gpio: nomadik: support shared GPIO IRQs

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>
Link: https://lore.kernel.org/r/20240228-mbly-gpio-v2-22-3ba757474006@bootlin.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c
index c22a0864ca70c70d7d218242a0df2da9b60f3957..ca5c28965224bc856cf66394f0c8e262f7fdfac4 100644 (file)
--- 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;
 }