Implementation of LTC4284 Driver. More...

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "ltc4284.h"
#include "no_os_delay.h"
#include "no_os_units.h"
#include "no_os_alloc.h"
#include "no_os_print_log.h"
#include "no_os_util.h"

Include dependency graph for ltc4284.c:

Functions
int	ltc4284_read_byte (struct ltc4284_dev dev, uint8_t reg, uint8_t val)
	Read a single byte from LTC4284 register.

int	ltc4284_write_byte (struct ltc4284_dev *dev, uint8_t cmd, uint8_t val)
	Write a single byte to LTC4284 register.

int	ltc4284_read_word (struct ltc4284_dev dev, uint8_t reg, uint16_t val)
	Read a 16-bit word from LTC4284 (big-endian)

int	ltc4284_write_word (struct ltc4284_dev *dev, uint8_t reg, uint16_t val)
	Write a 16-bit word to LTC4284 (big-endian)

int	ltc4284_update_bits (struct ltc4284_dev *dev, uint8_t reg, uint8_t mask, uint8_t val)
	Update register bits with mask.

int	ltc4284_init (struct ltc4284_dev *device, const struct ltc4284_init_param init_param)
	Initialize the LTC4284 device.

int	ltc4284_remove (struct ltc4284_dev *dev)
	Remove the LTC4284 device and free resources.

int	ltc4284_read_vin (struct ltc4284_dev dev, uint32_t vin_mv)
	Read input voltage (VPWR)

int	ltc4284_read_iin (struct ltc4284_dev dev, uint32_t iin_ma)
	Read input current (SENSE)

int	ltc4284_read_vds (struct ltc4284_dev dev, uint32_t vds_mv)
	Read drain-to-source voltage across the external MOSFET.

int	ltc4284_read_vout (struct ltc4284_dev dev, uint32_t vout_mv)
	Read output bus voltage delivered to the load.

int	ltc4284_read_power (struct ltc4284_dev dev, uint32_t power_mw)
	Read power consumption.

int	ltc4284_read_energy (struct ltc4284_dev dev, uint64_t energy_code)
	Read cumulative energy accumulator.

int	ltc4284_enable_fet (struct ltc4284_dev *dev, bool enable)
	Enable or disable FET drivers.

int	ltc4284_clear_faults (struct ltc4284_dev *dev)
	Clear all fault conditions.

int	ltc4284_read_status (struct ltc4284_dev dev, uint8_t status)
	Read system status register.

int	ltc4284_get_fault (struct ltc4284_dev dev, uint8_t faults)
	Get current fault conditions.

int	ltc4284_arm_fault_log (struct ltc4284_dev *dev)
	Arm the LTC4284 fault-log capture into EEPROM.

int	ltc4284_restore_from_eeprom (struct ltc4284_dev *dev)
	Restore configuration from EEPROM.

int	ltc4284_set_ilim_mv (struct ltc4284_dev *dev, uint8_t mv)
	Set steady-state V_ILIM in millivolts.

int	ltc4284_set_foldback (struct ltc4284_dev *dev, uint8_t code)
	Set current-limit foldback factor.

int	ltc4284_set_oc_retry (struct ltc4284_dev *dev, uint8_t code)
	Set overcurrent retry policy.

Detailed Description

Implementation of LTC4284 Driver.

Author: Carlos Jones Jr carlo.nosp@m.sjr..nosp@m.jones.nosp@m.@ana.nosp@m.log.c.nosp@m.om; Christopher de Guzman chris.nosp@m.toph.nosp@m.er.de.nosp@m.guzm.nosp@m.an@an.nosp@m.alog.nosp@m..com

SPDX-License-Identifier: BSD-3-Clause

Function Documentation

◆ ltc4284_arm_fault_log()

int ltc4284_arm_fault_log ( struct ltc4284_dev * dev )

Arm the LTC4284 fault-log capture into EEPROM.

