iio:bmi160: add drdy interrupt support
authorMartin Kelly <martin@martingkelly.com>
Sat, 2 Feb 2019 21:55:57 +0000 (13:55 -0800)
committerJonathan Cameron <Jonathan.Cameron@huawei.com>
Sat, 9 Feb 2019 15:14:42 +0000 (15:14 +0000)
Add interrupt support for the data ready signal on the BMI160, which fires
an interrupt whenever new accelerometer/gyroscope data is ready to read.

Signed-off-by: Martin Kelly <martin@martingkelly.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
drivers/iio/imu/bmi160/bmi160.h
drivers/iio/imu/bmi160/bmi160_core.c

index 2351049d930bfbe38f7124ba5d1d2609cf58695f..621f5309d735aa618e5e4c54b5f443f65606fcef 100644 (file)
@@ -2,9 +2,20 @@
 #ifndef BMI160_H_
 #define BMI160_H_
 
+#include <linux/iio/iio.h>
+
+struct bmi160_data {
+       struct regmap *regmap;
+       struct iio_trigger *trig;
+};
+
 extern const struct regmap_config bmi160_regmap_config;
 
 int bmi160_core_probe(struct device *dev, struct regmap *regmap,
                      const char *name, bool use_spi);
 
+int bmi160_enable_irq(struct regmap *regmap, bool enable);
+
+int bmi160_probe_trigger(struct iio_dev *indio_dev, int irq, u32 irq_type);
+
 #endif  /* BMI160_H_ */
index ce61026d84c3bfe6afde92b20818627e839015ff..007f7c532ac4f00131662e6e93bfb451a30a2488 100644 (file)
@@ -3,21 +3,25 @@
  * BMI160 - Bosch IMU (accel, gyro plus external magnetometer)
  *
  * Copyright (c) 2016, Intel Corporation.
+ * Copyright (c) 2019, Martin Kelly.
  *
  * IIO core driver for BMI160, with support for I2C/SPI busses
  *
- * TODO: magnetometer, interrupts, hardware FIFO
+ * TODO: magnetometer, hardware FIFO
  */
 #include <linux/module.h>
 #include <linux/regmap.h>
 #include <linux/acpi.h>
 #include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/of_irq.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
 
 #include "bmi160.h"
 
 #define BMI160_CMD_GYRO_PM_FAST_STARTUP        0x17
 #define BMI160_CMD_SOFTRESET           0xB6
 
+#define BMI160_REG_INT_EN              0x51
+#define BMI160_DRDY_INT_EN             BIT(4)
+
+#define BMI160_REG_INT_OUT_CTRL                0x53
+#define BMI160_INT_OUT_CTRL_MASK       0x0f
+#define BMI160_INT1_OUT_CTRL_SHIFT     0
+#define BMI160_INT2_OUT_CTRL_SHIFT     4
+#define BMI160_EDGE_TRIGGERED          BIT(0)
+#define BMI160_ACTIVE_HIGH             BIT(1)
+#define BMI160_OPEN_DRAIN              BIT(2)
+#define BMI160_OUTPUT_EN               BIT(3)
+
+#define BMI160_REG_INT_LATCH           0x54
+#define BMI160_INT1_LATCH_MASK         BIT(4)
+#define BMI160_INT2_LATCH_MASK         BIT(5)
+
+/* INT1 and INT2 are in the opposite order as in INT_OUT_CTRL! */
+#define BMI160_REG_INT_MAP             0x56
+#define BMI160_INT1_MAP_DRDY_EN                0x80
+#define BMI160_INT2_MAP_DRDY_EN                0x08
+
 #define BMI160_REG_DUMMY               0x7F
 
+#define BMI160_NORMAL_WRITE_USLEEP     2
+#define BMI160_SUSPENDED_WRITE_USLEEP  450
+
 #define BMI160_ACCEL_PMU_MIN_USLEEP    3800
 #define BMI160_GYRO_PMU_MIN_USLEEP     80000
 #define BMI160_SOFTRESET_USLEEP                1000
@@ -105,8 +133,9 @@ enum bmi160_sensor_type {
        BMI160_NUM_SENSORS /* must be last */
 };
 
-struct bmi160_data {
-       struct regmap *regmap;
+enum bmi160_int_pin {
+       BMI160_PIN_INT1,
+       BMI160_PIN_INT2
 };
 
 const struct regmap_config bmi160_regmap_config = {
@@ -495,6 +524,186 @@ static const char *bmi160_match_acpi_device(struct device *dev)
        return dev_name(dev);
 }
 
