diff options
Diffstat (limited to 'drivers/hwmon/sht15.c')
| -rw-r--r-- | drivers/hwmon/sht15.c | 747 |
1 files changed, 579 insertions, 168 deletions
diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c index f4e617adb22..cf4330b352e 100644 --- a/drivers/hwmon/sht15.c +++ b/drivers/hwmon/sht15.c @@ -1,6 +1,10 @@ /* * sht15.c - support for the SHT15 Temperature and Humidity Sensor * + * Portions Copyright (c) 2010-2011 Savoir-faire Linux Inc. + * Jerome Oufella <jerome.oufella@savoirfairelinux.com> + * Vivien Didelot <vivien.didelot@savoirfairelinux.com> + * * Copyright (c) 2009 Jonathan Cameron * * Copyright (c) 2007 Wouter Horre @@ -9,16 +13,7 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * - * Currently ignoring checksum on readings. - * Default resolution only (14bit temp, 12bit humidity) - * Ignoring battery status. - * Heater not enabled. - * Timings are all conservative. - * - * Data sheet available (1/2009) at - * http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf - * - * Regulator supply name = vcc + * For further information, see the Documentation/hwmon/sht15 file. */ #include <linux/interrupt.h> @@ -39,17 +34,31 @@ #include <linux/slab.h> #include <asm/atomic.h> -#define SHT15_MEASURE_TEMP 3 -#define SHT15_MEASURE_RH 5 - -#define SHT15_READING_NOTHING 0 -#define SHT15_READING_TEMP 1 -#define SHT15_READING_HUMID 2 - -/* Min timings in nsecs */ -#define SHT15_TSCKL 100 /* clock low */ -#define SHT15_TSCKH 100 /* clock high */ -#define SHT15_TSU 150 /* data setup time */ +/* Commands */ +#define SHT15_MEASURE_TEMP 0x03 +#define SHT15_MEASURE_RH 0x05 +#define SHT15_WRITE_STATUS 0x06 +#define SHT15_READ_STATUS 0x07 +#define SHT15_SOFT_RESET 0x1E + +/* Min timings */ +#define SHT15_TSCKL 100 /* (nsecs) clock low */ +#define SHT15_TSCKH 100 /* (nsecs) clock high */ +#define SHT15_TSU 150 /* (nsecs) data setup time */ +#define SHT15_TSRST 11 /* (msecs) soft reset time */ + +/* Status Register Bits */ +#define SHT15_STATUS_LOW_RESOLUTION 0x01 +#define SHT15_STATUS_NO_OTP_RELOAD 0x02 +#define SHT15_STATUS_HEATER 0x04 +#define SHT15_STATUS_LOW_BATTERY 0x40 + +/* Actions the driver may be doing */ +enum sht15_state { + SHT15_READING_NOTHING, + SHT15_READING_TEMP, + SHT15_READING_HUMID +}; /** * struct sht15_temppair - elements of voltage dependent temp calc @@ -61,9 +70,7 @@ struct sht15_temppair { int d1; }; -/* Table 9 from data sheet - relates temperature calculation - * to supply voltage. - */ +/* Table 9 from datasheet - relates temperature calculation to supply voltage */ static const struct sht15_temppair temppoints[] = { { 2500000, -39400 }, { 3000000, -39600 }, @@ -72,29 +79,70 @@ static const struct sht15_temppair temppoints[] = { { 5000000, -40100 }, }; +/* Table from CRC datasheet, section 2.4 */ +static const u8 sht15_crc8_table[] = { + 0, 49, 98, 83, 196, 245, 166, 151, + 185, 136, 219, 234, 125, 76, 31, 46, + 67, 114, 33, 16, 135, 182, 229, 212, + 250, 203, 152, 169, 62, 15, 92, 109, + 134, 183, 228, 213, 66, 115, 32, 17, + 63, 14, 93, 108, 251, 202, 153, 168, + 197, 244, 167, 150, 1, 48, 99, 82, + 124, 77, 30, 47, 184, 137, 218, 235, + 61, 12, 95, 110, 249, 200, 155, 170, + 132, 181, 230, 215, 64, 113, 34, 19, + 126, 79, 28, 45, 186, 139, 216, 233, + 199, 246, 165, 148, 3, 50, 97, 80, + 187, 138, 217, 232, 127, 78, 29, 44, + 2, 51, 96, 81, 198, 247, 164, 149, + 248, 201, 154, 171, 60, 13, 94, 111, + 65, 112, 35, 18, 133, 180, 231, 214, + 122, 75, 24, 41, 190, 143, 220, 237, + 195, 242, 161, 144, 7, 54, 101, 84, + 57, 8, 91, 106, 253, 204, 159, 174, + 128, 177, 226, 211, 68, 117, 38, 23, + 252, 205, 158, 175, 56, 9, 90, 107, + 69, 116, 39, 22, 129, 176, 227, 210, + 191, 142, 221, 236, 123, 74, 25, 40, + 6, 55, 100, 85, 194, 243, 160, 145, + 71, 118, 37, 20, 131, 178, 225, 208, + 254, 207, 156, 173, 58, 11, 88, 105, + 4, 53, 102, 87, 192, 241, 162, 147, + 189, 140, 223, 238, 121, 72, 27, 42, + 193, 240, 163, 146, 5, 52, 103, 86, + 120, 73, 26, 43, 188, 