linux-imx

// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)

//

// Copyright (c) 2018 Mellanox Technologies. All rights reserved.

// Copyright (c) 2018 Vadim Pasternak <vadimp@mellanox.com>

​

#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/hwmon.h>

#include <linux/module.h>

#include <linux/platform_data/mlxreg.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/thermal.h>

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#define MLXREG_FAN_MAX_TACHO        12

#define MLXREG_FAN_MAX_STATE        10

#define MLXREG_FAN_MIN_DUTY     51  /* 20% */

#define MLXREG_FAN_MAX_DUTY     255 /* 100% */

/*

 * Minimum and maximum FAN allowed speed in percent: from 20% to 100%. Values

 * MLXREG_FAN_MAX_STATE + x, where x is between 2 and 10 are used for

 * setting FAN speed dynamic minimum. For example, if value is set to 14 (40%)

 * cooling levels vector will be set to 4, 4, 4, 4, 4, 5, 6, 7, 8, 9, 10 to

 * introduce PWM speed in percent: 40, 40, 40, 40, 40, 50, 60. 70, 80, 90, 100.

 */

#define MLXREG_FAN_SPEED_MIN            (MLXREG_FAN_MAX_STATE + 2)

#define MLXREG_FAN_SPEED_MAX            (MLXREG_FAN_MAX_STATE * 2)

#define MLXREG_FAN_SPEED_MIN_LEVEL      2   /* 20 percent */

#define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF  44

#define MLXREG_FAN_TACHO_DIV_MIN        283

#define MLXREG_FAN_TACHO_DIV_DEF        (MLXREG_FAN_TACHO_DIV_MIN * 4)

#define MLXREG_FAN_TACHO_DIV_SCALE_MAX  64

/*

 * FAN datasheet defines the formula for RPM calculations as RPM = 15/t-high.

 * The logic in a programmable device measures the time t-high by sampling the

 * tachometer every t-sample (with the default value 11.32 uS) and increment

 * a counter (N) as long as the pulse has not change:

 * RPM = 15 / (t-sample * (K + Regval)), where:

 * Regval: is the value read from the programmable device register;

 *  - 0xff - represents tachometer fault;

 *  - 0xfe - represents tachometer minimum value , which is 4444 RPM;

 *  - 0x00 - represents tachometer maximum value , which is 300000 RPM;

 * K: is 44 and it represents the minimum allowed samples per pulse;

 * N: is equal K + Regval;

 * In order to calculate RPM from the register value the following formula is

 * used: RPM = 15 / ((Regval + K) * 11.32) * 10^(-6)), which in  the

 * default case is modified to:

 * RPM = 15000000 * 100 / ((Regval + 44) * 1132);

 * - for Regval 0x00, RPM will be 15000000 * 100 / (44 * 1132) = 30115;

 * - for Regval 0xfe, RPM will be 15000000 * 100 / ((254 + 44) * 1132) = 4446;

 * In common case the formula is modified to:

 * RPM = 15000000 * 100 / ((Regval + samples) * divider).

 */

#define MLXREG_FAN_GET_RPM(rval, d, s)  (DIV_ROUND_CLOSEST(15000000 * 100, \

                     ((rval) + (s)) * (d)))

#define MLXREG_FAN_GET_FAULT(val, mask) ((val) == (mask))

#define MLXREG_FAN_PWM_DUTY2STATE(duty) (DIV_ROUND_CLOSEST((duty) * \

                     MLXREG_FAN_MAX_STATE,      \

                     MLXREG_FAN_MAX_DUTY))

#define MLXREG_FAN_PWM_STATE2DUTY(stat) (DIV_ROUND_CLOSEST((stat) * \

                     MLXREG_FAN_MAX_DUTY,       \

                     MLXREG_FAN_MAX_STATE))

​