Re: [PATCH 2/3] gpio: dwapb: add support for GPIO interrupts

Sebastian Hesselbarth
2013-11-05T21:32:10Z

On 11/05/2013 05:55 PM, Alan Tull wrote:
> From: Jamie Iles <jamie@jamieiles.com>
>
> The controller supports interrupts on bank A (up to 8 interrupt

s/bank/port/g

> sources). Use the generic IRQ chip to implement interrupt support for
> this bank.
>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Cc: Linus Walleij <linus.walleij@stericsson.com>
> Acked-by: Rob Herring <rob.herring@calxeda.com>
> Signed-off-by: Jamie Iles <jamie@jamieiles.com>
> ---
> drivers/gpio/Kconfig | 2 +-
> drivers/gpio/gpio-dwapb.c | 181 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 182 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index c5e7868..4cc26ed 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -125,7 +125,7 @@ config GPIO_DWAPB
> bool "Synopsys DesignWare APB GPIO driver"
> select GPIO_GENERIC
> select GENERIC_IRQ_CHIP
> - depends on OF_GPIO
> + depends on OF_GPIO && IRQ_DOMAIN
> help
> Say Y or M here to build support for the Synopsys DesignWare APB
> GPIO block. This requires device tree support.
> diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
> index 3a28697..64c7183 100644
> --- a/drivers/gpio/gpio-dwapb.c
> +++ b/drivers/gpio/gpio-dwapb.c
> @@ -10,12 +10,22 @@
> #include <linux/init.h>
> #include <linux/io.h>
> #include <linux/ioport.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> #include <linux/module.h>
> #include <linux/basic_mmio_gpio.h>
> #include <linux/of.h>
> #include <linux/of_address.h>
> +#include <linux/of_irq.h>
> #include <linux/platform_device.h>
>
> +#define INT_EN_REG_OFFS 0x30
> +#define INT_MASK_REG_OFFS 0x34
> +#define INT_TYPE_REG_OFFS 0x38
> +#define INT_POLARITY_REG_OFFS 0x3c
> +#define INT_STATUS_REG_OFFS 0x40
> +#define EOI_REG_OFFS 0x4c

For sane register names, check [1] pp. 1271. I also suggest
to get rid of _REG_OFFS.

[1] http://www.altera.com/literature/hb/arria-v/hps.pdf

> struct dwapb_gpio;
>
> struct dwapb_gpio_bank {
> @@ -31,6 +41,8 @@ struct dwapb_gpio {
> void __iomem *regs;
> struct dwapb_gpio_bank *banks;
> unsigned int nr_banks;
> + struct irq_chip_generic *irq_gc;
> + unsigned long toggle_edge;
> };
>
> static unsigned int dwapb_gpio_nr_banks(struct device_node *of_node)
> @@ -44,6 +56,168 @@ static unsigned int dwapb_gpio_nr_banks(struct device_node *of_node)
> return nr_banks;
> }
>
> +static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
> +{
> + struct bgpio_chip *bgc = to_bgpio_chip(gc);
> + struct dwapb_gpio_bank *bank = container_of(bgc, struct
> + dwapb_gpio_bank, bgc);
> + struct dwapb_gpio *gpio = bank->gpio;
> +
> + return irq_domain_to_irq(&gpio->irq_gc->domain, offset);
> +}
> +
> +static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
> +{
> + u32 v = readl(gpio->regs + INT_TYPE_REG_OFFS);

s/readl/readl_relaxed/g
s/writel/writel_relaxed/g ?

> + if (gpio_get_value(gpio->banks[0].bgc.gc.base + offs))
> + v &= ~BIT(offs);
> + else
> + v |= BIT(offs);
> +
> + writel(v, gpio->regs + INT_TYPE_REG_OFFS);
> +}
> +
> +static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
> +{
> + struct dwapb_gpio *gpio = irq_get_handler_data(irq);
> + u32 irq_status = readl(gpio->regs + INT_STATUS_REG_OFFS);
> +
> + while (irq_status) {
> + int irqoffset = fls(irq_status) - 1;
> + int irq = irq_domain_to_irq(&gpio->irq_gc->domain, irqoffset);
> +
> + generic_handle_irq(irq);
> + irq_status &= ~(1 << irqoffset);
> +
> + if (gpio->toggle_edge & BIT(irqoffset))
> + dwapb_toggle_trigger(gpio, irqoffset);

if ((irq_get_trigger_type(irq) & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH)

and get rid of ->toggle_edge cache variable.

> + }
> +}
> +
> +static void dwapb_irq_enable(struct irq_data *d)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> + struct dwapb_gpio *gpio = gc->private;
> +
> + u32 val = readl(gpio->regs + INT_EN_REG_OFFS);
> + val |= 1 << d->hwirq;
> + writel(val, gpio->regs + INT_EN_REG_OFFS);
> +}
> +
> +static void dwapb_irq_disable(struct irq_data *d)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> + struct dwapb_gpio *gpio = gc->private;
> +
> + u32 val = readl(gpio->regs + INT_EN_REG_OFFS);
> + val &= ~(1 << d->hwirq);
> + writel(val, gpio->regs + INT_EN_REG_OFFS);
> +}
> +
> +static int dwapb_irq_set_type(struct irq_data *d, u32 type)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> + struct dwapb_gpio *gpio = gc->private;
> + int bit = d->hwirq;
> + unsigned long level, polarity;
> +
> + if (type & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING |
> + IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
> + return -EINVAL;
> +
> + level = readl(gpio->regs + INT_TYPE_REG_OFFS);
> + polarity = readl(gpio->regs + INT_POLARITY_REG_OFFS);
> +
> + gpio->toggle_edge &= ~BIT(bit);
> + if (type & IRQ_TYPE_EDGE_BOTH) {
> + gpio->toggle_edge |= BIT(bit);
> + level |= (1 << bit);

If you remove ->toggle_edge, read current pin value here and
set next edge accordingly.

