Added interrupt support for high/low temperature threshold
events to the max31722 driver.
Signed-off-by: Tiberiu Breana <tiberiu.a.breana@xxxxxxxxx>
---
drivers/iio/temperature/max31722.c | 303 ++++++++++++++++++++++++++++++++++++-
1 file changed, 301 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/temperature/max31722.c b/drivers/iio/temperature/max31722.c
index fa833b6..a8bfe35 100644
--- a/drivers/iio/temperature/max31722.c
+++ b/drivers/iio/temperature/max31722.c
@@ -10,21 +10,32 @@
#include <linux/kernel.h>
#include <linux/acpi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
+#include <linux/iio/events.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define MAX31722_REG_CFG 0x00
#define MAX31722_REG_TEMP_LSB 0x01
#define MAX31722_REG_TEMP_MSB 0x02
+#define MAX31722_REG_THIGH_LSB 0x03
+#define MAX31722_REG_TLOW_LSB 0x05
#define MAX31722_MAX_REG 0x86
#define MAX31722_MODE_CONTINUOUS 0x00
#define MAX31722_MODE_STANDBY 0x01
+#define MAX31722_MODE_THERMOSTAT 0x80
+
+#define MAX31722_MIN_TEMP -55
+#define MAX31722_MAX_TEMP 125
#define MAX31722_REGMAP_NAME "max31722_regmap"
+#define MAX31722_EVENT "max31722_event"
+#define MAX31722_GPIO "max31722_gpio"
#define MAX31722_SCALE_AVAILABLE "0.5 0.25 0.125 0.0625"
@@ -43,6 +54,8 @@ static const struct reg_field max31722_reg_field_state =
REG_FIELD(MAX31722_REG_CFG, 0, 0);
static const struct reg_field max31722_reg_field_resolution =
REG_FIELD(MAX31722_REG_CFG, 1, 2);
+static const struct reg_field max31722_reg_field_thermostat =
+ REG_FIELD(MAX31722_REG_CFG, 3, 3);
struct max31722_data {
struct spi_device *spi_device;
@@ -50,6 +63,8 @@ struct max31722_data {
struct regmap *regmap;
struct regmap_field *reg_state;
struct regmap_field *reg_resolution;
+ struct regmap_field *reg_thermostat;
+ u64 timestamp;
};
/*
@@ -71,11 +86,30 @@ static const struct attribute_group max31722_attribute_group = {
.attrs = max31722_attributes
};
+static const struct iio_event_spec max31722_events[] = {
+ /* High temperature event */
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_RISING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_ENABLE),
+ },
+ /* Low temperature event */
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_FALLING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
static const struct iio_chan_spec max31722_channels[] = {
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
+ .event_spec = max31722_events,
+ .num_event_specs = ARRAY_SIZE(max31722_events),
},
};
@@ -167,6 +201,172 @@ static void max31722_reg_to_float(u16 reg_val, int *val, int *val2)
}
}
+/* Convert a floating point value to a register value. */
+static u16 max31722_float_to_reg(int val, int val2)
+{
+ int i;
+ bool negative_nr;
+ u8 lsb;
+ u16 reg_val;
+
+ negative_nr = (val & 0x80) || val2 < 0;
+ if (val2 < 0)
+ val2 *= -1;
+
+ /*
+ * The LSB value will be an approximation of val2
+ * due to its limited 4-bit range.
+ */
+ lsb = 0;
+ for (i = 0 ; i < ARRAY_SIZE(max31722_scale_table) && val2 > 0; i++)
+ if (val2 - max31722_scale_table[i] >= 0) {
+ val2 -= max31722_scale_table[i];
+ lsb += 1 << (4 - i - 1);
+ }
+ lsb <<= 4;
+
+ if (negative_nr) {
+ /*
+ * Negative value. Temporarily use the complement of val for
+ * the MSB, then concatenate the LSB, reverse bits & add 1 for
+ * the final value.
