1074 lines
27 KiB
C
1074 lines
27 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* sht15.c - support for the SHT15 Temperature and Humidity Sensor
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*
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* Portions Copyright (c) 2010-2012 Savoir-faire Linux Inc.
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* Jerome Oufella <jerome.oufella@savoirfairelinux.com>
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* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
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*
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* Copyright (c) 2009 Jonathan Cameron
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*
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* Copyright (c) 2007 Wouter Horre
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*
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* For further information, see the Documentation/hwmon/sht15 file.
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*/
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/mutex.h>
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#include <linux/platform_device.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/jiffies.h>
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#include <linux/err.h>
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#include <linux/regulator/consumer.h>
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#include <linux/slab.h>
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#include <linux/atomic.h>
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#include <linux/bitrev.h>
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#include <linux/gpio/consumer.h>
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#include <linux/of.h>
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/* Commands */
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#define SHT15_MEASURE_TEMP 0x03
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#define SHT15_MEASURE_RH 0x05
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#define SHT15_WRITE_STATUS 0x06
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#define SHT15_READ_STATUS 0x07
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#define SHT15_SOFT_RESET 0x1E
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/* Min timings */
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#define SHT15_TSCKL 100 /* (nsecs) clock low */
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#define SHT15_TSCKH 100 /* (nsecs) clock high */
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#define SHT15_TSU 150 /* (nsecs) data setup time */
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#define SHT15_TSRST 11 /* (msecs) soft reset time */
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/* Status Register Bits */
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#define SHT15_STATUS_LOW_RESOLUTION 0x01
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#define SHT15_STATUS_NO_OTP_RELOAD 0x02
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#define SHT15_STATUS_HEATER 0x04
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#define SHT15_STATUS_LOW_BATTERY 0x40
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/* List of supported chips */
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enum sht15_chips { sht10, sht11, sht15, sht71, sht75 };
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/* Actions the driver may be doing */
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enum sht15_state {
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SHT15_READING_NOTHING,
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SHT15_READING_TEMP,
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SHT15_READING_HUMID
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};
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/**
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* struct sht15_temppair - elements of voltage dependent temp calc
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* @vdd: supply voltage in microvolts
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* @d1: see data sheet
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*/
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struct sht15_temppair {
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int vdd; /* microvolts */
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int d1;
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};
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/* Table 9 from datasheet - relates temperature calculation to supply voltage */
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static const struct sht15_temppair temppoints[] = {
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{ 2500000, -39400 },
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{ 3000000, -39600 },
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{ 3500000, -39700 },
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{ 4000000, -39800 },
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{ 5000000, -40100 },
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};
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/* Table from CRC datasheet, section 2.4 */
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static const u8 sht15_crc8_table[] = {
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0, 49, 98, 83, 196, 245, 166, 151,
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185, 136, 219, 234, 125, 76, 31, 46,
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67, 114, 33, 16, 135, 182, 229, 212,
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250, 203, 152, 169, 62, 15, 92, 109,
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134, 183, 228, 213, 66, 115, 32, 17,
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63, 14, 93, 108, 251, 202, 153, 168,
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197, 244, 167, 150, 1, 48, 99, 82,
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124, 77, 30, 47, 184, 137, 218, 235,
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61, 12, 95, 110, 249, 200, 155, 170,
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132, 181, 230, 215, 64, 113, 34, 19,
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126, 79, 28, 45, 186, 139, 216, 233,
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199, 246, 165, 148, 3, 50, 97, 80,
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187, 138, 217, 232, 127, 78, 29, 44,
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2, 51, 96, 81, 198, 247, 164, 149,
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248, 201, 154, 171, 60, 13, 94, 111,
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65, 112, 35, 18, 133, 180, 231, 214,
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122, 75, 24, 41, 190, 143, 220, 237,
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195, 242, 161, 144, 7, 54, 101, 84,
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57, 8, 91, 106, 253, 204, 159, 174,
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128, 177, 226, 211, 68, 117, 38, 23,
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252, 205, 158, 175, 56, 9, 90, 107,
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69, 116, 39, 22, 129, 176, 227, 210,
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191, 142, 221, 236, 123, 74, 25, 40,
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6, 55, 100, 85, 194, 243, 160, 145,
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71, 118, 37, 20, 131, 178, 225, 208,
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254, 207, 156, 173, 58, 11, 88, 105,
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4, 53, 102, 87, 192, 241, 162, 147,
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189, 140, 223, 238, 121, 72, 27, 42,
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193, 240, 163, 146, 5, 52, 103, 86,
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120, 73, 26, 43, 188, 141, 222, 239,
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130, 179, 224, 209, 70, 119, 36, 21,
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59, 10, 89, 104, 255, 206, 157, 172
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};
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/**
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* struct sht15_data - device instance specific data
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* @sck: clock GPIO line
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* @data: data GPIO line
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* @read_work: bh of interrupt handler.
