The LM73 supports four A/D conversion resolutions. The default used by the existing lm73 driver is the chip's default, 11-bit (0.25 C/LSB). This patch enables changing of this resolution from userspace via the temp1_update_interval attribute. The LM73 also supports a basic over-temperature indicator. When the measured temperature goes above the high temperature limit, temp1_max, the alarm is triggered. When it drops below the low temperature limit, temp1_min, the alarm is ended. Full details on use of these mechanisms are described in Documentation/hwmon/lm73. Signed-off-by: Chris Verges <kg4ysn@xxxxxxxxx> --- Documentation/hwmon/lm73 | 108 +++++++++++++++ drivers/hwmon/lm73.c | 263 +++++++++++++++++++++++++++++++++++- include/linux/platform_data/lm73.h | 38 ++++++ 3 files changed, 405 insertions(+), 4 deletions(-) create mode 100644 Documentation/hwmon/lm73 create mode 100644 include/linux/platform_data/lm73.h diff --git a/Documentation/hwmon/lm73 b/Documentation/hwmon/lm73 new file mode 100644 index 0000000..24dfd8a --- /dev/null +++ b/Documentation/hwmon/lm73 @@ -0,0 +1,108 @@ +Kernel driver lm73 +================== + +Supported chips: + * Texas Instruments LM73 + Prefix: 'lm73' + Addresses scanned: I2C 0x48, 0x49, 0x4a, 0x4c, 0x4d, and 0x4e + Datasheet: Publicly available at the Texas Instruments website + http://www.ti.com/product/lm73 + +Author: Chris Verges <kg4ysn@xxxxxxxxx> + + +Description +----------- + +The LM73 is a digital temperature sensor. All temperature values are +given in degrees Celsius. + +Measurement Resolution Support +------------------------------ + +The LM73 supports four resolutions, defined in terms of degrees C per +LSB: 0.25, 0.125, 0.0625, and 0.3125. Changing the resolution mode +affects the conversion time of the LM73's analog-to-digital converter. +From userspace, the desired resolution can be specified as a function of +conversion time via the 'update_interval' sysfs attribute for the +device. This attribute will normalize ranges of input values to the +maximum times defined for the resolution in the datasheet. + + Resolution Conv. Time Input Range + (C/LSB) (msec) (msec) + -------------------------------------- + 0.25 14 0..21 + 0.125 28 22..42 + 0.0625 56 43..84 + 0.03125 112 85..infinity + -------------------------------------- + +The following examples show how the 'update_interval' attribute can be +used to change the conversion time: + + $ echo 0 > temp1_update_interval + $ cat temp1_update_interval + 14 + $ cat temp1_input + 24250 + + $ echo 36 > temp1_update_interval + $ cat temp1_update_interval + 28 + $ cat temp1_input + 24125 + + $ echo 56 > temp1_update_interval + $ cat temp1_update_interval + 56 + $ cat temp1_input + 24062 + + $ echo 85 > temp1_update_interval + $ cat temp1_update_interval + 112 + $ cat temp1_input + 24031 + +As shown here, the lm73 driver automatically adjusts any user input for +'update_interval' via a step function. Reading back the +'update_interval' value after a write operation will confirm the +conversion time actively in use. + +Mathematically, the resolution can be derived from the conversion time +via the following function: + + g(x) = 0.250 * [log(x/14) / log(2)] + +where 'x' is the output from 'update_interval' and 'g(x)' is the +resolution in degrees C per LSB. + +Alarm Support +------------- + +The LM73 features a simple over-temperature alarm mechanism. This +feature is exposed via the sysfs attributes and (optionally) via +platform device interrupt handling hooks. + +The primary attribute is 'temp1_alarm.' When the measured temperature +exceeds the value stored in 'temp1_max', the alarm triggers. When the +measured temperature drops below the value stored in 'temp1_min', the +alarm is cleared. The alarm can also be cleared by writing a '0' to the +'temp1_alarm' attribute. + +The attributes 'temp1_max_alarm' and 'temp1_min_alarm' are flags +provided by the LM73 that indicate whether the measured temperature has +passed the 'temp1_max' and 'temp1_min' thresholds, respectively. These +values _must_ be read to clear the registers on the LM73. + +If the lm73 driver is provided a struct lm73_platform_data during +initialization, interrupt handling is enabled. The platform must define +the IRQ number and IRQ flags at a minimum, and can optionally also +define a callback function to supplement the IRQ handler provided by the +lm73 driver. This internal IRQ handler enables use of epoll() on the +'temp1_alarm' attribute via the sysfs_notify() method. + +Finally, the LM73 can set the polarity of the ALERT interrupt to either +active-high or active-low (default). If the platform desired the +polarity to be switched to active-high, it can declare this in the +struct lm73_platform_data used during initialization. diff --git a/drivers/hwmon/lm73.c b/drivers/hwmon/lm73.c index 7272176..4acb0e2 100644 --- a/drivers/hwmon/lm73.c +++ b/drivers/hwmon/lm73.c @@ -20,7 +20,8 @@ #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/err.h> - +#include <linux/interrupt.h> +#include <linux/platform_data/lm73.h> /* Addresses scanned */ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c, @@ -39,8 +40,91 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c, #define LM73_TEMP_MIN (-40) #define LM73_TEMP_MAX 150 +#define LM73_CTRL_RES_SHIFT 5 +#define LM73_CTRL_RES_SIZE 2 +#define LM73_CTRL_RES_MASK \ + (((1 << LM73_CTRL_RES_SIZE) - 1) << LM73_CTRL_RES_SHIFT) + +#define LM73_CTRL_ALERT_SHIFT 3 +#define LM73_CTRL_ALERT_SIZE 1 +#define LM73_CTRL_ALERT_MASK \ + (((1 << LM73_CTRL_ALERT_SIZE) - 1) << LM73_CTRL_ALERT_SHIFT) + +#define LM73_CTRL_HI_SHIFT 2 +#define LM73_CTRL_HI_SIZE 1 +#define LM73_CTRL_HI_MASK \ + (((1 << LM73_CTRL_HI_SIZE) - 1) << LM73_CTRL_HI_SHIFT) + +#define LM73_CTRL_LO_SHIFT 1 +#define LM73_CTRL_LO_SIZE 1 +#define LM73_CTRL_LO_MASK \ + (((1 << LM73_CTRL_LO_SIZE) - 1) << LM73_CTRL_LO_SHIFT) + +#define LM73_CTRL_HILO_MASK \ + (LM73_CTRL_HI_MASK | LM73_CTRL_LO_MASK) + +#define LM73_CONF_POL_SHIFT 4 +#define LM73_CONF_POL_SIZE 1 +#define LM73_CONF_POL_MASK \ + (((1 << LM73_CONF_POL_SIZE) - 1) << LM73_CONF_POL_SHIFT) + +#define LM73_CONF_RESET_SHIFT 3 +#define LM73_CONF_RESET_SIZE 1 +#define LM73_CONF_RESET_MASK \ + (((1 << LM73_CONF_RESET_SIZE) - 1) << LM73_CONF_RESET_SHIFT) + +#define SCALE_150_PERCENT(x) ((x) + (x)/2) + +static const unsigned short lm73_valid_convrates[] = { + 14, /* 11-bits (0.25000 C/LSB): RES1 Bit = 0, RES0 Bit = 0 */ + 28, /* 12-bits (0.12500 C/LSB): RES1 Bit = 0, RES0 Bit = 1 */ + 56, /* 13-bits (0.06250 C/LSB): RES1 Bit = 1, RES0 Bit = 0 */ + 112, /* 14-bits (0.03125 C/LSB): RES1 Bit = 1, RES0 Bit = 1 */ +}; + /*-----------------------------------------------------------------------*/ +/* utility functions */ + +static inline s32 lm73_read(struct i2c_client *client, u8 reg) +{ + return i2c_smbus_read_byte_data(client, reg); +} + +static inline s32 lm73_write(struct i2c_client *client, u8 reg, + u8 clear, u8 enable) +{ + s32 tmp = lm73_read(client, reg); + u8 value; + if (tmp < 0) + return tmp; + value = tmp; + value &= ~clear; + value |= enable; + return i2c_smbus_write_byte_data(client, reg, value); +} + +static inline s32 lm73_write_conf(struct i2c_client *client, u8 clear, + u8 enable) +{ + /* always clear bits 1:0 and set bit 6 */ + enable &= ~(3 << 0); + return lm73_write(client, LM73_REG_CONF, + clear | (3 << 0), + enable | (1 << 6)); +} + +static inline s32 lm73_write_ctrl(struct i2c_client *client, u8 clear, + u8 enable) +{ + /* always clear bits 4:3 and 0 */ + enable &= ~((3 << 3) | (1 << 0)); + return lm73_write(client, LM73_REG_CTRL, + clear | (3 << 3) | (1 << 0), + enable); +} + +/*-----------------------------------------------------------------------*/ static ssize_t set_temp(struct device *dev, struct device_attribute *da, const char *buf, size_t count) @@ -59,7 +143,9 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *da, value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4), (LM73_TEMP_MAX*4)) << 5; err = i2c_smbus_write_word_swapped(client, attr->index, value); - return (err < 0) ? err : count; + if (err < 0) + return err; + return count; } static ssize_t show_temp(struct device *dev, struct device_attribute *da, @@ -79,6 +165,121 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *da, return scnprintf(buf, PAGE_SIZE, "%d\n", temp); } +static ssize_t set_convrate(struct device *dev, struct device_attribute *da, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned long convrate; + s32 err; + u8 res_bits = 0; + + err = kstrtoul(buf, 10, &convrate); + if (err < 0) + return err; + + /* Convert the desired conversion rate into register bits */ + if (convrate < SCALE_150_PERCENT(lm73_valid_convrates[0])) + res_bits = 0; + else if (convrate < SCALE_150_PERCENT(lm73_valid_convrates[1])) + res_bits = 1; + else if (convrate < SCALE_150_PERCENT(lm73_valid_convrates[2])) + res_bits = 2; + else + res_bits = 3; + + err = lm73_write_ctrl(client, LM73_CTRL_RES_MASK, + res_bits << LM73_CTRL_RES_SHIFT); + if (err < 0) + return err; + + return count; +} + +static ssize_t show_convrate(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + s32 ctrl; + u8 res_bits = 0; + + /* Read existing control value */ + ctrl = lm73_read(client, LM73_REG_CTRL); + if (ctrl < 0) + return ctrl; + + res_bits = (ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT; + return scnprintf(buf, PAGE_SIZE, "%hu\n", + lm73_valid_convrates[res_bits]); +} + +static ssize_t reset_alarm(struct device *dev, struct device_attribute *da, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned long input; + s32 err; + + err = kstrtoul(buf, 10, &input); + if (err < 0) + return err; + + /* ignore everything but a reset request */ + if (input) + return -EINVAL; + + err = lm73_write_conf(client, 0, LM73_CONF_RESET_MASK); + if (err < 0) + return err; + return count; +} + +static ssize_t show_alarm(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + s32 ctrl; + s32 conf; + + ctrl = lm73_read(client, LM73_REG_CTRL); + if (ctrl < 0) + return ctrl; + + conf = lm73_read(client, LM73_REG_CONF); + if (conf < 0) + return conf; + + /* strip out just the ALERT bit */ + ctrl &= LM73_CTRL_ALERT_MASK; + ctrl >>= LM73_CTRL_ALERT_SHIFT; + + /* + * If ALERT's polarity is active-low, the bit needs to be + * flipped to match the semantics of the 'alarm' attribute. + */ + if (!(conf & LM73_CONF_POL_MASK)) + ctrl = !ctrl; + + return scnprintf(buf, PAGE_SIZE, "%d\n", ctrl); +} + +static ssize_t show_maxmin_alarm(struct device *dev, + struct device_attribute *da, + char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); + s32 ctrl; + + ctrl = lm73_read(client, LM73_REG_CTRL); + if (ctrl < 0) + return ctrl; + + /* strip out just the temperature hi/lo flag */ + ctrl >>= attr->index; + ctrl &= 0x1; + + return scnprintf(buf, PAGE_SIZE, "%d\n", ctrl); +} /*-----------------------------------------------------------------------*/ @@ -90,13 +291,23 @@ static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, LM73_REG_MIN); static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, LM73_REG_INPUT); - +static SENSOR_DEVICE_ATTR(temp1_update_interval, S_IWUSR | S_IRUGO, + show_convrate, set_convrate, 0); +static SENSOR_DEVICE_ATTR(temp1_alarm, S_IWUSR | S_IRUGO, + show_alarm, reset_alarm, 