File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
new file mode 100644
index 0000000..8d16db5
--- /dev/null
+++ b/drivers/base/regmap/regmap-irq.c
@@ -0,0 +1,625 @@
+/*
+ * regmap based irq_chip
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "internal.h"
+
+struct regmap_irq_chip_data {
+	struct mutex lock;
+	struct irq_chip irq_chip;
+
+	struct regmap *map;
+	const struct regmap_irq_chip *chip;
+
+	int irq_base;
+	struct irq_domain *domain;
+
+	int irq;
+	int wake_count;
+
+	void *status_reg_buf;
+	unsigned int *status_buf;
+	unsigned int *mask_buf;
+	unsigned int *mask_buf_def;
+	unsigned int *wake_buf;
+
+	unsigned int irq_reg_stride;
+};
+
+static inline const
+struct regmap_irq *irq_to_regmap_irq(struct regmap_irq_chip_data *data,
+				     int irq)
+{
+	return &data->chip->irqs[irq];
+}
+
+static void regmap_irq_lock(struct irq_data *data)
+{
+	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
+
+	mutex_lock(&d->lock);
+}
+
+static void regmap_irq_sync_unlock(struct irq_data *data)
+{
+	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
+	struct regmap *map = d->map;
+	int i, ret;
+	u32 reg;
+	u32 unmask_offset;
+
+	if (d->chip->runtime_pm) {
+		ret = pm_runtime_get_sync(map->dev);
+		if (ret < 0)
+			dev_err(map->dev, "IRQ sync failed to resume: %d\n",
+				ret);
+	}
+
+	/*
+	 * If there's been a change in the mask write it back to the
+	 * hardware.  We rely on the use of the regmap core cache to
+	 * suppress pointless writes.
+	 */
+	for (i = 0; i < d->chip->num_regs; i++) {
+		reg = d->chip->mask_base +
+			(i * map->reg_stride * d->irq_reg_stride);
+		if (d->chip->mask_invert) {
+			ret = regmap_update_bits(d->map, reg,
+					 d->mask_buf_def[i], ~d->mask_buf[i]);
+		} else if (d->chip->unmask_base) {
+			/* set mask with mask_base register */
+			ret = regmap_update_bits(d->map, reg,
+					d->mask_buf_def[i], ~d->mask_buf[i]);
+			if (ret < 0)
+				dev_err(d->map->dev,
+					"Failed to sync unmasks in %x\n",
+					reg);
+			unmask_offset = d->chip->unmask_base -
+							d->chip->mask_base;
+			/* clear mask with unmask_base register */
+			ret = regmap_update_bits(d->map,
+					reg + unmask_offset,
+					d->mask_buf_def[i],
+					d->mask_buf[i]);
+		} else {
+			ret = regmap_update_bits(d->map, reg,
+					 d->mask_buf_def[i], d->mask_buf[i]);
+		}
+		if (ret != 0)
+			dev_err(d->map->dev, "Failed to sync masks in %x\n",
+				reg);
+
+		reg = d->chip->wake_base +
+			(i * map->reg_stride * d->irq_reg_stride);
+		if (d->wake_buf) {
+			if (d->chip->wake_invert)
+				ret = regmap_update_bits(d->map, reg,
+							 d->mask_buf_def[i],
+							 ~d->wake_buf[i]);
+			else
+				ret = regmap_update_bits(d->map, reg,
+							 d->mask_buf_def[i],
+							 d->wake_buf[i]);
+			if (ret != 0)
+				dev_err(d->map->dev,
+					"Failed to sync wakes in %x: %d\n",
+					reg, ret);
+		}
+
+		if (!d->chip->init_ack_masked)
+			continue;
+		/*
