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Subject[PATCH v2 2/6] gpio: brcmstb: Add interrupt support
Date
Create an irq_chip for each GIO block.  Uses chained IRQ handling since
known uses of this block have a BCM7120 L2 interrupt controller as a
parent. Supports interrupts for all GPIOs.

In the IRQ handler, we check for raised IRQs for invalid GPIOs and warn
(ratelimited) if they're encountered.

Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
---
v2:
- since imask member of bank struct was removed, just read and write from mask
reg and don't maintain a shadow
- warn on invalid IRQs
- move some irq setup to a separate function since probe is getting unwieldy

drivers/gpio/Kconfig | 1 +
drivers/gpio/gpio-brcmstb.c | 276 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 277 insertions(+)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d86de6a..7249dba 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -131,6 +131,7 @@ config GPIO_BRCMSTB
default y if ARCH_BRCMSTB
depends on OF_GPIO && (ARCH_BRCMSTB || COMPILE_TEST)
select GPIO_GENERIC
+ select IRQ_DOMAIN
help
Say yes here to enable GPIO support for Broadcom STB (BCM7XXX) SoCs.

diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
index 7a3cb1f..b9962ff 100644
--- a/drivers/gpio/gpio-brcmstb.c
+++ b/drivers/gpio/gpio-brcmstb.c
@@ -17,6 +17,8 @@
#include <linux/of_irq.h>
#include <linux/module.h>
#include <linux/basic_mmio_gpio.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>

#define GIO_BANK_SIZE 0x20
#define GIO_ODEN(bank) (((bank) * GIO_BANK_SIZE) + 0x00)
@@ -40,7 +42,11 @@ struct brcmstb_gpio_priv {
struct list_head bank_list;
void __iomem *reg_base;
int num_banks;
+ int num_gpios;
struct platform_device *pdev;
+ struct irq_chip irq_chip;
+ struct irq_domain *irq_domain;
+ int parent_irq;
int gpio_base;
};

@@ -63,6 +69,231 @@ brcmstb_gpio_gc_to_priv(struct gpio_chip *gc)
return bank->parent_priv;
}

