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gpio: mockup: improve the user-space testing interface

PATCH Superseded Bartosz Golaszewski 2 participants 9 messages Feb 12, 2019 – Feb 14, 2019

Subsystems (3)

v3 of 6 Superseded Latest is v6 →

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#0 lore raw

v3 cover gpio: mockup: improve the user-space testing interface

From: Bartosz Golaszewski <[email protected]>

Hi Marc,

this is a trimmed down version of the previous series. All irq_sim patches from the previous implementation were dropped. The only change in irq_sim now is addition of the irq_sim_get_type() helper. We store the irq type in the irq_set_type() callback and allow users to retrieve it with the new function.

The entire logic handling the line state now lives directly in the only user that needs it - the GPIO testing module. Since the GPIO user API only supports edge interrupts, level types are not supported. This functionality is only needed for user-space tests. The testing module tracks the line state and makes sure to avoid impossible situations (like firing a rising edge interrupt if the line is being driven low).

Other gpio-mockup patches are unchanged - the only change in patch 7 is the line state tracking.

v1 -> v2:
- instead of providing the irq_sim_get_type() helper, move the irq type logic into the simulator and provide a helper that allows users to specify the type of the fired interrupt

v2 -> v3:
- switch back to having irq_sim_type() and put the line state logic into the GPIO testing module

Bartosz Golaszewski (7):
irq/irq_sim: provide irq_sim_get_type()
gpio: mockup: add locking
gpio: mockup: implement get_multiple()
gpio: mockup: don't create the debugfs link named after the label
gpio: mockup: change the type of 'offset' to unsigned int
gpio: mockup: change the signature of unlocked get/set helpers
gpio: mockup: rework debugfs interface

 drivers/gpio/gpio-mockup.c | 188 +++++++++++++++++++++++++++++++------
 include/linux/irq_sim.h    |   2 +
 kernel/irq/irq_sim.c       |  23 +++++
 3 files changed, 186 insertions(+), 27 deletions(-)
Signature · 1 line
2.20.1
#1 lore raw

PATCH v3 1/7 irq/irq_sim: provide irq_sim_get_type()

From: Bartosz Golaszewski <[email protected]>

Provide a helper that allows users to retrieve the current irq type of dummy interrupts.

Internally: store the type in the line context when the irq_set_type() callback is called.

This is required by the gpio-mockup module which wants to track the state of GPIO lines and simulate rising and falling edge interrupts.

---
 include/linux/irq_sim.h |  2 ++
 kernel/irq/irq_sim.c    | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)
include/linux/irq_sim.h +2 -0
index 4500d453a63e..c73be0a2c15c 100644
@@ -22,6 +22,7 @@ struct irq_sim_work_ctx {
 struct irq_sim_irq_ctx {
 	int			irqnum;
 	bool			enabled;
+	int			type;
 };
 
 struct irq_sim {
@@ -37,5 +38,6 @@ int devm_irq_sim_init(struct device *dev, struct irq_sim *sim,
 void irq_sim_fini(struct irq_sim *sim);
 void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
 int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
+unsigned int irq_sim_get_type(struct irq_sim *sim, unsigned int offset);
 
 #endif /* _LINUX_IRQ_SIM_H */
kernel/irq/irq_sim.c +23 -0
index 98a20e1594ce..74561a0dca65 100644
@@ -25,10 +25,20 @@ static void irq_sim_irqunmask(struct irq_data *data)
 	irq_ctx->enabled = true;
 }
 
+static int irq_sim_set_type(struct irq_data *data, unsigned int type)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->type = type;
+
+	return 0;
+}
+
 static struct irq_chip irq_sim_irqchip = {
 	.name		= "irq_sim",
 	.irq_mask	= irq_sim_irqmask,
 	.irq_unmask	= irq_sim_irqunmask,
+	.irq_set_type	= irq_sim_set_type,
 };
 
 static void irq_sim_handle_irq(struct irq_work *work)
@@ -180,3 +190,16 @@ int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
 	return sim->irqs[offset].irqnum;
 }
 EXPORT_SYMBOL_GPL(irq_sim_irqnum);
+
+/**
+ * irq_sim_get_type - Get the type configuration for a dummy interrupt.
+ *
+ * @sim:        The interrupt simulator object.
+ * @offset:     Offset of the simulated interrupt for which to retrieve
+ *              the type.
+ */
+unsigned int irq_sim_get_type(struct irq_sim *sim, unsigned int offset)
+{
+	return sim->irqs[offset].type;
+}
+EXPORT_SYMBOL_GPL(irq_sim_get_type);
Signature · 1 line
2.20.1
#2 lore raw

