[PATCH 0/5] I2C IRQ Probe Improvements

[PATCH 0/5] I2C IRQ Probe Improvements

[Charles Keepax]

Apologies for the resend adding Andy and Jarkko.

This series attempts to align as much IRQ handling into the
probe path as possible. Note that I don't have a great setup
for testing these patches so they are mostly just build tested
and need careful review and testing before any of them are
merged.

The series brings the ACPI path inline with the way the device
tree path handles the IRQ entirely at probe time. However,
it still leaves any IRQ specified through the board_info as
being handled at device time. In that case we need to cache
something from the board_info until probe time, which leaves
any alternative solution with something basically the same as
the current handling although perhaps caching more stuff.

Thanks,
Charles

See previous discussions:
 - https://lkml.org/lkml/2019/2/15/989
 - https://www.spinics.net/lists/linux-i2c/msg39541.html

Charles Keepax (5):
  i2c: acpi: Factor out getting the IRQ from ACPI
  i2c: acpi: Use available IRQ helper functions
  i2c: core: Move ACPI IRQ handling to probe time
  i2c: core: Move ACPI gpio IRQ handling into i2c_acpi_get_irq
  i2c: core: Tidy up handling of init_irq

 drivers/i2c/i2c-core-acpi.c | 50 ++++++++++++++++++++++++++++++---------------
 drivers/i2c/i2c-core-base.c | 11 +++++-----
 drivers/i2c/i2c-core.h      |  9 ++++++++
 3 files changed, 48 insertions(+), 22 deletions(-)

-- 
2.11.0

[PATCH 1/5] i2c: acpi: Factor out getting the IRQ from ACPI

[Charles Keepax]

In preparation for future refactoring factor out the fetch of the IRQ
into its own helper function.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 drivers/i2c/i2c-core-acpi.c | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 2728006920888..c3ac3ea184317 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -137,13 +137,35 @@ static int i2c_acpi_do_lookup(struct acpi_device *adev,
 	return 0;
 }
 
+static int i2c_acpi_get_irq(struct acpi_device *adev, int *irq)
+{
+	struct list_head resource_list;
+	struct resource_entry *entry;
+	int ret;
+
+	INIT_LIST_HEAD(&resource_list);
+
+	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+	if (ret < 0)
+		return -EINVAL;
+
+	resource_list_for_each_entry(entry, &resource_list) {
+		if (resource_type(entry->res) == IORESOURCE_IRQ) {
+			*irq = entry->res->start;
+			break;
+		}
+	}
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	return 0;
+}
+
 static int i2c_acpi_get_info(struct acpi_device *adev,
 			     struct i2c_board_info *info,
 			     struct i2c_adapter *adapter,
 			     acpi_handle *adapter_handle)
 {
-	struct list_head resource_list;
-	struct resource_entry *entry;
 	struct i2c_acpi_lookup lookup;
 	int ret;
 
@@ -175,19 +197,7 @@ static int i2c_acpi_get_info(struct acpi_device *adev,
 		*adapter_handle = lookup.adapter_handle;
 
 	/* Then fill IRQ number if any */
-	INIT_LIST_HEAD(&resource_list);
-	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
-	if (ret < 0)
-		return -EINVAL;
-
-	resource_list_for_each_entry(entry, &resource_list) {
-		if (resource_type(entry->res) == IORESOURCE_IRQ) {
-			info->irq = entry->res->start;
-			break;
-		}
-	}
-
-	acpi_dev_free_resource_list(&resource_list);
+	i2c_acpi_get_irq(adev, &info->irq);
 
 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
 			  sizeof(info->type));
-- 
2.11.0

[PATCH 2/5] i2c: acpi: Use available IRQ helper functions

[Charles Keepax]

Use the available IRQ helper functions, most of the functions have
additional helpful side affects like configuring the trigger type of the
IRQ.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 drivers/i2c/i2c-core-acpi.c | 23 ++++++++++++++---------
 drivers/i2c/i2c-core-base.c |  4 ++--
 drivers/i2c/i2c-core.h      |  2 ++
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index c3ac3ea184317..764cd10420a74 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -137,25 +137,30 @@ static int i2c_acpi_do_lookup(struct acpi_device *adev,
 	return 0;
 }
 
+static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
+{
+	int *irq = data;
+	struct resource r;
+
+	if (*irq < 0 && acpi_dev_resource_interrupt(ares, 0, &r))
+		*irq = i2c_dev_irq_from_resources(&r, 1);
+
+	return 1; /* No need to add resource to the list */
+}
+
 static int i2c_acpi_get_irq(struct acpi_device *adev, int *irq)
 {
 	struct list_head resource_list;
-	struct resource_entry *entry;
 	int ret;
 
