All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jonathan Cameron <jic23@kernel.org>
To: linux-iio@vger.kernel.org
Cc: Lars-Peter Clausen <lars@metafoo.de>,
	Michael Hennerich <Michael.Hennerich@analog.com>,
	song.bao.hua@hisilicon.com, robh+dt@kernel.org,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: [PATCH 12/24] staging:iio:cdc:ad7150: Rework interrupt handling.
Date: Sun,  7 Feb 2021 15:46:11 +0000	[thread overview]
Message-ID: <20210207154623.433442-13-jic23@kernel.org> (raw)
In-Reply-To: <20210207154623.433442-1-jic23@kernel.org>

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Note this doesn't support everything the chip can do as we ignore
window mode for now (in window / out of window).

* Given the chip doesn't have any way of disabling the threshold
  pins, use disable_irq() etc to mask them except when we actually
  want them enabled (previously events were always enabled).
  Note there are race conditions, but using the current state from
  the status register and disabling interrupts across changes in
  type of event should mean those races result in interrupts,
  but no events to userspace.

* Correctly reflect that there is one threshold line per channel.

* Only take notice of rising edge. If anyone wants the other edge
  then they should set the other threshold (they are available for
  rising and falling directions).  This isn't perfect but it makes
  it a lot simpler.

* If insufficient interrupts are specified in firnware, don't support
  events.

* Adaptive events use the same pos/neg values of thrMD as non adaptive
  ones.

Tested against qemu based emulation.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/staging/iio/cdc/ad7150.c | 258 ++++++++++++++++++-------------
 1 file changed, 153 insertions(+), 105 deletions(-)

diff --git a/drivers/staging/iio/cdc/ad7150.c b/drivers/staging/iio/cdc/ad7150.c
index f8183c540d5c..24be97456c03 100644
--- a/drivers/staging/iio/cdc/ad7150.c
+++ b/drivers/staging/iio/cdc/ad7150.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
+#include <linux/irq.h>
 #include <linux/module.h>
 
 #include <linux/iio/iio.h>
@@ -60,8 +61,6 @@ enum {
 /**
  * struct ad7150_chip_info - instance specific chip data
  * @client: i2c client for this device
- * @current_event: device always has one type of event enabled.
- *	This element stores the event code of the current one.
  * @threshold: thresholds for simple capacitance value events
  * @thresh_sensitivity: threshold for simple capacitance offset
  *	from 'average' value.
@@ -70,21 +69,23 @@ enum {
  *	value jumps to current value.  Note made up of two fields,
  *      3:0 are for timeout receding - applies if below lower threshold
  *      7:4 are for timeout approaching - applies if above upper threshold
- * @old_state: store state from previous event, allowing confirmation
- *	of new condition.
- * @conversion_mode: the current conversion mode.
  * @state_lock: ensure consistent state of this structure wrt the
  *	hardware.
+ * @interrupts: one or two interrupt numbers depending on device type.
+ * @int_enabled: is a given interrupt currently enabled.
+ * @type: threshold type
+ * @dir: threshold direction
  */
 struct ad7150_chip_info {
 	struct i2c_client *client;
-	u64 current_event;
 	u16 threshold[2][2];
 	u8 thresh_sensitivity[2][2];
 	u8 thresh_timeout[2][2];
-	int old_state;
-	char *conversion_mode;
 	struct mutex state_lock;
+	int interrupts[2];
+	bool int_enabled[2];
+	enum iio_event_type type;
+	enum iio_event_direction dir;
 };
 
 /*
@@ -158,8 +159,8 @@ static int ad7150_read_event_config(struct iio_dev *indio_dev,
 	switch (type) {
 	case IIO_EV_TYPE_THRESH_ADAPTIVE:
 		if (dir == IIO_EV_DIR_RISING)
-			return !thrfixed && (threshtype == 0x3);
-		return !thrfixed && (threshtype == 0x2);
+			return !thrfixed && (threshtype == 0x1);
+		return !thrfixed && (threshtype == 0x0);
 	case IIO_EV_TYPE_THRESH:
 		if (dir == IIO_EV_DIR_RISING)
 			return thrfixed && (threshtype == 0x1);
@@ -179,11 +180,9 @@ static int ad7150_write_event_params(struct iio_dev *indio_dev,
 {
 	struct ad7150_chip_info *chip = iio_priv(indio_dev);
 	int rising = (dir == IIO_EV_DIR_RISING);
-	u64 event_code;
 