Re: [PATCH v3 1/7] irq/irq_sim: provide irq_sim_get_type()

Quoted 43 lines · Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

Provide a helper that allows users to retrieve the current irq type of dummy interrupts.

Internally: store the type in the line context when the irq_set_type() callback is called.

This is required by the gpio-mockup module which wants to track the state of GPIO lines and simulate rising and falling edge interrupts.

---
 include/linux/irq_sim.h |  2 ++
 kernel/irq/irq_sim.c    | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)
include/linux/irq_sim.h +2 -0
index 4500d453a63e..c73be0a2c15c 100644
@@ -22,6 +22,7 @@ struct irq_sim_work_ctx {
 struct irq_sim_irq_ctx {
 	int			irqnum;
 	bool			enabled;
+	int			type;
 };
 
 struct irq_sim {
@@ -37,5 +38,6 @@ int devm_irq_sim_init(struct device *dev, struct irq_sim *sim,
 void irq_sim_fini(struct irq_sim *sim);
 void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
 int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
+unsigned int irq_sim_get_type(struct irq_sim *sim, unsigned int offset);
 
 #endif /* _LINUX_IRQ_SIM_H */
kernel/irq/irq_sim.c +0 -0
index 98a20e1594ce..74561a0dca65 100644
@@ -25,10 +25,20 @@ static void irq_sim_irqunmask(struct irq_data *data)
 	irq_ctx->enabled = true;

kernel/irq/irq_sim.c static void irq_sim_irqunmask(struct irq_data *data) · line 35

Quoted 10 lines
kernel/irq/irq_sim.c +8 -0
 }
 
+static int irq_sim_set_type(struct irq_data *data, unsigned int type)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->type = type;
+
+	return 0;
+}

In the cover letter, you say you only support edge. And yet you don't reject any of the level configuration. That's not right.

Quoted 16 lines
kernel/irq/irq_sim.c +5 -0
+
 static struct irq_chip irq_sim_irqchip = {
 	.name		= "irq_sim",
 	.irq_mask	= irq_sim_irqmask,
 	.irq_unmask	= irq_sim_irqunmask,
+	.irq_set_type	= irq_sim_set_type,
 };
 
 static void irq_sim_handle_irq(struct irq_work *work)
@@ -180,3 +190,16 @@ int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
 	return sim->irqs[offset].irqnum;
 }
 EXPORT_SYMBOL_GPL(irq_sim_irqnum);
+
+/**
+ * irq_sim_get_type - Get the type configuration for a dummy interrupt.

kernel/irq/irq_sim.c int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset) · line 205

Quoted 10 lines
kernel/irq/irq_sim.c +10 -0
+ *
+ * @sim:        The interrupt simulator object.
+ * @offset:     Offset of the simulated interrupt for which to retrieve
+ *              the type.
+ */
+unsigned int irq_sim_get_type(struct irq_sim *sim, unsigned int offset)
+{
+	return sim->irqs[offset].type;
+}
+EXPORT_SYMBOL_GPL(irq_sim_get_type);

This just shows that the way you have architected the whole thing is backward. The irq_set_type callback should push the configuration wherever it makes sense instead of offering a retrieving API exposing random bits of the data structures.

Thanks,

	M.
Signature · 1 line
Jazz is not dead, it just smell funny.
#3 lore raw

PATCH v3 2/7 gpio: mockup: add locking

In reply to Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

While no user reported any race condition problems with gpio-mockup, let's be on the safe side and use a mutex when performing any changes on the dummy chip structures.

