To use a GPIO pin as an interrupt line, two previous configurations have to be made:
a) Map the GPIO pin as an interrupt line into the Linux irq space b) Enable the GPIO bank and configure the GPIO direction as input Most GPIO/IRQ chip drivers just create a mapping for every single GPIO pin with irq_create_mapping() on .probe so users usually can assume a) and only have to do b) by using the following sequence: gpio_request(gpio, "foo IRQ"); gpio_direction_input(gpio); and then request a IRQ with: irq = gpio_to_irq(gpio); request_irq(irq, ...); Some drivers know that their IRQ line is being driven by a GPIO and use a similar sequence as the described above but others are not aware or don't care wether their IRQ is a real line from an interrupt controller or a GPIO pin acting as an IRQ. In these cases board files did all the necessary GPIO setup so the drivers could only call request_irq() on the provided IRQ. Unfortuntaly this does not work when booting with Device Trees since the OF irq core does neither request the GPIO nor set its direction. A DTS just defines the GPIO controller phandle as a interrupt-parent so drivers get the mapped GPIO-IRQ line but request_irq() fails since the setup was never made. The first attemp to solve this issue was by adding a custom .map() irq_domain_ops function handler in the gpio-omap driver that called gpio_request_one() to request and setup the GPIO direction as input. This was made on commits: 0e970cec ("gpio/omap: don't create an IRQ mapping for every GPIO on DT") b4419e1a ("gpio/omap: auto request GPIO as input if used as IRQ via DT") but they got reverted since broke OMAP1 platforms. This patch solves this issue with a different approach, by doing all the needed hardware setup on the GPIO/IRQ chip driver when a call to request_irq() is made. Signed-off-by: Javier Martinez Canillas <javier.marti...@collabora.co.uk> --- Hello, This patch is an attempt to solve the long standing issue that we have been discussing in thread: "[PATCH v3] gpio: interrupt consistency check for OF GPIO IRQs" [1] The fix is just for OMAP of course and not a kernel wide solution but Linus approach (which I think is the best general solution proposed so far) has some resistance so it seems that it won't be merged and we really need a solution for OMAP if we want to finish our migration to Device Tree soon. The patch is based on 3.12-rc1 but is not meant to be merged as a fix for this -rc cycle. I would like it to be tested ideally on every OMAP platform supported in mainline. So is better to wait until we are sure that this does not cause a regression on any platform than ending reverting the patch like it happened last time. Thanks a lot and best regards, Javier [1]: https://lkml.org/lkml/2013/8/26/260 drivers/gpio/gpio-omap.c | 54 +++++++++++++++++++++++++++--------------------- 1 file changed, 31 insertions(+), 23 deletions(-) diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c index 0ff4355..218ce3d 100644 --- a/drivers/gpio/gpio-omap.c +++ b/drivers/gpio/gpio-omap.c @@ -420,6 +420,29 @@ static int _set_gpio_triggering(struct gpio_bank *bank, int gpio, return 0; } +static void _set_gpio_mode(struct gpio_bank *bank, unsigned offset) +{ + if (bank->regs->pinctrl) { + void __iomem *reg = bank->base + bank->regs->pinctrl; + + /* Claim the pin for MPU */ + __raw_writel(__raw_readl(reg) | (1 << offset), reg); + } + + if (bank->regs->ctrl && !bank->mod_usage) { + void __iomem *reg = bank->base + bank->regs->ctrl; + u32 ctrl; + + ctrl = __raw_readl(reg); + /* Module is enabled, clocks are not gated */ + ctrl &= ~GPIO_MOD_CTRL_BIT; + __raw_writel(ctrl, reg); + bank->context.ctrl = ctrl; + } + + bank->mod_usage |= 1 << offset; +} + static int gpio_irq_type(struct irq_data *d, unsigned type) { struct gpio_bank *bank = irq_data_get_irq_chip_data(d); @@ -427,8 +450,8 @@ static int gpio_irq_type(struct irq_data *d, unsigned type) int retval; unsigned long flags; - if (WARN_ON(!bank->mod_usage)) - return -EINVAL; + if (!bank->mod_usage) + pm_runtime_get_sync(bank->dev); #ifdef CONFIG_ARCH_OMAP1 if (d->irq > IH_MPUIO_BASE) @@ -438,6 +461,11 @@ static int gpio_irq_type(struct irq_data *d, unsigned type) if (!gpio) gpio = irq_to_gpio(bank, d->hwirq); + spin_lock_irqsave(&bank->lock, flags); + _set_gpio_mode(bank, GPIO_INDEX(bank, gpio)); + _set_gpio_direction(bank, GPIO_INDEX(bank, gpio), 1); + spin_unlock_irqrestore(&bank->lock, flags); + if (type & ~IRQ_TYPE_SENSE_MASK) return -EINVAL; @@ -611,27 +639,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset) * request_irq() or set_irq_type(). */ _set_gpio_triggering(bank, offset, IRQ_TYPE_NONE); - - if (bank->regs->pinctrl) { - void __iomem *reg = bank->base + bank->regs->pinctrl; - - /* Claim the pin for MPU */ - __raw_writel(__raw_readl(reg) | (1 << offset), reg); - } - - if (bank->regs->ctrl && !bank->mod_usage) { - void __iomem *reg = bank->base + bank->regs->ctrl; - u32 ctrl; - - ctrl = __raw_readl(reg); - /* Module is enabled, clocks are not gated */ - ctrl &= ~GPIO_MOD_CTRL_BIT; - __raw_writel(ctrl, reg); - bank->context.ctrl = ctrl; - } - - bank->mod_usage |= 1 << offset; - + _set_gpio_mode(bank, offset); spin_unlock_irqrestore(&bank->lock, flags); return 0; -- 1.8.4.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/