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Commit 94a6d5cf authored by Jacek Anaszewski's avatar Jacek Anaszewski Committed by Jonathan Cameron
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iio:ak8975 Implement data ready interrupt handling 



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: default avatarJacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent f4b7f751

drivers/iio/magnetometer/ak8975.c

+89 −2
Original line number Diff line number Diff line
@@ -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[] = {
@@ -123,6 +128,51 @@ static int ak8975_write_data(struct i2c_client *client, 
	return 0;

}



/*

 * 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) {
@@ -415,6 +492,11 @@ 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) {
@@ -439,6 +521,8 @@ 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, data);

exit_gpio:

	if (gpio_is_valid(eoc_gpio))

		gpio_free(eoc_gpio);
@@ -453,6 +537,9 @@ static int ak8975_remove(struct i2c_client *client) 


	iio_device_unregister(indio_dev);



	if (data->eoc_irq)

		free_irq(data->eoc_irq, data);



	if (gpio_is_valid(data->eoc_gpio))

		gpio_free(data->eoc_gpio);