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* @wait_queue: wait queue for getting values from device.
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* @val_temp: last temperature value read from device.
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* @val_humid: last humidity value read from device.
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* @val_status: last status register value read from device.
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* @checksum_ok: last value read from the device passed CRC validation.
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* @checksumming: flag used to enable the data validation with CRC.
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* @state: state identifying the action the driver is doing.
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* @measurements_valid: are the current stored measures valid (start condition).
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* @status_valid: is the current stored status valid (start condition).
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* @last_measurement: time of last measure.
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* @last_status: time of last status reading.
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* @read_lock: mutex to ensure only one read in progress at a time.
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* @dev: associate device structure.
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* @hwmon_dev: device associated with hwmon subsystem.
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* @reg: associated regulator (if specified).
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* @nb: notifier block to handle notifications of voltage
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* changes.
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* @supply_uv: local copy of supply voltage used to allow use of
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* regulator consumer if available.
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* @supply_uv_valid: indicates that an updated value has not yet been
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* obtained from the regulator and so any calculations
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* based upon it will be invalid.
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* @update_supply_work: work struct that is used to update the supply_uv.
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* @interrupt_handled: flag used to indicate a handler has been scheduled.
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*/
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struct sht15_data {
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struct gpio_desc *sck;
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struct gpio_desc *data;
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struct work_struct read_work;
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wait_queue_head_t wait_queue;
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uint16_t val_temp;
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uint16_t val_humid;
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u8 val_status;
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bool checksum_ok;
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bool checksumming;
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enum sht15_state state;
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bool measurements_valid;
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bool status_valid;
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unsigned long last_measurement;
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unsigned long last_status;
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struct mutex read_lock;
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struct device *dev;
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struct device *hwmon_dev;
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struct regulator *reg;
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struct notifier_block nb;
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int supply_uv;
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bool supply_uv_valid;
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struct work_struct update_supply_work;
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atomic_t interrupt_handled;
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};
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/**
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* sht15_crc8() - compute crc8
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* @data: sht15 specific data.
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* @value: sht15 retrieved data.
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* @len: Length of retrieved data
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*
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* This implements section 2 of the CRC datasheet.
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*/
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static u8 sht15_crc8(struct sht15_data *data,
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const u8 *value,
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int len)
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{
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u8 crc = bitrev8(data->val_status & 0x0F);
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while (len--) {
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crc = sht15_crc8_table[*value ^ crc];
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value++;
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}
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return crc;
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}
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/**
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* sht15_connection_reset() - reset the comms interface
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* @data: sht15 specific data
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*
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* This implements section 3.4 of the data sheet
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*/
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static int sht15_connection_reset(struct sht15_data *data)
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{
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int i, err;
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err = gpiod_direction_output(data->data, 1);
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if (err)
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return err;
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ndelay(SHT15_TSCKL);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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for (i = 0; i < 9; ++i) {
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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}
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return 0;
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}
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/**
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* sht15_send_bit() - send an individual bit to the device
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* @data: device state data
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* @val: value of bit to be sent
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*/
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static inline void sht15_send_bit(struct sht15_data *data, int val)
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{
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gpiod_set_value(data->data, val);
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL); /* clock low time */
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}
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/**
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* sht15_transmission_start() - specific sequence for new transmission
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* @data: device state data
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*
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* Timings for this are not documented on the data sheet, so very
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* conservative ones used in implementation. This implements
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* figure 12 on the data sheet.
