iio:temperature:tmp007: Add irq and threshold events support

This patch adds ALERT irq and limit threshold events support for TI TMP007 - 16 bit IR thermopile sensor with integrated
math engine.

Following threshold events are supported:
1. TObj high limit
2. TObj low limit
3. TDie high limit
4. TDie low limit

Signed-off-by: Manivannan Sadhasivam <manivannanece23@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/temperature/tmp007.c

@@ -11,9 +11,10 @@
  *
  * (7-bit I2C slave address (0x40 - 0x47), changeable via ADR pins)
  *
- * Note: This driver assumes that the sensor has been calibrated beforehand
- *
- * TODO: ALERT irq, limit threshold events
+ * Note:
+ * 1. This driver assumes that the sensor has been calibrated beforehand
+ * 2. Limit threshold events are enabled at the start
+ * 3. Operating mode: INT
  *
  */
 
@@ -24,25 +25,38 @@
 #include <linux/pm.h>
 #include <linux/bitops.h>
 #include <linux/of.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
 
 #define TMP007_TDIE 0x01
 #define TMP007_CONFIG 0x02
 #define TMP007_TOBJECT 0x03
 #define TMP007_STATUS 0x04
 #define TMP007_STATUS_MASK 0x05
+#define TMP007_TOBJ_HIGH_LIMIT 0x06
+#define TMP007_TOBJ_LOW_LIMIT 0x07
+#define TMP007_TDIE_HIGH_LIMIT 0x08
+#define TMP007_TDIE_LOW_LIMIT 0x09
 #define TMP007_MANUFACTURER_ID 0x1e
 #define TMP007_DEVICE_ID 0x1f
 
 #define TMP007_CONFIG_CONV_EN BIT(12)
-#define TMP007_CONFIG_COMP_EN BIT(5)
 #define TMP007_CONFIG_TC_EN BIT(6)
 #define TMP007_CONFIG_CR_MASK GENMASK(11, 9)
+#define TMP007_CONFIG_ALERT_EN BIT(8)
 #define TMP007_CONFIG_CR_SHIFT 9
 
+/* Status register flags */
+#define TMP007_STATUS_ALERT BIT(15)
 #define TMP007_STATUS_CONV_READY BIT(14)
+#define TMP007_STATUS_OHF BIT(13)
+#define TMP007_STATUS_OLF BIT(12)
+#define TMP007_STATUS_LHF BIT(11)
+#define TMP007_STATUS_LLF BIT(10)
 #define TMP007_STATUS_DATA_VALID BIT(9)
 
 #define TMP007_MANUFACTURER_MAGIC 0x5449
@@ -52,7 +66,9 @@
 
 struct tmp007_data {
 	struct i2c_client *client;
+	struct mutex lock;
 	u16 config;
+	u16 status_mask;
 };
 
