Commit c626e8d6 authored by Mariusz Bialonczyk's avatar Mariusz Bialonczyk Committed by Phil Elwell
Browse files

w1: add support for DS2438 Smart Battery Monitor 



[ Upstream commit e3af95e6 ]

Detailed information about support and provided sysfs files
in my next commit which creates a documentation file:
Documentation/w1/slaves/w1_ds2438

Signed-off-by: default avatarMariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a914e138

drivers/w1/slaves/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -78,6 +78,12 @@ config W1_SLAVE_DS2433_CRC 
	  Each block has 30 bytes of data and a two byte CRC16.

	  Full block writes are only allowed if the CRC is valid.



config W1_SLAVE_DS2438

	tristate "DS2438 Smart Battery Monitor 0x26 family support"

	help

	  Say Y here if you want to use a 1-wire

	  DS2438 Smart Battery Monitor device support



config W1_SLAVE_DS2760

	tristate "Dallas 2760 battery monitor chip (HP iPAQ & others)"

	help

drivers/w1/slaves/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ obj-$(CONFIG_W1_SLAVE_DS2406) += w1_ds2406.o 
obj-$(CONFIG_W1_SLAVE_DS2423)	+= w1_ds2423.o

obj-$(CONFIG_W1_SLAVE_DS2431)	+= w1_ds2431.o

obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o

obj-$(CONFIG_W1_SLAVE_DS2438)	+= w1_ds2438.o

obj-$(CONFIG_W1_SLAVE_DS2760)	+= w1_ds2760.o

obj-$(CONFIG_W1_SLAVE_DS2780)	+= w1_ds2780.o

obj-$(CONFIG_W1_SLAVE_DS2781)	+= w1_ds2781.o

drivers/w1/slaves/w1_ds2438.c

0 → 100644
+390 −0
Original line number Diff line number Diff line 
/*

 * 1-Wire implementation for the ds2438 chip

 *

 * Copyright (c) 2017 Mariusz Bialonczyk <manio@skyboo.net>

 *

 * This source code is licensed under the GNU General Public License,

 * Version 2. See the file COPYING for more details.

 */



#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/types.h>

#include <linux/delay.h>



#include "../w1.h"

#include "../w1_family.h"



#define W1_DS2438_RETRIES		3



/* Memory commands */

#define W1_DS2438_READ_SCRATCH		0xBE

#define W1_DS2438_WRITE_SCRATCH		0x4E

#define W1_DS2438_COPY_SCRATCH		0x48

#define W1_DS2438_RECALL_MEMORY		0xB8

/* Register commands */

#define W1_DS2438_CONVERT_TEMP		0x44

#define W1_DS2438_CONVERT_VOLTAGE	0xB4



#define DS2438_PAGE_SIZE		8

#define DS2438_ADC_INPUT_VAD		0

#define DS2438_ADC_INPUT_VDD		1

#define DS2438_MAX_CONVERSION_TIME	10		/* ms */



/* Page #0 definitions */

#define DS2438_STATUS_REG		0x00		/* Status/Configuration Register */

#define DS2438_STATUS_IAD		(1 << 0)	/* Current A/D Control Bit */

#define DS2438_STATUS_CA		(1 << 1)	/* Current Accumulator Configuration */

#define DS2438_STATUS_EE		(1 << 2)	/* Current Accumulator Shadow Selector bit */

#define DS2438_STATUS_AD		(1 << 3)	/* Voltage A/D Input Select Bit */

#define DS2438_STATUS_TB		(1 << 4)	/* Temperature Busy Flag */

#define DS2438_STATUS_NVB		(1 << 5)	/* Nonvolatile Memory Busy Flag */

#define DS2438_STATUS_ADB		(1 << 6)	/* A/D Converter Busy Flag */



#define DS2438_TEMP_LSB			0x01

#define DS2438_TEMP_MSB			0x02

#define DS2438_VOLTAGE_LSB		0x03

#define DS2438_VOLTAGE_MSB		0x04

#define DS2438_CURRENT_LSB		0x05

#define DS2438_CURRENT_MSB		0x06

#define DS2438_THRESHOLD		0x07



int w1_ds2438_get_page(struct w1_slave *sl, int pageno, u8 *buf)