0); +static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, + show_maxmin_alarm, NULL, LM73_CTRL_HI_SHIFT); +static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, + show_maxmin_alarm, NULL, LM73_CTRL_LO_SHIFT); static struct attribute *lm73_attributes[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_temp1_max.dev_attr.attr, &sensor_dev_attr_temp1_min.dev_attr.attr, - + &sensor_dev_attr_temp1_update_interval.dev_attr.attr, + &sensor_dev_attr_temp1_alarm.dev_attr.attr, + &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, + &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, NULL }; @@ -106,11 +317,25 @@ static const struct attribute_group lm73_group = { /*-----------------------------------------------------------------------*/ +static irqreturn_t lm73_alarm_irq(int irq, void *arg) +{ + struct i2c_client *client = arg; + struct lm73_platform_data *data = client->dev.platform_data; + + sysfs_notify(&client->dev.kobj, NULL, "temp1_alarm"); + if (data && data->handler) + return data->handler(irq, arg); + return IRQ_HANDLED; +} + +/*-----------------------------------------------------------------------*/ + /* device probe and removal */ static int lm73_probe(struct i2c_client *client, const struct i2c_device_id *id) { + struct lm73_platform_data *data = client->dev.platform_data; struct device *hwmon_dev; int status; @@ -126,6 +351,32 @@ lm73_probe(struct i2c_client *client, const struct i2c_device_id *id) } i2c_set_clientdata(client, hwmon_dev); + if (data && data->alert_polarity_high) { + status = lm73_write_conf(client, 0, LM73_CONF_POL_MASK); + if (status < 0) { + dev_err(&client->dev, + "%s: unable to set ALERT polarity\n", + dev_name(hwmon_dev)); + status = -EIO; + goto exit_remove; + } + } + + if (data && data->use_irq) { + status = devm_request_irq(&client->dev, + data->irq, + lm73_alarm_irq, + data->irqflags, + dev_name(hwmon_dev), + client); + if (status < 0) { + dev_err(&client->dev, + "%s: unable to assign IRQ %d\n", + dev_name(hwmon_dev), data->irq); + goto exit_remove; + } + } + dev_info(&client->dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name); @@ -139,7 +390,11 @@ exit_remove: static int lm73_remove(struct i2c_client *client) { struct device *hwmon_dev = i2c_get_clientdata(client); + struct lm73_platform_data *data = client->dev.platform_data; + if (data && data->use_irq) + devm_free_irq(&client->dev, data->use_irq, + data->handler); hwmon_device_unregister(hwmon_dev); sysfs_remove_group(&client->dev.kobj, &lm73_group); return 0; diff --git a/include/linux/platform_data/lm73.h b/include/linux/platform_data/lm73.h new file mode 100644 index 0000000..bfe9382 --- /dev/null +++ b/include/linux/platform_data/lm73.h @@ -0,0 +1,38 @@ +/* + * LM73 Sensor driver + * Based on LM75 + * + * Copyright (C) 2007, CenoSYS (www.cenosys.com). + * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu). + * + * Guillaume Ligneul <guillaume.ligneul@xxxxxxxxx> + * Adrien Demarez <adrien.demarez@xxxxxxxxxxxxxxxxx> + * Jeremy Laine <jeremy.laine@xxxxxxxxxxxxxxxxx> + * + * This software program is licensed subject to the GNU General Public License + * (GPL).Version 2,June 1991, available at + * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html + */ +#ifndef _LINUX_LM73_H +#define _LINUX_LM73_H + +/** + * struct lm73_platform_data - static configuration settings for the + * LM73 temperature sensor. + * + * @alert_polarity_high: 0 if ALERT is active-high, 1 if active-low + * @use_irq: 0 if ALERT is wired to an active interrupt pin + * @irq: the interrupt to use + * @irqflags: the interrupt flags (see IRQF_*) + * @handler: the platform handler function + */ +struct lm73_platform_data { + int alert_polarity_high; + + int use_irq; + unsigned int irq; + unsigned long irqflags; + irq_handler_t handler; +}; + +#endif /* _LINUX_LM73_H */ -- 1.7.9.5 _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
