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([103.187.64.30]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-bd760ac62ecsm17935713a12.26.2025.11.25.19.18.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Nov 2025 19:18:28 -0800 (PST) From: Shrikant Raskar To: jic23@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org Cc: dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, heiko@sntech.de, neil.armstrong@linaro.org, skhan@linuxfoundation.org, david.hunter.linux@gmail.com, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Shrikant Raskar Subject: [PATCH 3/3] iio: proximity: rfd77402: Add interrupt handling support Date: Wed, 26 Nov 2025 08:44:40 +0530 Message-ID: <20251126031440.30065-4-raskar.shree97@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251126031440.30065-1-raskar.shree97@gmail.com> References: <20251126031440.30065-1-raskar.shree97@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. Signed-off-by: Shrikant Raskar --- drivers/iio/proximity/rfd77402.c | 127 ++++++++++++++++++++++++++----- 1 file changed, 107 insertions(+), 20 deletions(-) diff --git a/drivers/iio/proximity/rfd77402.c b/drivers/iio/proximity/rfd77= 402.c index 3262af6f6882..0e4763b34267 100644 --- a/drivers/iio/proximity/rfd77402.c +++ b/drivers/iio/proximity/rfd77402.c @@ -6,19 +6,22 @@ * * 7-bit I2C slave address 0x4c * - * TODO: interrupt * https://media.digikey.com/pdf/Data%20Sheets/RF%20Digital%20PDFs/RFD7740= 2.pdf */ =20 #include #include #include - +#include +#include +#include #include =20 #define RFD77402_DRV_NAME "rfd77402" =20 #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) @@ -26,6 +29,12 @@ #define RFD77402_ICSR_H2M_MSG BIT(6) #define RFD77402_ICSR_RESET BIT(7) =20 +#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 @@ -80,6 +89,10 @@ struct rfd77402_data { struct i2c_client *client; /* Serialize reads from the sensor */ struct mutex lock; + /* Completion for interrupt-driven measurements */ + struct completion completion; + /* Flag to indicate if interrupt is available */ + bool irq_en; }; =20 static const struct iio_chan_spec rfd77402_channels[] =3D { @@ -110,8 +123,24 @@ static int rfd77402_set_state(struct i2c_client *clien= t, u8 state, u16 check) return 0; } =20 -static int rfd77402_measure(struct i2c_client *client) +static irqreturn_t rfd77402_interrupt_handler(int irq, void *dev_id) +{ + struct rfd77402_data *data =3D dev_id; + int ret; + + /* Check if the interrupt is from our device */ + ret =3D i2c_smbus_read_byte_data(data->client, RFD77402_ICSR); + if (ret < 0 || !(ret & RFD77402_ICSR_RESULT)) + return IRQ_NONE; + + /* Signal completion of measurement */ + complete(&data->completion); + return IRQ_HANDLED; +} + +static int rfd77402_measure(struct rfd77402_data *data) { + struct i2c_client *client =3D data->client; int ret; int tries =3D 10; =20 @@ -120,24 +149,39 @@ static int rfd77402_measure(struct i2c_client *client) if (ret < 0) return ret; =20 + /* Initialize completion for interrupt mode */ + if (data->irq_en) + reinit_completion(&data->completion); + ret =3D i2c_smbus_write_byte_data(client, RFD77402_CMD_R, RFD77402_CMD_SINGLE | RFD77402_CMD_VALID); if (ret < 0) goto err; =20 - while (tries-- > 0) { - ret =3D i2c_smbus_read_byte_data(client, RFD77402_ICSR); - if (ret < 0) + if (data->irq_en) { + /* Wait for interrupt-driven completion */ + ret =3D wait_for_completion_timeout(&data->completion, + msecs_to_jiffies(200)); + if (ret =3D=3D 0) { + ret =3D -ETIMEDOUT; goto err; - if (ret & RFD77402_ICSR_RESULT) - break; - msleep(20); - } - - if (tries < 0) { - ret =3D -ETIMEDOUT; - goto err; + } + } else { + /* Fallback to polling mode */ + while (tries-- > 0) { + ret =3D i2c_smbus_read_byte_data(client, RFD77402_ICSR); + if (ret < 0) + goto err; + if (ret & RFD77402_ICSR_RESULT) + break; + msleep(20); + } + + if (tries < 0) { + ret =3D -ETIMEDOUT; + goto err; + } } =20 ret =3D i2c_smbus_read_word_data(client, RFD77402_RESULT_R); @@ -168,7 +212,7 @@ static int rfd77402_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: mutex_lock(&data->lock); - ret =3D rfd77402_measure(data->client); + ret =3D rfd77402_measure(data); mutex_unlock(&data->lock); if (ret < 0) return ret; @@ -190,6 +234,8 @@ static const struct iio_info rfd77402_info =3D { =20 static int rfd77402_init(struct i2c_client *client) { + struct iio_dev *indio_dev =3D i2c_get_clientdata(client); + struct rfd77402_data *data =3D iio_priv(indio_dev); int ret, i; =20 ret =3D rfd77402_set_state(client, RFD77402_CMD_STANDBY, @@ -197,11 +243,29 @@ static int rfd77402_init(struct i2c_client *client) if (ret < 0) return ret; =20 - /* configure INT pad as push-pull, active low */ - ret =3D i2c_smbus_write_byte_data(client, RFD77402_ICSR, - RFD77402_ICSR_INT_MODE); - if (ret < 0) - return ret; + if (data->irq_en) { + /* Configure ICSR: auto-clear on read, push-pull, falling edge */ + ret =3D i2c_smbus_write_byte_data(client, RFD77402_ICSR, + RFD77402_ICSR_CLR_CFG | + RFD77402_ICSR_INT_MODE); + if (ret < 0) + return ret; + + /* Enable 'new data available' interrupt in IER */ + ret =3D i2c_smbus_write_byte_data(client, RFD77402_IER, + RFD77402_IER_RESULT); + if (ret < 0) + return ret; + } else { + /* Disable interrupts */ + ret =3D i2c_smbus_write_byte_data(client, RFD77402_ICSR, 0); + if (ret < 0) + return ret; + + ret =3D i2c_smbus_write_byte_data(client, RFD77402_IER, 0); + if (ret < 0) + return ret; + } =20 /* I2C configuration */ ret =3D i2c_smbus_write_word_data(client, RFD77402_I2C_INIT_CFG, @@ -277,6 +341,29 @@ static int rfd77402_probe(struct i2c_client *client) data->client =3D client; mutex_init(&data->lock); =20 + init_completion(&data->completion); + + i2c_set_clientdata(client, indio_dev); + + /* Check if interrupt is mentioned in device tree */ + data->irq_en =3D false; + if (client->irq > 0) { + ret =3D devm_request_threaded_irq(&client->dev, client->irq, + NULL, rfd77402_interrupt_handler, + IRQF_TRIGGER_FALLING | IRQF_ONESHOT, + "rfd77402", data); + if (ret =3D=3D 0) { + data->irq_en =3D true; + dev_info(&client->dev, "Using interrupt mode\n"); + } else { + dev_warn(&client->dev, + "Failed to request IRQ %d, using polling mode: %d\n", + client->irq, ret); + } + } else { + dev_info(&client->dev, "No interrupt specified, using polling mode\n"); + } + indio_dev->info =3D &rfd77402_info; indio_dev->channels =3D rfd77402_channels; indio_dev->num_channels =3D ARRAY_SIZE(rfd77402_channels); --=20 2.43.0