2 * sht15.c - support for the SHT15 Temperature and Humidity Sensor
4 * Portions Copyright (c) 2010-2012 Savoir-faire Linux Inc.
5 * Jerome Oufella <jerome.oufella@savoirfairelinux.com>
6 * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
8 * Copyright (c) 2009 Jonathan Cameron
10 * Copyright (c) 2007 Wouter Horre
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
16 * For further information, see the Documentation/hwmon/sht15 file.
19 #include <linux/interrupt.h>
20 #include <linux/irq.h>
21 #include <linux/gpio.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/hwmon.h>
25 #include <linux/hwmon-sysfs.h>
26 #include <linux/mutex.h>
27 #include <linux/platform_data/sht15.h>
28 #include <linux/platform_device.h>
29 #include <linux/sched.h>
30 #include <linux/delay.h>
31 #include <linux/jiffies.h>
32 #include <linux/err.h>
33 #include <linux/regulator/consumer.h>
34 #include <linux/slab.h>
35 #include <linux/atomic.h>
36 #include <linux/bitrev.h>
37 #include <linux/of_gpio.h>
40 #define SHT15_MEASURE_TEMP 0x03
41 #define SHT15_MEASURE_RH 0x05
42 #define SHT15_WRITE_STATUS 0x06
43 #define SHT15_READ_STATUS 0x07
44 #define SHT15_SOFT_RESET 0x1E
47 #define SHT15_TSCKL 100 /* (nsecs) clock low */
48 #define SHT15_TSCKH 100 /* (nsecs) clock high */
49 #define SHT15_TSU 150 /* (nsecs) data setup time */
50 #define SHT15_TSRST 11 /* (msecs) soft reset time */
52 /* Status Register Bits */
53 #define SHT15_STATUS_LOW_RESOLUTION 0x01
54 #define SHT15_STATUS_NO_OTP_RELOAD 0x02
55 #define SHT15_STATUS_HEATER 0x04
56 #define SHT15_STATUS_LOW_BATTERY 0x40
58 /* List of supported chips */
59 enum sht15_chips { sht10, sht11, sht15, sht71, sht75 };
61 /* Actions the driver may be doing */
63 SHT15_READING_NOTHING,
69 * struct sht15_temppair - elements of voltage dependent temp calc
70 * @vdd: supply voltage in microvolts
73 struct sht15_temppair {
74 int vdd; /* microvolts */
78 /* Table 9 from datasheet - relates temperature calculation to supply voltage */
79 static const struct sht15_temppair temppoints[] = {
87 /* Table from CRC datasheet, section 2.4 */
88 static const u8 sht15_crc8_table[] = {
89 0, 49, 98, 83, 196, 245, 166, 151,
90 185, 136, 219, 234, 125, 76, 31, 46,
91 67, 114, 33, 16, 135, 182, 229, 212,
92 250, 203, 152, 169, 62, 15, 92, 109,
93 134, 183, 228, 213, 66, 115, 32, 17,
94 63, 14, 93, 108, 251, 202, 153, 168,
95 197, 244, 167, 150, 1, 48, 99, 82,
96 124, 77, 30, 47, 184, 137, 218, 235,
97 61, 12, 95, 110, 249, 200, 155, 170,
98 132, 181, 230, 215, 64, 113, 34, 19,
99 126, 79, 28, 45, 186, 139, 216, 233,
100 199, 246, 165, 148, 3, 50, 97, 80,
101 187, 138, 217, 232, 127, 78, 29, 44,
102 2, 51, 96, 81, 198, 247, 164, 149,
103 248, 201, 154, 171, 60, 13, 94, 111,
104 65, 112, 35, 18, 133, 180, 231, 214,
105 122, 75, 24, 41, 190, 143, 220, 237,
106 195, 242, 161, 144, 7, 54, 101, 84,
107 57, 8, 91, 106, 253, 204, 159, 174,
108 128, 177, 226, 211, 68, 117, 38, 23,
109 252, 205, 158, 175, 56, 9, 90, 107,
110 69, 116, 39, 22, 129, 176, 227, 210,
111 191, 142, 221, 236, 123, 74, 25, 40,
112 6, 55, 100, 85, 194, 243, 160, 145,
113 71, 118, 37, 20, 131, 178, 225, 208,
114 254, 207, 156, 173, 58, 11, 88, 105,
115 4, 53, 102, 87, 192, 241, 162, 147,
116 189, 140, 223, 238, 121, 72, 27, 42,
117 193, 240, 163, 146, 5, 52, 103, 86,
118 120, 73, 26, 43, 188, 141, 222, 239,
119 130, 179, 224, 209, 70, 119, 36, 21,
120 59, 10, 89, 104, 255, 206, 157, 172
124 * struct sht15_data - device instance specific data
125 * @pdata: platform data (gpio's etc).
