[PATCH AUTOSEL 6.15 090/110] gpio: grgpio: Make irq_chip immutable

[Sasha Levin]

From: Peng Fan <peng.fan@xxxxxxx>

[ Upstream commit a30be40bf1d4437646b6885e7e4e71530e6f82c1 ]

Kernel warns about mutable irq_chips:
"not an immutable chip, please consider fixing!"

Constify grgpio_irq_chip, flag the irq_chip as IRQCHIP_IMMUTABLE, add the
new helper functions, and call the appropriate gpiolib functions.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20250509-gpio-v1-2-639377c98288@xxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---

Now let me analyze this commit against stable backporting criteria:
**YES** ## Analysis: ### 1. Bug Fix Nature This commit fixes a kernel
warning about mutable irq_chips with the message "not an immutable chip,
please consider fixing!" This is clearly a bug fix that addresses a
runtime warning that affects users. ### 2. Code Changes Analysis The
changes are minimal and well-contained within the grgpio driver: -
**Line 173**: Added `gpiochip_disable_irq(&priv->gc, d->hwirq);` call in
`grgpio_irq_mask()` function - **Line 183**: Added
`gpiochip_enable_irq(&priv->gc, d->hwirq);` call in
`grgpio_irq_unmask()` function - **Line 191**: Made `grgpio_irq_chip`
struct `const` (immutable) - **Lines 196-197**: Added
`IRQCHIP_IMMUTABLE` flag and `GPIOCHIP_IRQ_RESOURCE_HELPERS` macro ###
3. Pattern Consistency with Similar Commits This commit follows the
exact same pattern as the approved backport commits in the reference
examples: - **Similar to gpio-104-idio-16** (Status: YES): Same pattern
of making irq_chip const, adding IRQCHIP_IMMUTABLE flag, and adding
gpiochip_enable/disable_irq calls - **Similar to gpio-vf610** (Status:
YES): Identical changes - const irq_chip, IRQCHIP_IMMUTABLE, and proper
helper function calls - **Similar to gpio-104-dio-48e** (Status: YES):
Same transformation pattern ### 4. Risk Assessment - **Low Risk**:
Changes are mechanical transformations following established GPIO
subsystem patterns - **No Architectural Changes**: The commit doesn't
modify core logic, just adapts to new GPIO framework requirements -
**Well-Tested Pattern**: This exact change pattern has been applied
across multiple GPIO drivers successfully ### 5. Stable Tree Compliance
- **Important Bug Fix**: Eliminates kernel warnings that users encounter
- **Minimal Risk**: The changes follow well-established patterns already
proven in other GPIO drivers - **Contained Changes**: All modifications
are within a single driver file with no cross-subsystem impact - **No
New Features**: This is purely a compliance fix for the GPIO framework
requirements ### 6. Framework Compliance The commit brings the grgpio
driver into compliance with the modern GPIO framework's requirements for
immutable irq_chips, which is a necessary change to prevent kernel
warnings and ensure proper resource management. The changes are
essential for maintaining driver functionality in current kernels and
preventing user-visible warnings, making this an ideal candidate for
stable tree backporting.

 drivers/gpio/gpio-grgpio.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c
index 30a0522ae735f..68cca7751c0e5 100644
--- a/drivers/gpio/gpio-grgpio.c
+++ b/drivers/gpio/gpio-grgpio.c
@@ -170,6 +170,8 @@ static void grgpio_irq_mask(struct irq_data *d)
 	grgpio_set_imask(priv, offset, 0);
 
 	raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
+
+	gpiochip_disable_irq(&priv->gc, d->hwirq);
 }
 
 static void grgpio_irq_unmask(struct irq_data *d)
@@ -178,6 +180,7 @@ static void grgpio_irq_unmask(struct irq_data *d)
 	int offset = d->hwirq;
 	unsigned long flags;
 
+	gpiochip_enable_irq(&priv->gc, d->hwirq);
 	raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags);
 
 	grgpio_set_imask(priv, offset, 1);
@@ -185,11 +188,13 @@ static void grgpio_irq_unmask(struct irq_data *d)
 	raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);
 }
 
-static struct irq_chip grgpio_irq_chip = {
+static const struct irq_chip grgpio_irq_chip = {
 	.name			= "grgpio",
 	.irq_mask		= grgpio_irq_mask,
 	.irq_unmask		= grgpio_irq_unmask,
 	.irq_set_type		= grgpio_irq_set_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static irqreturn_t grgpio_irq_handler(int irq, void *dev)
-- 
2.39.5