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authorAkira Shimahara <akira215corp@gmail.com>2020-05-11 23:38:01 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-05-15 17:29:00 +0300
commite2c94d6f572079511945e64537eb1218643f2e68 (patch)
treec3a49f9816cb8d93a98888edc4e15cabd55451b4 /drivers/w1/slaves/w1_therm.c
parent67b392f7b8edfa6f427fecd98722acab34c1c99f (diff)
downloadlinux-e2c94d6f572079511945e64537eb1218643f2e68.tar.xz
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: 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>
Diffstat (limited to 'drivers/w1/slaves/w1_therm.c')
-rw-r--r--drivers/w1/slaves/w1_therm.c161
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index 5a81ce2a4e74..825536196e61 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -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)