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From:   Adam Ward <Adam.Ward.opensource@diasemi.com>
Date:   Mon, 30 Nov 2020 16:59:14 +0000
Subject: [PATCH V3 10/10] regulator: da9121: add interrupt support
To:     Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>
CC:     Liam Girdwood <lgirdwood@gmail.com>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        Support Opensource <support.opensource@diasemi.com>
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Adds interrupt handler for variants, and notifications for events; over
temperature/voltage/current. Because the IRQs are triggered by persisting
status, they must be masked and the status polled until clear, before the
IRQ can be enabled again.

Signed-off-by: Adam Ward <Adam.Ward.opensource@diasemi.com>
---
 drivers/regulator/da9121-regulator.c | 286 +++++++++++++++++++++++++++++++++++
 1 file changed, 286 insertions(+)

diff --git a/drivers/regulator/da9121-regulator.c b/drivers/regulator/da9121-regulator.c
index 8e50f55..d9a8a4b 100644
--- a/drivers/regulator/da9121-regulator.c
+++ b/drivers/regulator/da9121-regulator.c
@@ -23,15 +23,21 @@
 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/regulator/da9121.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
 
 #include "da9121-regulator.h"
 
 /* Chip data */
 struct da9121 {
 	struct device *dev;
+	struct delayed_work work;
 	struct da9121_pdata *pdata;
 	struct regmap *regmap;
 	struct regulator_dev *rdev[DA9121_IDX_MAX];
+	unsigned int persistent[2];
+	unsigned int passive_delay;
+	int chip_irq;
 	int variant_id;
 };
 
@@ -106,6 +112,59 @@ struct da9121_field {
 	{ DA9xxx_REG_BUCK_BUCK2_4, DA9121_MASK_BUCK_BUCKx_4_CHx_A_MODE },
 };
 
+struct status_event_data {
+	int buck_id; /* 0=core, 1/2-buck */
+	int reg_index;  /* index for status/event/mask register selection */
+	int status_bit; /* bit masks... */
+	int event_bit;
+	int mask_bit;
+	unsigned long notification; /* Notification for status inception */
+	char *warn; /* if NULL, notify - otherwise dev_warn this string */
+};
+
+#define DA9121_STATUS(id, bank, name, notification, warning) \
+	{ id, bank, \
+	DA9121_MASK_SYS_STATUS_##bank##_##name, \
+	DA9121_MASK_SYS_EVENT_##bank##_E_##name, \
+	DA9121_MASK_SYS_MASK_##bank##_M_##name, \
+	notification, warning }
+
+/* For second buck related event bits that are specific to DA9122, DA9220 variants */
+#define DA9xxx_STATUS(id, bank, name, notification, warning) \
+	{ id, bank, \
+	DA9xxx_MASK_SYS_STATUS_##bank##_##name, \
+	DA9xxx_MASK_SYS_EVENT_##bank##_E_##name, \
+	DA9xxx_MASK_SYS_MASK_##bank##_M_##name, \
+	notification, warning }
+
+/* The status signals that may need servicing, depending on device variant.
+ * After assertion, they persist; so event is notified, the IRQ disabled,
+ * and status polled until clear again and IRQ is reenabled.
+ *
+ * SG/PG1/PG2 should be set when device first powers up and should never
+ * re-occur. When this driver starts, it is expected that these will have
+ * self-cleared for when the IRQs are enabled, so these should never be seen.
+ * If seen, the implication is that the device has reset.
+ *
+ * GPIO0/1/2 are not configured for use by default, so should not be seen.
+ */
+const struct status_event_data status_event_handling[] = {
+	DA9xxx_STATUS(0, 0, SG, 0, "Handled E_SG\n"),
+	DA9121_STATUS(0, 0, TEMP_CRIT, (REGULATOR_EVENT_OVER_TEMP|REGULATOR_EVENT_DISABLE), NULL),
+	DA9121_STATUS(0, 0, TEMP_WARN, REGULATOR_EVENT_OVER_TEMP, NULL),
+	DA9121_STATUS(1, 1, PG1, 0, "Handled E_PG1\n"),
+	DA9121_STATUS(1, 1, OV1, REGULATOR_EVENT_REGULATION_OUT, NULL),
+	DA9121_STATUS(1, 1, UV1, REGULATOR_EVENT_UNDER_VOLTAGE, NULL),
+	DA9121_STATUS(1, 1, OC1, REGULATOR_EVENT_OVER_CURRENT, NULL),
+	DA9xxx_STATUS(2, 1, PG2, 0, "Handled E_PG2\n"),
+	DA9xxx_STATUS(2, 1, OV2, REGULATOR_EVENT_REGULATION_OUT, NULL),
+	DA9xxx_STATUS(2, 1, UV2, REGULATOR_EVENT_UNDER_VOLTAGE, NULL),
+	DA9xxx_STATUS(2, 1, OC2, REGULATOR_EVENT_OVER_CURRENT, NULL),
+	DA9121_STATUS(0, 2, GPIO0, 0, "Handled E_GPIO0\n"),
+	DA9121_STATUS(0, 2, GPIO1, 0, "Handled E_GPIO1\n"),
+	DA9121_STATUS(0, 2, GPIO2, 0, "Handled E_GPIO2\n"),
+};
+
 static int da9121_get_current_limit(struct regulator_dev *rdev)
 {
 	struct da9121 *chip = rdev_get_drvdata(rdev);
@@ -479,6 +538,157 @@ static int da9121_of_parse_cb(struct device_node *np,
 	[DA9121_TYPE_DA9217] = { &da9217_reg, NULL },
 };
 