> + dwapb_toggle_trigger(gpio, bit);
> + } else if (type & IRQ_TYPE_EDGE_RISING) {
> + level |= (1 << bit);
> + polarity |= (1 << bit);
> + } else if (type & IRQ_TYPE_EDGE_FALLING) {
> + level |= (1 << bit);
> + polarity &= ~(1 << bit);
> + } else if (type & IRQ_TYPE_LEVEL_HIGH) {
> + level &= ~(1 << bit);
> + polarity |= (1 << bit);
> + } else if (type & IRQ_TYPE_LEVEL_LOW) {
> + level &= ~(1 << bit);
> + polarity &= ~(1 << bit);
> + }

switch (type) for the above if-else-if ?

> + writel(level, gpio->regs + INT_TYPE_REG_OFFS);
> + writel(polarity, gpio->regs + INT_POLARITY_REG_OFFS);
> +
> + return 0;
> +}
> +
> +static int dwapb_create_irqchip(struct dwapb_gpio *gpio,
> + struct dwapb_gpio_bank *bank,
> + unsigned int irq_base)
> +{
> + struct irq_chip_type *ct;
> +
> + gpio->irq_gc = irq_alloc_generic_chip("gpio-dwapb", 1, irq_base,
> + gpio->regs, handle_level_irq);
> + if (!gpio->irq_gc)
> + return -EIO;
> +
> + gpio->irq_gc->domain.of_node = of_node_get(bank->bgc.gc.of_node);
> + gpio->irq_gc->private = gpio;
> + ct = gpio->irq_gc->chip_types;
> + ct->chip.irq_ack = irq_gc_ack_set_bit;
> + ct->chip.irq_mask = irq_gc_mask_set_bit;
> + ct->chip.irq_unmask = irq_gc_mask_clr_bit;
> + ct->chip.irq_set_type = dwapb_irq_set_type;
> + ct->chip.irq_enable = dwapb_irq_enable;
> + ct->chip.irq_disable = dwapb_irq_disable;

I can see no functional difference between enable/mask and always
enable and mask initially. If there are no objections, remove
enable/disable callbacks and mask and enable in _probe().

> + ct->regs.ack = EOI_REG_OFFS;
> + ct->regs.mask = INT_MASK_REG_OFFS;
> + irq_setup_generic_chip(gpio->irq_gc, IRQ_MSK(bank->bgc.gc.ngpio),
> + IRQ_GC_INIT_NESTED_LOCK, IRQ_NOREQUEST, 0);
> +
> + return 0;
> +}
> +
> +static int dwapb_configure_irqs(struct dwapb_gpio *gpio,
> + struct dwapb_gpio_bank *bank)
> +{
> + unsigned int m, irq, ngpio = bank->bgc.gc.ngpio;
> + int irq_base;
> +
> + for (m = 0; m < ngpio; ++m) {
> + irq = irq_of_parse_and_map(bank->bgc.gc.of_node, m);

Only port A can raise interrupts. Are you sure, that all IP has
one irq per gpio? As you always use the same handler, just map
all irqs passed and install the handler; no need to match against
individual gpios here.

Sebastian

> + if (!irq && m == 0) {
> + dev_warn(gpio->dev, "no irq for bank %s\n",
> + bank->bgc.gc.of_node->full_name);
> + return -ENXIO;
> + } else if (!irq) {
> + break;
> + }
> +
> + irq_set_chained_handler(irq, dwapb_irq_handler);
> + irq_set_handler_data(irq, gpio);
> + }
> + bank->bgc.gc.to_irq = dwapb_gpio_to_irq;
> +
> + irq_base = irq_alloc_descs(-1, 0, ngpio, NUMA_NO_NODE);
> + if (irq_base < 0)
> + return irq_base;

I was going to mention irqdomain_linear here, but then I realized
that patch 3/3 reverts most of irq handling here and replaces it
with irqdomain. Alan, I think Jamie is fine with you mangling patches
2 and 3 into one.

> + if (dwapb_create_irqchip(gpio, bank, irq_base))
> + goto out_free_descs;
> +
> + return 0;
> +
> +out_free_descs:
> + irq_free_descs(irq_base, ngpio);
> +
> + return -EIO;
> +}
> +
> static int dwapb_gpio_add_bank(struct dwapb_gpio *gpio,
> struct device_node *bank_np,
> unsigned int offs)
> @@ -81,6 +255,13 @@ static int dwapb_gpio_add_bank(struct dwapb_gpio *gpio,
> bank->bgc.gc.ngpio = ngpio;
> bank->bgc.gc.of_node = bank_np;
>
> + /*
> + * Only bank A can provide interrupts in all configurations of the IP.
> + */
> + if (bank_idx == 0 &&
> + of_get_property(bank_np, "interrupt-controller", NULL))
> + dwapb_configure_irqs(gpio, bank);
> +
> err = gpiochip_add(&bank->bgc.gc);
> if (err)
> dev_err(gpio->dev, "failed to register gpiochip for %s\n",
>