+		 * Ack all the masked interrupts unconditionally,
+		 * OR if there is masked interrupt which hasn't been Acked,
+		 * it'll be ignored in irq handler, then may introduce irq storm
+		 */
+		if (d->mask_buf[i] && (d->chip->ack_base || d->chip->use_ack)) {
+			reg = d->chip->ack_base +
+				(i * map->reg_stride * d->irq_reg_stride);
+			/* some chips ack by write 0 */
+			if (d->chip->ack_invert)
+				ret = regmap_write(map, reg, ~d->mask_buf[i]);
+			else
+				ret = regmap_write(map, reg, d->mask_buf[i]);
+			if (ret != 0)
+				dev_err(d->map->dev, "Failed to ack 0x%x: %d\n",
+					reg, ret);
+		}
+	}
+
+	if (d->chip->runtime_pm)
+		pm_runtime_put(map->dev);
+
+	/* If we've changed our wakeup count propagate it to the parent */
+	if (d->wake_count < 0)
+		for (i = d->wake_count; i < 0; i++)
+			irq_set_irq_wake(d->irq, 0);
+	else if (d->wake_count > 0)
+		for (i = 0; i < d->wake_count; i++)
+			irq_set_irq_wake(d->irq, 1);
+
+	d->wake_count = 0;
+
+	mutex_unlock(&d->lock);
+}
+
+static void regmap_irq_enable(struct irq_data *data)
+{
+	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
+	struct regmap *map = d->map;
+	const struct regmap_irq *irq_data = irq_to_regmap_irq(d, data->hwirq);
+
+	d->mask_buf[irq_data->reg_offset / map->reg_stride] &= ~irq_data->mask;
+}
+
+static void regmap_irq_disable(struct irq_data *data)
+{
+	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
+	struct regmap *map = d->map;
+	const struct regmap_irq *irq_data = irq_to_regmap_irq(d, data->hwirq);
+
+	d->mask_buf[irq_data->reg_offset / map->reg_stride] |= irq_data->mask;
+}
+
+static int regmap_irq_set_wake(struct irq_data *data, unsigned int on)
+{
+	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
+	struct regmap *map = d->map;
+	const struct regmap_irq *irq_data = irq_to_regmap_irq(d, data->hwirq);
+
+	if (on) {
+		if (d->wake_buf)
+			d->wake_buf[irq_data->reg_offset / map->reg_stride]
+				&= ~irq_data->mask;
+		d->wake_count++;
+	} else {
+		if (d->wake_buf)
+			d->wake_buf[irq_data->reg_offset / map->reg_stride]
+				|= irq_data->mask;
+		d->wake_count--;
+	}
+
+	return 0;
+}
+
+static const struct irq_chip regmap_irq_chip = {
+	.irq_bus_lock		= regmap_irq_lock,
+	.irq_bus_sync_unlock	= regmap_irq_sync_unlock,
+	.irq_disable		= regmap_irq_disable,
+	.irq_enable		= regmap_irq_enable,
+	.irq_set_wake		= regmap_irq_set_wake,
+};
+
+static irqreturn_t regmap_irq_thread(int irq, void *d)
+{
+	struct regmap_irq_chip_data *data = d;
+	const struct regmap_irq_chip *chip = data->chip;
+	struct regmap *map = data->map;
+	int ret, i;
+	bool handled = false;
+	u32 reg;
+
+	if (chip->runtime_pm) {
+		ret = pm_runtime_get_sync(map->dev);
+		if (ret < 0) {
+			dev_err(map->dev, "IRQ thread failed to resume: %d\n",
+				ret);
+			pm_runtime_put(map->dev);
+			return IRQ_NONE;
+		}
+	}
+
+	/*
+	 * Read in the statuses, using a single bulk read if possible
+	 * in order to reduce the I/O overheads.