141, 222, 239, + 130, 179, 224, 209, 70, 119, 36, 21, + 59, 10, 89, 104, 255, 206, 157, 172 +}; + /** * struct sht15_data - device instance specific data - * @pdata: platform data (gpio's etc) - * @read_work: bh of interrupt handler - * @wait_queue: wait queue for getting values from device - * @val_temp: last temperature value read from device - * @val_humid: last humidity value read from device - * @flag: status flag used to identify what the last request was - * @valid: are the current stored values valid (start condition) - * @last_updat: time of last update - * @read_lock: mutex to ensure only one read in progress - * at a time. - * @dev: associate device structure - * @hwmon_dev: device associated with hwmon subsystem - * @reg: associated regulator (if specified) - * @nb: notifier block to handle notifications of voltage changes - * @supply_uV: local copy of supply voltage used to allow - * use of regulator consumer if available - * @supply_uV_valid: indicates that an updated value has not yet - * been obtained from the regulator and so any calculations - * based upon it will be invalid. - * @update_supply_work: work struct that is used to update the supply_uV - * @interrupt_handled: flag used to indicate a hander has been scheduled + * @pdata: platform data (gpio's etc). + * @read_work: bh of interrupt handler. + * @wait_queue: wait queue for getting values from device. + * @val_temp: last temperature value read from device. + * @val_humid: last humidity value read from device. + * @val_status: last status register value read from device. + * @checksum_ok: last value read from the device passed CRC validation. + * @checksumming: flag used to enable the data validation with CRC. + * @state: state identifying the action the driver is doing. + * @measurements_valid: are the current stored measures valid (start condition). + * @status_valid: is the current stored status valid (start condition). + * @last_measurement: time of last measure. + * @last_status: time of last status reading. + * @read_lock: mutex to ensure only one read in progress at a time. + * @dev: associate device structure. + * @hwmon_dev: device associated with hwmon subsystem. + * @reg: associated regulator (if specified). + * @nb: notifier block to handle notifications of voltage + * changes. + * @supply_uV: local copy of supply voltage used to allow use of + * regulator consumer if available. + * @supply_uV_valid: indicates that an updated value has not yet been + * obtained from the regulator and so any calculations + * based upon it will be invalid. + * @update_supply_work: work struct that is used to update the supply_uV. + * @interrupt_handled: flag used to indicate a handler has been scheduled. */ struct sht15_data { struct sht15_platform_data *pdata; @@ -102,21 +150,60 @@ struct sht15_data { wait_queue_head_t wait_queue; uint16_t val_temp; uint16_t val_humid; - u8 flag; - u8 valid; - unsigned long last_updat; + u8 val_status; + bool checksum_ok; + bool checksumming; + enum sht15_state state; + bool measurements_valid; + bool status_valid; + unsigned long last_measurement; + unsigned long last_status; struct mutex read_lock; struct device *dev; struct device *hwmon_dev; struct regulator *reg; struct notifier_block nb; int supply_uV; - int supply_uV_valid; + bool supply_uV_valid; struct work_struct update_supply_work; atomic_t interrupt_handled; }; /** + * sht15_reverse() - reverse a byte + * @byte: byte to reverse. + */ +static u8 sht15_reverse(u8 byte) +{ + u8 i, c; + + for (c = 0, i = 0; i < 8; i++) + c |= (!!