{

	unsigned int retries = W1_DS2438_RETRIES;

	u8 w1_buf[2];

	u8 crc;

	size_t count;



	while (retries--) {

		crc = 0;



		if (w1_reset_select_slave(sl))

			continue;

		w1_buf[0] = W1_DS2438_RECALL_MEMORY;

		w1_buf[1] = 0x00;

		w1_write_block(sl->master, w1_buf, 2);



		if (w1_reset_select_slave(sl))

			continue;

		w1_buf[0] = W1_DS2438_READ_SCRATCH;

		w1_buf[1] = 0x00;

		w1_write_block(sl->master, w1_buf, 2);



		count = w1_read_block(sl->master, buf, DS2438_PAGE_SIZE + 1);

		if (count == DS2438_PAGE_SIZE + 1) {

			crc = w1_calc_crc8(buf, DS2438_PAGE_SIZE);



			/* check for correct CRC */

			if ((u8)buf[DS2438_PAGE_SIZE] == crc)

				return 0;

		}

	}

	return -1;

}



int w1_ds2438_get_temperature(struct w1_slave *sl, int16_t *temperature)

{

	unsigned int retries = W1_DS2438_RETRIES;

	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];

	unsigned int tm = DS2438_MAX_CONVERSION_TIME;

	unsigned long sleep_rem;

	int ret;



	mutex_lock(&sl->master->bus_mutex);



	while (retries--) {

		if (w1_reset_select_slave(sl))

			continue;

		w1_write_8(sl->master, W1_DS2438_CONVERT_TEMP);



		mutex_unlock(&sl->master->bus_mutex);

		sleep_rem = msleep_interruptible(tm);

		if (sleep_rem != 0) {

			ret = -1;

			goto post_unlock;

		}



		if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) {

			ret = -1;

			goto post_unlock;

		}



		break;

	}



	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {

		*temperature = (((int16_t) w1_buf[DS2438_TEMP_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_TEMP_LSB]);

		ret = 0;

	} else

		ret = -1;



	mutex_unlock(&sl->master->bus_mutex);



post_unlock:

	return ret;

}



int w1_ds2438_change_config_bit(struct w1_slave *sl, u8 mask, u8 value)

{

	unsigned int retries = W1_DS2438_RETRIES;

	u8 w1_buf[3];

	u8 status;

	int perform_write = 0;



	while (retries--) {

		if (w1_reset_select_slave(sl))

			continue;

		w1_buf[0] = W1_DS2438_RECALL_MEMORY;

		w1_buf[1] = 0x00;

		w1_write_block(sl->master, w1_buf, 2);



		if (w1_reset_select_slave(sl))

			continue;

		w1_buf[0] = W1_DS2438_READ_SCRATCH;

		w1_buf[1] = 0x00;

		w1_write_block(sl->master, w1_buf, 2);



		/* reading one byte of result */

		status = w1_read_8(sl->master);



		/* if bit0=1, set a value to a mask for easy compare */

		if (value)

			value = mask;



		if ((status & mask) == value)

			return 0;	/* already set as requested */

		else {

			/* changing bit */

			status ^= mask;

			perform_write = 1;

		}

		break;

	}



	if (perform_write) {

		retries = W1_DS2438_RETRIES;

		while (retries--) {

			if (w1_reset_select_slave(sl))

				continue;

			w1_buf[0] = W1_DS2438_WRITE_SCRATCH;

			w1_buf[1] = 0x00;

			w1_buf[2] = status;

			w1_write_block(sl->master, w1_buf, 3);



			if (w1_reset_select_slave(sl))

				continue;

			w1_buf[0] = W1_DS2438_COPY_SCRATCH;

			w1_buf[1] = 0x00;

			w1_write_block(sl->master, w1_buf, 2);



			return 0;

		}

	}

	return -1;

}



uint16_t w1_ds2438_get_voltage(struct w1_slave *sl, int adc_input, uint16_t *voltage)

{

	unsigned int retries = W1_DS2438_RETRIES;

	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];

	unsigned int tm = DS2438_MAX_CONVERSION_TIME;

	unsigned long sleep_rem;

	int ret;



	mutex_lock(&sl->master->bus_mutex);



	if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_AD, adc_input)) {

		ret = -1;

		goto pre_unlock;

	}



	while (retries--) {

		if (w1_reset_select_slave(sl))

			continue;

		w1_write_8(sl->master, W1_DS2438_CONVERT_VOLTAGE);



		mutex_unlock(&sl->master->bus_mutex);

		sleep_rem = msleep_interruptible(tm);

		if (sleep_rem != 0) {

			ret = -1;

			goto post_unlock;

		}



		if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) {

			ret = -1;

			goto post_unlock;

		}



		break;

	}



	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {

		*voltage = (((uint16_t) w1_buf[DS2438_VOLTAGE_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_VOLTAGE_LSB]);

		ret = 0;