+static int bmi160_write_conf_reg(struct regmap *regmap, unsigned int reg,
+                                unsigned int mask, unsigned int bits,
+                                unsigned int write_usleep)
+{
+       int ret;
+       unsigned int val;
+
+       ret = regmap_read(regmap, reg, &val);
+       if (ret)
+               return ret;
+
+       val = (val & ~mask) | bits;
+
+       ret = regmap_write(regmap, reg, val);
+       if (ret)
+               return ret;
+
+       /*
+        * We need to wait after writing before we can write again. See the
+        * datasheet, page 93.
+        */
+       usleep_range(write_usleep, write_usleep + 1000);
+
+       return 0;
+}
+
+static int bmi160_config_pin(struct regmap *regmap, enum bmi160_int_pin pin,
+                            bool open_drain, u8 irq_mask,
+                            unsigned long write_usleep)
+{
+       int ret;
+       struct device *dev = regmap_get_device(regmap);
+       u8 int_out_ctrl_shift;
+       u8 int_latch_mask;
+       u8 int_map_mask;
+       u8 int_out_ctrl_mask;
+       u8 int_out_ctrl_bits;
+       const char *pin_name;
+
+       switch (pin) {
+       case BMI160_PIN_INT1:
+               int_out_ctrl_shift = BMI160_INT1_OUT_CTRL_SHIFT;
+               int_latch_mask = BMI160_INT1_LATCH_MASK;
+               int_map_mask = BMI160_INT1_MAP_DRDY_EN;
+               break;
+       case BMI160_PIN_INT2:
+               int_out_ctrl_shift = BMI160_INT2_OUT_CTRL_SHIFT;
+               int_latch_mask = BMI160_INT2_LATCH_MASK;
+               int_map_mask = BMI160_INT2_MAP_DRDY_EN;
+               break;
+       }
+       int_out_ctrl_mask = BMI160_INT_OUT_CTRL_MASK << int_out_ctrl_shift;
+
+       /*
+        * Enable the requested pin with the right settings:
+        * - Push-pull/open-drain
+        * - Active low/high
+        * - Edge/level triggered
+        */
+       int_out_ctrl_bits = BMI160_OUTPUT_EN;
+       if (open_drain)
+               /* Default is push-pull. */
+               int_out_ctrl_bits |= BMI160_OPEN_DRAIN;
+       int_out_ctrl_bits |= irq_mask;
+       int_out_ctrl_bits <<= int_out_ctrl_shift;
+
+       ret = bmi160_write_conf_reg(regmap, BMI160_REG_INT_OUT_CTRL,
+                                   int_out_ctrl_mask, int_out_ctrl_bits,
+                                   write_usleep);
+       if (ret)
+               return ret;
+
+       /* Set the pin to input mode with no latching. */
+       ret = bmi160_write_conf_reg(regmap, BMI160_REG_INT_LATCH,
+                                   int_latch_mask, int_latch_mask,
+                                   write_usleep);
+       if (ret)
+               return ret;
+
+       /* Map interrupts to the requested pin. */
+       ret = bmi160_write_conf_reg(regmap, BMI160_REG_INT_MAP,
+                                   int_map_mask, int_map_mask,
+                                   write_usleep);
+       if (ret) {
+               switch (pin) {
+               case BMI160_PIN_INT1:
+                       pin_name = "INT1";
+                       break;
+               case BMI160_PIN_INT2:
+                       pin_name = "INT2";
+                       break;
+               }
+               dev_err(dev, "Failed to configure %s IRQ pin", pin_name);
+       }
+
+       return ret;
+}
+
+int bmi160_enable_irq(struct regmap *regmap, bool enable)
+{
+       unsigned int enable_bit = 0;
+
+       if (enable)
+               enable_bit = BMI160_DRDY_INT_EN;
+
+       return bmi160_write_conf_reg(regmap, BMI160_REG_INT_EN,
+                                    BMI160_DRDY_INT_EN, enable_bit,
+                                    BMI160_NORMAL_WRITE_USLEEP);
+}
+EXPORT_SYMBOL(bmi160_enable_irq);
+
+static int bmi160_get_irq(struct device_node *of_node, enum bmi160_int_pin *pin)
+{
+       int irq;
+
+       /* Use INT1 if possible, otherwise fall back to INT2. */
+       irq = of_irq_get_byname(of_node, "INT1");
+       if (irq > 0) {
+               *pin = BMI160_PIN_INT1;
+               return irq;
+       }
+
+       irq = of_irq_get_byname(of_node, "INT2");
+       if (irq > 0)
+               *pin = BMI160_PIN_INT2;
+
+       return irq;
+}
+
+static int bmi160_config_device_irq(struct iio_dev *indio_dev, int irq_type,
+                                   enum bmi160_int_pin pin)
+{
+       bool open_drain;
+       u8 irq_mask;
+       struct bmi160_data *data = iio_priv(indio_dev);
+       struct device *dev = regmap_get_device(data->regmap);
+
+       /* Level-triggered, active-low is the default if we set all zeroes. */
+       if (irq_type == IRQF_TRIGGER_RISING)
+               irq_mask = BMI160_ACTIVE_HIGH | BMI160_EDGE_TRIGGERED;
+       else if (irq_type == IRQF_TRIGGER_FALLING)
+               irq_mask = BMI160_EDGE_TRIGGERED;
+       else if (irq_type == IRQF_TRIGGER_HIGH)
+               irq_mask = BMI160_ACTIVE_HIGH;
+       else if (irq_type == IRQF_TRIGGER_LOW)
+               irq_mask = 0;
+       else {
+               dev_err(&indio_dev->dev,
+                       "Invalid interrupt type 0x%x specified\n", irq_type);
+               return -EINVAL;
+       }
+
+       open_drain = of_property_read_bool(dev->of_node, "drive-open-drain");
+
+       return bmi160_config_pin(data->regmap, pin, open_drain, irq_mask,
+                                BMI160_NORMAL_WRITE_USLEEP);
+}
+
+static int bmi160_setup_irq(struct iio_dev *indio_dev, int irq,
+                           enum bmi160_int_pin pin)
+{
+       struct irq_data *desc;
+       u32 irq_type;
+       int ret;
+
+       desc = irq_get_irq_data(irq);
+       if (!desc) {
+               dev_err(&indio_dev->dev, "Could not find IRQ %d\n", irq);
+               return -EINVAL;
+       }
+
+       irq_type = irqd_get_trigger_type(desc);
+
+       ret = bmi160_config_device_irq(indio_dev, irq_type, pin);
+       if (ret)
+               return ret;
+
+       return bmi160_probe_trigger(indio_dev, irq, irq_type);
+}
+
 static int bmi160_chip_init(struct bmi160_data *data, bool use_spi)
 {
        int ret;
@@ -539,6 +748,49 @@ static int bmi160_chip_init(struct bmi160_data *data, bool use_spi)
        return 0;
 }
 
