Commit e2c94d6f authored by Akira Shimahara's avatar Akira Shimahara Committed by Greg Kroah-Hartman
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w1_therm: adding alarm sysfs entry 



Adding device alarms settings by a dedicated sysfs entry alarms (RW):
read or write TH and TL in the device RAM. Checking devices in alarm
state could be performed using the master search command.

As alarms temperature level are store in a 8 bit register on the device
and are signed values, a safe cast shall be performed using the min and
max temperature that device are able to measure. This is done by
int_to_short inline function.

A 'write_data' field is added in the device structure, to bind the
correct writing function, as some devices may have 2 or 3 bytes RAM.

Updating Documentation/ABI/testing/sysfs-driver-w1_therm accordingly.

Signed-off-by: default avatarAkira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203801.411253-1-akira215corp@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 67b392f7

Documentation/ABI/testing/sysfs-driver-w1_therm

+16 −0
Original line number Diff line number Diff line 
What:		/sys/bus/w1/devices/.../alarms

Date:		May 2020

Contact:	Akira Shimahara <akira215corp@gmail.com>

Description:

		(RW) read or write TH and TL (Temperature High an Low) alarms.

		Values shall be space separated and in the device range

		(typical -55 degC to 125 degC), if not values will be trimmed

		to device min/max capabilities. Values are integer as they are

		stored in a 8bit register in the device. Lowest value is

		automatically put to TL. Once set, alarms could be search at

		master level, refer to Documentation/w1/w1_generic.rst for

		detailed information

Users:		any user space application which wants to communicate with

		w1_term device





What:		/sys/bus/w1/devices/.../eeprom

Date:		May 2020

Contact:	Akira Shimahara <akira215corp@gmail.com>

drivers/w1/slaves/w1_therm.c

+161 −0
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ module_param_named(strong_pullup, w1_strong_pullup, int, 0); 
#define EEPROM_CMD_WRITE    "save"	/* cmd for write eeprom sysfs */

#define EEPROM_CMD_READ     "restore"	/* cmd for read eeprom sysfs */



#define MIN_TEMP	-55	/* min temperature that can be mesured */

#define MAX_TEMP	125	/* max temperature that can be mesured */



/* Helpers Macros */



/*
@@ -96,6 +99,7 @@ module_param_named(strong_pullup, w1_strong_pullup, int, 0); 
 * @get_conversion_time: pointer to the device conversion time function

 * @set_resolution: pointer to the device set_resolution function

 * @get_resolution: pointer to the device get_resolution function

 * @write_data: pointer to the device writing function (2 or 3 bytes)

 */

struct w1_therm_family_converter {

	u8		broken;
@@ -105,6 +109,7 @@ struct w1_therm_family_converter { 
	int		(*get_conversion_time)(struct w1_slave *sl);

	int		(*set_resolution)(struct w1_slave *sl, int val);

	int		(*get_resolution)(struct w1_slave *sl);

	int		(*write_data)(struct w1_slave *sl, const u8 *data);

};



/**
@@ -239,6 +244,12 @@ static ssize_t resolution_store(struct device *device, 
static ssize_t eeprom_store(struct device *device,

	struct device_attribute *attr, const char *buf, size_t size);



static ssize_t alarms_store(struct device *device,

	struct device_attribute *attr, const char *buf, size_t size);



static ssize_t alarms_show(struct device *device,

	struct device_attribute *attr, char *buf);



/* Attributes declarations */



static DEVICE_ATTR_RW(w1_slave);
@@ -247,6 +258,7 @@ static DEVICE_ATTR_RO(temperature); 
static DEVICE_ATTR_RO(ext_power);

static DEVICE_ATTR_RW(resolution);

static DEVICE_ATTR_WO(eeprom);

static DEVICE_ATTR_RW(alarms);



/* Interface Functions declaration */
@@ -278,6 +290,7 @@ static struct attribute *w1_therm_attrs[] = { 
	&dev_attr_ext_power.attr,

	&dev_attr_resolution.attr,

	&dev_attr_eeprom.attr,

	&dev_attr_alarms.attr,

	NULL,

};
@@ -286,6 +299,7 @@ static struct attribute *w1_ds18s20_attrs[] = { 
	&dev_attr_temperature.attr,

	&dev_attr_ext_power.attr,

	&dev_attr_eeprom.attr,

	&dev_attr_alarms.attr,

	NULL,

};
@@ -296,6 +310,7 @@ static struct attribute *w1_ds28ea00_attrs[] = { 
	&dev_attr_ext_power.attr,

	&dev_attr_resolution.attr,

	&dev_attr_eeprom.attr,

	&dev_attr_alarms.attr,

	NULL,

};
@@ -556,6 +571,7 @@ static struct w1_therm_family_converter w1_therm_families[] = { 
		.get_conversion_time	= w1_DS18S20_convert_time,

		.set_resolution		= NULL,	/* no config register */

		.get_resolution		= NULL,	/* no config register */

		.write_data			= w1_DS18S20_write_data,

	},

	{

		.f				= &w1_therm_family_DS1822,
@@ -563,6 +579,7 @@ static struct w1_therm_family_converter w1_therm_families[] = { 
		.get_conversion_time	= w1_DS18B20_convert_time,

		.set_resolution		= w1_DS18B20_set_resolution,

		.get_resolution		= w1_DS18B20_get_resolution,

		.write_data			= w1_DS18B20_write_data,

	},

	{

		.f				= &w1_therm_family_DS18B20,
@@ -570,6 +587,7 @@ static struct w1_therm_family_converter w1_therm_families[] = { 
		.get_conversion_time	= w1_DS18B20_convert_time,