+static void brcmstb_gpio_set_imask(struct brcmstb_gpio_bank *bank,
+ unsigned int offset, bool enable)
+{
+ struct bgpio_chip *bgc = &bank->bgc;
+ struct brcmstb_gpio_priv *priv = bank->parent_priv;
+ u32 mask = bgc->pin2mask(bgc, offset);
+ u32 imask;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ imask = bgc->read_reg(priv->reg_base + GIO_MASK(bank->id));
+ if (enable)
+ imask |= mask;
+ else
+ imask &= ~mask;
+ bgc->write_reg(priv->reg_base + GIO_MASK(bank->id), imask);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static int brcmstb_gpio_to_irq(struct gpio_chip *gc, unsigned gc_offset)
+{
+ struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
+ /* gc_offset is relative to this gpio_chip; want real offset */
+ int offset = gc_offset + (gc->base - priv->gpio_base);
+
+ if (offset >= priv->num_gpios)
+ return -ENXIO;
+ return irq_create_mapping(priv->irq_domain, offset);
+}
+
+/* -------------------- IRQ chip functions -------------------- */
+
+static int brcmstb_gpio_hwirq_to_offset(irq_hw_number_t hwirq,
+ struct brcmstb_gpio_bank *bank)
+{
+ return hwirq - (bank->bgc.gc.base - bank->parent_priv->gpio_base);
+}
+
+static void brcmstb_gpio_irq_mask(struct irq_data *d)
+{
+ struct brcmstb_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+ int offset = brcmstb_gpio_hwirq_to_offset(d->hwirq, bank);
+
+ brcmstb_gpio_set_imask(bank, offset, false);
+}
+
+static void brcmstb_gpio_irq_unmask(struct irq_data *d)
+{
+ struct brcmstb_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+ int offset = brcmstb_gpio_hwirq_to_offset(d->hwirq, bank);
+
+ brcmstb_gpio_set_imask(bank, offset, true);
+}
+
+static int brcmstb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+ struct brcmstb_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+ struct brcmstb_gpio_priv *priv = bank->parent_priv;
+ u32 mask = BIT(brcmstb_gpio_hwirq_to_offset(d->hwirq, bank));
+ u32 edge_insensitive, iedge_insensitive;
+ u32 edge_config, iedge_config;
+ u32 level, ilevel;
+ unsigned long flags;
+
+ switch (type) {
+ case IRQ_TYPE_LEVEL_LOW:
+ level = 0;
+ edge_config = 0;
+ edge_insensitive = 0;
+ break;
+ case IRQ_TYPE_LEVEL_HIGH:
+ level = mask;
+ edge_config = 0;
+ edge_insensitive = 0;
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ level = 0;
+ edge_config = 0;
+ edge_insensitive = 0;
+ break;
+ case IRQ_TYPE_EDGE_RISING:
+ level = 0;
+ edge_config = mask;
+ edge_insensitive = 0;
+ break;
+ case IRQ_TYPE_EDGE_BOTH:
+ level = 0;
+ edge_config = 0; /* don't care, but want known value */
+ edge_insensitive = mask;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&bank->bgc.lock, flags);
+
+ iedge_config = bank->bgc.read_reg(priv->reg_base +
+ GIO_EC(bank->id)) & ~mask;
+ iedge_insensitive = bank->bgc.read_reg(priv->reg_base +
+ GIO_EI(bank->id)) & ~mask;
+ ilevel = bank->bgc.read_reg(priv->reg_base +
+ GIO_LEVEL(bank->id)) & ~mask;
+
+ bank->bgc.write_reg(priv->reg_base + GIO_EC(bank->id),
+ iedge_config | edge_config);
+ bank->bgc.write_reg(priv->reg_base + GIO_EI(bank->id),
+ iedge_insensitive | edge_insensitive);
+ bank->bgc.write_reg(priv->reg_base + GIO_LEVEL(bank->id),
+ ilevel | level);
+
+ spin_unlock_irqrestore(&bank->bgc.lock, flags);
+ return 0;
+}
+
+static void brcmstb_gpio_irq_bank_handler(int irq,
+ struct brcmstb_gpio_bank *bank)
+{
+ struct brcmstb_gpio_priv *priv = bank->parent_priv;
+ void __iomem *reg_base = priv->reg_base;
+ unsigned long status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bank->bgc.lock, flags);
+ while ((status = bank->bgc.read_reg(reg_base + GIO_STAT(bank->id)) &
+ bank->bgc.read_reg(reg_base + GIO_MASK(bank->id)))) {
+ int bit;
+ for_each_set_bit(bit, &status, 32) {
+ int hwirq = bank->bgc.gc.base -
+ priv->gpio_base + bit;
+ int child_irq =
+ irq_find_mapping(priv->irq_domain,
+ hwirq);
+ u32 stat = bank->bgc.read_reg(reg_base +
+ GIO_STAT(bank->id));
+ if (bit >= bank->width)
+ dev_warn(&priv->pdev->dev,
+ "IRQ for invalid GPIO (bank=%d, offset=%d)\n",
+ bank->id, bit);
+ bank->bgc.write_reg(reg_base + GIO_STAT(bank->id),
+ stat | BIT(bit));
+ generic_handle_irq(child_irq);
+ }
+ }
+ spin_unlock_irqrestore(&bank->bgc.lock, flags);
+}
+
+/* Each UPG GIO block has one IRQ for all banks */
+static void brcmstb_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+ struct brcmstb_gpio_priv *priv = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct list_head *pos;
+
+ chained_irq_enter(chip, desc);
+ list_for_each(pos, &priv->bank_list) {
+ struct brcmstb_gpio_bank *bank =
+ list_entry(pos, struct brcmstb_gpio_bank, node);
+ brcmstb_gpio_irq_bank_handler(irq, bank);
+ }
+ chained_irq_exit(chip, desc);
+}
+
+static struct brcmstb_gpio_bank *brcmstb_gpio_hwirq_to_bank(
+ struct brcmstb_gpio_priv *priv, irq_hw_number_t hwirq)
+{
+ struct list_head *pos;
+ int i = 0;
+
+ /* banks are in descending order */
+ list_for_each_prev(pos, &priv->bank_list) {
+ struct brcmstb_gpio_bank *bank =
+ list_entry(pos, struct brcmstb_gpio_bank, node);
+ i += bank->bgc.gc.ngpio;
+ if (hwirq < i)
+ return bank;
+ }
+ return NULL;
+}
+
+/*
+ * This lock class tells lockdep that GPIO irqs are in a different
+ * category than their parents, so it won't report false recursion.
+ */
+static struct lock_class_key brcmstb_gpio_irq_lock_class;
+
+
+static int brcmstb_gpio_irq_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hwirq)
+{
+ struct brcmstb_gpio_priv *priv = d->host_data;
+ struct brcmstb_gpio_bank *bank =
+ brcmstb_gpio_hwirq_to_bank(priv, hwirq);
+ struct platform_device *pdev = priv->pdev;
+ int ret;
+
+ if (!bank)
+ return -EINVAL;
+
+ dev_dbg(&pdev->dev, "Mapping irq %d for gpio line %d (bank %d)\n",
+ irq, (int)hwirq, bank->id);
+ ret = irq_set_chip_data(irq, bank);
+ if (ret < 0)
+ return ret;
+ irq_set_lockdep_class(irq, &brcmstb_gpio_irq_lock_class);
+ irq_set_chip_and_handler(irq, &priv->irq_chip, handle_simple_irq);
+#ifdef CONFIG_ARM
+ set_irq_flags(irq, IRQF_VALID);
+#else
+ irq_set_noprobe(irq);
+#endif
+ return 0;
+}
+
+static void brcmstb_gpio_irq_unmap(struct irq_domain *d, unsigned int irq)
+{
+ irq_set_chip_and_handler(irq, NULL, NULL);
+ irq_set_chip_data(irq, NULL);
+}
+
+static struct irq_domain_ops brcmstb_gpio_irq_domain_ops = {
+ .map = brcmstb_gpio_irq_map,
+ .unmap = brcmstb_gpio_irq_unmap,
+ .xlate = irq_domain_xlate_twocell,
+};
+
/* Make sure that the number of banks matches up between properties */
static int brcmstb_gpio_sanity_check_banks(struct device *dev,
struct device_node *np, struct resource *res)
@@ -127,6 +358,32 @@ static int brcmstb_gpio_of_xlate(struct gpio_chip *gc,
return offset;
}

