gpio: max77620: Make the irqchip immutable

PATCH Superseded Jon Hunter 2 participants 3 messages May 4, 2022

Subsystems (2)

GPIO Tegra architecture support

lore

Share & tools

lore

Jon Hunter

author maintainer

2022-05-04 11:19 UTC #0 lore raw

PATCH 1/1 gpio: max77620: Make the irqchip immutable

Commit 6c846d026d49 ("gpio: Don't fiddle with irqchips marked as immutable") added a warning to indicate if the gpiolib is altering the internals of irqchips. Following this change the following warning is now observed for the max77620 gpio driver ...

WARNING KERN gpio gpiochip0: (max77620-gpio): not an immutable chip,
please consider fixing it!

Fix the above warning by making the max77620 gpio driver immutable.

Signed-off-by Jon Hunter <[email protected]>

---
This warning is observed with v5.18-rc5 and so it would be great if we can fix for v5.18. This is triggering a kernel warning test failure on one of our platforms.

 drivers/gpio/gpio-max77620.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

drivers/gpio/gpio-max77620.c +12 -3

index ebf9dea6546b..aa92658780d6 100644
@@ -119,14 +119,23 @@ static void max77620_gpio_bus_sync_unlock(struct irq_data *data)
 	mutex_unlock(&gpio->buslock);
 }
 
-static struct irq_chip max77620_gpio_irqchip = {
+static void max77620_gpio_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip max77620_gpio_irqchip = {
 	.name		= "max77620-gpio",
 	.irq_mask	= max77620_gpio_irq_mask,
 	.irq_unmask	= max77620_gpio_irq_unmask,
 	.irq_set_type	= max77620_gpio_set_irq_type,
 	.irq_bus_lock	= max77620_gpio_bus_lock,
 	.irq_bus_sync_unlock = max77620_gpio_bus_sync_unlock,
-	.flags		= IRQCHIP_MASK_ON_SUSPEND,
+	.irq_print_chip	= max77620_gpio_irq_print_chip,
+	.flags		= IRQCHIP_IMMUTABLE | IRQCHIP_MASK_ON_SUSPEND,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static int max77620_gpio_dir_input(struct gpio_chip *gc, unsigned int offset)

@@ -318,7 +327,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.base = -1;
 
 	girq = &mgpio->gpio_chip.irq;
-	girq->chip = &max77620_gpio_irqchip;
+	gpio_irq_chip_set_chip(girq, &max77620_gpio_irqchip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;

Signature · 1 line

2.25.1

Marc Zyngier

2022-05-04 11:35 UTC #1 lore raw

Hi Jon,

Quoted 10 lines · Jon Hunter

Commit 6c846d026d49 ("gpio: Don't fiddle with irqchips marked as immutable") added a warning to indicate if the gpiolib is altering the internals of irqchips. Following this change the following warning is now observed for the max77620 gpio driver ...
WARNING KERN gpio gpiochip0: (max77620-gpio): not an immutable chip,
please consider fixing it!
Fix the above warning by making the max77620 gpio driver immutable.

Thanks for looking into this. Comments below.

Quoted 6 lines

Signed-off-by Jon Hunter <[email protected]>
---
This warning is observed with v5.18-rc5 and so it would be great if we can fix for v5.18. This is triggering a kernel warning test failure on one of our platforms.

I'm surprised. This is definitely *not* 5.18 material, and I can't see the patches in Linus' tree. Are you sure you're not running -next instead?

Quoted 10 lines

 drivers/gpio/gpio-max77620.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

drivers/gpio/gpio-max77620.c +0 -0

index ebf9dea6546b..aa92658780d6 100644
@@ -119,14 +119,23 @@ static void max77620_gpio_bus_sync_unlock(struct irq_data *data)
 	mutex_unlock(&gpio->buslock);

drivers/gpio/gpio-max77620.c static void max77620_gpio_bus_sync_unlock(struct irq_data *data) · line 128

Quoted 10 lines

drivers/gpio/gpio-max77620.c +7 -1

 }
 
-static struct irq_chip max77620_gpio_irqchip = {
+static void max77620_gpio_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+

I'd rather you don't do this. This was added as a band-aid for drivers that display a device-specific string in /proc/interrupts, and that we cannot fix because the string is in effect an ABI.

