[PATCH v5 0/7] gpio: mockup: improve the user-space testing interface

[PATCH v5 0/7] gpio: mockup: improve the user-space testing interface

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Hi Marc,

please take a look at another, much simpler approach. The only change
in irq_sim is calling the irqd_set_trigger_type() in irq_set_type(). We
don't care about the actual type - we simply store it and any interested
user (for example gpio-mockup in this series) can retrieve it using
irq_get_trigger_type() and interpret it on its own.

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

v3 -> v4:
- drop irq_sim_get_type() and use a notifier chain instead so that any change
  in type configuration can be pushed out to interested users
- change the locking mechanism in gpio-mockup to a spinlock as we can't take
  a mutex when a hardirq-safe spinlock in irq_desc is being held when the
  irq_set_type() callback is called
- refuse to set any other type than falling or rising edge in irq_set_config

v4 -> v5:
- drop the notifier, use irqd_set_trigger_type() instead

Bartosz Golaszewski (7):
  irq/irq_sim: add irq_set_type() callback
  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 | 189 +++++++++++++++++++++++++++++++------
 kernel/irq/irq_sim.c       |   8 ++
 2 files changed, 170 insertions(+), 27 deletions(-)

-- 
2.20.1

[PATCH v5 1/7] irq/irq_sim: add irq_set_type() callback

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Implement the irq_set_type() callback and call irqd_set_trigger_type()
internally so that users interested in the configured trigger type can
later retrieve it using irqd_get_trigger_type().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 kernel/irq/irq_sim.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
index 98a20e1594ce..83ecc65d8be2 100644
--- a/kernel/irq/irq_sim.c
+++ b/kernel/irq/irq_sim.c
@@ -25,10 +25,18 @@ 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)
+{
+	irqd_set_trigger_type(data, 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)
-- 
2.20.1

Re: [PATCH v5 1/7] irq/irq_sim: add irq_set_type() callback

[Marc Zyngier]

On Mon, 18 Feb 2019 17:41:32 +0100
Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> Implement the irq_set_type() callback and call irqd_set_trigger_type()
> internally so that users interested in the configured trigger type can
> later retrieve it using irqd_get_trigger_type().
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  kernel/irq/irq_sim.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
> index 98a20e1594ce..83ecc65d8be2 100644
> --- a/kernel/irq/irq_sim.c
> +++ b/kernel/irq/irq_sim.c
> @@ -25,10 +25,18 @@ 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)
> +{
> +	irqd_set_trigger_type(data, type);
> +
> +	return 0;

You keep ignoring the requirement for sanitization of the trigger type.
Frankly, I'm getting tired of fighting over 3 lines of incorrect code.

I guess that despite all the noise, you don't really want this code in
after all.

	M.
-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH v5 1/7] irq/irq_sim: add irq_set_type() callback

[Bartosz Golaszewski]

wt., 19 lut 2019 o 13:25 Marc Zyngier <marc.zyngier@arm.com> napisał(a):
>
> On Mon, 18 Feb 2019 17:41:32 +0100
> Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >
> > Implement the irq_set_type() callback and call irqd_set_trigger_type()
> > internally so that users interested in the configured trigger type can
> > later retrieve it using irqd_get_trigger_type().
> >
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > ---
> >  kernel/irq/irq_sim.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
> > index 98a20e1594ce..83ecc65d8be2 100644
> > --- a/kernel/irq/irq_sim.c
> > +++ b/kernel/irq/irq_sim.c
> > @@ -25,10 +25,18 @@ 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)
> > +{
> > +     irqd_set_trigger_type(data, type);
> > +
> > +     return 0;
>
> You keep ignoring the requirement for sanitization of the trigger type.
> Frankly, I'm getting tired of fighting over 3 lines of incorrect code.
>

It used to be there in previous versions, but I removed it on purpose
in v5. I understand why we needed that earlier, but if we now moved
*all* the logic behind the trigger type to the users of this API and
we're now simply storing any config we get, then why would we impose
any limits on it here? We don't do this now and this patch doesn't
change the current behavior. I really don't understand how not
rejecting certain trigger types makes this patch incorrect.

> I guess that despite all the noise, you don't really want this code in
> after all.
>

I do want and need this, but I really can't figure out from your
reviews how you imagine the correct solution. You said previously that
the irq_set_type callback should push the configuration to wherever
it's needed. I believe the above patch does this. Should we then limit
the supported trigger types? That would mean that irq_sim would need
to know what users support. It seems inverted to me, but if you think
it's right, then my question is: will accepting only IRQ_TYPE_NONE,
IRQ_TYPE_EDGE_RISING and IRQ_TYPE_EDGE_FALLING in the above function
be enough for you to accept it? Is the rest fine?