Parameters

dev	- Device descriptor

Returns: 0 in case of success, negative error code otherwise

Sets FAULT_LOG_ENABLE (bit 7) in FAULT_LOG_CONTROL (0x90). The chip captures the fault + ADC snapshot into EEPROM on the next fault event; poll FAULT_LOG_DONE (bit 4) to detect completion. The EEPROM write itself is signalled by EEPROM_BUSY in SYSTEM_STATUS.

◆ ltc4284_clear_faults()

int ltc4284_clear_faults ( struct ltc4284_dev * dev )

Clear all fault conditions.

Parameters

dev	- Device descriptor

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_enable_fet()

int ltc4284_enable_fet	(	struct ltc4284_dev *	dev,
		bool	enable )

Enable or disable FET drivers.

Parameters

dev	- Device descriptor
enable	- True to enable, false to disable

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_get_fault()

int ltc4284_get_fault	(	struct ltc4284_dev *	dev,
		uint8_t *	faults )

Get current fault conditions.

Parameters

dev	- Device descriptor
faults	- Pointer to store fault byte

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_init()

int ltc4284_init	(	struct ltc4284_dev **	device,
		const struct ltc4284_init_param *	init_param )

Initialize the LTC4284 device.

Parameters

device	- Pointer to device descriptor pointer
init_param	- Initialization parameters

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_byte()

int ltc4284_read_byte	(	struct ltc4284_dev *	dev,
		uint8_t	reg,
		uint8_t *	val )

Read a single byte from LTC4284 register.

Parameters

dev	- Device descriptor
reg	- Register address
val	- Pointer to store read value

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_energy()

int ltc4284_read_energy	(	struct ltc4284_dev *	dev,
		uint64_t *	energy_code )

Read cumulative energy accumulator.

Parameters

dev	- Device descriptor
energy_code	- Pointer to store the raw 48-bit accumulator value

Returns: 0 in case of success, negative error code otherwise

Returns the raw 48-bit ENERGY accumulator code from registers 0x7A..0x7F (datasheet p.51), not a physical energy in millijoules. The physical conversion requires the ADC conversion time (t_conv, datasheet Table 12) and the sense-resistor value; callers can observe accumulation over time but must apply the conversion themselves.

◆ ltc4284_read_iin()

int ltc4284_read_iin	(	struct ltc4284_dev *	dev,
		uint32_t *	iin_ma )

Read input current (SENSE)

Parameters

dev	- Device descriptor
iin_ma	- Pointer to store current in milliamps

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_power()

int ltc4284_read_power	(	struct ltc4284_dev *	dev,
		uint32_t *	power_mw )

Read power consumption.

Parameters

dev	- Device descriptor
power_mw	- Pointer to store power in milliwatts

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_status()

int ltc4284_read_status	(	struct ltc4284_dev *	dev,
		uint8_t *	status )

Read system status register.

Parameters

dev	- Device descriptor
status	- Pointer to store status byte

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_vds()

int ltc4284_read_vds	(	struct ltc4284_dev *	dev,
		uint32_t *	vds_mv )

Read drain-to-source voltage across the external MOSFET.

Reads the DRAIN ADC register (0x65). The value is V_DRAIN referenced to VEE (the chip's ground = supply-side -48V), which equals the V_DS across the external hot-swap MOSFET. Under normal conduction V_DS ~= I * Rds_on (a few mV to tens of mV). When the FET is off, V_DS rises to approximately VIN, and inductive transients can push it further and peg the ADC at full-scale (drain_divider * 2.048 V, e.g. 81.92 V for a 40:1 divider).

Parameters

dev	- Device descriptor
vds_mv	- Pointer to store V_DS in millivolts

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_vin()

int ltc4284_read_vin	(	struct ltc4284_dev *	dev,
		uint32_t *	vin_mv )

Read input voltage (VPWR)

Parameters

dev	- Device descriptor
vin_mv	- Pointer to store voltage in millivolts

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_vout()

int ltc4284_read_vout	(	struct ltc4284_dev *	dev,
		uint32_t *	vout_mv )

Read output bus voltage delivered to the load.

