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* (C) Copyright 2007-2008
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* Dirk Eibach, Guntermann & Drunck GmbH, eibach@gdsys.de
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* based on lm75.c by Bill Hunter
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* SPDX-License-Identifier: GPL-2.0+
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* National LM63/LM64 Temperature Sensor
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* Main difference: LM 64 has -16 Kelvin temperature offset
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#define DTT_I2C_LM63_ADDR 0x4C /* National LM63 device */
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#define DTT_READ_TEMP_RMT_MSB 0x01
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#define DTT_CONFIG 0x03
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#define DTT_READ_TEMP_RMT_LSB 0x10
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#define DTT_TACHLIM_LSB 0x48
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#define DTT_TACHLIM_MSB 0x49
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#define DTT_FAN_CONFIG 0x4A
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#define DTT_PWM_FREQ 0x4D
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#define DTT_PWM_LOOKUP_BASE 0x50
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struct pwm_lookup_entry {
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int dtt_read(int sensor, int reg)
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* Calculate sensor address and register.
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sensor = DTT_I2C_LM63_ADDR; /* legacy config */
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* Now try to read the register.
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if (i2c_read(sensor, reg, 1, data, dlen) != 0)
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int dtt_write(int sensor, int reg, int val)
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* Calculate sensor address and register.
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sensor = DTT_I2C_LM63_ADDR; /* legacy config */
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data[0] = (char)(val & 0xff);
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* Write value to register.
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if (i2c_write(sensor, reg, 1, data, dlen) != 0)
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static int is_lm64(int sensor)
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return sensor && (sensor != DTT_I2C_LM63_ADDR);
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int dtt_init_one(int sensor)
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struct pwm_lookup_entry pwm_lookup[] = CONFIG_DTT_PWM_LOOKUPTABLE;
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* Set PWM Frequency to 2.5% resolution
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if (dtt_write(sensor, DTT_PWM_FREQ, val) != 0)
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* Set Tachometer Limit
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val = CONFIG_DTT_TACH_LIMIT;
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if (dtt_write(sensor, DTT_TACHLIM_LSB, val & 0xff) != 0)
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if (dtt_write(sensor, DTT_TACHLIM_MSB, (val >> 8) & 0xff) != 0)
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* Make sure PWM Lookup-Table is writeable
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if (dtt_write(sensor, DTT_FAN_CONFIG, 0x20) != 0)
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* Setup PWM Lookup-Table
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for (i = 0; i < ARRAY_SIZE(pwm_lookup); i++) {
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int address = DTT_PWM_LOOKUP_BASE + 2 * i;
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val = pwm_lookup[i].temp;
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if (dtt_write(sensor, address, val) != 0)
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val = dtt_read(sensor, address);
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val = pwm_lookup[i].pwm;
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if (dtt_write(sensor, address + 1, val) != 0)
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* Enable PWM Lookup-Table, PWM Clock 360 kHz, Tachometer Mode 2
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if (dtt_write(sensor, DTT_FAN_CONFIG, val) != 0)
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val = dtt_read(sensor, DTT_CONFIG) | 0x04;
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if (dtt_write(sensor, DTT_CONFIG, val) != 0)
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int dtt_get_temp(int sensor)
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s16 temp = (dtt_read(sensor, DTT_READ_TEMP_RMT_MSB) << 8)
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| (dtt_read(sensor, DTT_READ_TEMP_RMT_LSB));
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/* Ignore LSB for now, U-Boot only prints natural numbers */