[PATCH 2/2] ti-adc081c: Initial triggered buffer support

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Using this requires software triggers like CONFIG_IIO_HRTIMER_TRIGGER.

The device can be configured to do internal periodic sampling but does
not appear to offer some sort of interrupt on data ready. It only offers
interrupts on values out of a specific range.

Signed-off-by: Crestez Dan Leonard <leonard.crestez@xxxxxxxxx>
---
 drivers/iio/adc/ti-adc081c.c | 99 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 83 insertions(+), 16 deletions(-)

diff --git a/drivers/iio/adc/ti-adc081c.c b/drivers/iio/adc/ti-adc081c.c
index 9b2f26f..040e2aa 100644
--- a/drivers/iio/adc/ti-adc081c.c
+++ b/drivers/iio/adc/ti-adc081c.c
@@ -24,6 +24,9 @@
 #include <linux/of.h>
 
 #include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 #include <linux/regulator/consumer.h>
 
 struct adc081c {
@@ -69,27 +72,83 @@ static int adc081c_read_raw(struct iio_dev *iio,
 	return -EINVAL;
 }
 
-static const struct iio_chan_spec adc081c_channel = {
-	.type = IIO_VOLTAGE,
-	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
-	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-};
+static irqreturn_t adc081c_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct adc081c *data = iio_priv(indio_dev);
+	s64 ts;
+	u16 buf[8];
+	int ret;
+
+	/* Otherwise iio_push_to_buffers will corrupt the stack. */
+	if (indio_dev->scan_bytes > sizeof(buf)) {
+		dev_crit_once(&indio_dev->dev, "Bad iio_scan_bytes=%d > %d\n",
+				indio_dev->scan_bytes, (int)sizeof(buf));
+		goto out;
+	}
+
+	ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
+	ts = iio_get_time_ns();
+	if (ret < 0)
+		goto out;
+	buf[0] = ret;
+	iio_push_to_buffers_with_timestamp(indio_dev, buf, ts);
+out:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
 
 static const struct iio_info adc081c_info = {
 	.read_raw = adc081c_read_raw,
 	.driver_module = THIS_MODULE,
 };
 
+struct adcxx1c_model {
+	int bits;
+	const struct iio_chan_spec* channels;
+};
+
+#define ADCxx1C_CHAN(_bits) {					\
+	.type = IIO_VOLTAGE,					\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = (_bits),				\
+		.storagebits = 16,				\
+		.shift = 12 - (_bits),				\
+		.endianness = IIO_CPU,				\
+	},							\
+}
+
+#define DEFINE_ADCxx1C_MODEL(_name, _bits)				\
+	static const struct iio_chan_spec _name ## _channels[] = {	\
+		ADCxx1C_CHAN((_bits)),					\
+		IIO_CHAN_SOFT_TIMESTAMP(1),				\
+	};								\
+	static const struct adcxx1c_model _name ## _model = {		\
+		.bits = (_bits),					\
+		.channels = _name ## _channels,				\
+	}
+
+DEFINE_ADCxx1C_MODEL(adc081c,  8);
+DEFINE_ADCxx1C_MODEL(adc101c, 10);
+DEFINE_ADCxx1C_MODEL(adc121c, 12);
+
+struct adcxx1c_info {
+	int bits;
+	const struct adc081c_channels* channels;
+};
+
 static int adc081c_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct iio_dev *iio;
 	struct adc081c *adc;
+	struct adcxx1c_model *model = (struct adcxx1c_model*)id->driver_data;
 	int err;
 
-	if (id->driver_data != 8 && id->driver_data != 10 && id->driver_data != 12)
-		return -EINVAL;
-
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 		return -EOPNOTSUPP;
 
@@ -99,7 +158,7 @@ static int adc081c_probe(struct i2c_client *client,
 
 	adc = iio_priv(iio);
 	adc->i2c = client;
-	adc->bits = id->driver_data;
+	adc->bits = model->bits;
 
 	adc->ref = devm_regulator_get(&client->dev, "vref");
 	if (IS_ERR(adc->ref))
@@ -114,18 +173,26 @@ static int adc081c_probe(struct i2c_client *client,
 	iio->modes = INDIO_DIRECT_MODE;
 	iio->info = &adc081c_info;
 
-	iio->channels = &adc081c_channel;
-	iio->num_channels = 1;
+	iio->channels = model->channels;
+	iio->num_channels = 2;
+
+	err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
+	if (err < 0) {
+		dev_err(&client->dev, "iio triggered buffer setup failed\n");
+		goto err_regulator_disable;
+	}
 
 	err = iio_device_register(iio);
 	if (err < 0)
-		goto regulator_disable;
+		goto err_buffer_cleanup;
 
 	i2c_set_clientdata(client, iio);
 
 	return 0;
 
-regulator_disable:
+err_buffer_cleanup:
+	iio_triggered_buffer_cleanup(iio);
+err_regulator_disable:
 	regulator_disable(adc->ref);
 
 	return err;
@@ -143,9 +210,9 @@ static int adc081c_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id adc081c_id[] = {
-	{ "adc081c",  8 },
-	{ "adc101c", 10 },
-	{ "adc121c", 12 },
+	{ "adc081c", (long)&adc081c_model },
+	{ "adc101c", (long)&adc101c_model },
+	{ "adc121c", (long)&adc121c_model },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, adc081c_id);
-- 
2.8.0.rc3

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