126 * @read_work: bh of interrupt handler.
127 * @wait_queue: wait queue for getting values from device.
128 * @val_temp: last temperature value read from device.
129 * @val_humid: last humidity value read from device.
130 * @val_status: last status register value read from device.
131 * @checksum_ok: last value read from the device passed CRC validation.
132 * @checksumming: flag used to enable the data validation with CRC.
133 * @state: state identifying the action the driver is doing.
134 * @measurements_valid: are the current stored measures valid (start condition).
135 * @status_valid: is the current stored status valid (start condition).
136 * @last_measurement: time of last measure.
137 * @last_status: time of last status reading.
138 * @read_lock: mutex to ensure only one read in progress at a time.
139 * @dev: associate device structure.
140 * @hwmon_dev: device associated with hwmon subsystem.
141 * @reg: associated regulator (if specified).
142 * @nb: notifier block to handle notifications of voltage
144 * @supply_uv: local copy of supply voltage used to allow use of
145 * regulator consumer if available.
146 * @supply_uv_valid: indicates that an updated value has not yet been
147 * obtained from the regulator and so any calculations
148 * based upon it will be invalid.
149 * @update_supply_work: work struct that is used to update the supply_uv.
150 * @interrupt_handled: flag used to indicate a handler has been scheduled.
153 struct sht15_platform_data *pdata;
154 struct work_struct read_work;
155 wait_queue_head_t wait_queue;
161 enum sht15_state state;
162 bool measurements_valid;
164 unsigned long last_measurement;
165 unsigned long last_status;
166 struct mutex read_lock;
168 struct device *hwmon_dev;
169 struct regulator *reg;
170 struct notifier_block nb;
172 bool supply_uv_valid;
173 struct work_struct update_supply_work;
174 atomic_t interrupt_handled;
178 * sht15_crc8() - compute crc8
179 * @data: sht15 specific data.
180 * @value: sht15 retrieved data.
182 * This implements section 2 of the CRC datasheet.
184 static u8 sht15_crc8(struct sht15_data *data,
188 u8 crc = bitrev8(data->val_status & 0x0F);
191 crc = sht15_crc8_table[*value ^ crc];
199 * sht15_connection_reset() - reset the comms interface
200 * @data: sht15 specific data
202 * This implements section 3.4 of the data sheet
204 static int sht15_connection_reset(struct sht15_data *data)
208 err = gpio_direction_output(data->pdata->gpio_data, 1);
212 gpio_set_value(data->pdata->gpio_sck, 0);
214 for (i = 0; i < 9; ++i) {
215 gpio_set_value(data->pdata->gpio_sck, 1);
217 gpio_set_value(data->pdata->gpio_sck, 0);
224 * sht15_send_bit() - send an individual bit to the device
225 * @data: device state data
226 * @val: value of bit to be sent
228 static inline void sht15_send_bit(struct sht15_data *data, int val)
230 gpio_set_value(data->pdata->gpio_data, val);
232 gpio_set_value(data->pdata->gpio_sck, 1);
234 gpio_set_value(data->pdata->gpio_sck, 0);
235 ndelay(SHT15_TSCKL); /* clock low time */
239 * sht15_transmission_start() - specific sequence for new transmission
240 * @data: device state data
242 * Timings for this are not documented on the data sheet, so very
243 * conservative ones used in implementation. This implements
244 * figure 12 on the data sheet.