(byte & (1 << i))) << (7 - i); + return c; +} + +/** + * sht15_crc8() - compute crc8 + * @data: sht15 specific data. + * @value: sht15 retrieved data. + * + * This implements section 2 of the CRC datasheet. + */ +static u8 sht15_crc8(struct sht15_data *data, + const u8 *value, + int len) +{ + u8 crc = sht15_reverse(data->val_status & 0x0F); + + while (len--) { + crc = sht15_crc8_table[*value ^ crc]; + value++; + } + + return crc; +} + +/** * sht15_connection_reset() - reset the comms interface * @data: sht15 specific data * @@ -125,6 +212,7 @@ struct sht15_data { static void sht15_connection_reset(struct sht15_data *data) { int i; + gpio_direction_output(data->pdata->gpio_data, 1); ndelay(SHT15_TSCKL); gpio_set_value(data->pdata->gpio_sck, 0); @@ -136,14 +224,14 @@ static void sht15_connection_reset(struct sht15_data *data) ndelay(SHT15_TSCKL); } } + /** * sht15_send_bit() - send an individual bit to the device * @data: device state data * @val: value of bit to be sent - **/ + */ static inline void sht15_send_bit(struct sht15_data *data, int val) { - gpio_set_value(data->pdata->gpio_data, val); ndelay(SHT15_TSU); gpio_set_value(data->pdata->gpio_sck, 1); @@ -154,12 +242,12 @@ static inline void sht15_send_bit(struct sht15_data *data, int val) /** * sht15_transmission_start() - specific sequence for new transmission - * * @data: device state data + * * Timings for this are not documented on the data sheet, so very * conservative ones used in implementation. This implements * figure 12 on the data sheet. - **/ + */ static void sht15_transmission_start(struct sht15_data *data) { /* ensure data is high and output */ @@ -180,23 +268,26 @@ static void sht15_transmission_start(struct sht15_data *data) gpio_set_value(data->pdata->gpio_sck, 0); ndelay(SHT15_TSCKL); } + /** * sht15_send_byte() - send a single byte to the device * @data: device state * @byte: value to be sent - **/ + */ static void sht15_send_byte(struct sht15_data *data, u8 byte) { int i; + for (i = 0; i < 8; i++) { sht15_send_bit(data, !!(byte & 0x80)); byte <<= 1; } } + /** * sht15_wait_for_response() - checks for ack from device * @data: device state - **/ + */ static int sht15_wait_for_response(struct sht15_data *data) { gpio_direction_input(data->pdata->gpio_data); @@ -220,27 +311,199 @@ static int sht15_wait_for_response(struct sht15_data *data) * * On entry, sck is output low, data is output pull high * and the interrupt disabled. - **/ + */ static int sht15_send_cmd(struct sht15_data *data, u8 cmd) { int ret = 0; + sht15_transmission_start(data); sht15_send_byte(data, cmd); ret = sht15_wait_for_response(data); return ret; } + +/** + * sht15_soft_reset() - send a soft reset command + * @data: sht15 specific data. + * + * As described in section 3.2 of the datasheet. + */ +static int sht15_soft_reset(struct sht15_data *data) +{ + int ret; + + ret = sht15_send_cmd(data, SHT15_SOFT_RESET); + if (ret) + return ret; + msleep(SHT15_TSRST); + /* device resets default hardware status register value */ + data->val_status = 0; + + return ret; +} + +/** + * sht15_ack() - send a ack + * @data: sht15 specific data. + * + * Each byte of data is acknowledged by pulling the data line + * low for one clock pulse. + */ +static void sht15_ack(struct sht15_data *data) +{ + gpio_direction_output(data->pdata->gpio_data, 0); + ndelay(SHT15_TSU); + gpio_set_value(data->pdata->gpio_sck, 1); + ndelay(SHT15_TSU); + gpio_set_value(data->pdata->gpio_sck, 0); + ndelay(SHT15_TSU); + gpio_set_value(data->pdata->gpio_data, 1); + + gpio_direction_input(data->pdata->gpio_data); +} + +/** + * sht15_end_transmission() - notify device of end of transmission + * @data: device state. + * + * This is basically a NAK (single clock pulse, data high). + */ +static void sht15_end_transmission(struct sht15_data *data) +{ + gpio_direction_output(data->pdata->gpio_data, 1); + ndelay(SHT15_TSU); + gpio_set_value(data->pdata->gpio_sck, 1); + ndelay(SHT15_TSCKH); + gpio_set_value(data->pdata->gpio_sck, 0); + ndelay(SHT15_TSCKL); +} + +/** + * sht15_read_byte() - Read a byte back from the device + * @data: device state. + */ +static u8 sht15_read_byte(struct sht15_data *data) +{ + int i; + u8 byte = 0; + + for (i = 0; i < 8; ++i) { + byte <<= 1; + gpio_set_value(data->pdata->gpio_sck, 1); + ndelay(SHT15_TSCKH); + byte |= !!gpio_get_value(data->pdata->gpio_data); + gpio_set_value(data->pdata->gpio_sck, 