+ */
+ u8 msb = (u8)(-1 * val);
+ u16 rev = 0;
+ int num_bits = sizeof(rev) * 8;
+
+ reg_val = (msb << 8) | lsb;
+
+ for (i = 0 ; i < num_bits ; i++) {
+ rev |= !(reg_val & 0x01) << i;
+ reg_val >>= 1;
+ }
+ rev += 1;
+ return rev;
+
+ } else {
+ reg_val = ((u8)val << 8) | lsb;
+ }
+
+ return reg_val;
+}
+
+static int max31722_read_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir)
+{
+ unsigned int event_val;
+ int ret;
+ struct max31722_data *data = iio_priv(indio_dev);
+ struct spi_device *spi = data->spi_device;
+
+ mutex_lock(&data->lock);
+ ret = regmap_field_read(data->reg_thermostat, &event_val);
+ if (ret < 0) {
+ dev_err(&spi->dev, "failed to read thermostat status\n");
+ mutex_unlock(&data->lock);
+ return ret;
+ }
+ mutex_unlock(&data->lock);
+
+ return event_val;
+}
+
+static int max31722_write_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ int state)
+{
+ int ret;
+ struct max31722_data *data = iio_priv(indio_dev);
+ struct spi_device *spi = data->spi_device;
+
+ if (state != 0 && state != 1)
+ return -EINVAL;
+
+ /*
+ * Set thermostat mode:
+ * 0 : comparator mode (default)
+ * 1 : interrupt mode
+ */
+ mutex_lock(&data->lock);
+ ret = regmap_field_write(data->reg_thermostat, state);
+ if (ret < 0)
+ dev_err(&spi->dev, "failed to set thermostat mode\n");
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int max31722_read_event(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int *val, int *val2)
+{
+ int ret;
+ u8 reg;
+ u16 buf;
+ struct max31722_data *data = iio_priv(indio_dev);
+
+ if (info != IIO_EV_INFO_VALUE)
+ return -EINVAL;
+
+ if (dir == IIO_EV_DIR_RISING)
+ reg = MAX31722_REG_THIGH_LSB;
+ else if (dir == IIO_EV_DIR_FALLING)
+ reg = MAX31722_REG_TLOW_LSB;
+ else
+ return -EINVAL;
+
+ mutex_lock(&data->lock);
+ ret = regmap_bulk_read(data->regmap, reg, &buf, 2);
+ mutex_unlock(&data->lock);
+ if (ret < 0) {
+ dev_err(&data->spi_device->dev,
+ "failed to read threshold register\n");
+ return ret;
+ }
+ max31722_reg_to_float(buf, val, val2);
+
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int max31722_write_event(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int val, int val2)
+{
+ int ret;
+ u8 reg;
+ u16 buf;
+ struct max31722_data *data = iio_priv(indio_dev);
+
+ if (val < MAX31722_MIN_TEMP || val > MAX31722_MAX_TEMP)
+ return -EINVAL;
+
+ if (dir == IIO_EV_DIR_RISING)
+ reg = MAX31722_REG_THIGH_LSB;
+ else if (dir == IIO_EV_DIR_FALLING)
+ reg = MAX31722_REG_TLOW_LSB;
+ else
+ return -EINVAL;
+
+ buf = max31722_float_to_reg(val, val2);
+
+ ret = regmap_bulk_write(data->regmap, reg, &buf, 2);
+ if (ret < 0)
+ dev_err(&data->spi_device->dev,
+ "failed to write threshold register\n");
+
+ return ret;
+}
+
static int max31722_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
@@ -241,8 +441,63 @@ static const struct iio_info max31722_info = {
.read_raw = max31722_read_raw,
.write_raw = max31722_write_raw,
.attrs = &max31722_attribute_group,
+ .read_event_value = max31722_read_event,
+ .write_event_value = max31722_write_event,
+ .read_event_config = max31722_read_event_config,
+ .write_event_config = max31722_write_event_config,
};
+static irqreturn_t max31722_irq_handler(int irq, void *private)
+{
+ struct iio_dev *indio_dev = private;
+ struct max31722_data *data = iio_priv(indio_dev);
+
+ data->timestamp = iio_get_time_ns();
+
+ return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t max31722_irq_event_handler(int irq, void *private)
+{
+ int ret;
+ u64 event;
+ u16 temp;
+ u16 tlow;
+ u16 thigh;
+ unsigned int dir;
+ struct iio_dev *indio_dev = private;
+ struct max31722_data *data = iio_priv(indio_dev);
+
+ /*
+ * Do a quick temperature reading and compare it with TLOW/THIGH
+ * so we can tell which threshold has been met.