-	event_code = IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE, chan, type, dir);
-
-	if (event_code != chip->current_event)
+	/* Only update value live, if parameter is in use */
+	if ((type != chip->type) || (dir != chip->dir))
 		return 0;
 
 	switch (type) {
@@ -231,52 +230,91 @@ static int ad7150_write_event_config(struct iio_dev *indio_dev,
 	int ret;
 	struct ad7150_chip_info *chip = iio_priv(indio_dev);
 	int rising = (dir == IIO_EV_DIR_RISING);
-	u64 event_code;
-
-	/* Something must always be turned on */
-	if (!state)
-		return -EINVAL;
 
-	event_code = IIO_UNMOD_EVENT_CODE(chan->type, chan->channel, type, dir);
-	if (event_code == chip->current_event)
+	/*
+	 * There is only a single shared control and no on chip
+	 * interrupt disables for the two interrupt lines.
+	 * So, enabling will switch the events configured to enable
+	 * whatever was most recently requested and if necessary enable_irq()
+	 * the interrupt and any disable will disable_irq() for that
+	 * channels interrupt.
+	 */
+	if (!state) {
+		if ((chip->int_enabled[chan->channel]) &&
+		    (type == chip->type) && (dir == chip->dir)) {
+			disable_irq(chip->interrupts[chan->channel]);
+			chip->int_enabled[chan->channel] = false;
+		}
 		return 0;
+	}
+
 	mutex_lock(&chip->state_lock);
-	ret = i2c_smbus_read_byte_data(chip->client, AD7150_CFG);
-	if (ret < 0)
-		goto error_ret;
+	if ((type != chip->type) || (dir != chip->dir)) {
 
-	cfg = ret & ~((0x03 << 5) | BIT(7));
+		/*
+		 * Need to temporarily disable both interrupts if
+		 * enabled - this is to avoid races around changing
+		 * config and thresholds.
+		 * Note enable/disable_irq() are reference counted so
+		 * no need to check if already enabled.
+		 */
+		disable_irq(chip->interrupts[0]);
+		disable_irq(chip->interrupts[1]);
 
-	switch (type) {
-	case IIO_EV_TYPE_THRESH_ADAPTIVE:
-		adaptive = 1;
-		if (rising)
-			thresh_type = 0x3;
-		else
-			thresh_type = 0x2;
-		break;
-	case IIO_EV_TYPE_THRESH:
-		adaptive = 0;
-		if (rising)
-			thresh_type = 0x1;
-		else
-			thresh_type = 0x0;
-		break;
-	default:
-		ret = -EINVAL;
-		goto error_ret;
-	}
+		ret = i2c_smbus_read_byte_data(chip->client, AD7150_CFG);
+		if (ret < 0)
+			goto error_ret;
 
-	cfg |= (!adaptive << 7) | (thresh_type << 5);
+		cfg = ret & ~((0x03 << 5) | BIT(7));
 
-	ret = i2c_smbus_write_byte_data(chip->client, AD7150_CFG, cfg);
-	if (ret < 0)
-		goto error_ret;
+		switch (type) {
+		case IIO_EV_TYPE_THRESH_ADAPTIVE:
+			adaptive = 1;
+			if (rising)
+				thresh_type = 0x1;
+			else
+				thresh_type = 0x0;
+			break;
+		case IIO_EV_TYPE_THRESH:
+			adaptive = 0;
+			if (rising)
+				thresh_type = 0x1;
+			else
+				thresh_type = 0x0;
+			break;
+		default:
+			ret = -EINVAL;
+			goto error_ret;
+		}
 