 	INIT_LIST_HEAD(&resource_list);
+	*irq = -ENOENT;
 
-	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     i2c_acpi_add_resource, &irq);
 	if (ret < 0)
 		return -EINVAL;
 
-	resource_list_for_each_entry(entry, &resource_list) {
-		if (resource_type(entry->res) == IORESOURCE_IRQ) {
-			*irq = entry->res->start;
-			break;
-		}
-	}
-
 	acpi_dev_free_resource_list(&resource_list);
 
 	return 0;
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index d389d4fb0623a..84bf11b25a120 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -687,8 +687,8 @@ static void i2c_dev_set_name(struct i2c_adapter *adap,
 		     i2c_encode_flags_to_addr(client));
 }
 
-static int i2c_dev_irq_from_resources(const struct resource *resources,
-				      unsigned int num_resources)
+int i2c_dev_irq_from_resources(const struct resource *resources,
+			       unsigned int num_resources)
 {
 	struct irq_data *irqd;
 	int i;
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index c88cfef813431..8f3a08dc73a25 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -28,6 +28,8 @@ extern struct list_head	__i2c_board_list;
 extern int		__i2c_first_dynamic_bus_num;
 
 int i2c_check_7bit_addr_validity_strict(unsigned short addr);
+int i2c_dev_irq_from_resources(const struct resource *resources,
+			       unsigned int num_resources);
 
 /*
  * We only allow atomic transfers for very late communication, e.g. to send
-- 
2.11.0

[PATCH 3/5] i2c: core: Move ACPI IRQ handling to probe time

[Charles Keepax]

Bring the ACPI path in sync with the device tree path and handle all the
IRQ fetching at probe time. This leaves the only IRQ handling at device
registration time being that which is passed directly through the board
info as either a resource or an actual IRQ number.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 drivers/i2c/i2c-core-acpi.c | 6 ++----
 drivers/i2c/i2c-core-base.c | 6 +++++-
 drivers/i2c/i2c-core.h      | 7 +++++++
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 764cd10420a74..e332760bf9ebc 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -148,8 +148,9 @@ static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
 	return 1; /* No need to add resource to the list */
 }
 
-static int i2c_acpi_get_irq(struct acpi_device *adev, int *irq)
+int i2c_acpi_get_irq(struct i2c_client *client, int *irq)
 {
+	struct acpi_device *adev = ACPI_COMPANION(&client->adapter->dev);
 	struct list_head resource_list;
 	int ret;
 
@@ -201,9 +202,6 @@ static int i2c_acpi_get_info(struct acpi_device *adev,
 	if (adapter_handle)
 		*adapter_handle = lookup.adapter_handle;
 
-	/* Then fill IRQ number if any */
-	i2c_acpi_get_irq(adev, &info->irq);
-
 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
 			  sizeof(info->type));
 
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 84bf11b25a120..c1afa17a76bfc 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -335,7 +335,11 @@ static int i2c_device_probe(struct device *dev)
 			if (irq == -EINVAL || irq == -ENODATA)
 				irq = of_irq_get(dev->of_node, 0);
 		} else if (ACPI_COMPANION(dev)) {
-			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
+			i2c_acpi_get_irq(client, &irq);
+
+			if (irq == -ENOENT)
+				irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev),
+							    0);
 		}
 		if (irq == -EPROBE_DEFER)
 			return irq;
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index 8f3a08dc73a25..6bec145ab7d74 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -72,6 +72,8 @@ const struct acpi_device_id *
 i2c_acpi_match_device(const struct acpi_device_id *matches,
 		      struct i2c_client *client);
 void i2c_acpi_register_devices(struct i2c_adapter *adap);
+
+int i2c_acpi_get_irq(struct i2c_client *client, int *irq);
 #else /* CONFIG_ACPI */
 static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
 static inline const struct acpi_device_id *
@@ -80,6 +82,11 @@ i2c_acpi_match_device(const struct acpi_device_id *matches,
 {
 	return NULL;
 }
+
+static inline int i2c_acpi_get_irq(struct i2c_client *client, int *irq)
+{
+	return 0;
+}
 #endif /* CONFIG_ACPI */
 extern struct notifier_block i2c_acpi_notifier;
 
-- 
2.11.0

[PATCH 4/5] i2c: core: Move ACPI gpio IRQ handling into i2c_acpi_get_irq

[Charles Keepax]

It makes sense to contain all the ACPI IRQ handling in a single helper
function.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Note that this one is somewhat interesting, it seems the search
through the resource list is done against the companion device
of the adapter but the GPIO search is done against the companion
device of the client. It feels to me like these really should
be done on the same device, and certainly this is what SPI
does (both against the equivalent of the adapter). Perhaps
someone with more ACPI knowledge than myself could comment?