246 static int sht15_transmission_start(struct sht15_data *data)
250 /* ensure data is high and output */
251 err = gpio_direction_output(data->pdata->gpio_data, 1);
255 gpio_set_value(data->pdata->gpio_sck, 0);
257 gpio_set_value(data->pdata->gpio_sck, 1);
259 gpio_set_value(data->pdata->gpio_data, 0);
261 gpio_set_value(data->pdata->gpio_sck, 0);
263 gpio_set_value(data->pdata->gpio_sck, 1);
265 gpio_set_value(data->pdata->gpio_data, 1);
267 gpio_set_value(data->pdata->gpio_sck, 0);
273 * sht15_send_byte() - send a single byte to the device
274 * @data: device state
275 * @byte: value to be sent
277 static void sht15_send_byte(struct sht15_data *data, u8 byte)
281 for (i = 0; i < 8; i++) {
282 sht15_send_bit(data, !!(byte & 0x80));
288 * sht15_wait_for_response() - checks for ack from device
289 * @data: device state
291 static int sht15_wait_for_response(struct sht15_data *data)
295 err = gpio_direction_input(data->pdata->gpio_data);
298 gpio_set_value(data->pdata->gpio_sck, 1);
300 if (gpio_get_value(data->pdata->gpio_data)) {
301 gpio_set_value(data->pdata->gpio_sck, 0);
302 dev_err(data->dev, "Command not acknowledged\n");
303 err = sht15_connection_reset(data);
308 gpio_set_value(data->pdata->gpio_sck, 0);
314 * sht15_send_cmd() - Sends a command to the device.
315 * @data: device state
316 * @cmd: command byte to be sent
318 * On entry, sck is output low, data is output pull high
319 * and the interrupt disabled.
321 static int sht15_send_cmd(struct sht15_data *data, u8 cmd)
325 err = sht15_transmission_start(data);
328 sht15_send_byte(data, cmd);
329 return sht15_wait_for_response(data);
333 * sht15_soft_reset() - send a soft reset command
334 * @data: sht15 specific data.
336 * As described in section 3.2 of the datasheet.
338 static int sht15_soft_reset(struct sht15_data *data)
342 ret = sht15_send_cmd(data, SHT15_SOFT_RESET);
346 /* device resets default hardware status register value */
347 data->val_status = 0;
353 * sht15_ack() - send a ack
354 * @data: sht15 specific data.
356 * Each byte of data is acknowledged by pulling the data line
357 * low for one clock pulse.
359 static int sht15_ack(struct sht15_data *data)
363 err = gpio_direction_output(data->pdata->gpio_data, 0);
367 gpio_set_value(data->pdata->gpio_sck, 1);
369 gpio_set_value(data->pdata->gpio_sck, 0);
371 gpio_set_value(data->pdata->gpio_data, 1);
373 return gpio_direction_input(data->pdata->gpio_data);
377 * sht15_end_transmission() - notify device of end of transmission
378 * @data: device state.
380 * This is basically a NAK (single clock pulse, data high).
382 static int sht15_end_transmission(struct sht15_data *data)
386 err = gpio_direction_output(data->pdata->gpio_data, 1);
390 gpio_set_value(data->pdata->gpio_sck, 1);
392 gpio_set_value(data->pdata->gpio_sck, 0);
398 * sht15_read_byte() - Read a byte back from the device
399 * @data: device state.
401 static u8 sht15_read_byte(struct sht15_data *data)
406 for (i = 0; i < 8; ++i) {
408 gpio_set_value(data->pdata->gpio_sck, 1);
410 byte |= !!gpio_get_value(data->pdata->gpio_data);
411 gpio_set_value(data->pdata->gpio_sck, 0);
418 * sht15_send_status() - write the status register byte
419 * @data: sht15 specific data.