+static int bmi160_data_rdy_trigger_set_state(struct iio_trigger *trig,
+                                            bool enable)
+{
+       struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+       struct bmi160_data *data = iio_priv(indio_dev);
+
+       return bmi160_enable_irq(data->regmap, enable);
+}
+
+static const struct iio_trigger_ops bmi160_trigger_ops = {
+       .set_trigger_state = &bmi160_data_rdy_trigger_set_state,
+};
+
+int bmi160_probe_trigger(struct iio_dev *indio_dev, int irq, u32 irq_type)
+{
+       struct bmi160_data *data = iio_priv(indio_dev);
+       int ret;
+
+       data->trig = devm_iio_trigger_alloc(&indio_dev->dev, "%s-dev%d",
+                                           indio_dev->name, indio_dev->id);
+
+       if (data->trig == NULL)
+               return -ENOMEM;
+
+       ret = devm_request_irq(&indio_dev->dev, irq,
+                              &iio_trigger_generic_data_rdy_poll,
+                              irq_type, "bmi160", data->trig);
+       if (ret < 0)
+               return ret;
+
+       data->trig->dev.parent = regmap_get_device(data->regmap);
+       data->trig->ops = &bmi160_trigger_ops;
+       iio_trigger_set_drvdata(data->trig, indio_dev);
+
+       ret = devm_iio_trigger_register(&indio_dev->dev, data->trig);
+       if (ret)
+               return ret;
+
+       indio_dev->trig = iio_trigger_get(data->trig);
+
+       return 0;
+}
+
 static void bmi160_chip_uninit(void *data)
 {
        struct bmi160_data *bmi_data = data;
@@ -552,6 +804,8 @@ int bmi160_core_probe(struct device *dev, struct regmap *regmap,
 {
        struct iio_dev *indio_dev;
        struct bmi160_data *data;
+       int irq;
+       enum bmi160_int_pin int_pin;
        int ret;
 
        indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
@@ -585,6 +839,16 @@ int bmi160_core_probe(struct device *dev, struct regmap *regmap,
        if (ret < 0)
                return ret;
 
+       irq = bmi160_get_irq(dev->of_node, &int_pin);
+       if (irq > 0) {
+               ret = bmi160_setup_irq(indio_dev, irq, int_pin);
+               if (ret)
+                       dev_err(&indio_dev->dev, "Failed to setup IRQ %d\n",
+                               irq);
+       } else {
+               dev_info(&indio_dev->dev, "Not setting up IRQ trigger\n");
+       }
+
        ret = devm_iio_device_register(dev, indio_dev);
        if (ret < 0)
                return ret;