diff options
Diffstat (limited to 'arch/arm/plat-orion/gpio.c')
| -rw-r--r-- | arch/arm/plat-orion/gpio.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/arch/arm/plat-orion/gpio.c b/arch/arm/plat-orion/gpio.c index d86fc08..9671864 100644 --- a/arch/arm/plat-orion/gpio.c +++ b/arch/arm/plat-orion/gpio.c @@ -10,6 +10,7 @@ #include <linux/kernel.h> #include <linux/init.h> +#include <linux/irq.h> #include <linux/module.h> #include <linux/spinlock.h> #include <linux/bitops.h> @@ -237,3 +238,178 @@ void orion_gpio_set_blink(unsigned pin, int blink) spin_unlock_irqrestore(&gpio_lock, flags); } EXPORT_SYMBOL(orion_gpio_set_blink); + + +/***************************************************************************** + * Orion GPIO IRQ + * + * GPIO_IN_POL register controls whether GPIO_DATA_IN will hold the same + * value of the line or the opposite value. + * + * Level IRQ handlers: DATA_IN is used directly as cause register. + * Interrupt are masked by LEVEL_MASK registers. + * Edge IRQ handlers: Change in DATA_IN are latched in EDGE_CAUSE. + * Interrupt are masked by EDGE_MASK registers. + * Both-edge handlers: Similar to regular Edge handlers, but also swaps + * the polarity to catch the next line transaction. + * This is a race condition that might not perfectly + * work on some use cases. + * + * Every eight GPIO lines are grouped (OR'ed) before going up to main + * cause register. + * + * EDGE cause mask + * data-in /--------| |-----| |----\ + * -----| |----- ---- to main cause reg + * X \----------------| |----/ + * polarity LEVEL mask + * + ****************************************************************************/ +static void gpio_irq_edge_ack(u32 irq) +{ + int pin = irq_to_gpio(irq); + + writel(~(1 << (pin & 31)), GPIO_EDGE_CAUSE(pin)); +} + +static void gpio_irq_edge_mask(u32 irq) +{ + int pin = irq_to_gpio(irq); + u32 u; + + u = readl(GPIO_EDGE_MASK(pin)); + u &= ~(1 << (pin & 31)); + writel(u, GPIO_EDGE_MASK(pin)); +} + +static void gpio_irq_edge_unmask(u32 irq) +{ + int pin = irq_to_gpio(irq); + u32 u; + + u = readl(GPIO_EDGE_MASK(pin)); + u |= 1 << (pin & 31); + writel(u, GPIO_EDGE_MASK(pin)); +} + +static void gpio_irq_level_mask(u32 irq) +{ + int pin = irq_to_gpio(irq); + u32 u; + + u = readl(GPIO_LEVEL_MASK(pin)); + u &= ~(1 << (pin & 31)); + writel(u, GPIO_LEVEL_MASK(pin)); +} + +static void gpio_irq_level_unmask(u32 irq) +{ + int pin = irq_to_gpio(irq); + u32 u; + + u = readl(GPIO_LEVEL_MASK(pin)); + u |= 1 << (pin & 31); + writel(u, GPIO_LEVEL_MASK(pin)); +} + +static int gpio_irq_set_type(u32 irq, u32 type) +{ + int pin = irq_to_gpio(irq); + struct irq_desc *desc; + u32 u; + + u = readl(GPIO_IO_CONF(pin)) & (1 << (pin & 31)); + if (!u) { + printk(KERN_ERR "orion gpio_irq_set_type failed " + "(irq %d, pin %d).\n", irq, pin); + return -EINVAL; + } + + desc = irq_desc + irq; + + /* + * Set edge/level type. + */ + if (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) { + desc->chip = &orion_gpio_irq_edge_chip; + } else if (type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) { + desc->chip = &orion_gpio_irq_level_chip; + } else { + printk(KERN_ERR "failed to set irq=%d (type=%d)\n", irq, type); + return -EINVAL; + } + + /* + * Configure interrupt polarity. + */ + if (type == IRQ_TYPE_EDGE_RISING || type == IRQ_TYPE_LEVEL_HIGH) { + u = readl(GPIO_IN_POL(pin)); + u &= ~(1 << (pin & 31)); + writel(u, GPIO_IN_POL(pin)); + } else if (type == IRQ_TYPE_EDGE_FALLING || type == IRQ_TYPE_LEVEL_LOW) { + u = readl(GPIO_IN_POL(pin)); + u |= 1 << (pin & 31); + writel(u, GPIO_IN_POL(pin)); + } else if (type == IRQ_TYPE_EDGE_BOTH) { + u32 v; + + v = readl(GPIO_IN_POL(pin)) ^ readl(GPIO_DATA_IN(pin)); + + /* + * set initial polarity based on current input level + */ + u = readl(GPIO_IN_POL(pin)); + if (v & (1 << (pin & 31))) + u |= 1 << (pin & 31); /* falling */ + else + u &= ~(1 << (pin & 31)); /* rising */ + writel(u, GPIO_IN_POL(pin)); + } + + desc->status = (desc->status & ~IRQ_TYPE_SENSE_MASK) | type; + + return 0; +} + +struct irq_chip orion_gpio_irq_edge_chip = { + .name = "orion_gpio_irq_edge", + .ack = gpio_irq_edge_ack, + .mask = gpio_irq_edge_mask, + .unmask = gpio_irq_edge_unmask, + .set_type = gpio_irq_set_type, +}; + +struct irq_chip orion_gpio_irq_level_chip = { + .name = "orion_gpio_irq_level", + .mask = gpio_irq_level_mask, + .mask_ack = gpio_irq_level_mask, + .unmask = gpio_irq_level_unmask, + .set_type = gpio_irq_set_type, +}; + +void orion_gpio_irq_handler(int pinoff) +{ + u32 cause; + int pin; + + cause = readl(GPIO_DATA_IN(pinoff)) & readl(GPIO_LEVEL_MASK(pinoff)); + cause |= readl(GPIO_EDGE_CAUSE(pinoff)) & readl(GPIO_EDGE_MASK(pinoff)); + + for (pin = pinoff; pin < pinoff + 8; pin++) { + int irq = gpio_to_irq(pin); + struct irq_desc *desc = irq_desc + irq; + + if (!(cause & (1 << (pin & 31)))) + continue; + + if ((desc->status & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH) { + /* Swap polarity (race with GPIO line) */ + u32 polarity; + + polarity = readl(GPIO_IN_POL(pin)); + polarity ^= 1 << (pin & 31); + writel(polarity, GPIO_IN_POL(pin)); + } + desc_handle_irq(irq, desc); + } +} |