420 * @status: the byte to set the status register with.
422 * As described in figure 14 and table 5 of the datasheet.
424 static int sht15_send_status(struct sht15_data *data, u8 status)
428 err = sht15_send_cmd(data, SHT15_WRITE_STATUS);
431 err = gpio_direction_output(data->pdata->gpio_data, 1);
435 sht15_send_byte(data, status);
436 err = sht15_wait_for_response(data);
440 data->val_status = status;
445 * sht15_update_status() - get updated status register from device if too old
446 * @data: device instance specific data.
448 * As described in figure 15 and table 5 of the datasheet.
450 static int sht15_update_status(struct sht15_data *data)
459 mutex_lock(&data->read_lock);
460 if (time_after(jiffies, data->last_status + timeout)
461 || !data->status_valid) {
462 ret = sht15_send_cmd(data, SHT15_READ_STATUS);
465 status = sht15_read_byte(data);
467 if (data->checksumming) {
469 dev_checksum = bitrev8(sht15_read_byte(data));
470 checksum_vals[0] = SHT15_READ_STATUS;
471 checksum_vals[1] = status;
472 data->checksum_ok = (sht15_crc8(data, checksum_vals, 2)
476 ret = sht15_end_transmission(data);
481 * Perform checksum validation on the received data.
482 * Specification mentions that in case a checksum verification
483 * fails, a soft reset command must be sent to the device.
485 if (data->checksumming && !data->checksum_ok) {
486 previous_config = data->val_status & 0x07;
487 ret = sht15_soft_reset(data);
490 if (previous_config) {
491 ret = sht15_send_status(data, previous_config);
494 "CRC validation failed, unable "
495 "to restore device settings\n");
503 data->val_status = status;
504 data->status_valid = true;
505 data->last_status = jiffies;
509 mutex_unlock(&data->read_lock);
514 * sht15_measurement() - get a new value from device
515 * @data: device instance specific data
516 * @command: command sent to request value
517 * @timeout_msecs: timeout after which comms are assumed
518 * to have failed are reset.
520 static int sht15_measurement(struct sht15_data *data,
527 ret = sht15_send_cmd(data, command);
531 ret = gpio_direction_input(data->pdata->gpio_data);
534 atomic_set(&data->interrupt_handled, 0);
536 enable_irq(gpio_to_irq(data->pdata->gpio_data));
537 if (gpio_get_value(data->pdata->gpio_data) == 0) {
538 disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data));
539 /* Only relevant if the interrupt hasn't occurred. */
540 if (!atomic_read(&data->interrupt_handled))
541 schedule_work(&data->read_work);
543 ret = wait_event_timeout(data->wait_queue,
544 (data->state == SHT15_READING_NOTHING),
545 msecs_to_jiffies(timeout_msecs));
546 if (data->state != SHT15_READING_NOTHING) { /* I/O error occurred */
547 data->state = SHT15_READING_NOTHING;
549 } else if (ret == 0) { /* timeout occurred */
550 disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data));
551 ret = sht15_connection_reset(data);
558 * Perform checksum validation on the received data.
559 * Specification mentions that in case a checksum verification fails,
560 * a soft reset command must be sent to the device.