Thanks,
Bartosz

Re: [PATCH v5 1/7] irq/irq_sim: add irq_set_type() callback

[Marc Zyngier]

On Tue, 19 Feb 2019 14:20:03 +0100
Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> wt., 19 lut 2019 o 13:25 Marc Zyngier <marc.zyngier@arm.com> napisał(a):
> >
> > On Mon, 18 Feb 2019 17:41:32 +0100
> > Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> >  
> > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > >
> > > Implement the irq_set_type() callback and call irqd_set_trigger_type()
> > > internally so that users interested in the configured trigger type can
> > > later retrieve it using irqd_get_trigger_type().
> > >
> > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > ---
> > >  kernel/irq/irq_sim.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
> > > index 98a20e1594ce..83ecc65d8be2 100644
> > > --- a/kernel/irq/irq_sim.c
> > > +++ b/kernel/irq/irq_sim.c
> > > @@ -25,10 +25,18 @@ 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)
> > > +{
> > > +     irqd_set_trigger_type(data, type);
> > > +
> > > +     return 0;  
> >
> > You keep ignoring the requirement for sanitization of the trigger type.
> > Frankly, I'm getting tired of fighting over 3 lines of incorrect code.
> >  
> 
> It used to be there in previous versions, but I removed it on purpose
> in v5. I understand why we needed that earlier, but if we now moved
> *all* the logic behind the trigger type to the users of this API and
> we're now simply storing any config we get, then why would we impose
> any limits on it here? We don't do this now and this patch doesn't
> change the current behavior. I really don't understand how not
> rejecting certain trigger types makes this patch incorrect.

You expose a new set_type callback. Only a set of valid values can be
handled by the users of this interface. At least your mockup gpio only
handles a narrow set of configuration. Not rejecting erroneous values
is a bug. This isn't a new requirement; this is how the irqchip API
works, as drivers do expect such a failure if requiring an invalid
type.

> > I guess that despite all the noise, you don't really want this code in
> > after all.
> >  
> 
> I do want and need this, but I really can't figure out from your
> reviews how you imagine the correct solution. You said previously that
> the irq_set_type callback should push the configuration to wherever
> it's needed.

Yes. But it doesn't mean it should accept something that cannot be
handled by the irqchip. If you push it to the code that does the
handling, it still has to return an error if the backing code decides
that this is not a supported configuration.

At the end of the day, where you store it is irrelevant for the problem
at hand. There is an API, and you need to implement it correctly.

> I believe the above patch does this. Should we then limit
> the supported trigger types? That would mean that irq_sim would need
> to know what users support. It seems inverted to me, but if you think
> it's right, then my question is: will accepting only IRQ_TYPE_NONE,
> IRQ_TYPE_EDGE_RISING and IRQ_TYPE_EDGE_FALLING in the above function
> be enough for you to accept it? Is the rest fine?

IRQ_TYPE_NONE doesn't mean anything, apart from "whatever defaults were
there because I have no clue". In your case, I really don't see the
point. The EDGE settings are what you handle, and are the only values
that should be accepted.

As for the rest of the patches, I haven't looked at them, and probably
won't (if only because I'm on holiday and would like to do something
else...). All I'm asking from you is to give me a correct patch #1.
Once I see that, I'll gladly ack it.

	M.
-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH v5 1/7] irq/irq_sim: add irq_set_type() callback

[Bartosz Golaszewski]

