[PATCH v2 04/10] iio: adc: mcp3911: add support for interrupts

Marcus Folkesson
2022-06-25T10:37:32Z

Make it possible to read values upon interrupts.
Configure Data Ready Signal Output Pin to either HiZ or push-pull and
use it as interrupt source.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---

Notes:
v2:
- Removed blank lines (Andy Shevchenko)
- Removed dr_hiz variable (Andy Shevchenko)

drivers/iio/adc/mcp3911.c | 65 +++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 2a4bf374f140..f4ee0c27c2ab 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -26,6 +26,7 @@
#define MCP3911_REG_GAIN 0x09

#define MCP3911_REG_STATUSCOM 0x0a
+#define MCP3911_STATUSCOM_DRHIZ BIT(12)
#define MCP3911_STATUSCOM_CH1_24WIDTH BIT(4)
#define MCP3911_STATUSCOM_CH0_24WIDTH BIT(3)
#define MCP3911_STATUSCOM_EN_OFFCAL BIT(2)
@@ -58,6 +59,7 @@ struct mcp3911 {
struct regulator *vref;
struct clk *clki;
u32 dev_addr;
+ struct iio_trigger *trig;
struct {
u32 channels[2];
s64 ts __aligned(8);
@@ -252,6 +254,17 @@ static const struct iio_info mcp3911_info = {
.write_raw = mcp3911_write_raw,
};

+static irqreturn_t mcp3911_interrupt(int irq, void *dev_id)
+{
+ struct iio_dev *indio_dev = dev_id;
+ struct mcp3911 *adc = iio_priv(indio_dev);
+
+ if (iio_buffer_enabled(indio_dev))
+ iio_trigger_poll(adc->trig);
+
+ return IRQ_HANDLED;
+};
+
static int mcp3911_config(struct mcp3911 *adc)
{
struct device *dev = &adc->spi->dev;
@@ -298,6 +311,23 @@ static int mcp3911_config(struct mcp3911 *adc)
return mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2);
}

+static int mcp3911_set_trigger_state(struct iio_trigger *trig, bool enable)
+{
+ struct mcp3911 *adc = iio_trigger_get_drvdata(trig);
+
+ if (enable)
+ enable_irq(adc->spi->irq);
+ else
+ disable_irq(adc->spi->irq);
+
+ return 0;
+}
+
+static const struct iio_trigger_ops mcp3911_trigger_ops = {
+ .validate_device = iio_trigger_validate_own_device,
+ .set_trigger_state = mcp3911_set_trigger_state,
+};
+
static int mcp3911_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
@@ -352,6 +382,15 @@ static int mcp3911_probe(struct spi_device *spi)
if (ret)
goto clk_disable;

+ if (device_property_read_bool(&adc->spi->dev, "microchip,data-ready-hiz"))
+ ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_DRHIZ,
+ 0, 2);
+ else
+ ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM, MCP3911_STATUSCOM_DRHIZ,
+ MCP3911_STATUSCOM_DRHIZ, 2);
+ if (ret < 0)
+ goto clk_disable;
+
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
indio_dev->info = &mcp3911_info;
@@ -362,6 +401,32 @@ static int mcp3911_probe(struct spi_device *spi)

mutex_init(&adc->lock);

+ if (spi->irq > 0) {
+ adc->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
+ indio_dev->name,
+ iio_device_id(indio_dev));
+ if (!adc->trig)
+ goto clk_disable;
+
+ adc->trig->ops = &mcp3911_trigger_ops;
+ iio_trigger_set_drvdata(adc->trig, adc);
+ ret = devm_iio_trigger_register(&spi->dev, adc->trig);
+ if (ret)
+ goto clk_disable;
+
+ /*
+ * The device generates interrupts as long as it is powered up.
+ * Some platforms might not allow the option to power it down so
+ * don't enable the interrupt to avoid extra load on the system
+ */
+ ret = devm_request_irq(&spi->dev, spi->irq,
+ &mcp3911_interrupt,
+ IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN | IRQF_ONESHOT,
+ indio_dev->name, indio_dev);
+ if (ret)
+ goto clk_disable;
+ }
+
ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
NULL,
mcp3911_trigger_handler, NULL);
--
2.36.1