562 if (data->checksumming && !data->checksum_ok) {
563 previous_config = data->val_status & 0x07;
564 ret = sht15_soft_reset(data);
567 if (previous_config) {
568 ret = sht15_send_status(data, previous_config);
571 "CRC validation failed, unable "
572 "to restore device settings\n");
583 * sht15_update_measurements() - get updated measures from device if too old
584 * @data: device state
586 static int sht15_update_measurements(struct sht15_data *data)
591 mutex_lock(&data->read_lock);
592 if (time_after(jiffies, data->last_measurement + timeout)
593 || !data->measurements_valid) {
594 data->state = SHT15_READING_HUMID;
595 ret = sht15_measurement(data, SHT15_MEASURE_RH, 160);
598 data->state = SHT15_READING_TEMP;
599 ret = sht15_measurement(data, SHT15_MEASURE_TEMP, 400);
602 data->measurements_valid = true;
603 data->last_measurement = jiffies;
607 mutex_unlock(&data->read_lock);
612 * sht15_calc_temp() - convert the raw reading to a temperature
613 * @data: device state
615 * As per section 4.3 of the data sheet.
617 static inline int sht15_calc_temp(struct sht15_data *data)
619 int d1 = temppoints[0].d1;
620 int d2 = (data->val_status & SHT15_STATUS_LOW_RESOLUTION) ? 40 : 10;
623 for (i = ARRAY_SIZE(temppoints) - 1; i > 0; i--)
624 /* Find pointer to interpolate */
625 if (data->supply_uv > temppoints[i - 1].vdd) {
626 d1 = (data->supply_uv - temppoints[i - 1].vdd)
627 * (temppoints[i].d1 - temppoints[i - 1].d1)
628 / (temppoints[i].vdd - temppoints[i - 1].vdd)
629 + temppoints[i - 1].d1;
633 return data->val_temp * d2 + d1;
637 * sht15_calc_humid() - using last temperature convert raw to humid
638 * @data: device state
640 * This is the temperature compensated version as per section 4.2 of
643 * The sensor is assumed to be V3, which is compatible with V4.
644 * Humidity conversion coefficients are shown in table 7 of the datasheet.
646 static inline int sht15_calc_humid(struct sht15_data *data)
648 int rh_linear; /* milli percent */
649 int temp = sht15_calc_temp(data);
654 if (data->val_status & SHT15_STATUS_LOW_RESOLUTION) {
655 c2 = 648000; /* x 10 ^ -6 */
656 c3 = -7200; /* x 10 ^ -7 */
659 c2 = 40500; /* x 10 ^ -6 */
660 c3 = -28; /* x 10 ^ -7 */
664 rh_linear = c1 * 1000
665 + c2 * data->val_humid / 1000
666 + (data->val_humid * data->val_humid * c3) / 10000;
667 return (temp - 25000) * (10000 + t2 * data->val_humid)
668 / 1000000 + rh_linear;
672 * sht15_show_status() - show status information in sysfs
674 * @attr: device attribute.
675 * @buf: sysfs buffer where information is written to.
677 * Will be called on read access to temp1_fault, humidity1_fault
678 * and heater_enable sysfs attributes.
679 * Returns number of bytes written into buffer, negative errno on error.
681 static ssize_t sht15_show_status(struct device *dev,
682 struct device_attribute *attr,
686 struct sht15_data *data = dev_get_drvdata(dev);
687 u8 bit = to_sensor_dev_attr(attr)->index;
689 ret = sht15_update_status(data);
691 return ret ? ret : sprintf(buf, "%d\n", !!(data->val_status & bit));
695 * sht15_store_heater() - change heater state via sysfs
697 * @attr: device attribute.
698 * @buf: sysfs buffer to read the new heater state from.
699 * @count: length of the data.
701 * Will be called on write access to heater_enable sysfs attribute.
702 * Returns number of bytes actually decoded, negative errno on error.
704 static ssize_t sht15_store_heater(struct device *dev,
705 struct device_attribute *attr,
706 const char *buf, size_t count)
709 struct sht15_data *data = dev_get_drvdata(dev);
713 if (kstrtol(buf, 10, &value))
716 mutex_lock(&data->read_lock);
717 status = data->val_status & 0x07;
719 status |= SHT15_STATUS_HEATER;
721 status &= ~SHT15_STATUS_HEATER;
723 ret = sht15_send_status(data, status);
724 mutex_unlock(&data->read_lock);
726 return ret ? ret : count;
730 * sht15_show_temp() - show temperature measurement value in sysfs
732 * @attr: device attribute.