+static void da9121_status_poll_on(struct work_struct *work)
+{
+	struct da9121 *chip = container_of(work, struct da9121, work.work);
+	int status[3] = {0};
+	int clear[3] = {0};
+	unsigned long delay;
+	int i;
+	int ret;
+
+	ret = regmap_bulk_read(chip->regmap, DA9121_REG_SYS_STATUS_0, status, 2);
+	if (ret < 0) {
+		dev_err(chip->dev,
+			"Failed to read STATUS registers: %d\n", ret);
+		goto error;
+	}
+
+	/* Possible events are tested to be within range for the variant, potentially
+	 * masked by the IRQ handler (not just warned about), as having been masked,
+	 * and the respective state cleared - then flagged to unmask for next IRQ.
+	 */
+	for (i = 0; i < ARRAY_SIZE(status_event_handling); i++) {
+		const struct status_event_data *item = &status_event_handling[i];
+		int reg_idx = item->reg_index;
+		bool relevant = (item->buck_id <= variant_parameters[chip->variant_id].num_bucks);
+		bool supported = (item->warn == NULL);
+		bool persisting = (chip->persistent[reg_idx] & item->event_bit);
+		bool now_cleared = !(status[reg_idx] & item->status_bit);
+
+		if (relevant && supported && persisting && now_cleared) {
+			clear[reg_idx] |= item->mask_bit;
+			chip->persistent[reg_idx] &= ~item->event_bit;
+		}
+	}
+
+	for (i = 0; i < 2; i++) {
+		if (clear[i]) {
+			unsigned int reg = DA9121_REG_SYS_MASK_0 + i;
+			unsigned int mbit = clear[i];
+
+			ret = regmap_update_bits(chip->regmap, reg, mbit, 0);
+			if (ret < 0) {
+				dev_err(chip->dev,
+					"Failed to unmask 0x%02x %d\n",
+					reg, ret);
+				goto error;
+			}
+		}
+	}
+
+	if (chip->persistent[0] | chip->persistent[1]) {
+		delay = msecs_to_jiffies(chip->passive_delay);
+		queue_delayed_work(system_freezable_wq, &chip->work, delay);
+	}
+
+error:
+	return;
+}
+
+static irqreturn_t da9121_irq_handler(int irq, void *data)
+{
+	struct da9121 *chip = data;
+	struct regulator_dev *rdev;
+	int event[3] = {0};
+	int handled[3] = {0};
+	int mask[3] = {0};
+	int ret = IRQ_NONE;
+	int i;
+	int err;
+
+	err = regmap_bulk_read(chip->regmap, DA9121_REG_SYS_EVENT_0, event, 3);
+	if (err < 0) {
+		dev_err(chip->dev, "Failed to read EVENT registers %d\n", err);
+		ret = IRQ_NONE;
+		goto error;
+	}
+
+	err = regmap_bulk_read(chip->regmap, DA9121_REG_SYS_MASK_0, mask, 3);
+	if (err < 0) {
+		dev_err(chip->dev,
+			"Failed to read MASK registers: %d\n", ret);
+		ret = IRQ_NONE;
+		goto error;
+	}
+
+	rdev = chip->rdev[DA9121_IDX_BUCK1];
+
+	/* Possible events are tested to be within range for the variant, currently
+	 * enabled, and having triggered this IRQ. The event may then be notified,
+	 * or a warning given for unexpected events - those from device POR, and
+	 * currently unsupported GPIO configurations.
+	 */
+	for (i = 0; i < ARRAY_SIZE(status_event_handling); i++) {
+		const struct status_event_data *item = &status_event_handling[i];
+		int reg_idx = item->reg_index;
+		bool relevant = (item->buck_id <= variant_parameters[chip->variant_id].num_bucks);
+		bool enabled = !(mask[reg_idx] & item->mask_bit);
+		bool active = (event[reg_idx] & item->event_bit);
+		bool notify = (item->warn == NULL);
+
+		if (relevant && enabled && active) {
+			if (notify) {
+				chip->persistent[reg_idx] |= item->event_bit;
+				regulator_notifier_call_chain(rdev, item->notification, NULL);
+			} else {
+				dev_warn(chip->dev, item->warn);
+				handled[reg_idx] |= item->event_bit;
+				ret = IRQ_HANDLED;
+			}
+		}
+	}
+
+	for (i = 0; i < 3; i++) {
+		if (event[i] != handled[i]) {
+			dev_warn(chip->dev,
+				"Unhandled event(s) in bank%d 0x%02x\n", i,
+				event[i] ^ handled[i]);
+		}
+	}
+
+	/* Mask the interrupts for persistent events OV, OC, UV, WARN, CRIT */
+	for (i = 0; i < 2; i++) {
+		if (handled[i]) {
+			unsigned int reg = DA9121_REG_SYS_MASK_0 + i;
+			unsigned int mbit = handled[i];
+
+			err = regmap_update_bits(chip->regmap, reg, mbit, mbit);
+			if (err < 0) {
+				dev_err(chip->dev,
+					"Failed to mask 0x%02x interrupt %d\n",
+					reg, err);
+				ret = IRQ_NONE;
+				goto error;
+			}
+		}
+	}
+
+	/* clear the events */
+	if (handled[0] | handled[1] | handled[2]) {
+		err = regmap_bulk_write(chip->regmap, DA9121_REG_SYS_EVENT_0, handled, 3);
+		if (err < 0) {
+			dev_err(chip->dev, "Fail to write EVENTs %d\n", err);
+			ret = IRQ_NONE;
+			goto error;
+		}
+	}
+
+	queue_delayed_work(system_freezable_wq, &chip->work, 0);
+error:
+	return ret;
+}
+
 static int da9121_set_regulator_config(struct da9121 *chip)
 {
 	struct regulator_config config = { };
@@ -711,6 +921,56 @@ static int da9121_assign_chip_model(struct i2c_client *i2c,
 	return ret;
 }
 
