@@ -271,12 +271,59 @@ struct st_pctl_group {
struct st_pinconf *pin_conf;
};
+/*
+ * Edge triggers are not supported at hardware level, it is supported by
+ * software by exploiting the level trigger support in hardware.
+ * Software uses a virtual register (EDGE_CONF) for edge trigger configuration
+ * of each gpio pin in a GPIO bank.
+ *
+ * Each bank has a 32 bit EDGE_CONF register which is divided in to 8 parts of
+ * 4-bits. Each 4-bit space is allocated for each pin in a gpio bank.
+ *
+ * bit allocation per pin is:
+ * Bits: [0 - 3] | [4 - 7] [8 - 11] ... ... ... ... [ 28 - 31]
+ * --------------------------------------------------------
+ * | pin-0 | pin-2 | pin-3 | ... ... ... ... | pin -7 |
+ * --------------------------------------------------------
+ *
+ * A pin can have one of following the values in its edge configuration field.
+ *
+ * ------- ----------------------------
+ * [0-3] - Description
+ * ------- ----------------------------
+ * 0000 - No edge IRQ.
+ * 0001 - Falling edge IRQ.
+ * 0010 - Rising edge IRQ.
+ * 0011 - Rising and Falling edge IRQ.
+ * ------- ----------------------------
+ */
+
+#define ST_IRQ_EDGE_CONF_BITS_PER_PIN 4
+#define ST_IRQ_EDGE_MASK 0xf
+#define ST_IRQ_EDGE_FALLING BIT(0)
+#define ST_IRQ_EDGE_RISING BIT(1)
+#define ST_IRQ_EDGE_BOTH (BIT(0) | BIT(1))
+
+#define ST_IRQ_RISING_EDGE_CONF(pin) \
+ (ST_IRQ_EDGE_RISING << (pin * ST_IRQ_EDGE_CONF_BITS_PER_PIN))
+
+#define ST_IRQ_FALLING_EDGE_CONF(pin) \
+ (ST_IRQ_EDGE_FALLING << (pin * ST_IRQ_EDGE_CONF_BITS_PER_PIN))
+
+#define ST_IRQ_BOTH_EDGE_CONF(pin) \
+ (ST_IRQ_EDGE_BOTH << (pin * ST_IRQ_EDGE_CONF_BITS_PER_PIN))
+
+#define ST_IRQ_EDGE_CONF(conf, pin) \
+ (conf >> (pin * ST_IRQ_EDGE_CONF_BITS_PER_PIN) & ST_IRQ_EDGE_MASK)
+
struct st_gpio_bank {
struct gpio_chip gpio_chip;
struct pinctrl_gpio_range range;
void __iomem *base;
struct st_pio_control pc;
struct irq_domain *domain;
+ unsigned long irq_edge_conf;
+ spinlock_t lock;
};
struct st_pinctrl {
@@ -1262,18 +1309,37 @@ static int st_gpio_irq_set_type(struct irq_data *d, unsigned type)
unsigned long flags;
int comp, pin = d->hwirq;
u32 val;
+ u32 pin_edge_conf = 0;
switch (type) {
case IRQ_TYPE_LEVEL_HIGH:
comp = 0;
break;
+ case IRQ_TYPE_EDGE_FALLING:
+ comp = 0;
+ pin_edge_conf = ST_IRQ_FALLING_EDGE_CONF(pin);
+ break;
case IRQ_TYPE_LEVEL_LOW:
comp = 1;
break;
+ case IRQ_TYPE_EDGE_RISING:
+ comp = 1;
+ pin_edge_conf = ST_IRQ_RISING_EDGE_CONF(pin);
+ break;
+ case IRQ_TYPE_EDGE_BOTH:
+ comp = st_gpio_get(&bank->gpio_chip, pin);
+ pin_edge_conf = ST_IRQ_BOTH_EDGE_CONF(pin);
+ break;
default:
return -EINVAL;
}
+ spin_lock_irqsave(&bank->lock, flags);
+ bank->irq_edge_conf &= ~(ST_IRQ_EDGE_MASK << (
+ pin * ST_IRQ_EDGE_CONF_BITS_PER_PIN));
+ bank->irq_edge_conf |= pin_edge_conf;
+ spin_unlock_irqrestore(&bank->lock, flags);
+
val = readl(bank->base + REG_PIO_PCOMP);
val &= ~BIT(pin);
val |= (comp << pin);
@@ -1282,10 +1348,39 @@ static int st_gpio_irq_set_type(struct irq_data *d, unsigned type)
return 0;
}
+/*
+ * As edge triggers are not supported at hardware level, it is supported by
+ * software by exploiting the level trigger support in hardware.