0); + ndelay(SHT15_TSCKL); + } + return byte; +} + +/** + * sht15_send_status() - write the status register byte + * @data: sht15 specific data. + * @status: the byte to set the status register with. + * + * As described in figure 14 and table 5 of the datasheet. + */ +static int sht15_send_status(struct sht15_data *data, u8 status) +{ + int ret; + + ret = sht15_send_cmd(data, SHT15_WRITE_STATUS); + if (ret) + return ret; + gpio_direction_output(data->pdata->gpio_data, 1); + ndelay(SHT15_TSU); + sht15_send_byte(data, status); + ret = sht15_wait_for_response(data); + if (ret) + return ret; + + data->val_status = status; + return 0; +} + +/** + * sht15_update_status() - get updated status register from device if too old + * @data: device instance specific data. + * + * As described in figure 15 and table 5 of the datasheet. + */ +static int sht15_update_status(struct sht15_data *data) +{ + int ret = 0; + u8 status; + u8 previous_config; + u8 dev_checksum = 0; + u8 checksum_vals[2]; + int timeout = HZ; + + mutex_lock(&data->read_lock); + if (time_after(jiffies, data->last_status + timeout) + || !data->status_valid) { + ret = sht15_send_cmd(data, SHT15_READ_STATUS); + if (ret) + goto error_ret; + status = sht15_read_byte(data); + + if (data->checksumming) { + sht15_ack(data); + dev_checksum = sht15_reverse(sht15_read_byte(data)); + checksum_vals[0] = SHT15_READ_STATUS; + checksum_vals[1] = status; + data->checksum_ok = (sht15_crc8(data, checksum_vals, 2) + == dev_checksum); + } + + sht15_end_transmission(data); + + /* + * Perform checksum validation on the received data. + * Specification mentions that in case a checksum verification + * fails, a soft reset command must be sent to the device. + */ + if (data->checksumming && !data->checksum_ok) { + previous_config = data->val_status & 0x07; + ret = sht15_soft_reset(data); + if (ret) + goto error_ret; + if (previous_config) { + ret = sht15_send_status(data, previous_config); + if (ret) { + dev_err(data->dev, + "CRC validation failed, unable " + "to restore device settings\n"); + goto error_ret; + } + } + ret = -EAGAIN; + goto error_ret; + } + + data->val_status = status; + data->status_valid = true; + data->last_status = jiffies; + } +error_ret: + mutex_unlock(&data->read_lock); + + return ret; +} + /** - * sht15_update_single_val() - get a new value from device + * sht15_measurement() - get a new value from device * @data: device instance specific data * @command: command sent to request value * @timeout_msecs: timeout after which comms are assumed * to have failed are reset. - **/ -static inline int sht15_update_single_val(struct sht15_data *data, - int command, - int timeout_msecs) + */ +static int sht15_measurement(struct sht15_data *data, + int command, + int timeout_msecs) { int ret; + u8 previous_config; + ret = sht15_send_cmd(data, command); if (ret) return ret; @@ -256,38 +519,61 @@ static inline int sht15_update_single_val(struct sht15_data *data, schedule_work(&data->read_work); } ret = wait_event_timeout(data->wait_queue, - (data->flag == SHT15_READING_NOTHING), + (data->state == SHT15_READING_NOTHING), msecs_to_jiffies(timeout_msecs)); if (ret == 0) {/* timeout occurred */ disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data)); sht15_connection_reset(data); return -ETIME; } + + /* + * Perform checksum validation on the received data. + * Specification mentions that in case a checksum verification fails, + * a soft reset command must be sent to the device. + */ + if (data->checksumming && !data->checksum_ok) { + previous_config = data->val_status & 0x07; + ret = sht15_soft_reset(data); + if (ret) + return ret; + if (previous_config) { + ret = sht15_send_status(data, previous_config); + if (ret) { + dev_err(data->dev, + "CRC validation failed, unable " + "to restore device settings\n"); + return ret; + } + } + return -EAGAIN; + } + return 0; } /** - * sht15_update_vals() - get updated