-	chip->current_event = event_code;
+		cfg |= (!adaptive << 7) | (thresh_type << 5);
+
+		ret = i2c_smbus_write_byte_data(chip->client, AD7150_CFG, cfg);
+		if (ret < 0)
+			goto error_ret;
+
+		/*
+		 * There is a potential race condition here, but not easy
+		 * to close given we can't disable the interrupt at the
+		 * chip side of things. Rely on the status bit.
+		 */
+		chip->type = type;
+		chip->dir = dir;
+
+		/* update control attributes */
+		ret = ad7150_write_event_params(indio_dev, chan->channel, type,
+						dir);
+		if (ret)
+			goto error_ret;
+		/* reenable any irq's we disabled whilst changing mode */
+		enable_irq(chip->interrupts[0]);
+		enable_irq(chip->interrupts[1]);
+	}
+	if (!chip->int_enabled[chan->channel]) {
+		enable_irq(chip->interrupts[chan->channel]);
+		chip->int_enabled[chan->channel] = true;
+	}
 
-	/* update control attributes */
-	ret = ad7150_write_event_params(indio_dev, chan->channel, type, dir);
 error_ret:
 	mutex_unlock(&chip->state_lock);
 
@@ -434,59 +472,44 @@ static const struct iio_chan_spec ad7151_channels_no_irq[] = {
 	AD7150_CAPACITANCE_CHAN_NO_IRQ(0),
 };
 
-static irqreturn_t ad7150_event_handler(int irq, void *private)
+static irqreturn_t __ad7150_event_handler(void *private, u8 status_mask,
+					  int channel)
 {
 	struct iio_dev *indio_dev = private;
 	struct ad7150_chip_info *chip = iio_priv(indio_dev);
-	u8 int_status;
 	s64 timestamp = iio_get_time_ns(indio_dev);
-	int ret;
+	int int_status;
 
-	ret = i2c_smbus_read_byte_data(chip->client, AD7150_STATUS);
-	if (ret < 0)
+	int_status = i2c_smbus_read_byte_data(chip->client, AD7150_STATUS);
+	if (int_status < 0)
 		return IRQ_HANDLED;
 
-	int_status = ret;
-
-	if ((int_status & AD7150_STATUS_OUT1) &&
-	    !(chip->old_state & AD7150_STATUS_OUT1))
-		iio_push_event(indio_dev,
-			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
-						    0,
-						    IIO_EV_TYPE_THRESH,
-						    IIO_EV_DIR_RISING),
-				timestamp);
-	else if ((!(int_status & AD7150_STATUS_OUT1)) &&
-		 (chip->old_state & AD7150_STATUS_OUT1))
-		iio_push_event(indio_dev,
-			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
-						    0,
-						    IIO_EV_TYPE_THRESH,
-						    IIO_EV_DIR_FALLING),
-			       timestamp);
-
-	if ((int_status & AD7150_STATUS_OUT2) &&
-	    !(chip->old_state & AD7150_STATUS_OUT2))
-		iio_push_event(indio_dev,
-			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
-						    1,
-						    IIO_EV_TYPE_THRESH,
-						    IIO_EV_DIR_RISING),
-			       timestamp);
-	else if ((!(int_status & AD7150_STATUS_OUT2)) &&
-		 (chip->old_state & AD7150_STATUS_OUT2))
-		iio_push_event(indio_dev,
-			       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE,
-						    1,
-						    IIO_EV_TYPE_THRESH,
-						    IIO_EV_DIR_FALLING),
-			       timestamp);
-	/* store the status to avoid repushing same events */
-	chip->old_state = int_status;
+	/*
+	 * There are race conditions around enabling and disabling that
+	 * could easily land us here with a spurious interrupt.
+	 * Just eat it if so.
+	 */
+	if (!(int_status & status_mask))
+		return IRQ_HANDLED;
+
+	iio_push_event(indio_dev,
+		       IIO_UNMOD_EVENT_CODE(IIO_CAPACITANCE, channel,
+					    chip->type, chip->dir),
+		       timestamp);
 
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t ad7150_event_handler_ch1(int irq, void *private)
+{
+	return __ad7150_event_handler(private, AD7150_STATUS_OUT1, 0);
+}
+
+static irqreturn_t ad7150_event_handler_ch2(int irq, void *private)
+{
+	return __ad7150_event_handler(private, AD7150_STATUS_OUT2, 1);
+}
+
 static IIO_CONST_ATTR(in_capacitance_thresh_adaptive_timeout_available,
 		      "[0 0.01 0.15]");
 