733 * @buf: sysfs buffer where measurement values are written to.
735 * Will be called on read access to temp1_input sysfs attribute.
736 * Returns number of bytes written into buffer, negative errno on error.
738 static ssize_t sht15_show_temp(struct device *dev,
739 struct device_attribute *attr,
743 struct sht15_data *data = dev_get_drvdata(dev);
745 /* Technically no need to read humidity as well */
746 ret = sht15_update_measurements(data);
748 return ret ? ret : sprintf(buf, "%d\n",
749 sht15_calc_temp(data));
753 * sht15_show_humidity() - show humidity measurement value in sysfs
755 * @attr: device attribute.
756 * @buf: sysfs buffer where measurement values are written to.
758 * Will be called on read access to humidity1_input sysfs attribute.
759 * Returns number of bytes written into buffer, negative errno on error.
761 static ssize_t sht15_show_humidity(struct device *dev,
762 struct device_attribute *attr,
766 struct sht15_data *data = dev_get_drvdata(dev);
768 ret = sht15_update_measurements(data);
770 return ret ? ret : sprintf(buf, "%d\n", sht15_calc_humid(data));
773 static ssize_t name_show(struct device *dev,
774 struct device_attribute *attr,
777 struct platform_device *pdev = to_platform_device(dev);
778 return sprintf(buf, "%s\n", pdev->name);
781 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
782 sht15_show_temp, NULL, 0);
783 static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO,
784 sht15_show_humidity, NULL, 0);
785 static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, sht15_show_status, NULL,
786 SHT15_STATUS_LOW_BATTERY);
787 static SENSOR_DEVICE_ATTR(humidity1_fault, S_IRUGO, sht15_show_status, NULL,
788 SHT15_STATUS_LOW_BATTERY);
789 static SENSOR_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR, sht15_show_status,
790 sht15_store_heater, SHT15_STATUS_HEATER);
791 static DEVICE_ATTR_RO(name);
792 static struct attribute *sht15_attrs[] = {
793 &sensor_dev_attr_temp1_input.dev_attr.attr,
794 &sensor_dev_attr_humidity1_input.dev_attr.attr,
795 &sensor_dev_attr_temp1_fault.dev_attr.attr,
796 &sensor_dev_attr_humidity1_fault.dev_attr.attr,
797 &sensor_dev_attr_heater_enable.dev_attr.attr,
802 static const struct attribute_group sht15_attr_group = {
803 .attrs = sht15_attrs,
806 static irqreturn_t sht15_interrupt_fired(int irq, void *d)
808 struct sht15_data *data = d;
810 /* First disable the interrupt */
811 disable_irq_nosync(irq);
812 atomic_inc(&data->interrupt_handled);
813 /* Then schedule a reading work struct */
814 if (data->state != SHT15_READING_NOTHING)
815 schedule_work(&data->read_work);
819 static void sht15_bh_read_data(struct work_struct *work_s)
824 struct sht15_data *data
825 = container_of(work_s, struct sht15_data,
828 /* Firstly, verify the line is low */
829 if (gpio_get_value(data->pdata->gpio_data)) {
831 * If not, then start the interrupt again - care here as could
832 * have gone low in meantime so verify it hasn't!
834 atomic_set(&data->interrupt_handled, 0);
835 enable_irq(gpio_to_irq(data->pdata->gpio_data));
836 /* If still not occurred or another handler was scheduled */
837 if (gpio_get_value(data->pdata->gpio_data)
838 || atomic_read(&data->interrupt_handled))
842 /* Read the data back from the device */
843 val = sht15_read_byte(data);
847 val |= sht15_read_byte(data);
849 if (data->checksumming) {
851 * Ask the device for a checksum and read it back.
852 * Note: the device sends the checksum byte reversed.
856 dev_checksum = bitrev8(sht15_read_byte(data));
857 checksum_vals[0] = (data->state == SHT15_READING_TEMP) ?