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*/
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static int sht15_transmission_start(struct sht15_data *data)
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{
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int err;
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/* ensure data is high and output */
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err = gpiod_direction_output(data->data, 1);
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if (err)
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return err;
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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gpiod_set_value(data->data, 0);
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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gpiod_set_value(data->data, 1);
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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return 0;
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}
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/**
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* sht15_send_byte() - send a single byte to the device
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* @data: device state
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* @byte: value to be sent
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*/
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static void sht15_send_byte(struct sht15_data *data, u8 byte)
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{
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int i;
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for (i = 0; i < 8; i++) {
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sht15_send_bit(data, !!(byte & 0x80));
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byte <<= 1;
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}
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}
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/**
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* sht15_wait_for_response() - checks for ack from device
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* @data: device state
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*/
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static int sht15_wait_for_response(struct sht15_data *data)
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{
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int err;
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err = gpiod_direction_input(data->data);
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if (err)
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return err;
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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if (gpiod_get_value(data->data)) {
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gpiod_set_value(data->sck, 0);
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dev_err(data->dev, "Command not acknowledged\n");
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err = sht15_connection_reset(data);
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if (err)
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return err;
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return -EIO;
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}
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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return 0;
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}
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/**
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* sht15_send_cmd() - Sends a command to the device.
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* @data: device state
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* @cmd: command byte to be sent
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*
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* On entry, sck is output low, data is output pull high
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* and the interrupt disabled.
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*/
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static int sht15_send_cmd(struct sht15_data *data, u8 cmd)
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{
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int err;
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err = sht15_transmission_start(data);
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if (err)
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return err;
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sht15_send_byte(data, cmd);
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return sht15_wait_for_response(data);
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}
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/**
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* sht15_soft_reset() - send a soft reset command
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* @data: sht15 specific data.
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*
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* As described in section 3.2 of the datasheet.
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*/
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static int sht15_soft_reset(struct sht15_data *data)
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{
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int ret;
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ret = sht15_send_cmd(data, SHT15_SOFT_RESET);
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if (ret)
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return ret;
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msleep(SHT15_TSRST);
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/* device resets default hardware status register value */
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data->val_status = 0;
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return ret;
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}
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/**
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* sht15_ack() - send a ack
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* @data: sht15 specific data.
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*
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* Each byte of data is acknowledged by pulling the data line
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* low for one clock pulse.
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*/
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static int sht15_ack(struct sht15_data *data)
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{
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int err;
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err = gpiod_direction_output(data->data, 0);
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if (err)
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return err;
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSU);
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gpiod_set_value(data->data, 1);
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return gpiod_direction_input(data->data);
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}
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/**
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* sht15_end_transmission() - notify device of end of transmission
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* @data: device state.
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*
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* This is basically a NAK (single clock pulse, data high).
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*/
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static int sht15_end_transmission(struct sht15_data *data)
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{
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int err;
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err = gpiod_direction_output(data->data, 1);
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if (err)
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return err;
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ndelay(SHT15_TSU);
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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return 0;
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}
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/**
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* sht15_read_byte() - Read a byte back from the device
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* @data: device state.
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*/
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static u8 sht15_read_byte(struct sht15_data *data)
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{
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int i;
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u8 byte = 0;
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for (i = 0; i < 8; ++i) {
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byte <<= 1;
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gpiod_set_value(data->sck, 1);
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ndelay(SHT15_TSCKH);
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byte |= !!gpiod_get_value(data->data);
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gpiod_set_value(data->sck, 0);
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ndelay(SHT15_TSCKL);
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}
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return byte;
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}
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/**
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* sht15_send_status() - write the status register byte
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* @data: sht15 specific data.
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* @status: the byte to set the status register with.
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*
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* As described in figure 14 and table 5 of the datasheet.
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*/
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static int sht15_send_status(struct sht15_data *data, u8 status)
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{
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int err;
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err = sht15_send_cmd(data, SHT15_WRITE_STATUS);
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if (err)
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return err;
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err = gpiod_direction_output(data->data, 1);
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if (err)
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return err;
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ndelay(SHT15_TSU);
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sht15_send_byte(data, status);
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err = sht15_wait_for_response(data);
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if (err)
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return err;
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data->val_status = status;
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return 0;
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}
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/**
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* sht15_update_status() - get updated status register from device if too old
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* @data: device instance specific data.