readings from device if too old + * sht15_update_measurements() - get updated measures from device if too old * @data: device state - **/ -static int sht15_update_vals(struct sht15_data *data) + */ +static int sht15_update_measurements(struct sht15_data *data) { int ret = 0; int timeout = HZ; mutex_lock(&data->read_lock); - if (time_after(jiffies, data->last_updat + timeout) - || !data->valid) { - data->flag = SHT15_READING_HUMID; - ret = sht15_update_single_val(data, SHT15_MEASURE_RH, 160); + if (time_after(jiffies, data->last_measurement + timeout) + || !data->measurements_valid) { + data->state = SHT15_READING_HUMID; + ret = sht15_measurement(data, SHT15_MEASURE_RH, 160); if (ret) goto error_ret; - data->flag = SHT15_READING_TEMP; - ret = sht15_update_single_val(data, SHT15_MEASURE_TEMP, 400); + data->state = SHT15_READING_TEMP; + ret = sht15_measurement(data, SHT15_MEASURE_TEMP, 400); if (ret) goto error_ret; - data->valid = 1; - data->last_updat = jiffies; + data->measurements_valid = true; + data->last_measurement = jiffies; } error_ret: mutex_unlock(&data->read_lock); @@ -300,10 +586,11 @@ error_ret: * @data: device state * * As per section 4.3 of the data sheet. - **/ + */ static inline int sht15_calc_temp(struct sht15_data *data) { int d1 = temppoints[0].d1; + int d2 = (data->val_status & SHT15_STATUS_LOW_RESOLUTION) ? 40 : 10; int i; for (i = ARRAY_SIZE(temppoints) - 1; i > 0; i--) @@ -316,7 +603,7 @@ static inline int sht15_calc_temp(struct sht15_data *data) break; } - return data->val_temp*10 + d1; + return data->val_temp * d2 + d1; } /** @@ -325,23 +612,102 @@ static inline int sht15_calc_temp(struct sht15_data *data) * * This is the temperature compensated version as per section 4.2 of * the data sheet. - **/ + * + * The sensor is assumed to be V3, which is compatible with V4. + * Humidity conversion coefficients are shown in table 7 of the datasheet. + */ static inline int sht15_calc_humid(struct sht15_data *data) { - int RHlinear; /* milli percent */ + int rh_linear; /* milli percent */ int temp = sht15_calc_temp(data); - + int c2, c3; + int t2; const int c1 = -4; - const int c2 = 40500; /* x 10 ^ -6 */ - const int c3 = -28; /* x 10 ^ -7 */ - RHlinear = c1*1000 - + c2 * data->val_humid/1000 + if (data->val_status & SHT15_STATUS_LOW_RESOLUTION) { + c2 = 648000; /* x 10 ^ -6 */ + c3 = -7200; /* x 10 ^ -7 */ + t2 = 1280; + } else { + c2 = 40500; /* x 10 ^ -6 */ + c3 = -28; /* x 10 ^ -7 */ + t2 = 80; + } + + rh_linear = c1 * 1000 + + c2 * data->val_humid / 1000 + (data->val_humid * data->val_humid * c3) / 10000; - return (temp - 25000) * (10000 + 80 * data->val_humid) - / 1000000 + RHlinear; + return (temp - 25000) * (10000 + t2 * data->val_humid) + / 1000000 + rh_linear; +} + +/** + * sht15_show_status() - show status information in sysfs + * @dev: device. + * @attr: device attribute. + * @buf: sysfs buffer where information is written to. + * + * Will be called on read access to temp1_fault, humidity1_fault + * and heater_enable sysfs attributes. + * Returns number of bytes written into buffer, negative errno on error. + */ +static ssize_t sht15_show_status(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int ret; + struct sht15_data *data = dev_get_drvdata(dev); + u8 bit = to_sensor_dev_attr(attr)->index; + + ret = sht15_update_status(data); + + return ret ? ret : sprintf(buf, "%d\n", !!