---
 drivers/gpio/gpio-mockup.c | 50 ++++++++++++++++++++++++++++++++------
 1 file changed, 43 insertions(+), 7 deletions(-)
drivers/gpio/gpio-mockup.c +43 -7
index 6a50f9f59c90..b4c1de6acf74 100644
@@ -54,6 +54,7 @@ struct gpio_mockup_chip {
 	struct gpio_mockup_line_status *lines;
 	struct irq_sim irqsim;
 	struct dentry *dbg_dir;
+	struct mutex lock;
 };
 
 struct gpio_mockup_dbgfs_private {
@@ -82,29 +83,53 @@ static int gpio_mockup_range_ngpio(unsigned int index)
 	return gpio_mockup_ranges[index * 2 + 1];
 }
 
-static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
+static int __gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
 	return chip->lines[offset].value;
 }
 
-static void gpio_mockup_set(struct gpio_chip *gc,
-			    unsigned int offset, int value)
+static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+	int val;
+
+	mutex_lock(&chip->lock);
+	val = __gpio_mockup_get(gc, offset);
+	mutex_unlock(&chip->lock);
+
+	return val;
+}
+
+static void __gpio_mockup_set(struct gpio_chip *gc,
+			      unsigned int offset, int value)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
 	chip->lines[offset].value = !!value;
 }
 
+static void gpio_mockup_set(struct gpio_chip *gc,
+			   unsigned int offset, int value)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	mutex_lock(&chip->lock);
+	__gpio_mockup_set(gc, offset, value);
+	mutex_unlock(&chip->lock);
+}
+
 static void gpio_mockup_set_multiple(struct gpio_chip *gc,
 				     unsigned long *mask, unsigned long *bits)
 {
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 	unsigned int bit;
 
+	mutex_lock(&chip->lock);
 	for_each_set_bit(bit, mask, gc->ngpio)
-		gpio_mockup_set(gc, bit, test_bit(bit, bits));
-
+		__gpio_mockup_set(gc, bit, test_bit(bit, bits));
+	mutex_unlock(&chip->lock);
 }
 
 static int gpio_mockup_dirout(struct gpio_chip *gc,
@@ -112,8 +137,10 @@ static int gpio_mockup_dirout(struct gpio_chip *gc,
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
-	gpio_mockup_set(gc, offset, value);
+	mutex_lock(&chip->lock);
 	chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
+	__gpio_mockup_set(gc, offset, value);
+	mutex_unlock(&chip->lock);
 
 	return 0;
 }
@@ -122,7 +149,9 @@ static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
+	mutex_lock(&chip->lock);
 	chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
+	mutex_unlock(&chip->lock);
 
 	return 0;
 }
@@ -130,8 +159,13 @@ static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
 static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+	int direction;
 
-	return !chip->lines[offset].dir;
+	mutex_lock(&chip->lock);
+	direction = !chip->lines[offset].dir;
+	mutex_unlock(&chip->lock);
+
+	return direction;
 }
 
 static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
@@ -283,6 +317,8 @@ static int gpio_mockup_probe(struct platform_device *pdev)
 			return -ENOMEM;
 	}
 
+	mutex_init(&chip->lock);
+
 	gc = &chip->gc;
 	gc->base = base;
 	gc->ngpio = ngpio;
Signature · 1 line
2.20.1
#4 lore raw

PATCH v3 3/7 gpio: mockup: implement get_multiple()

In reply to Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

We already support set_multiple(). Implement get_multiple() as well.

---
 drivers/gpio/gpio-mockup.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
drivers/gpio/gpio-mockup.c +17 -0
index b4c1de6acf74..1c945c967f60 100644
@@ -102,6 +102,22 @@ static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
 	return val;
 }
 
+static int gpio_mockup_get_multiple(struct gpio_chip *gc,
+				    unsigned long *mask, unsigned long *bits)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+	unsigned int bit, val;
+
+	mutex_lock(&chip->lock);
+	for_each_set_bit(bit, mask, gc->ngpio) {
+		val = __gpio_mockup_get(gc, bit);
+		__assign_bit(bit, bits, val);
+	}
+	mutex_unlock(&chip->lock);
+
+	return 0;
+}
+
 static void __gpio_mockup_set(struct gpio_chip *gc,
 			      unsigned int offset, int value)
 {
@@ -327,6 +343,7 @@ static int gpio_mockup_probe(struct platform_device *pdev)
 	gc->parent = dev;
 	gc->get = gpio_mockup_get;
 	gc->set = gpio_mockup_set;
+	gc->get_multiple = gpio_mockup_get_multiple;
 	gc->set_multiple = gpio_mockup_set_multiple;
 	gc->direction_output = gpio_mockup_dirout;
 	gc->direction_input = gpio_mockup_dirin;
Signature · 1 line
2.20.1
#5 lore raw