Thanks,
Charles

 drivers/i2c/i2c-core-acpi.c | 3 +++
 drivers/i2c/i2c-core-base.c | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index e332760bf9ebc..0c882d956e9a4 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -164,6 +164,9 @@ int i2c_acpi_get_irq(struct i2c_client *client, int *irq)
 
 	acpi_dev_free_resource_list(&resource_list);
 
+	if (*irq < 0)
+		*irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(&client->dev), 0);
+
 	return 0;
 }
 
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index c1afa17a76bfc..f958b50c78c04 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -336,10 +336,6 @@ static int i2c_device_probe(struct device *dev)
 				irq = of_irq_get(dev->of_node, 0);
 		} else if (ACPI_COMPANION(dev)) {
 			i2c_acpi_get_irq(client, &irq);
-
-			if (irq == -ENOENT)
-				irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev),
-							    0);
 		}
 		if (irq == -EPROBE_DEFER)
 			return irq;
-- 
2.11.0

[PATCH 5/5] i2c: core: Tidy up handling of init_irq

[Charles Keepax]

Only set init_irq during i2c_device_new and only handle client->irq on
the probe/remove paths.

Suggested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 drivers/i2c/i2c-core-base.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index f958b50c78c04..c0a52802d23e7 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -322,6 +322,8 @@ static int i2c_device_probe(struct device *dev)
 
 	driver = to_i2c_driver(dev->driver);
 
+	client->irq = client->init_irq;
+
 	if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 		int irq = -ENOENT;
 
@@ -432,7 +434,7 @@ static int i2c_device_remove(struct device *dev)
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
 
-	client->irq = client->init_irq;
+	client->irq = 0;
 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 		pm_runtime_put(&client->adapter->dev);
 
@@ -749,7 +751,6 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 	if (!client->init_irq)
 		client->init_irq = i2c_dev_irq_from_resources(info->resources,
 							 info->num_resources);
-	client->irq = client->init_irq;
 
 	strlcpy(client->name, info->type, sizeof(client->name));
 
-- 
2.11.0

Re: [PATCH 2/5] i2c: acpi: Use available IRQ helper functions

[Andy Shevchenko]

On Tue, May 21, 2019 at 04:04:59PM +0100, Charles Keepax wrote:
> Use the available IRQ helper functions, most of the functions have
> additional helpful side affects like configuring the trigger type of the
> IRQ.

More logical to me is to do this as a first patch in the series.
Besides that, I would really split it into two:
- exporting helper;
- using it.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 3/5] i2c: core: Move ACPI IRQ handling to probe time

[Andy Shevchenko]

On Tue, May 21, 2019 at 04:05:00PM +0100, Charles Keepax wrote:
> Bring the ACPI path in sync with the device tree path and handle all the
> IRQ fetching at probe time. This leaves the only IRQ handling at device
> registration time being that which is passed directly through the board
> info as either a resource or an actual IRQ number.

> -static int i2c_acpi_get_irq(struct acpi_device *adev, int *irq)
> +int i2c_acpi_get_irq(struct i2c_client *client, int *irq)

Instead of ping-pong style of the programming, I would rather do this in the
same patch, where you introduce a helper (patch 2 I suppose, after my comments
against current patch 2 in the series).

Also possible to split exporting itself to a separate patch.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 4/5] i2c: core: Move ACPI gpio IRQ handling into i2c_acpi_get_irq

[Andy Shevchenko]

On Tue, May 21, 2019 at 04:05:01PM +0100, Charles Keepax wrote:
> It makes sense to contain all the ACPI IRQ handling in a single helper
> function.

> Note that this one is somewhat interesting, it seems the search
> through the resource list is done against the companion device
> of the adapter but the GPIO search is done against the companion
> device of the client. It feels to me like these really should
> be done on the same device, and certainly this is what SPI
> does (both against the equivalent of the adapter). Perhaps
> someone with more ACPI knowledge than myself could comment?

It would be interesting to see the path how you come to this conclusion.