(data->val_status & bit)); +} + +/** + * sht15_store_heater() - change heater state via sysfs + * @dev: device. + * @attr: device attribute. + * @buf: sysfs buffer to read the new heater state from. + * @count: length of the data. + * + * Will be called on read access to heater_enable sysfs attribute. + * Returns number of bytes actually decoded, negative errno on error. + */ +static ssize_t sht15_store_heater(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int ret; + struct sht15_data *data = dev_get_drvdata(dev); + long value; + u8 status; + + if (strict_strtol(buf, 10, &value)) + return -EINVAL; + + mutex_lock(&data->read_lock); + status = data->val_status & 0x07; + if (!!value) + status |= SHT15_STATUS_HEATER; + else + status &= ~SHT15_STATUS_HEATER; + + ret = sht15_send_status(data, status); + mutex_unlock(&data->read_lock); + + return ret ? ret : count; } +/** + * sht15_show_temp() - show temperature measurement value in sysfs + * @dev: device. + * @attr: device attribute. + * @buf: sysfs buffer where measurement values are written to. + * + * Will be called on read access to temp1_input sysfs attribute. + * Returns number of bytes written into buffer, negative errno on error. + */ static ssize_t sht15_show_temp(struct device *dev, struct device_attribute *attr, char *buf) @@ -350,12 +716,21 @@ static ssize_t sht15_show_temp(struct device *dev, struct sht15_data *data = dev_get_drvdata(dev); /* Technically no need to read humidity as well */ - ret = sht15_update_vals(data); + ret = sht15_update_measurements(data); return ret ? ret : sprintf(buf, "%d\n", sht15_calc_temp(data)); } +/** + * sht15_show_humidity() - show humidity measurement value in sysfs + * @dev: device. + * @attr: device attribute. + * @buf: sysfs buffer where measurement values are written to. + * + * Will be called on read access to humidity1_input sysfs attribute. + * Returns number of bytes written into buffer, negative errno on error. + */ static ssize_t sht15_show_humidity(struct device *dev, struct device_attribute *attr, char *buf) @@ -363,11 +738,11 @@ static ssize_t sht15_show_humidity(struct device *dev, int ret; struct sht15_data *data = dev_get_drvdata(dev); - ret = sht15_update_vals(data); + ret = sht15_update_measurements(data); return ret ? ret : sprintf(buf, "%d\n", sht15_calc_humid(data)); +} -}; static ssize_t show_name(struct device *dev, struct device_attribute *attr, char *buf) @@ -376,16 +751,23 @@ static ssize_t show_name(struct device *dev, return sprintf(buf, "%s\n", pdev->name); } -static SENSOR_DEVICE_ATTR(temp1_input, - S_IRUGO, sht15_show_temp, - NULL, 0); -static SENSOR_DEVICE_ATTR(humidity1_input, - S_IRUGO, sht15_show_humidity, - NULL, 0); +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, + sht15_show_temp, NULL, 0); +static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, + sht15_show_humidity, NULL, 0); +static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, sht15_show_status, NULL, + SHT15_STATUS_LOW_BATTERY); +static SENSOR_DEVICE_ATTR(humidity1_fault, S_IRUGO, sht15_show_status, NULL, + SHT15_STATUS_LOW_BATTERY); +static SENSOR_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR, sht15_show_status, + sht15_store_heater, SHT15_STATUS_HEATER); static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); static struct attribute *sht15_attrs[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_humidity1_input.dev_attr.attr, + &sensor_dev_attr_temp1_fault.dev_attr.attr, + &sensor_dev_attr_humidity1_fault.dev_attr.attr, + &sensor_dev_attr_heater_enable.dev_attr.attr, &dev_attr_name.attr, NULL, }; @@ -397,59 +779,31 @@ static const struct attribute_group sht15_attr_group = { static irqreturn_t sht15_interrupt_fired(int irq, void *d) { struct sht15_data *data = d; + /* First disable the interrupt */ disable_irq_nosync(irq); atomic_inc(&data->interrupt_handled); /* Then schedule a reading work struct */ - if (data->flag != SHT15_READING_NOTHING) + if (data->state != SHT15_READING_NOTHING) schedule_work(&data->read_work); return IRQ_HANDLED; } -/* Each byte of data is acknowledged by pulling the data line - * low for one clock pulse. - */ -static void sht15_ack(struct sht15_data *data) -{ - gpio_direction_output(data->pdata->gpio_data, 0); - ndelay(SHT15_TSU); - gpio_set_value(data->pdata->gpio_sck, 1); - ndelay(SHT15_TSU); - gpio_set_value(data->pdata->gpio_sck, 0); - ndelay(SHT15_TSU); - gpio_set_value(data->pdata->gpio_data, 1); - - gpio_direction_input(data->pdata->gpio_data); -} -/** - * sht15_end_transmission() - notify device