 static const int tmp007_avgs[5][2] = { {4, 0}, {2, 0}, {1, 0},
@@ -156,6 +172,188 @@ static int tmp007_write_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static irqreturn_t tmp007_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct tmp007_data *data = iio_priv(indio_dev);
+	int ret;
+
+	ret = i2c_smbus_read_word_swapped(data->client, TMP007_STATUS);
+	if ((ret < 0) || !(ret & (TMP007_STATUS_OHF | TMP007_STATUS_OLF |
+				TMP007_STATUS_LHF | TMP007_STATUS_LLF)))
+		return IRQ_NONE;
+
+	if (ret & TMP007_STATUS_OHF)
+		iio_push_event(indio_dev,
+				IIO_MOD_EVENT_CODE(IIO_TEMP, 0,
+					IIO_MOD_TEMP_OBJECT,
+					IIO_EV_TYPE_THRESH,
+					IIO_EV_DIR_RISING),
+				iio_get_time_ns(indio_dev));
+
+	if (ret & TMP007_STATUS_OLF)
+		iio_push_event(indio_dev,
+				IIO_MOD_EVENT_CODE(IIO_TEMP, 0,
+					IIO_MOD_TEMP_OBJECT,
+					IIO_EV_TYPE_THRESH,
+					IIO_EV_DIR_FALLING),
+				iio_get_time_ns(indio_dev));
+
+	if (ret & TMP007_STATUS_LHF)
+		iio_push_event(indio_dev,
+				IIO_MOD_EVENT_CODE(IIO_TEMP, 0,
+					IIO_MOD_TEMP_AMBIENT,
+					IIO_EV_TYPE_THRESH,
+					IIO_EV_DIR_RISING),
+				iio_get_time_ns(indio_dev));
+
+	if (ret & TMP007_STATUS_LLF)
+		iio_push_event(indio_dev,
+				IIO_MOD_EVENT_CODE(IIO_TEMP, 0,
+					IIO_MOD_TEMP_AMBIENT,
+					IIO_EV_TYPE_THRESH,
+					IIO_EV_DIR_FALLING),
+				iio_get_time_ns(indio_dev));
+
+	return IRQ_HANDLED;
+}
+
+static int tmp007_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)
+{
+	struct tmp007_data *data = iio_priv(indio_dev);
+	unsigned int status_mask;
+	int ret;
+
+	switch (chan->channel2) {
+	case IIO_MOD_TEMP_AMBIENT:
+	if (dir == IIO_EV_DIR_RISING)
+			status_mask = TMP007_STATUS_LHF;
+		else
+			status_mask = TMP007_STATUS_LLF;
+		break;
+	case IIO_MOD_TEMP_OBJECT:
+		if (dir == IIO_EV_DIR_RISING)
+			status_mask = TMP007_STATUS_OHF;
+		else
+			status_mask = TMP007_STATUS_OLF;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	mutex_lock(&data->lock);
+	ret = i2c_smbus_read_word_swapped(data->client, TMP007_STATUS_MASK);
+	mutex_unlock(&data->lock);
+	if (ret < 0)
+		return ret;
+
+	if (state)
+		ret |= status_mask;
+	else
+		ret &= ~status_mask;
+
+	return i2c_smbus_write_word_swapped(data->client, TMP007_STATUS_MASK,
+					data->status_mask = ret);
+}
+
+static int tmp007_read_event_config(struct iio_dev *indio_dev,
+		const struct iio_chan_spec *chan, enum iio_event_type type,
+		enum iio_event_direction dir)
+{
+	struct tmp007_data *data = iio_priv(indio_dev);
+	unsigned int mask;
+
+	switch (chan->channel2) {
+	case IIO_MOD_TEMP_AMBIENT:
+		if (dir == IIO_EV_DIR_RISING)
+			mask = TMP007_STATUS_LHF;
+		else
+			mask = TMP007_STATUS_LLF;
+		break;
+	case IIO_MOD_TEMP_OBJECT:
+		if (dir == IIO_EV_DIR_RISING)
+			mask = TMP007_STATUS_OHF;
+		else
+			mask = TMP007_STATUS_OLF;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return !!(data->status_mask & mask);
+}
+
+static int tmp007_read_thresh(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)
+{
+	struct tmp007_data *data = iio_priv(indio_dev);
+	int ret;
+	u8 reg;
+
+	switch (chan->channel2) {
+	case IIO_MOD_TEMP_AMBIENT: /* LSB: 0.5 degree Celsius */
+		if (dir == IIO_EV_DIR_RISING)
+			reg = TMP007_TDIE_HIGH_LIMIT;
+		else
+			reg = TMP007_TDIE_LOW_LIMIT;
+		break;
+	case IIO_MOD_TEMP_OBJECT:
+		if (dir == IIO_EV_DIR_RISING)
+			reg = TMP007_TOBJ_HIGH_LIMIT;
+	else
+			reg = TMP007_TOBJ_LOW_LIMIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = i2c_smbus_read_word_swapped(data->client, reg);
+	if (ret < 0)
+		return ret;
+
+	/* Shift length 7 bits = 6(15:6) + 1(0.5 LSB) */
+	*val = sign_extend32(ret, 15) >> 7;
+
+	return IIO_VAL_INT;
+}
+
+static int tmp007_write_thresh(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)
+{
+	struct tmp007_data *data = iio_priv(indio_dev);
+	u8 reg;
+
+	switch (chan->channel2) {
+	case IIO_MOD_TEMP_AMBIENT:
+		if (dir == IIO_EV_DIR_RISING)
+			reg = TMP007_TDIE_HIGH_LIMIT;
+		else
+			reg = TMP007_TDIE_LOW_LIMIT;
+		break;
+	case IIO_MOD_TEMP_OBJECT:
+		if (dir == IIO_EV_DIR_RISING)
+			reg = TMP007_TOBJ_HIGH_LIMIT;
+		else
+			reg = TMP007_TOBJ_LOW_LIMIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Full scale threshold value is +/- 256 degree Celsius */
+	if (val < -256 || val > 255)
+		return -EINVAL;
+
+	/* Shift length 7 bits = 6(15:6) + 1(0.5 LSB) */
+	return i2c_smbus_write_word_swapped(data->client, reg, (val << 7));
+}
+
 static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");
 
 static struct attribute *tmp007_attributes[] = {
@@ -167,6 +365,36 @@ static const struct attribute_group tmp007_attribute_group = {
 	.attrs = tmp007_attributes,
 };
 