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*
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* As described in figure 15 and table 5 of the datasheet.
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*/
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static int sht15_update_status(struct sht15_data *data)
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{
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int ret = 0;
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u8 status;
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u8 previous_config;
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u8 dev_checksum = 0;
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u8 checksum_vals[2];
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int timeout = HZ;
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mutex_lock(&data->read_lock);
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if (time_after(jiffies, data->last_status + timeout)
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|| !data->status_valid) {
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ret = sht15_send_cmd(data, SHT15_READ_STATUS);
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if (ret)
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goto unlock;
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status = sht15_read_byte(data);
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if (data->checksumming) {
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sht15_ack(data);
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dev_checksum = bitrev8(sht15_read_byte(data));
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checksum_vals[0] = SHT15_READ_STATUS;
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checksum_vals[1] = status;
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data->checksum_ok = (sht15_crc8(data, checksum_vals, 2)
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== dev_checksum);
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}
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ret = sht15_end_transmission(data);
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if (ret)
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goto unlock;
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/*
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* Perform checksum validation on the received data.
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* Specification mentions that in case a checksum verification
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* fails, a soft reset command must be sent to the device.
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*/
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if (data->checksumming && !data->checksum_ok) {
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previous_config = data->val_status & 0x07;
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ret = sht15_soft_reset(data);
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if (ret)
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goto unlock;
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if (previous_config) {
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ret = sht15_send_status(data, previous_config);
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if (ret) {
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dev_err(data->dev,
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"CRC validation failed, unable "
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"to restore device settings\n");
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goto unlock;
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}
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}
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ret = -EAGAIN;
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|
goto unlock;
|
|
}
|
|
|
|
data->val_status = status;
|
|
data->status_valid = true;
|
|
data->last_status = jiffies;
|
|
}
|
|
|
|
unlock:
|
|
mutex_unlock(&data->read_lock);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* 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 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;
|
|
|
|
ret = gpiod_direction_input(data->data);
|
|
if (ret)
|
|
return ret;
|
|
atomic_set(&data->interrupt_handled, 0);
|
|
|
|
enable_irq(gpiod_to_irq(data->data));
|
|
if (gpiod_get_value(data->data) == 0) {
|
|
disable_irq_nosync(gpiod_to_irq(data->data));
|
|
/* Only relevant if the interrupt hasn't occurred. */
|
|
if (!atomic_read(&data->interrupt_handled))
|
|
schedule_work(&data->read_work);
|
|
}
|
|
ret = wait_event_timeout(data->wait_queue,
|
|
(data->state == SHT15_READING_NOTHING),
|
|
msecs_to_jiffies(timeout_msecs));
|
|
if (data->state != SHT15_READING_NOTHING) { /* I/O error occurred */
|
|
data->state = SHT15_READING_NOTHING;
|
|
return -EIO;
|
|
} else if (ret == 0) { /* timeout occurred */
|
|
disable_irq_nosync(gpiod_to_irq(data->data));
|
|
ret = sht15_connection_reset(data);
|
|
if (ret)
|
|
return ret;
|
|
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_measurements() - get updated measures from device if too old
|
|