of end of transmission - * @data: device state - * - * This is basically a NAK. (single clock pulse, data high) - **/ -static void sht15_end_transmission(struct sht15_data *data) -{ - gpio_direction_output(data->pdata->gpio_data, 1); - ndelay(SHT15_TSU); - gpio_set_value(data->pdata->gpio_sck, 1); - ndelay(SHT15_TSCKH); - gpio_set_value(data->pdata->gpio_sck, 0); - ndelay(SHT15_TSCKL); -} - static void sht15_bh_read_data(struct work_struct *work_s) { - int i; uint16_t val = 0; + u8 dev_checksum = 0; + u8 checksum_vals[3]; struct sht15_data *data = container_of(work_s, struct sht15_data, read_work); + /* Firstly, verify the line is low */ if (gpio_get_value(data->pdata->gpio_data)) { - /* If not, then start the interrupt again - care - here as could have gone low in meantime so verify - it hasn't! - */ + /* + * If not, then start the interrupt again - care here as could + * have gone low in meantime so verify it hasn't! + */ atomic_set(&data->interrupt_handled, 0); enable_irq(gpio_to_irq(data->pdata->gpio_data)); /* If still not occurred or another handler has been scheduled */ @@ -457,30 +811,43 @@ static void sht15_bh_read_data(struct work_struct *work_s) || atomic_read(&data->interrupt_handled)) return; } + /* Read the data back from the device */ - for (i = 0; i < 16; ++i) { - val <<= 1; - gpio_set_value(data->pdata->gpio_sck, 1); - ndelay(SHT15_TSCKH); - val |= !!gpio_get_value(data->pdata->gpio_data); - gpio_set_value(data->pdata->gpio_sck, 0); - ndelay(SHT15_TSCKL); - if (i == 7) - sht15_ack(data); + val = sht15_read_byte(data); + val <<= 8; + sht15_ack(data); + val |= sht15_read_byte(data); + + if (data->checksumming) { + /* + * Ask the device for a checksum and read it back. + * Note: the device sends the checksum byte reversed. + */ + sht15_ack(data); + dev_checksum = sht15_reverse(sht15_read_byte(data)); + checksum_vals[0] = (data->state == SHT15_READING_TEMP) ? + SHT15_MEASURE_TEMP : SHT15_MEASURE_RH; + checksum_vals[1] = (u8) (val >> 8); + checksum_vals[2] = (u8) val; + data->checksum_ok + = (sht15_crc8(data, checksum_vals, 3) == dev_checksum); } + /* Tell the device we are done */ sht15_end_transmission(data); - switch (data->flag) { + switch (data->state) { case SHT15_READING_TEMP: data->val_temp = val; break; case SHT15_READING_HUMID: data->val_humid = val; break; + default: + break; } - data->flag = SHT15_READING_NOTHING; + data->state = SHT15_READING_NOTHING; wake_up(&data->wait_queue); } @@ -500,10 +867,10 @@ static void sht15_update_voltage(struct work_struct *work_s) * * Note that as the notification code holds the regulator lock, we have * to schedule an update of the supply voltage rather than getting it directly. - **/ + */ static int sht15_invalidate_voltage(struct notifier_block *nb, - unsigned long event, - void *ignored) + unsigned long event, + void *ignored) { struct sht15_data *data = container_of(nb, struct sht15_data, nb); @@ -518,10 +885,11 @@ static int __devinit sht15_probe(struct platform_device *pdev) { int ret = 0; struct sht15_data *data = kzalloc(sizeof(*data), GFP_KERNEL); + u8 status = 0; if (!data) { ret = -ENOMEM; - dev_err(&pdev->dev, "kzalloc failed"); + dev_err(&pdev->dev, "kzalloc failed\n"); goto error_ret; } @@ -533,13 +901,22 @@ static int __devinit sht15_probe(struct platform_device *pdev) init_waitqueue_head(&data->wait_queue); if (pdev->dev.platform_data == NULL) { - dev_err(&pdev->dev, "no platform data supplied"); + dev_err(&pdev->dev, "no platform data supplied\n"); goto err_free_data; } data->pdata = pdev->dev.platform_data; - data->supply_uV = data->pdata->supply_mv*1000; - -/* If a regulator is available, query what the supply voltage actually is!