iio: light: Add threshold interrupt support for STK3310

Added interrupt support for proximity threshold events
to the stk3310 driver.

Signed-off-by: Tiberiu Breana <tiberiu.a.breana@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/stk3310.c

@@ -12,15 +12,22 @@
 
 #include <linux/acpi.h>
 #include <linux/i2c.h>
+#include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 
 #define STK3310_REG_STATE			0x00
 #define STK3310_REG_PSCTRL			0x01
 #define STK3310_REG_ALSCTRL			0x02
+#define STK3310_REG_INT				0x04
+#define STK3310_REG_THDH_PS			0x06
+#define STK3310_REG_THDL_PS			0x08
+#define STK3310_REG_FLAG			0x10
 #define STK3310_REG_PS_DATA_MSB			0x11
 #define STK3310_REG_PS_DATA_LSB			0x12
 #define STK3310_REG_ALS_DATA_MSB		0x13
@@ -34,10 +41,14 @@
 
 #define STK3310_CHIP_ID_VAL			0x13
 #define STK3311_CHIP_ID_VAL			0x1D
+#define STK3310_PSINT_EN			0x01
 #define STK3310_PS_MAX_VAL			0xFFFF
+#define STK3310_THRESH_MAX			0xFFFF
 
 #define STK3310_DRIVER_NAME			"stk3310"
 #define STK3310_REGMAP_NAME			"stk3310_regmap"
+#define STK3310_EVENT				"stk3310_event"
+#define STK3310_GPIO				"stk3310_gpio"
 
 #define STK3310_SCALE_AVAILABLE			"6.4 1.6 0.4 0.1"
 
@@ -67,7 +78,12 @@ static const struct reg_field stk3310_reg_field_als_it =
 				REG_FIELD(STK3310_REG_ALSCTRL, 0, 3);
 static const struct reg_field stk3310_reg_field_ps_it =
 				REG_FIELD(STK3310_REG_PSCTRL, 0, 3);
-
+static const struct reg_field stk3310_reg_field_int_ps =
+				REG_FIELD(STK3310_REG_INT, 0, 2);
+static const struct reg_field stk3310_reg_field_flag_psint =
+				REG_FIELD(STK3310_REG_FLAG, 4, 4);
+static const struct reg_field stk3310_reg_field_flag_nf =
+				REG_FIELD(STK3310_REG_FLAG, 0, 0);
 /*
  * Maximum PS values with regard to scale. Used to export the 'inverse'
  * PS value (high values for far objects, low values for near objects).
@@ -96,12 +112,33 @@ struct stk3310_data {
 	struct mutex lock;
 	bool als_enabled;
 	bool ps_enabled;
+	u64 timestamp;
 	struct regmap *regmap;
 	struct regmap_field *reg_state;
 	struct regmap_field *reg_als_gain;
 	struct regmap_field *reg_ps_gain;
 	struct regmap_field *reg_als_it;
 	struct regmap_field *reg_ps_it;
+	struct regmap_field *reg_int_ps;
+	struct regmap_field *reg_flag_psint;
+	struct regmap_field *reg_flag_nf;
+};
+
+static const struct iio_event_spec stk3310_events[] = {
+	/* Proximity event */
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	},
+	/* Out-of-proximity event */
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	},
 };
 
 static const struct iio_chan_spec stk3310_channels[] = {
@@ -118,6 +155,8 @@ static const struct iio_chan_spec stk3310_channels[] = {
 			BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE) |
 			BIT(IIO_CHAN_INFO_INT_TIME),
+		.event_spec = stk3310_events,
+		.num_event_specs = ARRAY_SIZE(stk3310_events),
 	}
 };
 
@@ -156,6 +195,118 @@ static int stk3310_get_index(const int table[][2], int table_size,
 	return -EINVAL;
 }
 
+static int stk3310_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)
+{
+	u8 reg;
+	u16 buf;
+	int ret;
+	unsigned int index;
+	struct stk3310_data *data = iio_priv(indio_dev);
+
+	if (info != IIO_EV_INFO_VALUE)
+		return -EINVAL;
+
+	/*
+	 * Only proximity interrupts are implemented at the moment.
+	 * Since we're inverting proximity values, the sensor's 'high'
+	 * threshold will become our 'low' threshold, associated with
+	 * 'near' events. Similarly, the sensor's 'low' threshold will
+	 * be our 'high' threshold, associated with 'far' events.
+	 */
+	if (dir == IIO_EV_DIR_RISING)
+		reg = STK3310_REG_THDL_PS;
+	else if (dir == IIO_EV_DIR_FALLING)
+		reg = STK3310_REG_THDH_PS;
+	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->client->dev, "register read failed\n");
+		return ret;
+	}
+	regmap_field_read(data->reg_ps_gain, &index);
+	*val = swab16(stk3310_ps_max[index] - buf);
+
+	return IIO_VAL_INT;
+}
+
+static int stk3310_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)
+{
+	u8 reg;
+	u16 buf;
+	int ret;
+	unsigned int index;
+	struct stk3310_data *data = iio_priv(indio_dev);
+	struct i2c_client *client = data->client;
+
+	regmap_field_read(data->reg_ps_gain, &index);
+	if (val > stk3310_ps_max[index])
+		return -EINVAL;
+
+	if (dir == IIO_EV_DIR_RISING)
+		reg = STK3310_REG_THDL_PS;
+	else if (dir == IIO_EV_DIR_FALLING)
+		reg = STK3310_REG_THDH_PS;
+	else
+		return -EINVAL;
+
+	buf = swab16(stk3310_ps_max[index] - val);
+	ret = regmap_bulk_write(data->regmap, reg, &buf, 2);
+	if (ret < 0)
+		dev_err(&client->dev, "failed to set PS threshold!\n");
+
+	return ret;
+}
+
+static int stk3310_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;
+	struct stk3310_data *data = iio_priv(indio_dev);
+
+	regmap_field_read(data->reg_int_ps, &event_val);
+
+	return event_val;
+}
+
+static int stk3310_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 stk3310_data *data = iio_priv(indio_dev);
+	struct i2c_client *client = data->client;
+
+	if (state < 0 || state > 7)
+		return -EINVAL;
+
+	/* Set INT_PS value */
+	mutex_lock(&data->lock);
+	ret = regmap_field_write(data->reg_int_ps, state);
+	if (ret < 0)
+		dev_err(&client->dev, "failed to set interrupt mode\n");
+	mutex_unlock(&data->lock);
+
+	return ret;
+}
+
 static int stk3310_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int *val, int *val2, long mask)
@@ -266,6 +417,10 @@ static const struct iio_info stk3310_info = {
 	.read_raw		= stk3310_read_raw,
 	.write_raw		= stk3310_write_raw,
 	.attrs			= &stk3310_attribute_group,
+	.read_event_value	= stk3310_read_event,
+	.write_event_value	= stk3310_write_event,
+	.read_event_config	= stk3310_read_event_config,
+	.write_event_config	= stk3310_write_event_config,
 };
 