+static int da9121_config_irq(struct i2c_client *i2c,
+			struct da9121 *chip)
+{
+	unsigned int p_delay = DA9121_DEFAULT_POLLING_PERIOD_MS;
+	const int mask_all[4] = { 0, 0, 0xFF, 0xFF };
+	int ret = 0;
+
+	chip->chip_irq = i2c->irq;
+
+	if (chip->chip_irq != 0) {
+		if (!of_property_read_u32(chip->dev->of_node,
+					  "dlg,irq-polling-delay-passive-ms",
+					  &p_delay)) {
+			if (p_delay < DA9121_MIN_POLLING_PERIOD_MS ||
+			    p_delay > DA9121_MAX_POLLING_PERIOD_MS) {
+				dev_warn(chip->dev,
+					 "Out-of-range polling period %d ms\n",
+					 p_delay);
+				p_delay = DA9121_DEFAULT_POLLING_PERIOD_MS;
+			}
+		}
+
+		chip->passive_delay = p_delay;
+
+		ret = devm_request_threaded_irq(chip->dev,
+					chip->chip_irq, NULL,
+					da9121_irq_handler,
+					IRQF_TRIGGER_LOW|IRQF_ONESHOT,
+					"da9121", chip);
+		if (ret != 0) {
+			dev_err(chip->dev, "Failed IRQ request: %d\n",
+				chip->chip_irq);
+			goto error;
+		}
+
+		ret = regmap_bulk_write(chip->regmap, DA9121_REG_SYS_MASK_0, mask_all, 4);
+		if (ret != 0) {
+			dev_err(chip->dev, "Failed to set IRQ masks: %d\n",
+				ret);
+			goto error;
+		}
+
+		INIT_DELAYED_WORK(&chip->work, da9121_status_poll_on);
+		dev_info(chip->dev, "Interrupt polling period set at %d ms\n",
+			 chip->passive_delay);
+	}
+error:
+	return ret;
+}
+
 static const struct of_device_id da9121_dt_ids[] = {
 	{ .compatible = "dlg,da9121", .data = (void *) DA9121_TYPE_DA9121_DA9130 },
 	{ .compatible = "dlg,da9130", .data = (void *) DA9121_TYPE_DA9121_DA9130 },
@@ -738,6 +998,7 @@ static int da9121_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
 	struct da9121 *chip;
+	const int mask_all[4] = { 0xFF, 0xFF, 0xFF, 0xFF };
 	int ret = 0;
 