* @data: device state
|
|
*/
|
|
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_measurement + timeout)
|
|
|| !data->measurements_valid) {
|
|
data->state = SHT15_READING_HUMID;
|
|
ret = sht15_measurement(data, SHT15_MEASURE_RH, 160);
|
|
if (ret)
|
|
goto unlock;
|
|
data->state = SHT15_READING_TEMP;
|
|
ret = sht15_measurement(data, SHT15_MEASURE_TEMP, 400);
|
|
if (ret)
|
|
goto unlock;
|
|
data->measurements_valid = true;
|
|
data->last_measurement = jiffies;
|
|
}
|
|
|
|
unlock:
|
|
mutex_unlock(&data->read_lock);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sht15_calc_temp() - convert the raw reading to a temperature
|
|
* @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--)
|
|
/* Find pointer to interpolate */
|
|
if (data->supply_uv > temppoints[i - 1].vdd) {
|
|
d1 = (data->supply_uv - temppoints[i - 1].vdd)
|
|
* (temppoints[i].d1 - temppoints[i - 1].d1)
|
|
/ (temppoints[i].vdd - temppoints[i - 1].vdd)
|
|
+ temppoints[i - 1].d1;
|
|
break;
|
|
}
|
|
|
|
return data->val_temp * d2 + d1;
|
|
}
|
|
|
|
/**
|
|
* sht15_calc_humid() - using last temperature convert raw to humid
|
|
* @data: device state
|
|
*
|
|
* 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 rh_linear; /* milli percent */
|
|
int temp = sht15_calc_temp(data);
|
|
int c2, c3;
|
|
int t2;
|
|
const int c1 = -4;
|
|
|
|
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 + 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 write 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 (kstrtol(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)
|
|
{
|
|
int ret;
|
|
struct sht15_data *data = dev_get_drvdata(dev);
|
|
|
|
/* Technically no need to read humidity as well */
|
|
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)
|
|
{
|
|
int ret;
|
|
struct sht15_data *data = dev_get_drvdata(dev);
|
|
|
|
ret = sht15_update_measurements(data);
|
|
|
|
return ret ? ret : sprintf(buf, "%d\n", sht15_calc_humid(data));
|
|
}
|
|
|
|
static ssize_t name_show(struct device *dev,
|
|
struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
struct platform_device *pdev = to_platform_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_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_RO(name);
|
|
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,
|
|
};
|
|
|
|
static const struct attribute_group sht15_attr_group = {
|
|
.attrs = sht15_attrs,
|
|
};
|
|
|
|
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->state != SHT15_READING_NOTHING)
|
|
schedule_work(&data->read_work);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static void sht15_bh_read_data(struct work_struct *work_s)
|
|
{
|
|
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 (gpiod_get_value(data->data)) {
|
|
/*
|
|
* 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(gpiod_to_irq(data->data));
|
|
/* If still not occurred or another handler was scheduled */
|
|
if (gpiod_get_value(data->data)
|
|
|| atomic_read(&data->interrupt_handled))
|
|
return;
|
|
}
|
|
|
|
/* Read the data back from the device */
|
|
val = sht15_read_byte(data);
|
|
val <<= 8;
|
|
if (sht15_ack(data))
|
|
goto wakeup;
|
|
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.
|
|
*/
|
|
if (sht15_ack(data))
|
|
goto wakeup;
|
|
dev_checksum = bitrev8(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 */
|
|
if (sht15_end_transmission(data))
|
|
goto wakeup;
|
|
|
|
switch (data->state) {
|
|
case SHT15_READING_TEMP:
|
|
data->val_temp = val;
|
|
break;
|
|
case SHT15_READING_HUMID:
|
|
data->val_humid = val;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
data->state = SHT15_READING_NOTHING;
|
|
wakeup:
|
|
wake_up(&data->wait_queue);
|
|
}
|
|
|
|
static void sht15_update_voltage(struct work_struct *work_s)
|
|
{
|
|
struct sht15_data *data
|
|
= container_of(work_s, struct sht15_data,
|
|
update_supply_work);
|
|
data->supply_uv = regulator_get_voltage(data->reg);
|
|
}
|
|
|
|
/**
|
|
* sht15_invalidate_voltage() - mark supply voltage invalid when notified by reg
|
|
* @nb: associated notification structure
|
|
* @event: voltage regulator state change event code
|
|
* @ignored: function parameter - ignored here
|
|
*
|
|
* 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)
|
|
{
|
|
struct sht15_data *data = container_of(nb, struct sht15_data, nb);
|
|
|
|
if (event == REGULATOR_EVENT_VOLTAGE_CHANGE)
|
|
data->supply_uv_valid = false;
|
|
schedule_work(&data->update_supply_work);
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id sht15_dt_match[] = {
|
|
{ .compatible = "sensirion,sht15" },
|
|
{ },
|
|
};
|
|
MODULE_DEVICE_TABLE(of, sht15_dt_match);
|
|
#endif
|
|
|
|
static int sht15_probe(struct platform_device *pdev)
|
|
{
|
|
int ret;
|
|
struct sht15_data *data;
|
|
|
|
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
|
|
if (!data)
|
|
return -ENOMEM;
|
|
|
|
INIT_WORK(&data->read_work, sht15_bh_read_data);
|
|
INIT_WORK(&data->update_supply_work, sht15_update_voltage);
|
|
platform_set_drvdata(pdev, data);
|
|
mutex_init(&data->read_lock);
|
|
data->dev = &pdev->dev;
|
|
init_waitqueue_head(&data->wait_queue);
|
|
|
|
/*
|
|
* If a regulator is available,
|
|
* query what the supply voltage actually is!