Here, you're going in the opposite direction (making the name device-specific while it was constant so far). This has the same ABI-breaking effect, and we shouldn't do that. It is also rather pointless, as we already have all the required debugging information in debugfs (and I assume that this is the reason this is added).

drivers/gpio/gpio-max77620.c static void max77620_gpio_bus_sync_unlock(struct irq_data *data) · line 132

Quoted 4 lines

drivers/gpio/gpio-max77620.c +1 -0

+static const struct irq_chip max77620_gpio_irqchip = {
 	.name		= "max77620-gpio",
 	.irq_mask	= max77620_gpio_irq_mask,
 	.irq_unmask	= max77620_gpio_irq_unmask,

You seem to be missing the updates for these two functions. Please see the updated documentation in commit 5644b66a9c63 ("Documentation:
Update the recommended pattern for GPIO irqchips").

Quoted 23 lines

drivers/gpio/gpio-max77620.c +4 -2

 	.irq_set_type	= max77620_gpio_set_irq_type,
 	.irq_bus_lock	= max77620_gpio_bus_lock,
 	.irq_bus_sync_unlock = max77620_gpio_bus_sync_unlock,
-	.flags		= IRQCHIP_MASK_ON_SUSPEND,
+	.irq_print_chip	= max77620_gpio_irq_print_chip,
+	.flags		= IRQCHIP_IMMUTABLE | IRQCHIP_MASK_ON_SUSPEND,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static int max77620_gpio_dir_input(struct gpio_chip *gc, unsigned int offset)

@@ -318,7 +327,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.base = -1;
 
 	girq = &mgpio->gpio_chip.irq;
-	girq->chip = &max77620_gpio_irqchip;
+	gpio_irq_chip_set_chip(girq, &max77620_gpio_irqchip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;

Signature · 1 line

2.25.1

Thanks,

M.

Signature · 1 line

Without deviation from the norm, progress is not possible.

Jon Hunter

author maintainer

2022-05-04 13:05 UTC #2 lore raw

Quoted 24 lines · Marc Zyngier

Hi Jon,
Quoted 10 lines · Jon Hunter
Commit 6c846d026d49 ("gpio: Don't fiddle with irqchips marked as immutable") added a warning to indicate if the gpiolib is altering the internals of irqchips. Following this change the following warning is now observed for the max77620 gpio driver ...
WARNING KERN gpio gpiochip0: (max77620-gpio): not an immutable chip,
please consider fixing it!
Fix the above warning by making the max77620 gpio driver immutable.
Thanks for looking into this. Comments below.
Quoted 6 lines
Signed-off-by Jon Hunter <[email protected]>
---
This warning is observed with v5.18-rc5 and so it would be great if we can fix for v5.18. This is triggering a kernel warning test failure on one of our platforms.

Quoted 3 lines

I'm surprised. This is definitely *not* 5.18 material, and I can't see the patches in Linus' tree. Are you sure you're not running -next instead?

Ah, you are correct, it was -next and not v5.18-rc5!

Quoted 25 lines

Quoted 10 lines
  drivers/gpio/gpio-max77620.c | 15 ++++++++++++---
  1 file changed, 12 insertions(+), 3 deletions(-)
drivers/gpio/gpio-max77620.c +0 -0
index ebf9dea6546b..aa92658780d6 100644
@@ -119,14 +119,23 @@ static void max77620_gpio_bus_sync_unlock(struct irq_data *data)
  	mutex_unlock(&gpio->buslock);
drivers/gpio/gpio-max77620.c static void max77620_gpio_bus_sync_unlock(struct irq_data *data) · line 128
Quoted 10 lines
drivers/gpio/gpio-max77620.c +7 -1
  }
 
-static struct irq_chip max77620_gpio_irqchip = {
+static void max77620_gpio_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
I'd rather you don't do this. This was added as a band-aid for drivers that display a device-specific string in /proc/interrupts, and that we cannot fix because the string is in effect an ABI.

Quoted 5 lines

Here, you're going in the opposite direction (making the name device-specific while it was constant so far). This has the same ABI-breaking effect, and we shouldn't do that. It is also rather pointless, as we already have all the required debugging information in debugfs (and I assume that this is the reason this is added).

OK, I will drop this.

Quoted 8 lines

drivers/gpio/gpio-max77620.c static void max77620_gpio_bus_sync_unlock(struct irq_data *data) · line 132
Quoted 4 lines
drivers/gpio/gpio-max77620.c +1 -0
+static const struct irq_chip max77620_gpio_irqchip = {
  	.name		= "max77620-gpio",
  	.irq_mask	= max77620_gpio_irq_mask,
  	.irq_unmask	= max77620_gpio_irq_unmask,
You seem to be missing the updates for these two functions. Please see the updated documentation in commit 5644b66a9c63 ("Documentation:
Update the recommended pattern for GPIO irqchips").

Yes I see. OK, I will add that.

Thanks! Jon

Signature · 1 line

nvpublic