 	chip = devm_kzalloc(&i2c->dev, sizeof(struct da9121), GFP_KERNEL);
@@ -753,12 +1014,36 @@ static int da9121_i2c_probe(struct i2c_client *i2c,
 	if (ret < 0)
 		goto error;
 
+	ret = regmap_bulk_write(chip->regmap, DA9121_REG_SYS_MASK_0, mask_all, 4);
+	if (ret != 0) {
+		dev_err(chip->dev, "Failed to set IRQ masks: %d\n", ret);
+		goto error;
+	}
+
 	ret = da9121_set_regulator_config(chip);
+	if (ret < 0)
+		goto error;
+
+	ret = da9121_config_irq(i2c, chip);
 
 error:
 	return ret;
 }
 
+static int da9121_i2c_remove(struct i2c_client *i2c)
+{
+	struct da9121 *chip = i2c_get_clientdata(i2c);
+	const int mask_all[4] = { 0xFF, 0xFF, 0xFF, 0xFF };
+	int ret = 0;
+
+	cancel_delayed_work_sync(&chip->work);
+
+	ret = regmap_bulk_write(chip->regmap, DA9121_REG_SYS_MASK_0, mask_all, 4);
+	if (ret != 0)
+		dev_err(chip->dev, "Failed to set IRQ masks: %d\n", ret);
+	return ret;
+}
+
 static const struct i2c_device_id da9121_i2c_id[] = {
 	{"da9121", DA9121_TYPE_DA9121_DA9130},
 	{"da9130", DA9121_TYPE_DA9121_DA9130},
@@ -777,6 +1062,7 @@ static int da9121_i2c_probe(struct i2c_client *i2c,
 		.of_match_table = of_match_ptr(da9121_dt_ids),
 	},
 	.probe = da9121_i2c_probe,
+	.remove = da9121_i2c_remove,
 	.id_table = da9121_i2c_id,
 };
 
-- 
1.9.1