	} else

		ret = -1;



pre_unlock:

	mutex_unlock(&sl->master->bus_mutex);



post_unlock:

	return ret;

}



static ssize_t iad_write(struct file *filp, struct kobject *kobj,

			 struct bin_attribute *bin_attr, char *buf,

			 loff_t off, size_t count)

{

	struct w1_slave *sl = kobj_to_w1_slave(kobj);

	int ret;



	if (count != 1 || off != 0)

		return -EFAULT;



	mutex_lock(&sl->master->bus_mutex);



	if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_IAD, *buf & 0x01) == 0)

		ret = 1;

	else

		ret = -EIO;



	mutex_unlock(&sl->master->bus_mutex);



	return ret;

}



static ssize_t page0_read(struct file *filp, struct kobject *kobj,

			  struct bin_attribute *bin_attr, char *buf,

			  loff_t off, size_t count)

{

	struct w1_slave *sl = kobj_to_w1_slave(kobj);

	int ret;

	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];



	if (off != 0)

		return 0;

	if (!buf)

		return -EINVAL;



	mutex_lock(&sl->master->bus_mutex);



	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {

		memcpy(buf, &w1_buf, DS2438_PAGE_SIZE);

		ret = DS2438_PAGE_SIZE;

	} else

		ret = -EIO;



	mutex_unlock(&sl->master->bus_mutex);



	return ret;

}



static ssize_t temperature_read(struct file *filp, struct kobject *kobj,

				struct bin_attribute *bin_attr, char *buf,

				loff_t off, size_t count)

{

	struct w1_slave *sl = kobj_to_w1_slave(kobj);

	int ret;

	ssize_t c = PAGE_SIZE;

	int16_t temp;



	if (off != 0)

		return 0;

	if (!buf)

		return -EINVAL;



	if (w1_ds2438_get_temperature(sl, &temp) == 0) {

		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", temp);

		ret = PAGE_SIZE - c;

	} else

		ret = -EIO;



	return ret;

}



static ssize_t vad_read(struct file *filp, struct kobject *kobj,

			struct bin_attribute *bin_attr, char *buf,

			loff_t off, size_t count)

{

	struct w1_slave *sl = kobj_to_w1_slave(kobj);

	int ret;

	ssize_t c = PAGE_SIZE;

	uint16_t voltage;



	if (off != 0)

		return 0;

	if (!buf)

		return -EINVAL;



	if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) {

		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);

		ret = PAGE_SIZE - c;

	} else

		ret = -EIO;



	return ret;

}



static ssize_t vdd_read(struct file *filp, struct kobject *kobj,

			struct bin_attribute *bin_attr, char *buf,

			loff_t off, size_t count)

{

	struct w1_slave *sl = kobj_to_w1_slave(kobj);

	int ret;

	ssize_t c = PAGE_SIZE;

	uint16_t voltage;



	if (off != 0)

		return 0;

	if (!buf)

		return -EINVAL;



	if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) {

		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);

		ret = PAGE_SIZE - c;

	} else

		ret = -EIO;



	return ret;

}



static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, NULL, iad_write, 1);

static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE);

static BIN_ATTR_RO(temperature, 0/* real length varies */);

static BIN_ATTR_RO(vad, 0/* real length varies */);

static BIN_ATTR_RO(vdd, 0/* real length varies */);



static struct bin_attribute *w1_ds2438_bin_attrs[] = {

	&bin_attr_iad,

	&bin_attr_page0,

	&bin_attr_temperature,

	&bin_attr_vad,

	&bin_attr_vdd,

	NULL,

};



static const struct attribute_group w1_ds2438_group = {

	.bin_attrs = w1_ds2438_bin_attrs,

};



static const struct attribute_group *w1_ds2438_groups[] = {

	&w1_ds2438_group,

	NULL,

};



static struct w1_family_ops w1_ds2438_fops = {

	.groups		= w1_ds2438_groups,

};



static struct w1_family w1_ds2438_family = {

	.fid = W1_FAMILY_DS2438,

	.fops = &w1_ds2438_fops,

};

module_w1_family(w1_ds2438_family);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");

MODULE_DESCRIPTION("1-wire driver for Maxim/Dallas DS2438 Smart Battery Monitor");

MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2438));

drivers/w1/w1_family.h

+1 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#define W1_COUNTER_DS2423	0x1D

#define W1_THERM_DS1822  	0x22

#define W1_EEPROM_DS2433  	0x23

#define W1_FAMILY_DS2438	0x26

#define W1_THERM_DS18B20 	0x28

#define W1_FAMILY_DS2408	0x29

#define W1_EEPROM_DS2431	0x2D