[PATCH v2 22/30] gpio: nomadik: support shared GPIO IRQs

Théo Lebrun
2024-02-28T11:33:00Z

Support a single IRQs used by multiple GPIO banks. Change the IRQ
handler type from a chained handler (as used by gpiolib
for ->parent_handler) to a threaded IRQ.

Use the generic_handle_domain_irq_safe() helper. The non-safe version
must be called in a no-IRQ context.

The Mobileye EyeQ5 platform uses this GPIO controller and share an IRQ
for its two banks.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
drivers/gpio/gpio-nomadik.c | 68 ++++++++++++++++++++++++---------------------
1 file changed, 36 insertions(+), 32 deletions(-)

diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c
index c22a0864ca70..ca5c28965224 100644
--- a/drivers/gpio/gpio-nomadik.c
+++ b/drivers/gpio/gpio-nomadik.c
@@ -255,27 +255,28 @@ static void nmk_gpio_irq_shutdown(struct irq_data *d)
clk_disable(nmk_chip->clk);
}

-static void nmk_gpio_irq_handler(struct irq_desc *desc)
+static irqreturn_t nmk_gpio_irq_handler(int irq, void *dev_id)
{
- struct irq_chip *host_chip = irq_desc_get_chip(desc);
- struct gpio_chip *chip = irq_desc_get_handler_data(desc);
- struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
- u32 status;
-
- chained_irq_enter(host_chip, desc);
+ struct nmk_gpio_chip *nmk_chip = dev_id;
+ struct gpio_chip *chip = &nmk_chip->chip;
+ unsigned long mask = GENMASK(chip->ngpio - 1, 0);
+ unsigned long status;
+ int bit;

clk_enable(nmk_chip->clk);
+
status = readl(nmk_chip->addr + NMK_GPIO_IS);
- clk_disable(nmk_chip->clk);

- while (status) {
- int bit = __ffs(status);
+ /* Ensure we cannot leave pending bits; this should never occur. */
+ if (unlikely(status & ~mask))
+ writel(status & ~mask, nmk_chip->addr + NMK_GPIO_IC);

- generic_handle_domain_irq(chip->irq.domain, bit);
- status &= ~BIT(bit);
- }
+ clk_disable(nmk_chip->clk);

- chained_irq_exit(host_chip, desc);
+ for_each_set_bit(bit, &status, chip->ngpio)
+ generic_handle_domain_irq_safe(chip->irq.domain, bit);
+
+ return IRQ_RETVAL((status & mask) != 0);
}

/* I/O Functions */
@@ -568,19 +569,20 @@ static const struct irq_chip nmk_irq_chip = {
GPIOCHIP_IRQ_RESOURCE_HELPERS,
};

-static int nmk_gpio_probe(struct platform_device *dev)
+static int nmk_gpio_probe(struct platform_device *pdev)
{
- struct device_node *np = dev->dev.of_node;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
struct nmk_gpio_chip *nmk_chip;
- struct gpio_chip *chip;
struct gpio_irq_chip *girq;
bool supports_sleepmode;
+ struct gpio_chip *chip;
int irq;
int ret;

- nmk_chip = nmk_gpio_populate_chip(np, dev);
+ nmk_chip = nmk_gpio_populate_chip(np, pdev);
if (IS_ERR(nmk_chip)) {
- dev_err(&dev->dev, "could not populate nmk chip struct\n");
+ dev_err(dev, "could not populate nmk chip struct\n");
return PTR_ERR(nmk_chip);
}

@@ -588,9 +590,9 @@ static int nmk_gpio_probe(struct platform_device *dev)
device_property_read_bool(dev, "st,supports-sleepmode");

/* Correct platform device ID */
- dev->id = nmk_chip->bank;
+ pdev->id = nmk_chip->bank;

- irq = platform_get_irq(dev, 0);
+ irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;

@@ -602,7 +604,7 @@ static int nmk_gpio_probe(struct platform_device *dev)
spin_lock_init(&nmk_chip->lock);

chip = &nmk_chip->chip;
- chip->parent = &dev->dev;
+ chip->parent = dev;
chip->request = gpiochip_generic_request;
chip->free = gpiochip_generic_free;
chip->get_direction = nmk_gpio_get_dir;
@@ -616,17 +618,19 @@ static int nmk_gpio_probe(struct platform_device *dev)

girq = &chip->irq;
gpio_irq_chip_set_chip(girq, &nmk_irq_chip);
- girq->parent_handler = nmk_gpio_irq_handler;
- girq->num_parents = 1;
- girq->parents = devm_kcalloc(&dev->dev, 1,
- sizeof(*girq->parents),
- GFP_KERNEL);
- if (!girq->parents)
- return -ENOMEM;
- girq->parents[0] = irq;
+ girq->parent_handler = NULL;
+ girq->num_parents = 0;
+ girq->parents = NULL;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_edge_irq;

+ ret = devm_request_irq(dev, irq, nmk_gpio_irq_handler, IRQF_SHARED,
+ dev_name(dev), nmk_chip);
+ if (ret) {
+ dev_err(dev, "failed requesting IRQ\n");
+ return ret;
+ }
+
clk_enable(nmk_chip->clk);
nmk_chip->lowemi = readl_relaxed(nmk_chip->addr + NMK_GPIO_LOWEMI);
clk_disable(nmk_chip->clk);
@@ -635,9 +639,9 @@ static int nmk_gpio_probe(struct platform_device *dev)
if (ret)
return ret;

- platform_set_drvdata(dev, nmk_chip);
+ platform_set_drvdata(pdev, nmk_chip);

- dev_info(&dev->dev, "chip registered\n");
+ dev_info(dev, "chip registered\n");

return 0;
}

--
2.44.0