+/* priv->parent_irq and priv->num_gpios must be set before calling */
+static int brcmstb_gpio_irq_setup(struct platform_device *pdev,
+ struct brcmstb_gpio_priv *priv)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+
+ priv->irq_chip.name = dev_name(dev);
+ priv->irq_chip.irq_mask = brcmstb_gpio_irq_mask;
+ priv->irq_chip.irq_unmask = brcmstb_gpio_irq_unmask;
+ priv->irq_chip.irq_set_type = brcmstb_gpio_irq_set_type;
+ priv->irq_domain =
+ irq_domain_add_linear(np, priv->num_gpios,
+ &brcmstb_gpio_irq_domain_ops,
+ priv);
+ if (!priv->irq_domain) {
+ dev_err(dev, "Couldn't allocate IRQ domain\n");
+ return -ENXIO;
+ }
+ irq_set_chained_handler(priv->parent_irq,
+ brcmstb_gpio_irq_handler);
+ irq_set_handler_data(priv->parent_irq, priv);
+
+ return 0;
+}
+
static int brcmstb_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -153,6 +410,16 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
priv->reg_base = reg_base;
priv->pdev = pdev;

+ if (of_find_property(np, "interrupt-controller", NULL)) {
+ priv->parent_irq = platform_get_irq(pdev, 0);
+ if (priv->parent_irq < 0) {
+ dev_err(dev, "Couldn't get IRQ");
+ return -ENOENT;
+ }
+ } else {
+ priv->parent_irq = -ENOENT;
+ }
+
INIT_LIST_HEAD(&priv->bank_list);
if (brcmstb_gpio_sanity_check_banks(dev, np, res))
return -EINVAL;
@@ -201,6 +468,8 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
gc->of_xlate = brcmstb_gpio_of_xlate;
/* not all ngpio lines are valid, will use bank width later */
gc->ngpio = MAX_GPIO_PER_BANK;
+ if (priv->parent_irq >= 0)
+ gc->to_irq = brcmstb_gpio_to_irq;

err = gpiochip_add(gc);
if (err) {
@@ -218,6 +487,13 @@ static int brcmstb_gpio_probe(struct platform_device *pdev)
priv->num_banks++;
}

+ priv->num_gpios = gpio_base - priv->gpio_base;
+ if (priv->parent_irq >= 0) {
+ err = brcmstb_gpio_irq_setup(pdev, priv);
+ if (err)
+ goto fail;
+ }
+
dev_info(dev, "Registered %d banks (GPIO(s): %d-%d)\n",
priv->num_banks, priv->gpio_base, gpio_base - 1);

--
1.9.1


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