+ */
+ mutex_lock(&data->lock);
+ ret = regmap_bulk_read(data->regmap, MAX31722_REG_TEMP_LSB, &temp, 2);
+ if (ret < 0)
+ goto exit_err;
+ ret = regmap_bulk_read(data->regmap, MAX31722_REG_TLOW_LSB, &tlow, 2);
+ if (ret < 0)
+ goto exit_err;
+ ret = regmap_bulk_read(data->regmap, MAX31722_REG_THIGH_LSB, &thigh, 2);
+ if (ret < 0)
+ goto exit_err;
+ mutex_unlock(&data->lock);
+
+ dir = (temp > thigh ? 1 : 0);
+ event = IIO_UNMOD_EVENT_CODE(IIO_TEMP, 0, IIO_EV_TYPE_THRESH,
+ (dir ? IIO_EV_DIR_RISING :
+ IIO_EV_DIR_FALLING));
+ iio_push_event(indio_dev, event, data->timestamp);
+
+ return IRQ_HANDLED;
+
+exit_err:
+ dev_err(&data->spi_device->dev, "failed to read temperature register\n");
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
static int max31722_init(struct max31722_data *data)
{
int ret = 0;
@@ -259,15 +514,40 @@ static int max31722_init(struct max31722_data *data)
MAX31722_REGFIELD(state);
MAX31722_REGFIELD(resolution);
+ MAX31722_REGFIELD(thermostat);
/* Set SD bit to 0 so we can have continuous measurements. */
ret = regmap_field_write(data->reg_state, MAX31722_MODE_CONTINUOUS);
+ if (ret < 0) {
+ dev_err(&spi->dev, "failed to configure sensor.\n");
+ return ret;
+ }
+
+ /* Set thermostat interrupt mode */
+ ret = regmap_field_write(data->reg_thermostat, 1);
if (ret < 0)
dev_err(&spi->dev, "failed to configure sensor.\n");
return ret;
}
+static int max31722_gpio_probe(struct spi_device *spi)
+{
+ struct gpio_desc *gpio;
+
+ if (!spi)
+ return -EINVAL;
+
+ /* gpio interrupt pin */
+ gpio = devm_gpiod_get_index(&spi->dev, MAX31722_GPIO, 0, GPIOD_IN);
+ if (IS_ERR(gpio)) {
+ dev_err(&spi->dev, "gpio request failed.\n");
+ return PTR_ERR(gpio);
+ }
+
+ return gpiod_to_irq(gpio);
+}
+
static int max31722_probe(struct spi_device *spi)
{
int ret;
@@ -294,15 +574,34 @@ static int max31722_probe(struct spi_device *spi)
ret = max31722_init(data);
if (ret < 0)
- return ret;
+ goto err_standby;
+
+ ret = max31722_gpio_probe(data->spi_device);
+ if (ret < 0)
+ goto err_standby;
+
+ spi->irq = ret;
+ ret = devm_request_threaded_irq(&spi->dev, spi->irq,
+ max31722_irq_handler,
+ max31722_irq_event_handler,
+ IRQF_TRIGGER_LOW,
+ MAX31722_EVENT, indio_dev);
+ if (ret < 0) {
+ dev_err(&spi->dev, "request irq %d failed\n", spi->irq);
+ goto err_standby;
+ }
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&spi->dev, "iio_device_register failed\n");
- regmap_field_write(data->reg_state, MAX31722_MODE_STANDBY);
+ goto err_standby;
}
return ret;
+
+err_standby:
+ regmap_field_write(data->reg_state, MAX31722_MODE_STANDBY);
+ return ret;
}
static int max31722_remove(struct spi_device *spi)
--
1.9.1
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