITTING(int v, int a, int b)
{
	int fit_shift = sFRACTION_BITS_FITTING(a) - b;

	v >>= sSHIFT;
	v >>= fit_shift > 0 ? fit_shift : 0;

	return clamp_t(int, v, sISP_VAL_MIN, sISP_VAL_MAX);
}

static inline unsigned int uDIGIT_FITTING(unsigned int v, int a, int b)
{
	int fit_shift = uFRACTION_BITS_FITTING(a) - b;

	v >>= uSHIFT;
	v >>= fit_shift > 0 ? fit_shift : 0;

	return clamp_t(unsigned int, v, uISP_VAL_MIN, uISP_VAL_MAX);
}

#endif /* __SH_CSS_FRAC_H */