Computed as VIN - V_DS. This is the actual bus voltage the load sees, not a raw ADC register. When the FET is conducting, VOUT ~= VIN. When the FET is off, VOUT collapses toward 0 (the load is disconnected).

Parameters

dev	- Device descriptor
vout_mv	- Pointer to store output voltage in millivolts

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_read_word()

int ltc4284_read_word	(	struct ltc4284_dev *	dev,
		uint8_t	reg,
		uint16_t *	val )

Read a 16-bit word from LTC4284 (big-endian)

Parameters

dev	- Device descriptor
reg	- Register address
val	- Pointer to store read value

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_remove()

int ltc4284_remove ( struct ltc4284_dev * dev )

Remove the LTC4284 device and free resources.

Parameters

dev	- Device descriptor

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_restore_from_eeprom()

int ltc4284_restore_from_eeprom ( struct ltc4284_dev * dev )

Restore configuration from EEPROM.

Parameters

dev	- Device descriptor

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_set_foldback()

int ltc4284_set_foldback	(	struct ltc4284_dev *	dev,
		uint8_t	code )

Set current-limit foldback factor.

Parameters

dev	- Device descriptor
code	- Foldback code (0: 100%, 1: 50%, 2: 20%, 3: 10%)

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_set_ilim_mv()

int ltc4284_set_ilim_mv	(	struct ltc4284_dev *	dev,
		uint8_t	mv )

Set steady-state V_ILIM in millivolts.

Parameters

dev	- Device descriptor
mv	- Desired V_ILIM in millivolts (15..30 mV)

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_set_oc_retry()

int ltc4284_set_oc_retry	(	struct ltc4284_dev *	dev,
		uint8_t	code )

Set overcurrent retry policy.

Parameters

dev	- Device descriptor
code	- Retry code (0: latch-off, 1: 1 retry, 2: 7 retries, 3: unlimited)

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_update_bits()

int ltc4284_update_bits	(	struct ltc4284_dev *	dev,
		uint8_t	reg,
		uint8_t	mask,
		uint8_t	val )

Update register bits with mask.

Parameters

dev	- Device descriptor
reg	- Register address
mask	- Bit mask
val	- New value for masked bits

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_write_byte()

int ltc4284_write_byte	(	struct ltc4284_dev *	dev,
		uint8_t	cmd,
		uint8_t	val )

Write a single byte to LTC4284 register.

Parameters

dev	- Device descriptor
cmd	- Command byte which contains register address
val	- Value to write

Returns: 0 in case of success, negative error code otherwise

◆ ltc4284_write_word()

int ltc4284_write_word	(	struct ltc4284_dev *	dev,
		uint8_t	reg,
		uint16_t	val )

Write a 16-bit word to LTC4284 (big-endian)

Parameters

dev	- Device descriptor
reg	- Register address
val	- Value to write

Returns: 0 in case of success, negative error code otherwise

Functions

Detailed Description

Function Documentation

◆ ltc4284_arm_fault_log()

◆ ltc4284_clear_faults()

◆ ltc4284_enable_fet()

◆ ltc4284_get_fault()

◆ ltc4284_init()

◆ ltc4284_read_byte()

◆ ltc4284_read_energy()

◆ ltc4284_read_iin()

◆ ltc4284_read_power()

◆ ltc4284_read_status()

◆ ltc4284_read_vds()

◆ ltc4284_read_vin()

◆ ltc4284_read_vout()

◆ ltc4284_read_word()

◆ ltc4284_remove()

◆ ltc4284_restore_from_eeprom()

◆ ltc4284_set_foldback()

◆ ltc4284_set_ilim_mv()

◆ ltc4284_set_oc_retry()

◆ ltc4284_update_bits()

◆ ltc4284_write_byte()

◆ ltc4284_write_word()