PATCH v3 4/7 gpio: mockup: don't create the debugfs link named after the label

In reply to Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

User-space tests no longer use it and we're breaking the interface anyway.

---
 drivers/gpio/gpio-mockup.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
drivers/gpio/gpio-mockup.c +1 -5
index 1c945c967f60..0317917a3678 100644
@@ -234,7 +234,7 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
 				      struct gpio_mockup_chip *chip)
 {
 	struct gpio_mockup_dbgfs_private *priv;
-	struct dentry *evfile, *link;
+	struct dentry *evfile;
 	struct gpio_chip *gc;
 	const char *devname;
 	char *name;
@@ -247,10 +247,6 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
 	if (IS_ERR_OR_NULL(chip->dbg_dir))
 		goto err;
 
-	link = debugfs_create_symlink(gc->label, gpio_mockup_dbg_dir, devname);
-	if (IS_ERR_OR_NULL(link))
-		goto err;
-
 	for (i = 0; i < gc->ngpio; i++) {
 		name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
 		if (!name)
Signature · 1 line
2.20.1
#6 lore raw

PATCH v3 5/7 gpio: mockup: change the type of 'offset' to unsigned int

In reply to Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

This field can never be negative.

---
 drivers/gpio/gpio-mockup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/gpio/gpio-mockup.c +1 -1
index 0317917a3678..433adb3b4617 100644
@@ -60,7 +60,7 @@ struct gpio_mockup_chip {
 struct gpio_mockup_dbgfs_private {
 	struct gpio_mockup_chip *chip;
 	struct gpio_desc *desc;
-	int offset;
+	unsigned int offset;
 };
 
 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
Signature · 1 line
2.20.1
#7 lore raw

PATCH v3 6/7 gpio: mockup: change the signature of unlocked get/set helpers

In reply to Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

The unlocked variants only get called from places where we already have the pointer to the underlying gpio_mockup_chip structure, so take it as parameter instead of struct gpio_chip.

---
 drivers/gpio/gpio-mockup.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)
drivers/gpio/gpio-mockup.c +8 -11
index 433adb3b4617..c498b0fbbec8 100644
@@ -83,10 +83,9 @@ static int gpio_mockup_range_ngpio(unsigned int index)
 	return gpio_mockup_ranges[index * 2 + 1];
 }
 
-static int __gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
+static int __gpio_mockup_get(struct gpio_mockup_chip *chip,
+			     unsigned int offset)
 {
-	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
-
 	return chip->lines[offset].value;
 }
 
@@ -96,7 +95,7 @@ static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
 	int val;
 
 	mutex_lock(&chip->lock);
-	val = __gpio_mockup_get(gc, offset);
+	val = __gpio_mockup_get(chip, offset);
 	mutex_unlock(&chip->lock);
 
 	return val;
@@ -110,7 +109,7 @@ static int gpio_mockup_get_multiple(struct gpio_chip *gc,
 
 	mutex_lock(&chip->lock);
 	for_each_set_bit(bit, mask, gc->ngpio) {
-		val = __gpio_mockup_get(gc, bit);
+		val = __gpio_mockup_get(chip, bit);
 		__assign_bit(bit, bits, val);
 	}
 	mutex_unlock(&chip->lock);
@@ -118,11 +117,9 @@ static int gpio_mockup_get_multiple(struct gpio_chip *gc,
 	return 0;
 }
 
-static void __gpio_mockup_set(struct gpio_chip *gc,
+static void __gpio_mockup_set(struct gpio_mockup_chip *chip,
 			      unsigned int offset, int value)
 {
-	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
-
 	chip->lines[offset].value = !!value;
 }
 