+ *
+ * Steps for detection raising edge interrupt in software.
+ *
+ * Step 1: CONFIGURE pin to detect level LOW interrupts.
+ *
+ * Step 2: DETECT level LOW interrupt and in irqmux/gpio bank interrupt handler,
+ * if the value of pin is low, then CONFIGURE pin for level HIGH interrupt.
+ * IGNORE calling the actual interrupt handler for the pin at this stage.
+ *
+ * Step 3: DETECT level HIGH interrupt and in irqmux/gpio-bank interrupt handler
+ * if the value of pin is HIGH, CONFIGURE pin for level LOW interrupt and then
+ * DISPATCH the interrupt to the interrupt handler of the pin.
+ *
+ * step-1 ________ __________
+ * | | step - 3
+ * | |
+ * step -2 |_____|
+ *
+ * falling edge is also detected int the same way.
+ *
+ */
static void __gpio_irq_handler(struct st_gpio_bank *bank)
{
unsigned long port_in, port_mask, port_comp, active_irqs;
- int n;
+ unsigned long bank_edge_mask, flags;
+ int n, val, ecfg;
+
+ spin_lock_irqsave(&bank->lock, flags);
+ bank_edge_mask = bank->irq_edge_conf;
+ spin_unlock_irqrestore(&bank->lock, flags);
for (;;) {
port_in = readl(bank->base + REG_PIO_PIN);
@@ -1298,6 +1393,22 @@ static void __gpio_irq_handler(struct st_gpio_bank *bank)
break;
for_each_set_bit(n, &active_irqs, BITS_PER_LONG) {
+ /* check if we are detecting fake edges ... */
+ ecfg = ST_IRQ_EDGE_CONF(bank_edge_mask, n);
+
+ if (ecfg) {
+ /* edge detection. */
+ val = st_gpio_get(&bank->gpio_chip, n);
+
+ writel(BIT(n),
+ val ? bank->base + REG_PIO_SET_PCOMP :
+ bank->base + REG_PIO_CLR_PCOMP);
+
+ if (ecfg != ST_IRQ_EDGE_BOTH &&
+ !((ecfg & ST_IRQ_EDGE_FALLING) ^ val))
+ continue;
+ }
+
generic_handle_irq(irq_find_mapping(bank->domain, n));
}
}
@@ -1359,7 +1470,7 @@ static int st_gpio_irq_domain_map(struct irq_domain *h,
struct st_gpio_bank *bank = h->host_data;
irq_set_chip(virq, &st_gpio_irqchip);
- irq_set_handler(virq, handle_level_irq);
+ irq_set_handler(virq, handle_simple_irq);
set_irq_flags(virq, IRQF_VALID);
irq_set_chip_data(virq, bank);
@@ -1392,6 +1503,7 @@ static int st_gpiolib_register_bank(struct st_pinctrl *info,
bank->gpio_chip.base = bank_num * ST_GPIO_PINS_PER_BANK;
bank->gpio_chip.ngpio = ST_GPIO_PINS_PER_BANK;
bank->gpio_chip.of_node = np;
+ spin_lock_init(&bank->lock);
of_property_read_string(np, "st,bank-name", &range->name);
bank->gpio_chip.label = range->name;