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References: <20220511183210.5248-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
 <20220511183210.5248-6-prabhakar.mahadev-lad.rj@bp.renesas.com> <87zgjn57eb.wl-maz@kernel.org>
In-Reply-To: <87zgjn57eb.wl-maz@kernel.org>
From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Thu, 12 May 2022 18:46:25 +0100
Message-ID: <CA+V-a8shYmRXvxV76NZenuLKDAGBYRVwbt7HofcdnPoMjgx=ZA@mail.gmail.com>
Subject: Re: [PATCH v3 5/5] pinctrl: renesas: pinctrl-rzg2l: Add IRQ domain to
 handle GPIO interrupt
To:     Marc Zyngier <maz@kernel.org>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Linus Walleij <linus.walleij@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Phil Edworthy <phil.edworthy@renesas.com>,
        Biju Das <biju.das.jz@bp.renesas.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Marc,

Thank you for the review.

On Thu, May 12, 2022 at 12:15 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Wed, 11 May 2022 19:32:10 +0100,
> Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> >
> > Add IRQ domian to RZ/G2L pinctrl driver to handle GPIO interrupt.
> >
> > GPIO0-GPIO122 pins can be used as IRQ lines but only 32 pins can be
> > used as IRQ lines at given time. Selection of pins as IRQ lines
> > is handled by IA55 (which is the IRQC block) which sits in between the
> > GPIO and GIC.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> >  drivers/pinctrl/renesas/pinctrl-rzg2l.c | 202 ++++++++++++++++++++++++
> >  1 file changed, 202 insertions(+)
> >
> > diff --git a/drivers/pinctrl/renesas/pinctrl-rzg2l.c b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > index a48cac55152c..af2c739cdbaa 100644
> > --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > @@ -9,8 +9,10 @@
> >  #include <linux/clk.h>
> >  #include <linux/gpio/driver.h>
> >  #include <linux/io.h>
> > +#include <linux/interrupt.h>
> >  #include <linux/module.h>
> >  #include <linux/of_device.h>
> > +#include <linux/of_irq.h>
> >  #include <linux/pinctrl/pinconf-generic.h>
> >  #include <linux/pinctrl/pinconf.h>
> >  #include <linux/pinctrl/pinctrl.h>
> > @@ -89,6 +91,7 @@
> >  #define PIN(n)                       (0x0800 + 0x10 + (n))
> >  #define IOLH(n)                      (0x1000 + (n) * 8)
> >  #define IEN(n)                       (0x1800 + (n) * 8)
> > +#define ISEL(n)                      (0x2c80 + (n) * 8)
> >  #define PWPR                 (0x3014)
> >  #define SD_CH(n)             (0x3000 + (n) * 4)
> >  #define QSPI                 (0x3008)
> > @@ -112,6 +115,10 @@
> >  #define RZG2L_PIN_ID_TO_PORT_OFFSET(id)      (RZG2L_PIN_ID_TO_PORT(id) + 0x10)
> >  #define RZG2L_PIN_ID_TO_PIN(id)              ((id) % RZG2L_PINS_PER_PORT)
> >
> > +#define RZG2L_TINT_MAX_INTERRUPT     32
> > +#define RZG2L_TINT_IRQ_START_INDEX   9
> > +#define RZG2L_PACK_HWIRQ(t, i)               (((t) << 16) | (i))
> > +
> >  struct rzg2l_dedicated_configs {
> >       const char *name;
> >       u32 config;
> > @@ -137,6 +144,9 @@ struct rzg2l_pinctrl {
> >
> >       struct gpio_chip                gpio_chip;
> >       struct pinctrl_gpio_range       gpio_range;
> > +     DECLARE_BITMAP(tint_slot, RZG2L_TINT_MAX_INTERRUPT);
> > +     spinlock_t                      bitmap_lock;
> > +     unsigned int                    hwirq[RZG2L_TINT_MAX_INTERRUPT];
> >
> >       spinlock_t                      lock;
> >  };
> > @@ -883,6 +893,8 @@ static int rzg2l_gpio_get(struct gpio_chip *chip, unsigned int offset)
> >
> >  static void rzg2l_gpio_free(struct gpio_chip *chip, unsigned int offset)
> >  {
> > +     unsigned int virq;
> > +
> >       pinctrl_gpio_free(chip->base + offset);
> >
> >       /*
> > @@ -890,6 +902,10 @@ static void rzg2l_gpio_free(struct gpio_chip *chip, unsigned int offset)
> >        * drive the GPIO pin as an output.