@@ -132,7 +129,7 @@ static void gpio_mockup_set(struct gpio_chip *gc,
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
 
 	mutex_lock(&chip->lock);
-	__gpio_mockup_set(gc, offset, value);
+	__gpio_mockup_set(chip, offset, value);
 	mutex_unlock(&chip->lock);
 }
 
@@ -144,7 +141,7 @@ static void gpio_mockup_set_multiple(struct gpio_chip *gc,
 
 	mutex_lock(&chip->lock);
 	for_each_set_bit(bit, mask, gc->ngpio)
-		__gpio_mockup_set(gc, bit, test_bit(bit, bits));
+		__gpio_mockup_set(chip, bit, test_bit(bit, bits));
 	mutex_unlock(&chip->lock);
 }
 
@@ -155,7 +152,7 @@ static int gpio_mockup_dirout(struct gpio_chip *gc,
 
 	mutex_lock(&chip->lock);
 	chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
-	__gpio_mockup_set(gc, offset, value);
+	__gpio_mockup_set(chip, offset, value);
 	mutex_unlock(&chip->lock);
 
 	return 0;
Signature · 1 line
2.20.1
#8 lore raw

PATCH v3 7/7 gpio: mockup: rework debugfs interface

In reply to Bartosz Golaszewski

From: Bartosz Golaszewski <[email protected]>

Modify the way the debugfs interface works in gpio-mockup. Introduce the concept of dummy pull config which will keep the mockup lines in known state. The pull values can be modified by writing to the debugfs files corresponding to lines. Lines in input mode always report the current pull value, lines in output mode change the line value but it will revert back to the one specified by current pull when released.

---
 drivers/gpio/gpio-mockup.c | 116 ++++++++++++++++++++++++++++++++-----
 1 file changed, 102 insertions(+), 14 deletions(-)
drivers/gpio/gpio-mockup.c +102 -14
index c498b0fbbec8..6424bd710de5 100644
@@ -47,6 +47,7 @@ enum {
 struct gpio_mockup_line_status {
 	int dir;
 	int value;
+	int pull;
 };
 
 struct gpio_mockup_chip {
@@ -188,15 +189,57 @@ static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
 	return irq_sim_irqnum(&chip->irqsim, offset);
 }
 
-static ssize_t gpio_mockup_event_write(struct file *file,
-				       const char __user *usr_buf,
-				       size_t size, loff_t *ppos)
+static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
+{
+	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+	__gpio_mockup_set(chip, offset, chip->lines[offset].pull);
+}
+
+static ssize_t gpio_mockup_debugfs_read(struct file *file,
+					char __user *usr_buf,
+					size_t size, loff_t *ppos)
+{
+	struct gpio_mockup_dbgfs_private *priv;
+	struct gpio_mockup_chip *chip;
+	struct seq_file *sfile;
+	struct gpio_chip *gc;
+	char buf[3];
+	int val, rv;
+
+	if (*ppos != 0)
+		return 0;
+
+	sfile = file->private_data;
+	priv = sfile->private;
+	chip = priv->chip;
+	gc = &chip->gc;
+
+	val = gpio_mockup_get(gc, priv->offset);
+	snprintf(buf, sizeof(buf), "%d\n", val);
+
+	rv = copy_to_user(usr_buf, buf, sizeof(buf));
+	if (rv)
+		return rv;
+
+	return sizeof(buf) - 1;
+}
+
+static ssize_t gpio_mockup_debugfs_write(struct file *file,
+					 const char __user *usr_buf,
+					 size_t size, loff_t *ppos)
 {
 	struct gpio_mockup_dbgfs_private *priv;
 	struct gpio_mockup_chip *chip;
 	struct seq_file *sfile;
 	struct gpio_desc *desc;
-	int rv, val;
+	unsigned int irq_type;
+	struct gpio_chip *gc;
+	struct irq_sim *sim;
+	int rv, val, curr;
+
+	if (*ppos != 0)
+		return -EINVAL;
 
 	rv = kstrtoint_from_user(usr_buf, size, 0, &val);
 	if (rv)
@@ -206,24 +249,68 @@ static ssize_t gpio_mockup_event_write(struct file *file,
 
 	sfile = file->private_data;
 	priv = sfile->private;
-	desc = priv->desc;
 	chip = priv->chip;
+	gc = &chip->gc;
+	desc = &gc->gpiodev->descs[priv->offset];
+	sim = &chip->irqsim;
+
+	mutex_lock(&chip->lock);
 
