Implement "data ready" interrupt handling in addition to the
two existing read modes - DRDY GPIO polling and ST1 register
DRDY bit polling.
Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Andrew Chew <achew@xxxxxxxxxx>
---
drivers/iio/magnetometer/ak8975.c | 91 ++++++++++++++++++++++++++++++++++++-
1 files changed, 89 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index eb17eca..d379c4c 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -24,10 +24,11 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/i2c.h>
+#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>
-
+#include <linux/bitops.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
@@ -83,6 +84,7 @@
*/
#define AK8975_MAX_CONVERSION_TIMEOUT 500
#define AK8975_CONVERSION_DONE_POLL_TIME 10
+#define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000)
/*
* Per-instance context data for the device.
@@ -95,6 +97,9 @@ struct ak8975_data {
long raw_to_gauss[3];
u8 reg_cache[AK8975_MAX_REGS];
int eoc_gpio;
+ int eoc_irq;
+ wait_queue_head_t data_ready_queue;
+ unsigned long flags;
};
static const int ak8975_index_to_reg[] = {
@@ -124,6 +129,51 @@ static int ak8975_write_data(struct i2c_client *client,
}
/*
+ * Handle data ready irq
+ */
+static irqreturn_t ak8975_irq_handler(int irq, void *data)
+{
+ struct ak8975_data *ak8975 = data;
+
+ set_bit(0, &ak8975->flags);
+ wake_up(&ak8975->data_ready_queue);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Install data ready interrupt handler
+ */
+static int ak8975_setup_irq(struct ak8975_data *data)
+{
+ struct i2c_client *client = data->client;
+ int rc;
+ int irq;
+
+ if (client->irq)
+ irq = client->irq;
+ else
+ irq = gpio_to_irq(data->eoc_gpio);
+
+ rc = request_irq(irq, ak8975_irq_handler,
+ IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+ dev_name(&client->dev), data);
+ if (rc < 0) {
+ dev_err(&client->dev,
+ "irq %d request failed, (gpio %d): %d\n",
+ irq, data->eoc_gpio, rc);
+ return rc;
+ }
+
+ init_waitqueue_head(&data->data_ready_queue);
+ clear_bit(0, &data->flags);
+ data->eoc_irq = irq;
+
+ return rc;
+}
+
+
+/*
* Perform some start-of-day setup, including reading the asa calibration
* values and caching them.
*/
@@ -171,6 +221,16 @@ static int ak8975_setup(struct i2c_client *client)
AK8975_REG_CNTL_MODE_POWER_DOWN,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
+
+ if (data->eoc_gpio > 0 || client->irq) {
+ ret = ak8975_setup_irq(data);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "Error setting data ready interrupt\n");
+ return ret;
+ }
+ }
+
if (ret < 0) {
dev_err(&client->dev, "Error in setting power-down mode\n");
return ret;
@@ -267,9 +327,23 @@ static int wait_conversion_complete_polled(struct ak8975_data *data)
dev_err(&client->dev, "Conversion timeout happened\n");
return -EINVAL;
}
+
return read_status;
}
+/* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
+static int wait_conversion_complete_interrupt(struct ak8975_data *data)
+{
+ int ret;
+
+ ret = wait_event_timeout(data->data_ready_queue,
+ test_bit(0, &data->flags),
+ AK8975_DATA_READY_TIMEOUT);
+ clear_bit(0, &data->flags);
+
+ return ret > 0 ? 0 : -ETIME;
+}
+
/*
* Emits the raw flux value for the x, y, or z axis.
*/
@@ -295,13 +369,16 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
}
/* Wait for the conversion to complete. */
- if (gpio_is_valid(data->eoc_gpio))
+ if (data->eoc_irq)
+ ret = wait_conversion_complete_interrupt(data);
+ else if (gpio_is_valid(data->eoc_gpio))
ret = wait_conversion_complete_gpio(data);
else
ret = wait_conversion_complete_polled(data);
if (ret < 0)
goto exit;
+ /* This will be executed only for non-interrupt based waiting case */
if (ret & AK8975_REG_ST1_DRDY_MASK) {
ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2);
if (ret < 0) {
@@ -412,6 +489,11 @@ static int ak8975_probe(struct i2c_client *client,
}
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
+
+ data->client = client;
+ data->eoc_gpio = eoc_gpio;
+ data->eoc_irq = 0;
+
/* Perform some basic start-of-day setup of the device. */
err = ak8975_setup(client);
if (err < 0) {
@@ -436,6 +518,8 @@ static int ak8975_probe(struct i2c_client *client,
exit_free_iio:
iio_device_free(indio_dev);
+ if (data->eoc_irq)
+ free_irq(data->eoc_irq, NULL);
exit_gpio:
if (gpio_is_valid(eoc_gpio))
gpio_free(eoc_gpio);
@@ -450,6 +534,9 @@ static int ak8975_remove(struct i2c_client *client)
iio_device_unregister(indio_dev);
+ if (data->eoc_irq)
+ free_irq(data->eoc_irq, NULL);
+
if (gpio_is_valid(data->eoc_gpio))
gpio_free(data->eoc_gpio);
--
1.7.5.4
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