[PATCH v2 5/9] iio: adc: ad4062: Add IIO Trigger support

[Jorge Marques <jorge.marques@analog.com>]

Adds support for IIO Trigger. Optionally, gp1 is assigned as Data Ready
signal, if not present, fallback to an I3C IBI with the same role.
The software trigger is allocated by the device, but must be attached by
the user before enabling the buffer. The purpose is to not impede
removing the driver due to the increased reference count when
iio_trigger_set_immutable or iio_trigger_get is used.

Signed-off-by: Jorge Marques <jorge.marques@analog.com>
---
 drivers/iio/adc/Kconfig  |   2 +
 drivers/iio/adc/ad4062.c | 164 +++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 161 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index e506dbe83f488..ddb7820f0bdcc 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -74,6 +74,8 @@ config AD4062
 	tristate "Analog Devices AD4062 Driver"
 	depends on I3C
 	select REGMAP_I3C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	  Say yes here to build support for Analog Devices AD4062 I3C analog
 	  to digital converters (ADC).
diff --git a/drivers/iio/adc/ad4062.c b/drivers/iio/adc/ad4062.c
index 6866393ffef8d..4e4be7358047f 100644
--- a/drivers/iio/adc/ad4062.c
+++ b/drivers/iio/adc/ad4062.c
@@ -12,8 +12,12 @@
 #include <linux/err.h>
 #include <linux/i3c/device.h>
 #include <linux/i3c/master.h>
+#include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 #include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/math.h>
@@ -60,6 +64,7 @@
 #define     AD4062_REG_DEVICE_STATUS_DEVICE_RESET	BIT(6)
 #define AD4062_REG_IBI_STATUS				0x48
 #define AD4062_REG_CONV_READ_LSB			0x50
+#define AD4062_REG_CONV_READ				0x53
 #define AD4062_REG_CONV_TRIGGER				0x59
 #define AD4062_REG_CONV_AUTO				0x61
 #define AD4062_MAX_REG					AD4062_REG_CONV_AUTO
@@ -134,6 +139,7 @@ struct ad4062_state {
 	const struct ad4062_chip_info *chip;
 	const struct ad4062_bus_ops *ops;
 	enum ad4062_operation_mode mode;
+	struct work_struct trig_conv;
 	struct completion completion;
 	struct iio_trigger *trigger;
 	struct iio_dev *indio_dev;
@@ -143,6 +149,7 @@ struct ad4062_state {
 	int vref_uv;
 	int samp_freqs[ARRAY_SIZE(ad4062_conversion_freqs)];
 	u8 oversamp_ratio;
+	bool gpo_irq[2];
 	union {
 		__be32 be32;
 		__be16 be16;
@@ -396,7 +403,10 @@ static irqreturn_t ad4062_irq_handler_drdy(int irq, void *private)
 	struct iio_dev *indio_dev = private;
 	struct ad4062_state *st = iio_priv(indio_dev);
 
-	complete(&st->completion);
+	if (iio_buffer_enabled(indio_dev) && iio_trigger_using_own(indio_dev))
+		iio_trigger_poll(st->trigger);
+	else
+		complete(&st->completion);
 
 	return IRQ_HANDLED;
 }
@@ -406,7 +416,56 @@ static void ad4062_ibi_handler(struct i3c_device *i3cdev,
 {
 	struct ad4062_state *st = i3cdev_get_drvdata(i3cdev);
 
-	complete(&st->completion);
+	if (iio_buffer_enabled(st->indio_dev))
+		iio_trigger_poll_nested(st->trigger);
+	else
+		complete(&st->completion);
+}
+
+static void ad4062_trigger_work(struct work_struct *work)
+{
+	struct ad4062_state *st = container_of(work, struct ad4062_state,
+					       trig_conv);
+	int ret;
+
+	/* Read current conversion, if at reg CONV_READ, stop bit triggers
+	 * next sample and does not need writing the address.
+	 */
+	struct i3c_priv_xfer t[2] = {
+		{
+			.data.in = &st->buf.be32,
+			.len = sizeof(st->buf.be32),
+			.rnw = true,
+		},
+		{
+			.data.out = &st->reg_addr_conv,
+			.len = sizeof(st->reg_addr_conv),
+			.rnw = false,
+		},
+	};
+
+	ret = i3c_device_do_priv_xfers(st->i3cdev, &t[0], 1);
+	if (ret)
+		return;
+
+	iio_push_to_buffers_with_timestamp(st->indio_dev, &st->buf.be32,
+					   iio_get_time_ns(st->indio_dev));
+	if (st->gpo_irq[1])
+		return;
+
+	i3c_device_do_priv_xfers(st->i3cdev, &t[1], 1);
+}
+
+static irqreturn_t ad4062_poll_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ad4062_state *st = iio_priv(indio_dev);
+
+	iio_trigger_notify_done(indio_dev->trig);
+	schedule_work(&st->trig_conv);
+
+	return IRQ_HANDLED;
 }
 