@@ -533,12 +556,44 @@ static int ad7150_probe(struct i2c_client *client,
 
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	if (client->irq) {
+	chip->interrupts[0] = fwnode_irq_get(dev_fwnode(&client->dev), 0);
+	if (chip->interrupts[0] < 0)
+		return chip->interrupts[0];
+	if (id->driver_data == AD7150) {
+		chip->interrupts[1] = fwnode_irq_get(dev_fwnode(&client->dev), 1);
+		if (chip->interrupts[1] < 0)
+			return chip->interrupts[1];
+	}
+	if (chip->interrupts[0] &&
+	    (id->driver_data == AD7151 || chip->interrupts[1])) {
+		irq_set_status_flags(chip->interrupts[0], IRQ_NOAUTOEN);
+		ret = devm_request_threaded_irq(&client->dev,
+						chip->interrupts[0],
+						NULL,
+						&ad7150_event_handler_ch1,
+						IRQF_TRIGGER_RISING |
+						IRQF_ONESHOT,
+						"ad7150_irq1",
+						indio_dev);
+		if (ret)
+			return ret;
+
 		indio_dev->info = &ad7150_info;
 		switch (id->driver_data) {
 		case AD7150:
 			indio_dev->channels = ad7150_channels;
 			indio_dev->num_channels = ARRAY_SIZE(ad7150_channels);
+			irq_set_status_flags(chip->interrupts[1], IRQ_NOAUTOEN);
+			ret = devm_request_threaded_irq(&client->dev,
+							chip->interrupts[1],
+							NULL,
+							&ad7150_event_handler_ch2,
+							IRQF_TRIGGER_RISING |
+							IRQF_ONESHOT,
+							"ad7150_irq2",
+							indio_dev);
+			if (ret)
+				return ret;
 			break;
 		case AD7151:
 			indio_dev->channels = ad7151_channels;
@@ -548,25 +603,18 @@ static int ad7150_probe(struct i2c_client *client,
 			return -EINVAL;
 		}
 
-		ret = devm_request_threaded_irq(&client->dev, client->irq,
-						NULL,
-						&ad7150_event_handler,
-						IRQF_TRIGGER_RISING |
-						IRQF_ONESHOT,
-						"ad7150_irq1",
-						indio_dev);
-		if (ret)
-			return ret;
 	} else {
 		indio_dev->info = &ad7150_info_no_irq;
 		switch (id->driver_data) {
 		case AD7150:
 			indio_dev->channels = ad7150_channels_no_irq;
-			indio_dev->num_channels = ARRAY_SIZE(ad7150_channels_no_irq);
+			indio_dev->num_channels =
+				ARRAY_SIZE(ad7150_channels_no_irq);
 			break;
 		case AD7151:
 			indio_dev->channels = ad7151_channels_no_irq;
-			indio_dev->num_channels = ARRAY_SIZE(ad7151_channels_no_irq);
+			indio_dev->num_channels =
+				ARRAY_SIZE(ad7151_channels_no_irq);
 			break;
 		default:
 			return -EINVAL;
-- 
2.30.0