+	 */
+	if (!map->use_single_read && map->reg_stride == 1 &&
+	    data->irq_reg_stride == 1) {
+		u8 *buf8 = data->status_reg_buf;
+		u16 *buf16 = data->status_reg_buf;
+		u32 *buf32 = data->status_reg_buf;
+
+		BUG_ON(!data->status_reg_buf);
+
+		ret = regmap_bulk_read(map, chip->status_base,
+				       data->status_reg_buf,
+				       chip->num_regs);
+		if (ret != 0) {
+			dev_err(map->dev, "Failed to read IRQ status: %d\n",
+				ret);
+			return IRQ_NONE;
+		}
+
+		for (i = 0; i < data->chip->num_regs; i++) {
+			switch (map->format.val_bytes) {
+			case 1:
+				data->status_buf[i] = buf8[i];
+				break;
+			case 2:
+				data->status_buf[i] = buf16[i];
+				break;
+			case 4:
+				data->status_buf[i] = buf32[i];
+				break;
+			default:
+				BUG();
+				return IRQ_NONE;
+			}
+		}
+
+	} else {
+		for (i = 0; i < data->chip->num_regs; i++) {
+			ret = regmap_read(map, chip->status_base +
+					  (i * map->reg_stride
+					   * data->irq_reg_stride),
+					  &data->status_buf[i]);
+
+			if (ret != 0) {
+				dev_err(map->dev,
+					"Failed to read IRQ status: %d\n",
+					ret);
+				if (chip->runtime_pm)
+					pm_runtime_put(map->dev);
+				return IRQ_NONE;
+			}
+		}
+	}
+
+	/*
+	 * Ignore masked IRQs and ack if we need to; we ack early so
+	 * there is no race between handling and acknowleding the
+	 * interrupt.  We assume that typically few of the interrupts
+	 * will fire simultaneously so don't worry about overhead from
+	 * doing a write per register.
+	 */
+	for (i = 0; i < data->chip->num_regs; i++) {
+		data->status_buf[i] &= ~data->mask_buf[i];
+
+		if (data->status_buf[i] && (chip->ack_base || chip->use_ack)) {
+			reg = chip->ack_base +
+				(i * map->reg_stride * data->irq_reg_stride);
+			ret = regmap_write(map, reg, data->status_buf[i]);
+			if (ret != 0)
+				dev_err(map->dev, "Failed to ack 0x%x: %d\n",
+					reg, ret);
+		}
+	}
+
+	for (i = 0; i < chip->num_irqs; i++) {
+		if (data->status_buf[chip->irqs[i].reg_offset /
+				     map->reg_stride] & chip->irqs[i].mask) {
+			handle_nested_irq(irq_find_mapping(data->domain, i));
+			handled = true;
+		}
+	}
+
+	if (chip->runtime_pm)
+		pm_runtime_put(map->dev);
+
+	if (handled)
+		return IRQ_HANDLED;
+	else
+		return IRQ_NONE;
+}
+
+static int regmap_irq_map(struct irq_domain *h, unsigned int virq,
+			  irq_hw_number_t hw)
+{
+	struct regmap_irq_chip_data *data = h->host_data;
+
+	irq_set_chip_data(virq, data);
+	irq_set_chip(virq, &data->irq_chip);
+	irq_set_nested_thread(virq, 1);
+	irq_set_noprobe(virq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops regmap_domain_ops = {
+	.map	= regmap_irq_map,
+	.xlate	= irq_domain_xlate_twocell,
+};
+
+/**
+ * regmap_add_irq_chip(): Use standard regmap IRQ controller handling
+ *
+ * map:       The regmap for the device.
+ * irq:       The IRQ the device uses to signal interrupts
+ * irq_flags: The IRQF_ flags to use for the primary interrupt.
+ * chip:      Configuration for the interrupt controller.
+ * data:      Runtime data structure for the controller, allocated on success
+ *
+ * Returns 0 on success or an errno on failure.
+ *
+ * In order for this to be efficient the chip really should use a
+ * register cache.  The chip driver is responsible for restoring the
+ * register values used by the IRQ controller over suspend and resume.
