Messages in this thread Patch in this message | | | From | Akira Shimahara <> | Subject | [PATCH v5 8/9] w1_therm: adding alarm sysfs entry | Date | Sun, 10 May 2020 02:02:32 +0200 |
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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> --- Changes in v5: - All patch serie in one .c file - Correcting some comments - adding <linux/string.h> include
.../ABI/testing/sysfs-driver-w1_therm | 16 ++ drivers/w1/slaves/w1_therm.c | 158 ++++++++++++++++++ 2 files changed, 174 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-driver-w1_therm b/Documentation/ABI/testing/sysfs-driver-w1_therm index 6ffd3e3..f289520 100644 --- a/Documentation/ABI/testing/sysfs-driver-w1_therm +++ b/Documentation/ABI/testing/sysfs-driver-w1_therm @@ -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> diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 2955cae..cd65d0b 100644 --- a/drivers/w1/slaves/w1_therm.c +++ b/drivers/w1/slaves/w1_therm.c @@ -57,6 +57,9 @@ 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 */ + /*-------------------------------Macros-------------------------------------*/ /* return a pointer on the slave w1_therm_family_converter struct: @@ -97,6 +100,7 @@ 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); }; /** @@ -248,6 +252,18 @@ 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); +/** \brief A callback function to set the alarms level + * \param device represents the master device + */ +static ssize_t alarms_store(struct device *device, + struct device_attribute *attr, const char *buf, size_t size); + +/** \brief A callback function to get the alarms level + * \return Low and High alarm, separate by one space + */ +static ssize_t alarms_show(struct device *device, + struct device_attribute *attr, char *buf); + /*-----------------------------Attributes declarations----------------------*/ static DEVICE_ATTR_RW(w1_slave); @@ -256,6 +272,7 @@ 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-----------------------*/ @@ -280,6 +297,7 @@ static struct attribute *w1_therm_attrs[] = { &dev_attr_ext_power.attr, &dev_attr_resolution.attr, &dev_attr_eeprom.attr, + &dev_attr_alarms.attr, NULL, }; @@ -288,6 +306,7 @@ static struct attribute *w1_ds18s20_attrs[] = { &dev_attr_temperature.attr, &dev_attr_ext_power.attr, &dev_attr_eeprom.attr, + &dev_attr_alarms.attr, NULL, }; @@ -298,6 +317,7 @@ static struct attribute *w1_ds28ea00_attrs[] = { &dev_attr_ext_power.attr, &dev_attr_resolution.attr, &dev_attr_eeprom.attr, + &dev_attr_alarms.attr, NULL, }; @@ -543,6 +563,7 @@ 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, @@ -550,6 +571,7 @@ 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, @@ -557,6 +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_DS28EA00, @@ -564,6 +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_DS1825, @@ -571,6 +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, } }; @@ -651,6 +676,19 @@ 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 + * min/max values are defined by macro + * \param i integer to be converted to short + * \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) @@ -1221,6 +1259,126 @@ 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) -- 2.26.2
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