*/ + data->supply_uV = data->pdata->supply_mv * 1000; + if (data->pdata->checksum) + data->checksumming = true; + if (data->pdata->no_otp_reload) + status |= SHT15_STATUS_NO_OTP_RELOAD; + if (data->pdata->low_resolution) + status |= SHT15_STATUS_LOW_RESOLUTION; + + /* + * If a regulator is available, + * query what the supply voltage actually is! + */ data->reg = regulator_get(data->dev, "vcc"); if (!IS_ERR(data->reg)) { int voltage; @@ -549,28 +926,34 @@ static int __devinit sht15_probe(struct platform_device *pdev) data->supply_uV = voltage; regulator_enable(data->reg); - /* setup a notifier block to update this if another device - * causes the voltage to change */ + /* + * Setup a notifier block to update this if another device + * causes the voltage to change + */ data->nb.notifier_call = &sht15_invalidate_voltage; ret = regulator_register_notifier(data->reg, &data->nb); + if (ret) { + dev_err(&pdev->dev, + "regulator notifier request failed\n"); + regulator_disable(data->reg); + regulator_put(data->reg); + goto err_free_data; + } } -/* Try requesting the GPIOs */ + + /* Try requesting the GPIOs */ ret = gpio_request(data->pdata->gpio_sck, "SHT15 sck"); if (ret) { - dev_err(&pdev->dev, "gpio request failed"); - goto err_free_data; + dev_err(&pdev->dev, "gpio request failed\n"); + goto err_release_reg; } gpio_direction_output(data->pdata->gpio_sck, 0); + ret = gpio_request(data->pdata->gpio_data, "SHT15 data"); if (ret) { - dev_err(&pdev->dev, "gpio request failed"); + dev_err(&pdev->dev, "gpio request failed\n"); goto err_release_gpio_sck; } - ret = sysfs_create_group(&pdev->dev.kobj, &sht15_attr_group); - if (ret) { - dev_err(&pdev->dev, "sysfs create failed"); - goto err_release_gpio_data; - } ret = request_irq(gpio_to_irq(data->pdata->gpio_data), sht15_interrupt_fired, @@ -578,30 +961,53 @@ static int __devinit sht15_probe(struct platform_device *pdev) "sht15 data", data); if (ret) { - dev_err(&pdev->dev, "failed to get irq for data line"); + dev_err(&pdev->dev, "failed to get irq for data line\n"); goto err_release_gpio_data; } disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data)); sht15_connection_reset(data); - sht15_send_cmd(data, 0x1E); + ret = sht15_soft_reset(data); + if (ret) + goto err_release_irq; + + /* write status with platform data options */ + if (status) { + ret = sht15_send_status(data, status); + if (ret) + goto err_release_irq; + } + + ret = sysfs_create_group(&pdev->dev.kobj, &sht15_attr_group); + if (ret) { + dev_err(&pdev->dev, "sysfs create failed\n"); + goto err_release_irq; + } data->hwmon_dev = hwmon_device_register(data->dev); if (IS_ERR(data->hwmon_dev)) { ret = PTR_ERR(data->hwmon_dev); - goto err_release_irq; + goto err_release_sysfs_group; } + return 0; +err_release_sysfs_group: + sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group); err_release_irq: free_irq(gpio_to_irq(data->pdata->gpio_data), data); err_release_gpio_data: gpio_free(data->pdata->gpio_data); err_release_gpio_sck: gpio_free(data->pdata->gpio_sck); +err_release_reg: + if (!IS_ERR(data->reg)) { + regulator_unregister_notifier(data->reg, &data->nb); + regulator_disable(data->reg); + regulator_put(data->reg); + } err_free_data: kfree(data); error_ret: - return ret; } @@ -609,9 +1015,15 @@ static int __devexit sht15_remove(struct platform_device *pdev) { struct sht15_data *data = platform_get_drvdata(pdev); - /* Make sure any reads from the device are done and - * prevent new ones from beginning */ + /* + * Make sure any reads from the device are done and + * prevent new ones beginning + */ mutex_lock(&data->read_lock); + if (sht15_soft_reset(data)) { + mutex_unlock(&data->read_lock); + return -EFAULT; + } hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group); if (!IS_ERR(data->reg)) { @@ -625,10 +1037,10 @@ static int __devexit sht15_remove(struct platform_device *pdev) gpio_free(data->pdata->gpio_sck); mutex_unlock(&data->read_lock); kfree(data); + return 0; } - /* * sht_drivers simultaneously refers to __devinit and __devexit function * which causes spurious section mismatch warning. So use __refdata to @@ -673,7 +1085,6 @@ static struct platform_driver __refdata sht_drivers[] = { }, }; - static int __init sht15_init(void) { int ret; |