+ */
+int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
+			int irq_base, const struct regmap_irq_chip *chip,
+			struct regmap_irq_chip_data **data)
+{
+	struct regmap_irq_chip_data *d;
+	int i;
+	int ret = -ENOMEM;
+	u32 reg;
+	u32 unmask_offset;
+
+	if (chip->num_regs <= 0)
+		return -EINVAL;
+
+	for (i = 0; i < chip->num_irqs; i++) {
+		if (chip->irqs[i].reg_offset % map->reg_stride)
+			return -EINVAL;
+		if (chip->irqs[i].reg_offset / map->reg_stride >=
+		    chip->num_regs)
+			return -EINVAL;
+	}
+
+	if (irq_base) {
+		irq_base = irq_alloc_descs(irq_base, 0, chip->num_irqs, 0);
+		if (irq_base < 0) {
+			dev_warn(map->dev, "Failed to allocate IRQs: %d\n",
+				 irq_base);
+			return irq_base;
+		}
+	}
+
+	d = kzalloc(sizeof(*d), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+
+	d->status_buf = kzalloc(sizeof(unsigned int) * chip->num_regs,
+				GFP_KERNEL);
+	if (!d->status_buf)
+		goto err_alloc;
+
+	d->mask_buf = kzalloc(sizeof(unsigned int) * chip->num_regs,
+			      GFP_KERNEL);
+	if (!d->mask_buf)
+		goto err_alloc;
+
+	d->mask_buf_def = kzalloc(sizeof(unsigned int) * chip->num_regs,
+				  GFP_KERNEL);
+	if (!d->mask_buf_def)
+		goto err_alloc;
+
+	if (chip->wake_base) {
+		d->wake_buf = kzalloc(sizeof(unsigned int) * chip->num_regs,
+				      GFP_KERNEL);
+		if (!d->wake_buf)
+			goto err_alloc;
+	}
+
+	d->irq_chip = regmap_irq_chip;
+	d->irq_chip.name = chip->name;
+	d->irq = irq;
+	d->map = map;
+	d->chip = chip;
+	d->irq_base = irq_base;
+
+	if (chip->irq_reg_stride)
+		d->irq_reg_stride = chip->irq_reg_stride;
+	else
+		d->irq_reg_stride = 1;
+
+	if (!map->use_single_read && map->reg_stride == 1 &&
+	    d->irq_reg_stride == 1) {
+		d->status_reg_buf = kmalloc(map->format.val_bytes *
+					    chip->num_regs, GFP_KERNEL);
+		if (!d->status_reg_buf)
+			goto err_alloc;
+	}
+
+	mutex_init(&d->lock);
+
+	for (i = 0; i < chip->num_irqs; i++)
+		d->mask_buf_def[chip->irqs[i].reg_offset / map->reg_stride]
+			|= chip->irqs[i].mask;
+
+	/* Mask all the interrupts by default */
+	for (i = 0; i < chip->num_regs; i++) {
+		d->mask_buf[i] = d->mask_buf_def[i];
+		reg = chip->mask_base +
+			(i * map->reg_stride * d->irq_reg_stride);
+		if (chip->mask_invert)
+			ret = regmap_update_bits(map, reg,
+					 d->mask_buf[i], ~d->mask_buf[i]);
+		else if (d->chip->unmask_base) {
+			unmask_offset = d->chip->unmask_base -
+					d->chip->mask_base;
+			ret = regmap_update_bits(d->map,
+					reg + unmask_offset,
+					d->mask_buf[i],
+					d->mask_buf[i]);
+		} else
+			ret = regmap_update_bits(map, reg,
+					 d->mask_buf[i], d->mask_buf[i]);
+		if (ret != 0) {
+			dev_err(map->dev, "Failed to set masks in 0x%x: %d\n",
+				reg, ret);
+			goto err_alloc;
+		}
+
+		if (!chip->init_ack_masked)
+			continue;
+
+		/* Ack masked but set interrupts */
+		reg = chip->status_base +
+			(i * map->reg_stride * d->irq_reg_stride);
+		ret = regmap_read(map, reg, &d->status_buf[i]);
+		if (ret != 0) {
+			dev_err(map->dev, "Failed to read IRQ status: %d\n",
+				ret);
+			goto err_alloc;
+		}
+
+		if (d->status_buf[i] && (chip->ack_base || chip->use_ack)) {
+			reg = chip->ack_base +
+				(i * map->reg_stride * d->irq_reg_stride);
+			if (chip->ack_invert)
+				ret = regmap_write(map, reg,
+					~(d->status_buf[i] & d->mask_buf[i]));
+			else
+				ret = regmap_write(map, reg,
+					d->status_buf[i] & d->mask_buf[i]);
+			if (ret != 0) {
+				dev_err(map->dev, "Failed to ack 0x%x: %d\n",
+					reg, ret);
