[PATCH v5 6/9] iio: adc: mcp3911: add support for interrupts

Marcus Folkesson
2022-08-09T07:32:54Z

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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
drivers/iio/adc/mcp3911.c | 53 +++++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 87ab7e24ab08..ac614030e400 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -30,6 +30,7 @@
#define MCP3911_REG_GAIN 0x09

#define MCP3911_REG_STATUSCOM 0x0a
+#define MCP3911_STATUSCOM_DRHIZ BIT(12)
#define MCP3911_STATUSCOM_READ GENMASK(7, 6)
#define MCP3911_STATUSCOM_CH1_24WIDTH BIT(4)
#define MCP3911_STATUSCOM_CH0_24WIDTH BIT(3)
@@ -63,6 +64,7 @@ struct mcp3911 {
struct regulator *vref;
struct clk *clki;
u32 dev_addr;
+ struct iio_trigger *trig;
struct {
u32 channels[MCP3911_NUM_CHANNELS];
s64 ts __aligned(8);
@@ -352,6 +354,23 @@ static void mcp3911_cleanup_regulator(void *_adc)
regulator_disable(adc->vref);
}

+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;
@@ -415,6 +434,15 @@ static int mcp3911_probe(struct spi_device *spi)
if (ret)
return ret;

+ 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)
+ return ret;
+
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &mcp3911_info;
@@ -425,6 +453,31 @@ 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)
+ return PTR_ERR(adc->trig);
+
+ adc->trig->ops = &mcp3911_trigger_ops;
+ iio_trigger_set_drvdata(adc->trig, adc);
+ ret = devm_iio_trigger_register(&spi->dev, adc->trig);
+ if (ret)
+ return ret;
+
+ /*
+ * 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,
+ &iio_trigger_generic_data_rdy_poll, IRQF_NO_AUTOEN | IRQF_ONESHOT,
+ indio_dev->name, adc->trig);
+ if (ret)
+ return ret;
+ }
+
ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
NULL,
mcp3911_trigger_handler, NULL);
--
2.37.1