This patch implements level-triggered IRQs in the Hollywood GPIO driver.
Edge triggered interrupts are not supported in this GPIO controller, so
I moved their emulation into a separate patch.

Signed-off-by: Jonathan Neuschäfer <[email protected]>
---

I'm not entirely sure about the locking, but lockdep doesn't complain.
---
 drivers/gpio/Kconfig     |   1 +
 drivers/gpio/gpio-hlwd.c | 136 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 136 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b5a2845347ec..f77180dd87bd 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -258,6 +258,7 @@ config GPIO_HLWD
        tristate "Nintendo Wii (Hollywood) GPIO"
        depends on OF_GPIO
        select GPIO_GENERIC
+       select GPIOLIB_IRQCHIP
        help
          Select this to support the GPIO controller of the Nintendo Wii.
 
diff --git a/drivers/gpio/gpio-hlwd.c b/drivers/gpio/gpio-hlwd.c
index a63136a68ba3..9a93546f3d11 100644
--- a/drivers/gpio/gpio-hlwd.c
+++ b/drivers/gpio/gpio-hlwd.c
@@ -48,9 +48,107 @@
 
 struct hlwd_gpio {
        struct gpio_chip gpioc;
+       struct irq_chip irqc;
        void __iomem *regs;
+       int irq;
 };
 
+static void hlwd_gpio_irqhandler(struct irq_desc *desc)
+{
+       struct hlwd_gpio *hlwd =
+               gpiochip_get_data(irq_desc_get_handler_data(desc));
+       struct irq_chip *chip = irq_desc_get_chip(desc);
+       unsigned long flags;
+       unsigned long pending;
+       int hwirq;
+
+       spin_lock_irqsave(&hlwd->gpioc.bgpio_lock, flags);
+       pending = hlwd->gpioc.read_reg(hlwd->regs + HW_GPIOB_INTFLAG);
+       pending &= hlwd->gpioc.read_reg(hlwd->regs + HW_GPIOB_INTMASK);
+       spin_unlock_irqrestore(&hlwd->gpioc.bgpio_lock, flags);
+
+       chained_irq_enter(chip, desc);
+
+       for_each_set_bit(hwirq, &pending, 32) {
+               int irq = irq_find_mapping(hlwd->gpioc.irq.domain, hwirq);
+
+               generic_handle_irq(irq);
+       }
+
+       chained_irq_exit(chip, desc);
+}
+
+static void hlwd_gpio_irq_ack(struct irq_data *data)
+{
+       struct hlwd_gpio *hlwd =
+               gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+       hlwd->gpioc.write_reg(hlwd->regs + HW_GPIOB_INTFLAG, BIT(data->hwirq));
+}
+
+static void hlwd_gpio_irq_mask(struct irq_data *data)
+{
+       struct hlwd_gpio *hlwd =
+               gpiochip_get_data(irq_data_get_irq_chip_data(data));
+       unsigned long flags;
+       u32 mask;
+
+       spin_lock_irqsave(&hlwd->gpioc.bgpio_lock, flags);
+       mask = hlwd->gpioc.read_reg(hlwd->regs + HW_GPIOB_INTMASK);
+       mask &= ~BIT(data->hwirq);
+       hlwd->gpioc.write_reg(hlwd->regs + HW_GPIOB_INTMASK, mask);
+       spin_unlock_irqrestore(&hlwd->gpioc.bgpio_lock, flags);
+}
+
+static void hlwd_gpio_irq_unmask(struct irq_data *data)
+{
+       struct hlwd_gpio *hlwd =
+               gpiochip_get_data(irq_data_get_irq_chip_data(data));
+       unsigned long flags;
+       u32 mask;
+
+       spin_lock_irqsave(&hlwd->gpioc.bgpio_lock, flags);
+       mask = hlwd->gpioc.read_reg(hlwd->regs + HW_GPIOB_INTMASK);
+       mask |= BIT(data->hwirq);
+       hlwd->gpioc.write_reg(hlwd->regs + HW_GPIOB_INTMASK, mask);
+       spin_unlock_irqrestore(&hlwd->gpioc.bgpio_lock, flags);
+}
+
+static void hlwd_gpio_irq_enable(struct irq_data *data)
+{
+       hlwd_gpio_irq_ack(data);
+       hlwd_gpio_irq_unmask(data);
+}
+
+static int hlwd_gpio_irq_set_type(struct irq_data *data, unsigned int 
flow_type)
+{
+       struct hlwd_gpio *hlwd =
+               gpiochip_get_data(irq_data_get_irq_chip_data(data));
+       unsigned long flags;
+       u32 level;
+
+       spin_lock_irqsave(&hlwd->gpioc.bgpio_lock, flags);
+
+       switch (flow_type) {
+       case IRQ_TYPE_LEVEL_HIGH:
+               level = hlwd->gpioc.read_reg(hlwd->regs + HW_GPIOB_INTLVL);
+               level |= BIT(data->hwirq);
+               hlwd->gpioc.write_reg(hlwd->regs + HW_GPIOB_INTLVL, level);
+               break;
+       case IRQ_TYPE_LEVEL_LOW:
+               level = hlwd->gpioc.read_reg(hlwd->regs + HW_GPIOB_INTLVL);
+               level &= ~BIT(data->hwirq);
+               hlwd->gpioc.write_reg(hlwd->regs + HW_GPIOB_INTLVL, level);
+               break;
+       default:
+               spin_unlock_irqrestore(&hlwd->gpioc.bgpio_lock, flags);
+               return -EINVAL;
+       }
+
+       spin_unlock_irqrestore(&hlwd->gpioc.bgpio_lock, flags);
+       return 0;
+}
+
 static int hlwd_gpio_probe(struct platform_device *pdev)
 {
        struct hlwd_gpio *hlwd;
@@ -92,7 +190,43 @@ static int hlwd_gpio_probe(struct platform_device *pdev)
                ngpios = 32;
        hlwd->gpioc.ngpio = ngpios;
 