+				goto err_alloc;
+			}
+		}
+	}
+
+	/* Wake is disabled by default */
+	if (d->wake_buf) {
+		for (i = 0; i < chip->num_regs; i++) {
+			d->wake_buf[i] = d->mask_buf_def[i];
+			reg = chip->wake_base +
+				(i * map->reg_stride * d->irq_reg_stride);
+
+			if (chip->wake_invert)
+				ret = regmap_update_bits(map, reg,
+							 d->mask_buf_def[i],
+							 0);
+			else
+				ret = regmap_update_bits(map, reg,
+							 d->mask_buf_def[i],
+							 d->wake_buf[i]);
+			if (ret != 0) {
+				dev_err(map->dev, "Failed to set masks in 0x%x: %d\n",
+					reg, ret);
+				goto err_alloc;
+			}
+		}
+	}
+
+	if (irq_base)
+		d->domain = irq_domain_add_legacy(map->dev->of_node,
+						  chip->num_irqs, irq_base, 0,
+						  &regmap_domain_ops, d);
+	else
+		d->domain = irq_domain_add_linear(map->dev->of_node,
+						  chip->num_irqs,
+						  &regmap_domain_ops, d);
+	if (!d->domain) {
+		dev_err(map->dev, "Failed to create IRQ domain\n");
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	ret = request_threaded_irq(irq, NULL, regmap_irq_thread,
+				   irq_flags | IRQF_ONESHOT,
+				   chip->name, d);
+	if (ret != 0) {
+		dev_err(map->dev, "Failed to request IRQ %d for %s: %d\n",
+			irq, chip->name, ret);
+		goto err_domain;
+	}
+
+	*data = d;
+
+	return 0;
+
+err_domain:
+	/* Should really dispose of the domain but... */
+err_alloc:
+	kfree(d->wake_buf);
+	kfree(d->mask_buf_def);
+	kfree(d->mask_buf);
+	kfree(d->status_buf);
+	kfree(d->status_reg_buf);
+	kfree(d);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_add_irq_chip);
+
+/**
+ * regmap_del_irq_chip(): Stop interrupt handling for a regmap IRQ chip
+ *
+ * @irq: Primary IRQ for the device
+ * @d:   regmap_irq_chip_data allocated by regmap_add_irq_chip()
+ */
+void regmap_del_irq_chip(int irq, struct regmap_irq_chip_data *d)
+{
+	if (!d)
+		return;
+
+	free_irq(irq, d);
+	irq_domain_remove(d->domain);
+	kfree(d->wake_buf);
+	kfree(d->mask_buf_def);
+	kfree(d->mask_buf);
+	kfree(d->status_reg_buf);
+	kfree(d->status_buf);
+	kfree(d);
+}
+EXPORT_SYMBOL_GPL(regmap_del_irq_chip);
+
+/**
+ * regmap_irq_chip_get_base(): Retrieve interrupt base for a regmap IRQ chip
+ *
+ * Useful for drivers to request their own IRQs.
+ *
+ * @data: regmap_irq controller to operate on.
+ */
+int regmap_irq_chip_get_base(struct regmap_irq_chip_data *data)
+{
+	WARN_ON(!data->irq_base);
+	return data->irq_base;
+}
+EXPORT_SYMBOL_GPL(regmap_irq_chip_get_base);
+
+/**
+ * regmap_irq_get_virq(): Map an interrupt on a chip to a virtual IRQ
+ *
+ * Useful for drivers to request their own IRQs.
+ *
+ * @data: regmap_irq controller to operate on.
+ * @irq: index of the interrupt requested in the chip IRQs
+ */
+int regmap_irq_get_virq(struct regmap_irq_chip_data *data, int irq)
+{
+	/* Handle holes in the IRQ list */
+	if (!data->chip->irqs[irq].mask)
+		return -EINVAL;
+
+	return irq_create_mapping(data->domain, irq);
+}
+EXPORT_SYMBOL_GPL(regmap_irq_get_virq);
+
+/**
+ * regmap_irq_get_domain(): Retrieve the irq_domain for the chip
+ *
+ * Useful for drivers to request their own IRQs and for integration
+ * with subsystems.  For ease of integration NULL is accepted as a
+ * domain, allowing devices to just call this even if no domain is
+ * allocated.
+ *
+ * @data: regmap_irq controller to operate on.
+ */
+struct irq_domain *regmap_irq_get_domain(struct regmap_irq_chip_data *data)
+{
+	if (data)
+		return data->domain;
+	else
+		return NULL;
+}
+EXPORT_SYMBOL_GPL(regmap_irq_get_domain);