> >        */
> >       rzg2l_gpio_direction_input(chip, offset);
> > +
> > +     virq = irq_find_mapping(chip->irq.domain, offset);
> > +     if (virq)
> > +             irq_dispose_mapping(virq);
> >  }
> >
> >  static const char * const rzg2l_gpio_names[] = {
> > @@ -1104,14 +1120,190 @@ static struct {
> >       }
> >  };
> >
> > +static int rzg2l_gpio_get_gpioint(unsigned int virq)
> > +{
> > +     unsigned int gpioint;
> > +     unsigned int i;
> > +     u32 port, bit;
> > +
> > +     port = virq / 8;
> > +     bit = virq % 8;
> > +
> > +     if (port >= ARRAY_SIZE(rzg2l_gpio_configs) ||
> > +         bit >= RZG2L_GPIO_PORT_GET_PINCNT(rzg2l_gpio_configs[port]))
> > +             return -EINVAL;
> > +
> > +     gpioint = bit;
> > +     for (i = 0; i < port; i++)
> > +             gpioint += RZG2L_GPIO_PORT_GET_PINCNT(rzg2l_gpio_configs[i]);
> > +
> > +     return gpioint;
> > +}
> > +
> > +static void rzg2l_gpio_irq_domain_free(struct irq_domain *domain, unsigned int virq,
> > +                                    unsigned int nr_irqs)
> > +{
> > +     struct irq_data *d;
> > +
> > +     d = irq_domain_get_irq_data(domain, virq);
> > +     if (d) {
> > +             struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > +             struct rzg2l_pinctrl *pctrl = container_of(gc, struct rzg2l_pinctrl, gpio_chip);
> > +             irq_hw_number_t hwirq = irqd_to_hwirq(d);
> > +             unsigned long flags;
> > +             unsigned int i;
> > +
> > +             for (i = 0; i < RZG2L_TINT_MAX_INTERRUPT; i++) {
> > +                     if (pctrl->hwirq[i] == hwirq) {
> > +                             spin_lock_irqsave(&pctrl->bitmap_lock, flags);
> > +                             bitmap_release_region(pctrl->tint_slot, i, get_order(1));
> > +                             spin_unlock_irqrestore(&pctrl->bitmap_lock, flags);
> > +                             pctrl->hwirq[i] = 0;
> > +                             break;
> > +                     }
> > +             }
> > +     }
> > +     irq_domain_free_irqs_common(domain, virq, nr_irqs);
> > +}
> > +
> > +static void rzg2l_gpio_irq_disable(struct irq_data *d)
> > +{
> > +     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > +     struct rzg2l_pinctrl *pctrl = container_of(gc, struct rzg2l_pinctrl, gpio_chip);
> > +     unsigned int hwirq = irqd_to_hwirq(d);
> > +     unsigned long flags;
> > +     void __iomem *addr;
> > +     u32 port;
> > +     u8 bit;
> > +
> > +     port = RZG2L_PIN_ID_TO_PORT(hwirq);
> > +     bit = RZG2L_PIN_ID_TO_PIN(hwirq);
> > +
> > +     addr = pctrl->base + ISEL(port);
> > +     if (bit >= 4) {
> > +             bit -= 4;
> > +             addr += 4;
> > +     }
> > +
> > +     spin_lock_irqsave(&pctrl->lock, flags);
> > +     writel(readl(addr) & ~BIT(bit * 8), addr);
> > +     spin_unlock_irqrestore(&pctrl->lock, flags);
> > +
> > +     irq_chip_disable_parent(d);
> > +}
> > +
> > +static void rzg2l_gpio_irq_enable(struct irq_data *d)
> > +{
> > +     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > +     struct rzg2l_pinctrl *pctrl = container_of(gc, struct rzg2l_pinctrl, gpio_chip);
> > +     unsigned int hwirq = irqd_to_hwirq(d);
> > +     unsigned long flags;
> > +     void __iomem *addr;
> > +     u32 port;
> > +     u8 bit;
> > +
> > +     port = RZG2L_PIN_ID_TO_PORT(hwirq);
> > +     bit = RZG2L_PIN_ID_TO_PIN(hwirq);
> > +
> > +     addr = pctrl->base + ISEL(port);
> > +     if (bit >= 4) {
> > +             bit -= 4;
> > +             addr += 4;
> > +     }
> > +
> > +     spin_lock_irqsave(&pctrl->lock, flags);
> > +     writel(readl(addr) | BIT(bit * 8), addr);
> > +     spin_unlock_irqrestore(&pctrl->lock, flags);
> > +
> > +     irq_chip_enable_parent(d);
> > +}
> > +
> > +static int rzg2l_gpio_irq_set_type(struct irq_data *d, unsigned int type)
> > +{
> > +     return irq_chip_set_type_parent(d, type);
> > +}
> > +
> > +static void rzg2l_gpio_irqc_eoi(struct irq_data *d)
> > +{
> > +     irq_chip_eoi_parent(d);
> > +}
> > +
> > +static struct irq_chip rzg2l_gpio_irqchip = {
> > +     .name = "rzg2l-gpio",
> > +     .irq_disable = rzg2l_gpio_irq_disable,
> > +     .irq_enable = rzg2l_gpio_irq_enable,
> > +     .irq_mask = irq_chip_mask_parent,
> > +     .irq_unmask = irq_chip_unmask_parent,
> > +     .irq_set_type = rzg2l_gpio_irq_set_type,
> > +     .irq_eoi = rzg2l_gpio_irqc_eoi,
>
> Please see the changes[1] that are queued in -next around immutable
> GPIO irqchips. This needs to be made const, the enable/disable methods
> have the right callbacks added, the resource management methods
> plumbed, and the correct flag exposed.