 static int stk3310_set_state(struct stk3310_data *data, u8 state)
@@ -308,8 +463,43 @@ static int stk3310_init(struct iio_dev *indio_dev)
 
 	state = STK3310_STATE_EN_ALS | STK3310_STATE_EN_PS;
 	ret = stk3310_set_state(data, state);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(&client->dev, "failed to enable sensor");
+		return ret;
+	}
+
+	/* Enable PS interrupts */
+	ret = regmap_field_write(data->reg_int_ps, STK3310_PSINT_EN);
+	if (ret < 0)
+		dev_err(&client->dev, "failed to enable interrupts!\n");
+
+	return ret;
+}
+
+static int stk3310_gpio_probe(struct i2c_client *client)
+{
+	struct device *dev;
+	struct gpio_desc *gpio;
+	int ret;
+
+	if (!client)
+		return -EINVAL;
+
+	dev = &client->dev;
+
+	/* gpio interrupt pin */
+	gpio = devm_gpiod_get_index(dev, STK3310_GPIO, 0);
+	if (IS_ERR(gpio)) {
+		dev_err(dev, "acpi gpio get index failed\n");
+		return PTR_ERR(gpio);
+	}
+
+	ret = gpiod_direction_input(gpio);
+	if (ret)
+		return ret;
+
+	ret = gpiod_to_irq(gpio);
+	dev_dbg(dev, "GPIO resource, no:%d irq:%d\n", desc_to_gpio(gpio), ret);
 
 	return ret;
 }
@@ -321,6 +511,7 @@ static bool stk3310_is_volatile_reg(struct device *dev, unsigned int reg)
 	case STK3310_REG_ALS_DATA_LSB:
 	case STK3310_REG_PS_DATA_LSB:
 	case STK3310_REG_PS_DATA_MSB:
+	case STK3310_REG_FLAG:
 		return true;
 	default:
 		return false;
@@ -354,10 +545,55 @@ static int stk3310_regmap_init(struct stk3310_data *data)
 	STK3310_REGFIELD(ps_gain);
 	STK3310_REGFIELD(als_it);
 	STK3310_REGFIELD(ps_it);
+	STK3310_REGFIELD(int_ps);
+	STK3310_REGFIELD(flag_psint);
+	STK3310_REGFIELD(flag_nf);
 
 	return 0;
 }
 
+static irqreturn_t stk3310_irq_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct stk3310_data *data = iio_priv(indio_dev);
+
+	data->timestamp = iio_get_time_ns();
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t stk3310_irq_event_handler(int irq, void *private)
+{
+	int ret;
+	unsigned int dir;
+	u64 event;
+
+	struct iio_dev *indio_dev = private;
+	struct stk3310_data *data = iio_priv(indio_dev);
+
+	/* Read FLAG_NF to figure out what threshold has been met. */
+	mutex_lock(&data->lock);
+	ret = regmap_field_read(data->reg_flag_nf, &dir);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "register read failed\n");
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+	event = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 1,
+				     IIO_EV_TYPE_THRESH,
+				     (dir ? IIO_EV_DIR_RISING :
+					    IIO_EV_DIR_FALLING));
+	iio_push_event(indio_dev, event, data->timestamp);
+
+	/* Reset the interrupt flag */
+	ret = regmap_field_write(data->reg_flag_psint, 0);
+	if (ret < 0)
+		dev_err(&data->client->dev, "failed to reset interrupts\n");
+	mutex_unlock(&data->lock);
+
+	return IRQ_HANDLED;
+}
+
 static int stk3310_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -397,6 +633,21 @@ static int stk3310_probe(struct i2c_client *client,
 		stk3310_set_state(data, STK3310_STATE_STANDBY);
 	}
 
+	if (client->irq <= 0)
+		client->irq = stk3310_gpio_probe(client);
+
+	if (client->irq >= 0) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						stk3310_irq_handler,
+						stk3310_irq_event_handler,
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+						STK3310_EVENT, indio_dev);
+		if (ret < 0)
+			dev_err(&client->dev, "request irq %d failed\n",
+					client->irq);
+	}
+
 	return ret;
 }