wt., 19 lut 2019 o 14:40 Marc Zyngier <marc.zyngier@arm.com> napisał(a):
>
> On Tue, 19 Feb 2019 14:20:03 +0100
> Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> > wt., 19 lut 2019 o 13:25 Marc Zyngier <marc.zyngier@arm.com> napisał(a):
> > >
> > > On Mon, 18 Feb 2019 17:41:32 +0100
> > > Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > >
> > > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > >
> > > > Implement the irq_set_type() callback and call irqd_set_trigger_type()
> > > > internally so that users interested in the configured trigger type can
> > > > later retrieve it using irqd_get_trigger_type().
> > > >
> > > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > > ---
> > > >  kernel/irq/irq_sim.c | 8 ++++++++
> > > >  1 file changed, 8 insertions(+)
> > > >
> > > > diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
> > > > index 98a20e1594ce..83ecc65d8be2 100644
> > > > --- a/kernel/irq/irq_sim.c
> > > > +++ b/kernel/irq/irq_sim.c
> > > > @@ -25,10 +25,18 @@ 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)
> > > > +{
> > > > +     irqd_set_trigger_type(data, type);
> > > > +
> > > > +     return 0;
> > >
> > > You keep ignoring the requirement for sanitization of the trigger type.
> > > Frankly, I'm getting tired of fighting over 3 lines of incorrect code.
> > >
> >
> > It used to be there in previous versions, but I removed it on purpose
> > in v5. I understand why we needed that earlier, but if we now moved
> > *all* the logic behind the trigger type to the users of this API and
> > we're now simply storing any config we get, then why would we impose
> > any limits on it here? We don't do this now and this patch doesn't
> > change the current behavior. I really don't understand how not
> > rejecting certain trigger types makes this patch incorrect.
>
> You expose a new set_type callback. Only a set of valid values can be
> handled by the users of this interface. At least your mockup gpio only
> handles a narrow set of configuration. Not rejecting erroneous values
> is a bug. This isn't a new requirement; this is how the irqchip API
> works, as drivers do expect such a failure if requiring an invalid
> type.
>
> > > I guess that despite all the noise, you don't really want this code in
> > > after all.
> > >
> >
> > I do want and need this, but I really can't figure out from your
> > reviews how you imagine the correct solution. You said previously that
> > the irq_set_type callback should push the configuration to wherever
> > it's needed.
>
> Yes. But it doesn't mean it should accept something that cannot be
> handled by the irqchip. If you push it to the code that does the
> handling, it still has to return an error if the backing code decides
> that this is not a supported configuration.
>
> At the end of the day, where you store it is irrelevant for the problem
> at hand. There is an API, and you need to implement it correctly.
>
> > I believe the above patch does this. Should we then limit
> > the supported trigger types? That would mean that irq_sim would need
> > to know what users support. It seems inverted to me, but if you think
> > it's right, then my question is: will accepting only IRQ_TYPE_NONE,
> > IRQ_TYPE_EDGE_RISING and IRQ_TYPE_EDGE_FALLING in the above function
> > be enough for you to accept it? Is the rest fine?
>
> IRQ_TYPE_NONE doesn't mean anything, apart from "whatever defaults were
> there because I have no clue". In your case, I really don't see the
> point. The EDGE settings are what you handle, and are the only values
> that should be accepted.
>

Right, irq_set_type() isn't even called if there's no trigger set.

> As for the rest of the patches, I haven't looked at them, and probably
> won't (if only because I'm on holiday and would like to do something
> else...). All I'm asking from you is to give me a correct patch #1.
> Once I see that, I'll gladly ack it.
>

Thanks,
Bartosz

[PATCH v5 2/7] gpio: mockup: add locking

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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.

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-mockup.c | 50 ++++++++++++++++++++++++++++++++------
 1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 6a50f9f59c90..b4c1de6acf74 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -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;
-- 
2.20.1

[PATCH v5 3/7] gpio: mockup: implement get_multiple()

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-mockup.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index b4c1de6acf74..1c945c967f60 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -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;
-- 
2.20.1

[PATCH v5 4/7] gpio: mockup: don't create the debugfs link named after the label

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-mockup.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 1c945c967f60..0317917a3678 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -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)
-- 
2.20.1

[PATCH v5 5/7] gpio: mockup: change the type of 'offset' to unsigned int

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

This field can never be negative.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-mockup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 0317917a3678..433adb3b4617 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -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];
-- 
2.20.1

[PATCH v5 6/7] gpio: mockup: change the signature of unlocked get/set helpers

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-mockup.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 433adb3b4617..c498b0fbbec8 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -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;
-- 
2.20.1

[PATCH v5 7/7] gpio: mockup: rework debugfs interface

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpio-mockup.c | 117 ++++++++++++++++++++++++++++++++-----
 1 file changed, 103 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index c498b0fbbec8..154d959e8993 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -47,6 +47,7 @@ enum {
 struct gpio_mockup_line_status {
 	int dir;
 	int value;
+	int pull;
 };
 
 struct gpio_mockup_chip {
@@ -188,15 +189,56 @@ 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;
+	int rv, val, curr, irq, irq_type;
+	struct gpio_mockup_chip *chip;
+	struct seq_file *sfile;
 	struct gpio_desc *desc;
-	int rv, val;
+	struct gpio_chip *gc;
+	struct irq_sim *sim;
+
+	if (*ppos != 0)
+		return -EINVAL;
 
 	rv = kstrtoint_from_user(usr_buf, size, 0, &val);
 	if (rv)
@@ -206,24 +248,70 @@ 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);
+
+	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;
 
-	gpiod_set_value_cansleep(desc, val);
-	irq_sim_fire(&chip->irqsim, priv->offset);
+		irq = irq_sim_irqnum(sim, priv->offset);
+		irq_type = irq_get_trigger_type(irq);
+
+		if ((val == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
+		    (val == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
+			irq_sim_fire(sim, 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 +346,7 @@ 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 +354,7 @@ 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 +430,7 @@ 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 +504,7 @@ 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");
 
-- 
2.20.1