>
Thank you for the pointer, I'll rebase my patches on top of it and
implement an immutable GPIO irqchip.

Cheers,
Prabhakar

> > +};
> > +
> > +static int rzg2l_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
> > +                                         unsigned int child,
> > +                                         unsigned int child_type,
> > +                                         unsigned int *parent,
> > +                                         unsigned int *parent_type)
> > +{
> > +     struct rzg2l_pinctrl *pctrl = gpiochip_get_data(gc);
> > +     unsigned long flags;
> > +     int gpioint, irq;
> > +
> > +     gpioint = rzg2l_gpio_get_gpioint(child);
> > +     if (gpioint < 0)
> > +             return gpioint;
> > +
> > +     spin_lock_irqsave(&pctrl->bitmap_lock, flags);
> > +     irq = bitmap_find_free_region(pctrl->tint_slot, RZG2L_TINT_MAX_INTERRUPT, get_order(1));
> > +     spin_unlock_irqrestore(&pctrl->bitmap_lock, flags);
> > +     if (irq < 0)
> > +             return -ENOSPC;
> > +     pctrl->hwirq[irq] = child;
> > +     irq += RZG2L_TINT_IRQ_START_INDEX;
> > +
> > +     /* All these interrupts are level high in the CPU */
> > +     *parent_type = IRQ_TYPE_LEVEL_HIGH;
> > +     *parent = RZG2L_PACK_HWIRQ(gpioint, irq);
> > +     return 0;
> > +}
> > +
> > +static void *rzg2l_gpio_populate_parent_fwspec(struct gpio_chip *chip,
> > +                                            unsigned int parent_hwirq,
> > +                                            unsigned int parent_type)
> > +{
> > +     struct irq_fwspec *fwspec;
> > +
> > +     fwspec = kzalloc(sizeof(*fwspec), GFP_KERNEL);
> > +     if (!fwspec)
> > +             return NULL;
> > +
> > +     fwspec->fwnode = chip->irq.parent_domain->fwnode;
> > +     fwspec->param_count = 2;
> > +     fwspec->param[0] = parent_hwirq;
> > +     fwspec->param[1] = parent_type;
> > +
> > +     return fwspec;
> > +}
> > +
> >  static int rzg2l_gpio_register(struct rzg2l_pinctrl *pctrl)
> >  {
> >       struct device_node *np = pctrl->dev->of_node;
> >       struct gpio_chip *chip = &pctrl->gpio_chip;
> >       const char *name = dev_name(pctrl->dev);
> > +     struct irq_domain *parent_domain;
> >       struct of_phandle_args of_args;
> > +     struct device_node *parent_np;
> > +     struct gpio_irq_chip *girq;
> >       int ret;
> >
> > +     parent_np = of_irq_find_parent(np);
> > +     if (!parent_np)
> > +             return -ENXIO;
> > +
> > +     parent_domain = irq_find_host(parent_np);
> > +     of_node_put(parent_np);
> > +     if (!parent_domain)
> > +             return -EPROBE_DEFER;
> > +
> >       ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &of_args);
> >       if (ret) {
> >               dev_err(pctrl->dev, "Unable to parse gpio-ranges\n");
> > @@ -1138,6 +1330,15 @@ static int rzg2l_gpio_register(struct rzg2l_pinctrl *pctrl)
> >       chip->base = -1;
> >       chip->ngpio = of_args.args[2];
> >
> > +     girq = &chip->irq;
>
> Same thing, this needs to use the appropriate setter.
>
> > +     girq->chip = &rzg2l_gpio_irqchip;
> > +     girq->fwnode = of_node_to_fwnode(np);
> > +     girq->parent_domain = parent_domain;
> > +     girq->child_to_parent_hwirq = rzg2l_gpio_child_to_parent_hwirq;
> > +     girq->populate_parent_alloc_arg = rzg2l_gpio_populate_parent_fwspec;
> > +     girq->child_irq_domain_ops.free = rzg2l_gpio_irq_domain_free;
> > +     girq->ngirq = RZG2L_TINT_MAX_INTERRUPT;
> > +
> >       pctrl->gpio_range.id = 0;
> >       pctrl->gpio_range.pin_base = 0;
> >       pctrl->gpio_range.base = 0;
> > @@ -1253,6 +1454,7 @@ static int rzg2l_pinctrl_probe(struct platform_device *pdev)
> >       }
> >
> >       spin_lock_init(&pctrl->lock);
> > +     spin_lock_init(&pctrl->bitmap_lock);
> >
> >       platform_set_drvdata(pdev, pctrl);
> >
> > --
> > 2.25.1
> >
> >
>
> Thanks,
>
>         M.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=irq/gpio-immutable
>
> --
> Without deviation from the norm, progress is not possible.