-       return devm_gpiochip_add_data(&pdev->dev, &hlwd->gpioc, hlwd);
+       res = devm_gpiochip_add_data(&pdev->dev, &hlwd->gpioc, hlwd);
+       if (res)
+               return res;
+
+       /* Mask and ack all interrupts */
+       iowrite32be(0, hlwd->regs + HW_GPIOB_INTMASK);
+       iowrite32be(0xffffffff, hlwd->regs + HW_GPIOB_INTFLAG);
+
+       /*
+        * If this GPIO controller is not marked as an interrupt controller in
+        * the DT, return.
+        */
+       if (!of_property_read_bool(pdev->dev.of_node, "interrupt-controller"))
+               return 0;
+
+       hlwd->irq = platform_get_irq(pdev, 0);
+       if (hlwd->irq < 0) {
+               dev_info(&pdev->dev, "platform_get_irq returned %d\n",
+                        hlwd->irq);
+               return hlwd->irq;
+       }
+
+       hlwd->irqc.name = "GPIO";
+       hlwd->irqc.irq_mask = hlwd_gpio_irq_mask;
+       hlwd->irqc.irq_unmask = hlwd_gpio_irq_unmask;
+       hlwd->irqc.irq_enable = hlwd_gpio_irq_enable;
+       hlwd->irqc.irq_set_type = hlwd_gpio_irq_set_type;
+
+       res = gpiochip_irqchip_add(&hlwd->gpioc, &hlwd->irqc, 0,
+                                  handle_level_irq, IRQ_TYPE_NONE);
+       if (res)
+               return res;
+
+       gpiochip_set_chained_irqchip(&hlwd->gpioc, &hlwd->irqc,
+                                    hlwd->irq, hlwd_gpio_irqhandler);
+
+       return 0;
 }
 
 static const struct of_device_id hlwd_gpio_match[] = {
-- 
2.20.1

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