		.set_resolution		= w1_DS18B20_set_resolution,

		.get_resolution		= w1_DS18B20_get_resolution,

		.write_data			= w1_DS18B20_write_data,

	},

	{

		.f				= &w1_therm_family_DS28EA00,
@@ -577,6 +595,7 @@ static struct w1_therm_family_converter w1_therm_families[] = { 
		.get_conversion_time	= w1_DS18B20_convert_time,

		.set_resolution		= w1_DS18B20_set_resolution,

		.get_resolution		= w1_DS18B20_get_resolution,

		.write_data			= w1_DS18B20_write_data,

	},

	{

		.f				= &w1_therm_family_DS1825,
@@ -584,6 +603,7 @@ static struct w1_therm_family_converter w1_therm_families[] = { 
		.get_conversion_time	= w1_DS18B20_convert_time,

		.set_resolution		= w1_DS18B20_set_resolution,

		.get_resolution		= w1_DS18B20_get_resolution,

		.write_data			= w1_DS18B20_write_data,

	}

};
@@ -678,6 +698,26 @@ static inline int temperature_from_RAM(struct w1_slave *sl, u8 rom[9]) 
	return 0;  /* No device family */

}



/**

 * int_to_short() - Safe casting of int to short

 *

 * @i: integer to be converted to short

 *

 * Device register use 1 byte to store signed integer.

 * This helper function convert the int in a signed short,

 * using the min/max values that device can measure as limits.

 * min/max values are defined by macro.

 *

 * Return: a short in the range of min/max value

 */

static inline s8 int_to_short(int i)

{

	/* Prepare to cast to short by eliminating out of range values */

	i = i > MAX_TEMP ? MAX_TEMP : i;

	i = i < MIN_TEMP ? MIN_TEMP : i;

	return (s8) i;

}



/* Interface Functions */



static int w1_therm_add_slave(struct w1_slave *sl)
@@ -1251,6 +1291,127 @@ static ssize_t eeprom_store(struct device *device, 
	return size;

}



static ssize_t alarms_show(struct device *device,

	struct device_attribute *attr, char *buf)

{

	struct w1_slave *sl = dev_to_w1_slave(device);

	int ret = -ENODEV;

	s8 th = 0, tl = 0;

	struct therm_info scratchpad;



	ret = read_scratchpad(sl, &scratchpad);



	if (!ret)	{

		th = scratchpad.rom[2]; /* TH is byte 2 */

		tl = scratchpad.rom[3]; /* TL is byte 3 */

	} else {

		dev_info(device,

			"%s: error reading alarms register %d\n",

			__func__, ret);

	}



	return sprintf(buf, "%hd %hd\n", tl, th);

}



static ssize_t alarms_store(struct device *device,

	struct device_attribute *attr, const char *buf, size_t size)

{

	struct w1_slave *sl = dev_to_w1_slave(device);

	struct therm_info info;

	u8 new_config_register[3];	/* array of data to be written */

	int temp, ret = -EINVAL;

	char *token = NULL;

	s8 tl, th, tt;	/* 1 byte per value + temp ring order */

	char *p_args = kmalloc(size, GFP_KERNEL);



	/* Safe string copys as buf is const */

	if (!p_args) {

		dev_warn(device,

			"%s: error unable to allocate memory %d\n",

			__func__, -ENOMEM);

		return size;

	}

	strcpy(p_args, buf);



	/* Split string using space char */

	token = strsep(&p_args, " ");



	if (!token)	{

		dev_info(device,

			"%s: error parsing args %d\n", __func__, -EINVAL);

		goto free_m;

	}



	/* Convert 1st entry to int */

	ret = kstrtoint (token, 10, &temp);

	if (ret) {

		dev_info(device,

			"%s: error parsing args %d\n", __func__, ret);

		goto free_m;

	}



	tl = int_to_short(temp);



	/* Split string using space char */

	token = strsep(&p_args, " ");

	if (!token)	{

		dev_info(device,

			"%s: error parsing args %d\n", __func__, -EINVAL);

		goto free_m;

	}

	/* Convert 2nd entry to int */

	ret = kstrtoint (token, 10, &temp);

	if (ret) {

		dev_info(device,

			"%s: error parsing args %d\n", __func__, ret);

		goto free_m;

	}



	/* Prepare to cast to short by eliminating out of range values */

	th = int_to_short(temp);



	/* Reorder if required th and tl */

	if (tl > th) {

		tt = tl; tl = th; th = tt;

	}



	/*

	 * Read the scratchpad to change only the required bits

	 * (th : byte 2 - tl: byte 3)

	 */

	ret = read_scratchpad(sl, &info);

	if (!ret) {

		new_config_register[0] = th;	/* Byte 2 */

		new_config_register[1] = tl;	/* Byte 3 */

		new_config_register[2] = info.rom[4];/* Byte 4 */

	} else {

		dev_info(device,

			"%s: error reading from the slave device %d\n",

			__func__, ret);

		goto free_m;

	}



	/* Write data in the device RAM */

	if (!SLAVE_SPECIFIC_FUNC(sl)) {

		dev_info(device,

			"%s: Device not supported by the driver %d\n",

			__func__, -ENODEV);

		goto free_m;

	}



	ret = SLAVE_SPECIFIC_FUNC(sl)->write_data(sl, new_config_register);

	if (ret)

		dev_info(device,

			"%s: error writing to the slave device %d\n",

			__func__, ret);



free_m:

	/* free allocated memory */

	kfree(p_args);



	return size;

}



#if IS_REACHABLE(CONFIG_HWMON)

static int w1_read_temp(struct device *device, u32 attr, int channel,

			long *val)

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