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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: Jacek Anaszewski <j.anaszewski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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f4b7f751c6
commit
94a6d5cf7c
1 changed files with 89 additions and 2 deletions
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@ -24,10 +24,11 @@
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/delay.h>
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#include <linux/bitops.h>
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#include <linux/gpio.h>
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#include <linux/of_gpio.h>
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@ -83,6 +84,7 @@
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*/
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#define AK8975_MAX_CONVERSION_TIMEOUT 500
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#define AK8975_CONVERSION_DONE_POLL_TIME 10
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#define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000)
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/*
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* Per-instance context data for the device.
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@ -95,6 +97,9 @@ struct ak8975_data {
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long raw_to_gauss[3];
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u8 reg_cache[AK8975_MAX_REGS];
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int eoc_gpio;
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int eoc_irq;
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wait_queue_head_t data_ready_queue;
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unsigned long flags;
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};
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static const int ak8975_index_to_reg[] = {
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@ -123,6 +128,51 @@ static int ak8975_write_data(struct i2c_client *client,
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return 0;
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}
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/*
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* Handle data ready irq
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*/
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static irqreturn_t ak8975_irq_handler(int irq, void *data)
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{
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struct ak8975_data *ak8975 = data;
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set_bit(0, &ak8975->flags);
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wake_up(&ak8975->data_ready_queue);
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return IRQ_HANDLED;
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}
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/*
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* Install data ready interrupt handler
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*/
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static int ak8975_setup_irq(struct ak8975_data *data)
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{
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struct i2c_client *client = data->client;
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int rc;
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int irq;
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if (client->irq)
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irq = client->irq;
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else
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irq = gpio_to_irq(data->eoc_gpio);
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rc = request_irq(irq, ak8975_irq_handler,
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IRQF_TRIGGER_RISING | IRQF_ONESHOT,
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dev_name(&client->dev), data);
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if (rc < 0) {
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dev_err(&client->dev,
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"irq %d request failed, (gpio %d): %d\n",
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irq, data->eoc_gpio, rc);
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return rc;
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}
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init_waitqueue_head(&data->data_ready_queue);
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clear_bit(0, &data->flags);
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data->eoc_irq = irq;
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return rc;
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}
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/*
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* Perform some start-of-day setup, including reading the asa calibration
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* values and caching them.
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@ -171,6 +221,16 @@ static int ak8975_setup(struct i2c_client *client)
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AK8975_REG_CNTL_MODE_POWER_DOWN,
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AK8975_REG_CNTL_MODE_MASK,
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AK8975_REG_CNTL_MODE_SHIFT);
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if (data->eoc_gpio > 0 || client->irq) {
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ret = ak8975_setup_irq(data);
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if (ret < 0) {
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dev_err(&client->dev,
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"Error setting data ready interrupt\n");
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return ret;
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}
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}
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if (ret < 0) {
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dev_err(&client->dev, "Error in setting power-down mode\n");
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return ret;
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@ -267,9 +327,23 @@ static int wait_conversion_complete_polled(struct ak8975_data *data)
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dev_err(&client->dev, "Conversion timeout happened\n");
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return -EINVAL;
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}
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return read_status;
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}
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/* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
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static int wait_conversion_complete_interrupt(struct ak8975_data *data)
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{
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int ret;
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ret = wait_event_timeout(data->data_ready_queue,
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test_bit(0, &data->flags),
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AK8975_DATA_READY_TIMEOUT);
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clear_bit(0, &data->flags);
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return ret > 0 ? 0 : -ETIME;
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}
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/*
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* Emits the raw flux value for the x, y, or z axis.
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*/
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@ -295,13 +369,16 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
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}
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/* Wait for the conversion to complete. */
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if (gpio_is_valid(data->eoc_gpio))
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if (data->eoc_irq)
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ret = wait_conversion_complete_interrupt(data);
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else if (gpio_is_valid(data->eoc_gpio))
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ret = wait_conversion_complete_gpio(data);
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else
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ret = wait_conversion_complete_polled(data);
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if (ret < 0)
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goto exit;
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/* This will be executed only for non-interrupt based waiting case */
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if (ret & AK8975_REG_ST1_DRDY_MASK) {
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ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2);
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if (ret < 0) {
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@ -415,6 +492,11 @@ static int ak8975_probe(struct i2c_client *client,
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}
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data = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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data->client = client;
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data->eoc_gpio = eoc_gpio;
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data->eoc_irq = 0;
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/* Perform some basic start-of-day setup of the device. */
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err = ak8975_setup(client);
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if (err < 0) {
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@ -439,6 +521,8 @@ static int ak8975_probe(struct i2c_client *client,
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exit_free_iio:
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iio_device_free(indio_dev);
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if (data->eoc_irq)
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free_irq(data->eoc_irq, data);
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exit_gpio:
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if (gpio_is_valid(eoc_gpio))
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gpio_free(eoc_gpio);
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@ -453,6 +537,9 @@ static int ak8975_remove(struct i2c_client *client)
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iio_device_unregister(indio_dev);
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if (data->eoc_irq)
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free_irq(data->eoc_irq, data);
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if (gpio_is_valid(data->eoc_gpio))
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gpio_free(data->eoc_gpio);
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