858 SHT15_MEASURE_TEMP : SHT15_MEASURE_RH;
859 checksum_vals[1] = (u8) (val >> 8);
860 checksum_vals[2] = (u8) val;
862 = (sht15_crc8(data, checksum_vals, 3) == dev_checksum);
865 /* Tell the device we are done */
866 if (sht15_end_transmission(data))
869 switch (data->state) {
870 case SHT15_READING_TEMP:
871 data->val_temp = val;
873 case SHT15_READING_HUMID:
874 data->val_humid = val;
880 data->state = SHT15_READING_NOTHING;
882 wake_up(&data->wait_queue);
885 static void sht15_update_voltage(struct work_struct *work_s)
887 struct sht15_data *data
888 = container_of(work_s, struct sht15_data,
890 data->supply_uv = regulator_get_voltage(data->reg);
894 * sht15_invalidate_voltage() - mark supply voltage invalid when notified by reg
895 * @nb: associated notification structure
896 * @event: voltage regulator state change event code
897 * @ignored: function parameter - ignored here
899 * Note that as the notification code holds the regulator lock, we have
900 * to schedule an update of the supply voltage rather than getting it directly.
902 static int sht15_invalidate_voltage(struct notifier_block *nb,
906 struct sht15_data *data = container_of(nb, struct sht15_data, nb);
908 if (event == REGULATOR_EVENT_VOLTAGE_CHANGE)
909 data->supply_uv_valid = false;
910 schedule_work(&data->update_supply_work);
916 static const struct of_device_id sht15_dt_match[] = {
917 { .compatible = "sensirion,sht15" },
920 MODULE_DEVICE_TABLE(of, sht15_dt_match);
923 * This function returns NULL if pdev isn't a device instatiated by dt,
924 * a pointer to pdata if it could successfully get all information
925 * from dt or a negative ERR_PTR() on error.
927 static struct sht15_platform_data *sht15_probe_dt(struct device *dev)
929 struct device_node *np = dev->of_node;
930 struct sht15_platform_data *pdata;
932 /* no device tree device */
936 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
938 return ERR_PTR(-ENOMEM);
940 pdata->gpio_data = of_get_named_gpio(np, "data-gpios", 0);
941 if (pdata->gpio_data < 0) {
942 if (pdata->gpio_data != -EPROBE_DEFER)
943 dev_err(dev, "data-gpios not found\n");
944 return ERR_PTR(pdata->gpio_data);
947 pdata->gpio_sck = of_get_named_gpio(np, "clk-gpios", 0);
948 if (pdata->gpio_sck < 0) {
949 if (pdata->gpio_sck != -EPROBE_DEFER)
950 dev_err(dev, "clk-gpios not found\n");
951 return ERR_PTR(pdata->gpio_sck);
957 static inline struct sht15_platform_data *sht15_probe_dt(struct device *dev)
963 static int sht15_probe(struct platform_device *pdev)
966 struct sht15_data *data;
969 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
973 INIT_WORK(&data->read_work, sht15_bh_read_data);
974 INIT_WORK(&data->update_supply_work, sht15_update_voltage);
975 platform_set_drvdata(pdev, data);
976 mutex_init(&data->read_lock);
977 data->dev = &pdev->dev;
978 init_waitqueue_head(&data->wait_queue);
980 data->pdata = sht15_probe_dt(&pdev->dev);
981 if (IS_ERR(data->pdata))
982 return PTR_ERR(data->pdata);
983 if (data->pdata == NULL) {
984 data->pdata = dev_get_platdata(&pdev->dev);
985 if (data->pdata == NULL) {
986 dev_err(&pdev->dev, "no platform data supplied\n");
991 data->supply_uv = data->pdata->supply_mv * 1000;
992 if (data->pdata->checksum)
993 data->checksumming = true;
994 if (data->pdata->no_otp_reload)
995 status |= SHT15_STATUS_NO_OTP_RELOAD;
996 if (data->pdata->low_resolution)
997 status |= SHT15_STATUS_LOW_RESOLUTION;
1000 * If a regulator is available,
1001 * query what the supply voltage actually is!