 static void ad4062_remove_ibi(void *data)
@@ -451,10 +510,14 @@ static int ad4062_request_irq(struct iio_dev *indio_dev)
 	if (ret == -EPROBE_DEFER) {
 		return ret;
 	} else if (ret < 0) {
+		st->gpo_irq[1] = false;
+		st->reg_addr_conv = AD4062_REG_CONV_TRIGGER;
 		ret = regmap_update_bits(st->regmap, AD4062_REG_ADC_IBI_EN,
 					 AD4062_REG_ADC_IBI_EN_CONV_TRIGGER,
 					 AD4062_REG_ADC_IBI_EN_CONV_TRIGGER);
 	} else {
+		st->gpo_irq[1] = true;
+		st->reg_addr_conv = AD4062_REG_CONV_READ;
 		ret = devm_request_threaded_irq(dev, ret,
 						ad4062_irq_handler_drdy,
 						NULL, IRQF_ONESHOT, indio_dev->name,
@@ -464,6 +527,34 @@ static int ad4062_request_irq(struct iio_dev *indio_dev)
 	return ret;
 }
 
+static const struct iio_trigger_ops ad4062_trigger_ops = {
+	.validate_device = &iio_trigger_validate_own_device,
+};
+
+static int ad4062_request_trigger(struct iio_dev *indio_dev)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+	struct device *dev = &st->i3cdev->dev;
+	int ret;
+
+	st->trigger = devm_iio_trigger_alloc(dev, "%s-dev%d",
+					     indio_dev->name,
+					     iio_device_id(indio_dev));
+	if (!st->trigger)
+		return -ENOMEM;
+
+	st->trigger->ops = &ad4062_trigger_ops;
+	iio_trigger_set_drvdata(st->trigger, indio_dev);
+
+	ret = devm_iio_trigger_register(dev, st->trigger);
+	if (ret)
+		return ret;
+
+	indio_dev->trig = iio_trigger_get(st->trigger);
+
+	return 0;
+}
+
 static const int ad4062_oversampling_avail[] = {
 	1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096,
 };
@@ -579,8 +670,8 @@ static int __ad4062_read_chan_raw(struct ad4062_state *st, int *val)
 	int ret;
 
 	reinit_completion(&st->completion);
-	/* Change address pointer to trigger conversion */
-	ret = i3c_device_do_priv_xfers(i3cdev, &t[0], 1);
+	/* Change address pointer (and read if CONV_READ) to trigger conversion. */
+	ret = i3c_device_do_priv_xfers(i3cdev, t, st->gpo_irq[1] ? 2 : 1);
 	if (ret)
 		return ret;
 	/*
@@ -689,6 +780,57 @@ static int ad4062_write_raw(struct iio_dev *indio_dev,
 	return ret;
 }
 
+static int ad4062_triggered_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = pm_runtime_resume_and_get(&st->i3cdev->dev);
+	if (ret)
+		return ret;
+
+	ret = ad4062_set_operation_mode(st, st->mode);
+	if (ret)
+		goto out_mode_error;
+
+	/* CONV_READ requires read to trigger first sample. */
+	struct i3c_priv_xfer t[2] = {
+		{
+			.data.out = &st->reg_addr_conv,
+			.len = sizeof(st->reg_addr_conv),
+			.rnw = false,
+		},
+		{
+			.data.in = &st->buf.be32,
+			.len = sizeof(st->buf.be32),
+			.rnw = true,
+		}
+	};
+
+	ret = i3c_device_do_priv_xfers(st->i3cdev, t, st->gpo_irq[1] ? 2 : 1);
+	if (ret)
+		goto out_mode_error;
+	return 0;
+
+out_mode_error:
+	pm_runtime_put_autosuspend(&st->i3cdev->dev);
+
+	return ret;
+}
+
+static int ad4062_triggered_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+
+	pm_runtime_put_autosuspend(&st->i3cdev->dev);
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops ad4062_triggered_buffer_setup_ops = {
+	.postenable = &ad4062_triggered_buffer_postenable,
+	.predisable = &ad4062_triggered_buffer_predisable,
+};
+
 static int ad4062_debugfs_reg_access(struct iio_dev *indio_dev, unsigned int reg,
 				     unsigned int writeval, unsigned int *readval)
 {
@@ -801,7 +943,6 @@ static int ad4062_probe(struct i3c_device *i3cdev)
 	st->sampling_frequency = 0;
 	st->oversamp_ratio = BIT(0);
 	st->indio_dev = indio_dev;
-	st->reg_addr_conv = AD4062_REG_CONV_TRIGGER;
 
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->num_channels = 1;
@@ -825,6 +966,17 @@ static int ad4062_probe(struct i3c_device *i3cdev)
 	if (ret)
 		return ret;
 
+	ret = ad4062_request_trigger(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_triggered_buffer_setup(&i3cdev->dev, indio_dev,
+					      iio_pollfunc_store_time,
+					      ad4062_poll_handler,
+					      &ad4062_triggered_buffer_setup_ops);
+	if (ret)
+		return ret;
+
 	pm_runtime_set_active(dev);
 	ret = devm_pm_runtime_enable(dev);
 	if (ret)
@@ -837,6 +989,8 @@ static int ad4062_probe(struct i3c_device *i3cdev)
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to request i3c ibi\n");
 
+	INIT_WORK(&st->trig_conv, ad4062_trigger_work);
+
 	return devm_iio_device_register(dev, indio_dev);
 }
 

-- 
2.51.1