Re: [PATCH v3] gpio-mlxbf2: only get IRQ for device instances 0 and 3

On Mon, Jul 21, 2025 at 6:22 PM David Thompson davthompson@nvidia.com wrote:

The gpio-mlxbf2 driver interfaces with four GPIO controllers, device instances 0-3. There are two IRQ resources shared between the four controllers, and they are found in the ACPI table for device instances 0 and 3. The driver should not attempt to get an IRQ resource when probing device instance 1 or 2, otherwise the following error is logged: mlxbf2_gpio MLNXBF22:01: error -ENXIO: IRQ index 0 not found

Fixes: 2b725265cb08 ("gpio: mlxbf2: Introduce IRQ support") Cc: stable@vger.kernel.org Signed-off-by: David Thompson davthompson@nvidia.com Reviewed-by: Shravan Kumar Ramani shravankr@nvidia.com

---

v3: added version history v2: added tag "Cc: stable@vger.kernel.org"

drivers/gpio/gpio-mlxbf2.c | 56 ++++++++++++++++++++++++-------------- 1 file changed, 36 insertions(+), 20 deletions(-)

diff --git a/drivers/gpio/gpio-mlxbf2.c b/drivers/gpio/gpio-mlxbf2.c index 6f3dda6b635f..fc56ac81e344 100644 --- a/drivers/gpio/gpio-mlxbf2.c +++ b/drivers/gpio/gpio-mlxbf2.c @@ -353,7 +353,9 @@ mlxbf2_gpio_probe(struct platform_device *pdev) struct gpio_chip *gc; unsigned int npins; const char *name;

•   char *colon_ptr;
    int ret, irq;
  

•   long num;
  
    name = dev_name(dev);
  
  

@@ -397,26 +399,40 @@ mlxbf2_gpio_probe(struct platform_device *pdev) gc->ngpio = npins; gc->owner = THIS_MODULE;

•   irq = platform_get_irq(pdev, 0);
  

•   if (irq >= 0) {
  

•           girq = &gs->gc.irq;
  

•           gpio_irq_chip_set_chip(girq, &mlxbf2_gpio_irq_chip);
  

•           girq->handler = handle_simple_irq;
  

•           girq->default_type = IRQ_TYPE_NONE;
  

•           /* This will let us handle the parent IRQ in the driver */
  

•           girq->num_parents = 0;
  

•           girq->parents = NULL;
  

•           girq->parent_handler = NULL;
  

•           /*
  

•            * Directly request the irq here instead of passing
  

•            * a flow-handler because the irq is shared.
  

•            */
  

•           ret = devm_request_irq(dev, irq, mlxbf2_gpio_irq_handler,
  

•                                  IRQF_SHARED, name, gs);
  

•           if (ret) {
  

•                   dev_err(dev, "failed to request IRQ");
  

•                   return ret;
  

•   colon_ptr = strchr(dev_name(dev), ':');
  

•   if (!colon_ptr) {
  

•           dev_err(dev, "invalid device name format\n");
  

•           return -EINVAL;
  

•   }
  

•   ret = kstrtol(++colon_ptr, 16, &num);
  

•   if (ret) {
  

•           dev_err(dev, "invalid device instance\n");
  

•           return ret;
  

•   }
  

That is *really* fragile. Andy, Mika: does this look remotely correct to you? I don't know much about ACPI systems.

Bart

•   if (!num || num == 3) {
  

•           irq = platform_get_irq(pdev, 0);
  

•           if (irq >= 0) {
  

•                   girq = &gs->gc.irq;
  

•                   gpio_irq_chip_set_chip(girq, &mlxbf2_gpio_irq_chip);
  

•                   girq->handler = handle_simple_irq;
  

•                   girq->default_type = IRQ_TYPE_NONE;
  

•                   /* This will let us handle the parent IRQ in the driver */
  

•                   girq->num_parents = 0;
  

•                   girq->parents = NULL;
  

•                   girq->parent_handler = NULL;
  

•                   /*
  

•                    * Directly request the irq here instead of passing
  

•                    * a flow-handler because the irq is shared.
  

•                    */
  

•                   ret = devm_request_irq(dev, irq, mlxbf2_gpio_irq_handler,
  

•                                          IRQF_SHARED, name, gs);
  

•                   if (ret) {
  

•                           dev_err(dev, "failed to request IRQ");
  

•                           return ret;
  

•                   }
            }
    }
  
  

-- 2.30.1