1003 data->reg = devm_regulator_get_optional(data->dev, "vcc");
1004 if (!IS_ERR(data->reg)) {
1007 voltage = regulator_get_voltage(data->reg);
1009 data->supply_uv = voltage;
1011 ret = regulator_enable(data->reg);
1014 "failed to enable regulator: %d\n", ret);
1019 * Setup a notifier block to update this if another device
1020 * causes the voltage to change
1022 data->nb.notifier_call = &sht15_invalidate_voltage;
1023 ret = regulator_register_notifier(data->reg, &data->nb);
1026 "regulator notifier request failed\n");
1027 regulator_disable(data->reg);
1032 /* Try requesting the GPIOs */
1033 ret = devm_gpio_request_one(&pdev->dev, data->pdata->gpio_sck,
1034 GPIOF_OUT_INIT_LOW, "SHT15 sck");
1036 dev_err(&pdev->dev, "clock line GPIO request failed\n");
1037 goto err_release_reg;
1040 ret = devm_gpio_request(&pdev->dev, data->pdata->gpio_data,
1043 dev_err(&pdev->dev, "data line GPIO request failed\n");
1044 goto err_release_reg;
1047 ret = devm_request_irq(&pdev->dev, gpio_to_irq(data->pdata->gpio_data),
1048 sht15_interrupt_fired,
1049 IRQF_TRIGGER_FALLING,
1053 dev_err(&pdev->dev, "failed to get irq for data line\n");
1054 goto err_release_reg;
1056 disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data));
1057 ret = sht15_connection_reset(data);
1059 goto err_release_reg;
1060 ret = sht15_soft_reset(data);
1062 goto err_release_reg;
1064 /* write status with platform data options */
1066 ret = sht15_send_status(data, status);
1068 goto err_release_reg;
1071 ret = sysfs_create_group(&pdev->dev.kobj, &sht15_attr_group);
1073 dev_err(&pdev->dev, "sysfs create failed\n");
1074 goto err_release_reg;
1077 data->hwmon_dev = hwmon_device_register(data->dev);
1078 if (IS_ERR(data->hwmon_dev)) {
1079 ret = PTR_ERR(data->hwmon_dev);
1080 goto err_release_sysfs_group;
1085 err_release_sysfs_group:
1086 sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group);
1088 if (!IS_ERR(data->reg)) {
1089 regulator_unregister_notifier(data->reg, &data->nb);
1090 regulator_disable(data->reg);
1095 static int sht15_remove(struct platform_device *pdev)
1097 struct sht15_data *data = platform_get_drvdata(pdev);
1100 * Make sure any reads from the device are done and
1101 * prevent new ones beginning
1103 mutex_lock(&data->read_lock);
1104 if (sht15_soft_reset(data)) {
1105 mutex_unlock(&data->read_lock);
1108 hwmon_device_unregister(data->hwmon_dev);
1109 sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group);
1110 if (!IS_ERR(data->reg)) {
1111 regulator_unregister_notifier(data->reg, &data->nb);
1112 regulator_disable(data->reg);
1115 mutex_unlock(&data->read_lock);
1120 static const struct platform_device_id sht15_device_ids[] = {
1128 MODULE_DEVICE_TABLE(platform, sht15_device_ids);
1130 static struct platform_driver sht15_driver = {
1133 .of_match_table = of_match_ptr(sht15_dt_match),
1135 .probe = sht15_probe,
1136 .remove = sht15_remove,
1137 .id_table = sht15_device_ids,
1139 module_platform_driver(sht15_driver);
1141 MODULE_LICENSE("GPL");
1142 MODULE_DESCRIPTION("Sensirion SHT15 temperature and humidity sensor driver");