>  	acpi_dev_free_resource_list(&resource_list);
>  
> +	if (*irq < 0)
> +		*irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(&client->dev), 0);

I think adev here is what we may use here.

You may put assert here and see if it happens when you test your series.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 4/5] i2c: core: Move ACPI gpio IRQ handling into i2c_acpi_get_irq

[Charles Keepax]

On Tue, May 21, 2019 at 08:27:26PM +0300, Andy Shevchenko wrote:
> On Tue, May 21, 2019 at 04:05:01PM +0100, Charles Keepax wrote:
> > It makes sense to contain all the ACPI IRQ handling in a single helper
> > function.
> 
> > Note that this one is somewhat interesting, it seems the search
> > through the resource list is done against the companion device
> > of the adapter but the GPIO search is done against the companion
> > device of the client. It feels to me like these really should
> > be done on the same device, and certainly this is what SPI
> > does (both against the equivalent of the adapter). Perhaps
> > someone with more ACPI knowledge than myself could comment?
> 
> It would be interesting to see the path how you come to this conclusion.
> 

Apologies but I am not sure which conclusion you are referencing.
Assuming it is them being called with different acpi_device's.
It is perhaps me misunderstanding things but it looks like
i2c_acpi_get_info implies the adev should correspond to the
adapter. Where as acpi_dev_gpio_irq_get is called with the result
of ACPI_COMPANION(dev) where dev is client->dev.

> >  	acpi_dev_free_resource_list(&resource_list);
> >  
> > +	if (*irq < 0)
> > +		*irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(&client->dev), 0);
> 
> I think adev here is what we may use here.
> 

Indeed that is what I would have expected as well, I will update
the code to do so and hopefully any issues will come out in
testing.

> You may put assert here and see if it happens when you test your series.
> 

Alas I don't have a good way to test this series, they come out
of some additional work Wolfram wanted based on some issues
caused by a device tree fix I made a while back.

Thanks,
Charles

[PATCH 2/5] i2c: acpi: Use available IRQ helper functions

[Charles Keepax]

Use the available IRQ helper functions, most of the functions have
additional helpful side affects like configuring the trigger type of the
IRQ.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 drivers/i2c/i2c-core-acpi.c | 23 ++++++++++++++---------
 drivers/i2c/i2c-core-base.c |  4 ++--
 drivers/i2c/i2c-core.h      |  2 ++
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index c3ac3ea184317..764cd10420a74 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -137,25 +137,30 @@ static int i2c_acpi_do_lookup(struct acpi_device *adev,
 	return 0;
 }
 
+static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
+{
+	int *irq = data;
+	struct resource r;
+
+	if (*irq < 0 && acpi_dev_resource_interrupt(ares, 0, &r))
+		*irq = i2c_dev_irq_from_resources(&r, 1);
+
+	return 1; /* No need to add resource to the list */
+}
+
 static int i2c_acpi_get_irq(struct acpi_device *adev, int *irq)
 {
 	struct list_head resource_list;
-	struct resource_entry *entry;
 	int ret;
 
 	INIT_LIST_HEAD(&resource_list);
+	*irq = -ENOENT;
 
-	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     i2c_acpi_add_resource, &irq);
 	if (ret < 0)
 		return -EINVAL;
 
-	resource_list_for_each_entry(entry, &resource_list) {
-		if (resource_type(entry->res) == IORESOURCE_IRQ) {
-			*irq = entry->res->start;
-			break;
-		}
-	}
-
 	acpi_dev_free_resource_list(&resource_list);
 
 	return 0;
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index d389d4fb0623a..84bf11b25a120 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -687,8 +687,8 @@ static void i2c_dev_set_name(struct i2c_adapter *adap,
 		     i2c_encode_flags_to_addr(client));
 }
 
-static int i2c_dev_irq_from_resources(const struct resource *resources,
-				      unsigned int num_resources)
+int i2c_dev_irq_from_resources(const struct resource *resources,
+			       unsigned int num_resources)
 {
 	struct irq_data *irqd;
 	int i;
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index c88cfef813431..8f3a08dc73a25 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -28,6 +28,8 @@ extern struct list_head	__i2c_board_list;
 extern int		__i2c_first_dynamic_bus_num;
 
 int i2c_check_7bit_addr_validity_strict(unsigned short addr);
+int i2c_dev_irq_from_resources(const struct resource *resources,
+			       unsigned int num_resources);
 
 /*
  * We only allow atomic transfers for very late communication, e.g. to send
-- 
2.11.0