+static const struct iio_event_spec tmp007_obj_event[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.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_event_spec tmp007_die_event[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.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 tmp007_channels[] = {
 	{
 		.type = IIO_TEMP,
@@ -175,6 +403,8 @@ static const struct iio_chan_spec tmp007_channels[] = {
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				BIT(IIO_CHAN_INFO_SCALE),
 		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.event_spec = tmp007_die_event,
+		.num_event_specs = ARRAY_SIZE(tmp007_die_event),
 	},
 	{
 		.type = IIO_TEMP,
@@ -183,12 +413,18 @@ static const struct iio_chan_spec tmp007_channels[] = {
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				BIT(IIO_CHAN_INFO_SCALE),
 		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.event_spec = tmp007_obj_event,
+		.num_event_specs = ARRAY_SIZE(tmp007_obj_event),
 	}
 };
 
 static const struct iio_info tmp007_info = {
 	.read_raw = tmp007_read_raw,
 	.write_raw = tmp007_write_raw,
+	.read_event_config = tmp007_read_event_config,
+	.write_event_config = tmp007_write_event_config,
+	.read_event_value = tmp007_read_thresh,
+	.write_event_value = tmp007_write_thresh,
 	.attrs = &tmp007_attribute_group,
 	.driver_module = THIS_MODULE,
 };
@@ -214,7 +450,6 @@ static int tmp007_probe(struct i2c_client *client,
 	struct tmp007_data *data;
 	struct iio_dev *indio_dev;
 	int ret;
-	u16  status;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 		return -EOPNOTSUPP;
@@ -231,6 +466,7 @@ static int tmp007_probe(struct i2c_client *client,
 	data = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
+	mutex_init(&data->lock);
 
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->name = "tmp007";
@@ -243,7 +479,7 @@ static int tmp007_probe(struct i2c_client *client,
 	/*
 	 * Set Configuration register:
 	 * 1. Conversion ON
-	 * 2. Comparator mode
+	 * 2. ALERT enable
 	 * 3. Transient correction enable
 	 */
 
@@ -252,7 +488,7 @@ static int tmp007_probe(struct i2c_client *client,
 		return ret;
 
 	data->config = ret;
-	data->config |= (TMP007_CONFIG_CONV_EN | TMP007_CONFIG_COMP_EN | TMP007_CONFIG_TC_EN);
+	data->config |= (TMP007_CONFIG_CONV_EN | TMP007_CONFIG_ALERT_EN | TMP007_CONFIG_TC_EN);
 
 	ret = i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
 					data->config);
@@ -260,22 +496,39 @@ static int tmp007_probe(struct i2c_client *client,
 		return ret;
 
 	/*
+	 * Only the following flags can activate ALERT pin. Data conversion/validity flags
+	 * flags can still be polled for getting temperature data
+	 *
 	 * Set Status Mask register:
-	 * 1. Conversion ready enable
-	 * 2. Data valid enable
+	 * 1. Object temperature high limit enable
+	 * 2. Object temperature low limit enable
+	 * 3. TDIE temperature high limit enable
+	 * 4. TDIE temperature low limit enable
 	 */
 
 	ret = i2c_smbus_read_word_swapped(data->client, TMP007_STATUS_MASK);
 	if (ret < 0)
 		goto error_powerdown;
 
-	status = ret;
-	status |= (TMP007_STATUS_CONV_READY | TMP007_STATUS_DATA_VALID);
+	data->status_mask = ret;
+	data->status_mask |= (TMP007_STATUS_OHF | TMP007_STATUS_OLF
+				| TMP007_STATUS_LHF | TMP007_STATUS_LLF);
 
-	ret = i2c_smbus_write_word_swapped(data->client, TMP007_STATUS_MASK, status);
+	ret = i2c_smbus_write_word_swapped(data->client, TMP007_STATUS_MASK, data->status_mask);
 	if (ret < 0)
 		goto error_powerdown;
 
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+				NULL, tmp007_interrupt_handler,
+				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				tmp007_id->name, indio_dev);
+		if (ret) {
+			dev_err(&client->dev, "irq request error %d\n", -ret);
+			goto error_powerdown;
+		}
+	}
+
 	return iio_device_register(indio_dev);
 
 error_powerdown: