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iio: proximity: rfd77402: Add interrupt handling support

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Add interrupt handling support to enable event-driven data acquisition
instead of continuous polling. This improves responsiveness, reduces
CPU overhead, and supports low-power operation by allowing the system
to remain idle until an interrupt occurs.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Shrikant Raskar <raskar.shree97@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Shrikant Raskar 2026-01-28 23:21:53 +05:30 • committed by Jonathan Cameron
parent 53516b6fde
commit dc81be96a7
1 changed files with 113 additions and 8 deletions
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121
drivers/iio/proximity/rfd77402.c
View file

@ -6,20 +6,28 @@
*
* 7-bit I2C slave address 0x4c
*
* TODO: interrupt
* https://media.digikey.com/pdf/Data%20Sheets/RF%20Digital%20PDFs/RFD77402.pdf
*/
#include <linux/bits.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dev_printk.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/iio/iio.h>
#define RFD77402_DRV_NAME "rfd77402"
#define RFD77402_ICSR 0x00 /* Interrupt Control Status Register */
#define RFD77402_ICSR_CLR_CFG BIT(0)
#define RFD77402_ICSR_CLR_TYPE BIT(1)
#define RFD77402_ICSR_INT_MODE BIT(2)
#define RFD77402_ICSR_INT_POL BIT(3)
#define RFD77402_ICSR_RESULT BIT(4)
@ -27,6 +35,12 @@
#define RFD77402_ICSR_H2M_MSG BIT(6)
#define RFD77402_ICSR_RESET BIT(7)
#define RFD77402_IER 0x02
#define RFD77402_IER_RESULT BIT(0)
#define RFD77402_IER_M2H_MSG BIT(1)
#define RFD77402_IER_H2M_MSG BIT(2)
#define RFD77402_IER_RESET BIT(3)
#define RFD77402_CMD_R 0x04
#define RFD77402_CMD_SINGLE 0x01
#define RFD77402_CMD_STANDBY 0x10
@ -81,10 +95,14 @@ static const struct {
* struct rfd77402_data - device-specific data for the RFD77402 sensor
* @client: I2C client handle
* @lock: mutex to serialize sensor reads
* @completion: completion used for interrupt-driven measurements
* @irq_en: indicates whether interrupt mode is enabled
*/
struct rfd77402_data {
struct i2c_client *client;
struct mutex lock;
struct completion completion;
bool irq_en;
};
static const struct iio_chan_spec rfd77402_channels[] = {
@ -95,6 +113,41 @@ static const struct iio_chan_spec rfd77402_channels[] = {
},
};
static irqreturn_t rfd77402_interrupt_handler(int irq, void *pdata)
{
struct rfd77402_data *data = pdata;
int ret;
ret = i2c_smbus_read_byte_data(data->client, RFD77402_ICSR);
if (ret < 0)
return IRQ_NONE;
/* Check if the interrupt is from our device */
if (!(ret & RFD77402_ICSR_RESULT))
return IRQ_NONE;
/* Signal completion of measurement */
complete(&data->completion);
return IRQ_HANDLED;
}
static int rfd77402_wait_for_irq(struct rfd77402_data *data)
{
int ret;
/*
* According to RFD77402 Datasheet v1.8,
* Section 3.1.1 "Single Measure" (Figure: Single Measure Flow Chart),
* the suggested timeout for single measure is 100 ms.
*/
ret = wait_for_completion_timeout(&data->completion,
msecs_to_jiffies(100));
if (ret == 0)
return -ETIMEDOUT;
return 0;
}
static int rfd77402_set_state(struct i2c_client *client, u8 state, u16 check)
{
int ret;
@ -120,6 +173,11 @@ static int rfd77402_wait_for_result(struct rfd77402_data *data)
struct i2c_client *client = data->client;
int val, ret;
if (data->irq_en) {
reinit_completion(&data->completion);
return rfd77402_wait_for_irq(data);
}
/*
* As per RFD77402 datasheet section '3.1.1 Single Measure', the
* suggested timeout value for single measure is 100ms.
@ -204,8 +262,20 @@ static const struct iio_info rfd77402_info = {
.read_raw = rfd77402_read_raw,
};
static int rfd77402_init(struct i2c_client *client)
static int rfd77402_config_irq(struct i2c_client *client, u8 csr, u8 ier)
{
int ret;
ret = i2c_smbus_write_byte_data(client, RFD77402_ICSR, csr);
if (ret)
return ret;
return i2c_smbus_write_byte_data(client, RFD77402_IER, ier);
}
static int rfd77402_init(struct rfd77402_data *data)
{
struct i2c_client *client = data->client;
int ret, i;
ret = rfd77402_set_state(client, RFD77402_CMD_STANDBY,
@ -213,10 +283,26 @@ static int rfd77402_init(struct i2c_client *client)
if (ret < 0)
return ret;
/* configure INT pad as push-pull, active low */
ret = i2c_smbus_write_byte_data(client, RFD77402_ICSR,
RFD77402_ICSR_INT_MODE);
if (ret < 0)
if (data->irq_en) {
/*
* Enable interrupt mode:
* - Configure ICSR for auto-clear on read and
* push-pull output
* - Enable "result ready" interrupt in IER
*/
ret = rfd77402_config_irq(client,
RFD77402_ICSR_CLR_CFG |
RFD77402_ICSR_INT_MODE,
RFD77402_IER_RESULT);
} else {
/*
* Disable all interrupts:
* - Clear ICSR configuration
* - Disable all interrupts in IER
*/
ret = rfd77402_config_irq(client, 0, 0);
}
if (ret)
return ret;
/* I2C configuration */
@ -296,13 +382,29 @@ static int rfd77402_probe(struct i2c_client *client)
if (ret)
return ret;
init_completion(&data->completion);
if (client->irq > 0) {
ret = devm_request_threaded_irq(&client->dev, client->irq,
NULL, rfd77402_interrupt_handler,
IRQF_ONESHOT,
"rfd77402", data);
if (ret)
return ret;
data->irq_en = true;
dev_dbg(&client->dev, "Using interrupt mode\n");
} else {
dev_dbg(&client->dev, "Using polling mode\n");
}
indio_dev->info = &rfd77402_info;
indio_dev->channels = rfd77402_channels;
indio_dev->num_channels = ARRAY_SIZE(rfd77402_channels);
indio_dev->name = RFD77402_DRV_NAME;
indio_dev->modes = INDIO_DIRECT_MODE;
ret = rfd77402_init(client);
ret = rfd77402_init(data);
if (ret < 0)
return ret;
@ -320,7 +422,10 @@ static int rfd77402_suspend(struct device *dev)
static int rfd77402_resume(struct device *dev)
{
return rfd77402_init(to_i2c_client(dev));
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct rfd77402_data *data = iio_priv(indio_dev);
return rfd77402_init(data);
}
static DEFINE_SIMPLE_DEV_PM_OPS(rfd77402_pm_ops, rfd77402_suspend,