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w1_therm: adding alarm sysfs entry

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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: Akira Shimahara <akira215corp@gmail.com>
Link: https://lore.kernel.org/r/20200511203801.411253-1-akira215corp@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Akira Shimahara 2020-05-11 22:38:01 +02:00 committed by Greg Kroah-Hartman
parent 67b392f7b8
commit e2c94d6f57
2 changed files with 177 additions and 0 deletions
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16
Documentation/ABI/testing/sysfs-driver-w1_therm
View File

@ -1,3 +1,19 @@
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>

161
drivers/w1/slaves/w1_therm.c
View File

@ -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)