|
|
*/
|
|
data->reg = devm_regulator_get_optional(data->dev, "vcc");
|
|
if (!IS_ERR(data->reg)) {
|
|
int voltage;
|
|
|
|
voltage = regulator_get_voltage(data->reg);
|
|
if (voltage)
|
|
data->supply_uv = voltage;
|
|
|
|
ret = regulator_enable(data->reg);
|
|
if (ret != 0) {
|
|
dev_err(&pdev->dev,
|
|
"failed to enable regulator: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
/* Try requesting the GPIOs */
|
|
data->sck = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_LOW);
|
|
if (IS_ERR(data->sck)) {
|
|
ret = PTR_ERR(data->sck);
|
|
dev_err(&pdev->dev, "clock line GPIO request failed\n");
|
|
goto err_release_reg;
|
|
}
|
|
data->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN);
|
|
if (IS_ERR(data->data)) {
|
|
ret = PTR_ERR(data->data);
|
|
dev_err(&pdev->dev, "data line GPIO request failed\n");
|
|
goto err_release_reg;
|
|
}
|
|
|
|
ret = devm_request_irq(&pdev->dev, gpiod_to_irq(data->data),
|
|
sht15_interrupt_fired,
|
|
IRQF_TRIGGER_FALLING,
|
|
"sht15 data",
|
|
data);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "failed to get irq for data line\n");
|
|
goto err_release_reg;
|
|
}
|
|
disable_irq_nosync(gpiod_to_irq(data->data));
|
|
ret = sht15_connection_reset(data);
|
|
if (ret)
|
|
goto err_release_reg;
|
|
ret = sht15_soft_reset(data);
|
|
if (ret)
|
|
goto err_release_reg;
|
|
|
|
ret = sysfs_create_group(&pdev->dev.kobj, &sht15_attr_group);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "sysfs create failed\n");
|
|
goto err_release_reg;
|
|
}
|
|
|
|
data->hwmon_dev = hwmon_device_register(data->dev);
|
|
if (IS_ERR(data->hwmon_dev)) {
|
|
ret = PTR_ERR(data->hwmon_dev);
|
|
goto err_release_sysfs_group;
|
|
}
|
|
|
|
return 0;
|
|
|
|
err_release_sysfs_group:
|
|
sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group);
|
|
err_release_reg:
|
|
if (!IS_ERR(data->reg)) {
|
|
regulator_unregister_notifier(data->reg, &data->nb);
|
|
regulator_disable(data->reg);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int 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 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)) {
|
|
regulator_unregister_notifier(data->reg, &data->nb);
|
|
regulator_disable(data->reg);
|
|
}
|
|
|
|
mutex_unlock(&data->read_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct platform_device_id sht15_device_ids[] = {
|
|
{ "sht10", sht10 },
|
|
{ "sht11", sht11 },
|
|
{ "sht15", sht15 },
|
|
{ "sht71", sht71 },
|
|
{ "sht75", sht75 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(platform, sht15_device_ids);
|
|
|
|
static struct platform_driver sht15_driver = {
|
|
.driver = {
|
|
.name = "sht15",
|
|
.of_match_table = of_match_ptr(sht15_dt_match),
|
|
},
|
|
.probe = sht15_probe,
|
|
.remove = sht15_remove,
|
|
.id_table = sht15_device_ids,
|
|
};
|
|
module_platform_driver(sht15_driver);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Sensirion SHT15 temperature and humidity sensor driver");
|