From dc81be96a73a67d47da336497b888529c73d389b Mon Sep 17 00:00:00 2001 From: Shrikant Raskar Date: Wed, 28 Jan 2026 23:21:53 +0530 Subject: [PATCH] iio: proximity: rfd77402: Add interrupt handling support 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 Signed-off-by: Shrikant Raskar Signed-off-by: Jonathan Cameron --- drivers/iio/proximity/rfd77402.c | 121 +++++++++++++++++++++++++++++-- 1 file changed, 113 insertions(+), 8 deletions(-) diff --git a/drivers/iio/proximity/rfd77402.c b/drivers/iio/proximity/rfd77402.c index 0be49a6e401d..6afdbfca3e5a 100644 --- a/drivers/iio/proximity/rfd77402.c +++ b/drivers/iio/proximity/rfd77402.c @@ -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 +#include #include +#include +#include #include +#include #include +#include #include +#include #include #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, -- 2.47.3