-	gpiod_set_value_cansleep(desc, val);
-	irq_sim_fire(&chip->irqsim, priv->offset);
+	if (test_bit(FLAG_REQUESTED, &desc->flags) &&
+	    !test_bit(FLAG_IS_OUT, &desc->flags)) {
+		curr = __gpio_mockup_get(chip, priv->offset);
+		if (curr == val)
+			goto out;
+
+		irq_type = irq_sim_get_type(sim, priv->offset);
+		if ((val == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
+		    (val == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
+			irq_sim_fire(&chip->irqsim, priv->offset);
+	}
+
+	/* Change the value unless we're actively driving the line. */
+	if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
+	    !test_bit(FLAG_IS_OUT, &desc->flags))
+		__gpio_mockup_set(chip, priv->offset, val);
+
+out:
+	chip->lines[priv->offset].pull = val;
+	mutex_unlock(&chip->lock);
 
 	return size;
 }
 
-static int gpio_mockup_event_open(struct inode *inode, struct file *file)
+static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, NULL, inode->i_private);
 }
 
-static const struct file_operations gpio_mockup_event_ops = {
+/*
+ * Each mockup chip is represented by a directory named after the chip's device
+ * name under /sys/kernel/debug/gpio-mockup/. Each line is represented by
+ * a file using the line's offset as the name under the chip's directory.
+ *
+ * Reading from the line's file yields the current *value*, writing to the
+ * line's file changes the current *pull*. Default pull for mockup lines is
+ * down.
+ *
+ * Examples:
+ * - when a line pulled down is requested in output mode and driven high, its
+ *   value will return to 0 once it's released
+ * - when the line is requested in output mode and driven high, writing 0 to
+ *   the corresponding debugfs file will change the pull to down but the
+ *   reported value will still be 1 until the line is released
+ * - line requested in input mode always reports the same value as its pull
+ *   configuration
+ * - when the line is requested in input mode and monitored for events, writing
+ *   the same value to the debugfs file will be a noop, while writing the
+ *   opposite value will generate a dummy interrupt with an appropriate edge
+ */
+static const struct file_operations gpio_mockup_debugfs_ops = {
 	.owner = THIS_MODULE,
-	.open = gpio_mockup_event_open,
-	.write = gpio_mockup_event_write,
+	.open = gpio_mockup_debugfs_open,
+	.read = gpio_mockup_debugfs_read,
+	.write = gpio_mockup_debugfs_write,
 	.llseek = no_llseek,
 };
 
@@ -258,7 +345,7 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
 		priv->desc = &gc->gpiodev->descs[i];
 
 		evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
-					     &gpio_mockup_event_ops);
+					     &gpio_mockup_debugfs_ops);
 		if (IS_ERR_OR_NULL(evfile))
 			goto err;
 	}
@@ -266,7 +353,7 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
 	return;
 
 err:
-	dev_err(dev, "error creating debugfs event files\n");
+	dev_err(dev, "error creating debugfs files\n");
 }
 
 static int gpio_mockup_name_lines(struct device *dev,
@@ -342,6 +429,7 @@ static int gpio_mockup_probe(struct platform_device *pdev)
 	gc->direction_input = gpio_mockup_dirin;
 	gc->get_direction = gpio_mockup_get_direction;
 	gc->to_irq = gpio_mockup_to_irq;
+	gc->free = gpio_mockup_free;
 
 	chip->lines = devm_kcalloc(dev, gc->ngpio,
 				   sizeof(*chip->lines), GFP_KERNEL);
@@ -415,7 +503,7 @@ static int __init gpio_mockup_init(void)
 			return -EINVAL;
 	}
 
-	gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
+	gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL);
 	if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
 		gpio_mockup_err("error creating debugfs directory\n");
 
Signature · 1 line
2.20.1