  parent reply	other threads:[~2021-02-07 15:50 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-07 15:45 [PATCH 00/24] staging:iio:cdc:ad7150: cleanup / fixup / graduate Jonathan Cameron
2021-02-07 15:46 ` [PATCH 01/24] staging:iio:cdc:ad7150: use swapped reads for i2c rather than open coding Jonathan Cameron
2021-02-07 15:46 ` [PATCH 02/24] staging:iio:cdc:ad7150: Remove magnitude adaptive events Jonathan Cameron
2021-02-07 15:46 ` [PATCH 03/24] staging:iio:cdc:ad7150: Refactor event parameter update Jonathan Cameron
2021-02-07 15:46 ` [PATCH 04/24] staging:iio:cdc:ad7150: Timeout register covers both directions so both need updating Jonathan Cameron
2021-02-07 15:46 ` [PATCH 05/24] staging:iio:cdc:ad7150: Drop platform data support Jonathan Cameron
2021-02-08  8:01   ` Song Bao Hua (Barry Song)
2021-02-08 11:12     ` Jonathan Cameron
2021-02-07 15:46 ` [PATCH 06/24] staging:iio:cdc:ad7150: Handle variation in chan_spec across device and irq present or not Jonathan Cameron
2021-02-07 15:46 ` [PATCH 07/24] staging:iio:cdc:ad7150: Simplify event handling by only using rising direction Jonathan Cameron
2021-02-07 15:46 ` [PATCH 08/24] staging:iio:cdc:ad7150: Drop noisy print in probe Jonathan Cameron
2021-02-08  8:02   ` Song Bao Hua (Barry Song)
2021-02-07 15:46 ` [PATCH 09/24] staging:iio:cdc:ad7150: Add sampling_frequency support Jonathan Cameron
2021-02-07 15:46 ` [PATCH 10/24] iio:event: Add timeout event info type Jonathan Cameron
2021-02-07 15:46 ` [PATCH 11/24] staging:iio:cdc:ad7150: Change timeout units to seconds and use core support Jonathan Cameron
2021-02-07 15:46 ` Jonathan Cameron [this message]
2021-02-07 15:46 ` [PATCH 13/24] staging:iio:cdc:ad7150: More consistent register and field naming Jonathan Cameron
2021-03-14 17:43   ` Jonathan Cameron
2021-03-16 10:16     ` Alexandru Ardelean
2021-02-07 15:46 ` [PATCH 14/24] staging:iio:cdc:ad7150: Reorganize headers Jonathan Cameron
2021-02-08  7:54   ` Song Bao Hua (Barry Song)
2021-02-07 15:46 ` [PATCH 15/24] staging:iio:cdc:ad7150: Tidy up local variable positioning Jonathan Cameron
2021-02-08  7:54   ` Song Bao Hua (Barry Song)
2021-03-14 17:46     ` Jonathan Cameron
2021-02-07 15:46 ` [PATCH 16/24] staging:iio:cdc:ad7150: Drop unnecessary block comments Jonathan Cameron
2021-02-08  7:52   ` Song Bao Hua (Barry Song)
2021-02-07 15:46 ` [PATCH 17/24] staging:iio:cdc:ad7150: Shift the _raw readings by 4 bits Jonathan Cameron
2021-02-07 15:46 ` [PATCH 18/24] staging:iio:cdc:ad7150: Add scale and offset to info_mask_shared_by_type Jonathan Cameron
2021-02-07 15:46 ` [PATCH 19/24] staging:iio:cdc:ad7150: Really basic regulator support Jonathan Cameron
2021-02-07 15:46 ` [PATCH 20/24] staging:iio:cdc:ad7150: Add of_match_table Jonathan Cameron
2021-02-08  7:11   ` Alexandru Ardelean
2021-02-11 15:51     ` Jonathan Cameron
2021-02-08  7:50   ` Song Bao Hua (Barry Song)
2021-02-08  8:01     ` Alexandru Ardelean
2021-02-07 15:46 ` [PATCH 21/24] dt-bindings:iio:cdc:adi,ad7150 binding doc Jonathan Cameron
2021-02-07 16:00   ` Lars-Peter Clausen
2021-02-07 16:18     ` Jonathan Cameron
2021-02-08  8:12     ` Song Bao Hua (Barry Song)
2021-02-08 11:20       ` Jonathan Cameron
2021-02-21 15:59   ` Jonathan Cameron
2021-02-07 15:46 ` [PATCH 22/24] iio:Documentation:ABI Add missing elements as used by the adi,ad7150 Jonathan Cameron
2021-02-07 15:46 ` [PATCH 23/24] staging:iio:cdc:ad7150: Add copyright notice given substantial changes Jonathan Cameron
2021-02-07 15:46 ` [PATCH 24/24] iio:cdc:ad7150: Move driver out of staging Jonathan Cameron
2021-02-07 16:21   ` Jonathan Cameron
2021-02-07 16:12 ` [PATCH 00/24] staging:iio:cdc:ad7150: cleanup / fixup / graduate Jonathan Cameron
2021-02-08  7:20   ` Alexandru Ardelean

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210207154623.433442-13-jic23@kernel.org \
    --to=jic23@kernel.org \
    --cc=Jonathan.Cameron@huawei.com \
    --cc=Michael.Hennerich@analog.com \
    --cc=lars@metafoo.de \
    --cc=linux-iio@vger.kernel.org \
    --cc=robh+dt@kernel.org \
    --cc=song.bao.hua@hisilicon.com \
    --subject='Re: [PATCH 12/24] staging:iio:cdc:ad7150: Rework interrupt handling.' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.