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-rw-r--r--drivers/hwmon/sht15.c747
1 files changed, 579 insertions, 168 deletions
diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c
index f4e617adb220..cf4330b352ef 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;