Re: [PATCH v2 03/16] gpio: aspeed: Convert to immutable irq_chip

Joel Stanley
2023-03-08T01:22:10Z

On Tue, 7 Mar 2023 at 13:04, Linus Walleij <linus.walleij@linaro.org> wrote:
>
> Convert the driver to immutable irq-chip with a bit of
> intuition.
>
> Cc: Marc Zyngier <maz@kernel.org>
> Tested-by: Joel Stanley <joel@jms.id.au>
> Acked-by: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> drivers/gpio/gpio-aspeed.c | 44 ++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 38 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c
> index a94da80d3a95..9c4852de2733 100644
> --- a/drivers/gpio/gpio-aspeed.c
> +++ b/drivers/gpio/gpio-aspeed.c
> @@ -15,6 +15,7 @@
> #include <linux/module.h>
> #include <linux/pinctrl/consumer.h>
> #include <linux/platform_device.h>
> +#include <linux/seq_file.h>
> #include <linux/spinlock.h>
> #include <linux/string.h>
>
> @@ -53,7 +54,7 @@ struct aspeed_gpio_config {
> */
> struct aspeed_gpio {
> struct gpio_chip chip;
> - struct irq_chip irqc;
> + struct device *dev;
> raw_spinlock_t lock;
> void __iomem *base;
> int irq;
> @@ -566,6 +567,10 @@ static void aspeed_gpio_irq_set_mask(struct irq_data *d, bool set)
>
> addr = bank_reg(gpio, bank, reg_irq_enable);
>
> + /* Unmasking the IRQ */
> + if (set)
> + gpiochip_enable_irq(&gpio->chip, irqd_to_hwirq(d));
> +
> raw_spin_lock_irqsave(&gpio->lock, flags);
> copro = aspeed_gpio_copro_request(gpio, offset);
>
> @@ -579,6 +584,10 @@ static void aspeed_gpio_irq_set_mask(struct irq_data *d, bool set)
> if (copro)
> aspeed_gpio_copro_release(gpio, offset);
> raw_spin_unlock_irqrestore(&gpio->lock, flags);
> +
> + /* Masking the IRQ */
> + if (!set)
> + gpiochip_disable_irq(&gpio->chip, irqd_to_hwirq(d));
> }
>
> static void aspeed_gpio_irq_mask(struct irq_data *d)
> @@ -1080,6 +1089,30 @@ int aspeed_gpio_copro_release_gpio(struct gpio_desc *desc)
> }
> EXPORT_SYMBOL_GPL(aspeed_gpio_copro_release_gpio);
>
> +static void aspeed_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
> +{
> + const struct aspeed_gpio_bank *bank;
> + struct aspeed_gpio *gpio;
> + u32 bit;
> + int rc, offset;
> +
> + rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit, &offset);

Why do we call this instead of using irq_data_get_irq_chip_data?

Actually, the callback appears to do the same as the default
implementation, so we could just drop it?

from kernel/irq/proc.c:

if (desc->irq_data.chip) {
if (desc->irq_data.chip->irq_print_chip)
desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
else if (desc->irq_data.chip->name)
seq_printf(p, " %8s", desc->irq_data.chip->name);

A test on the rainier ast2600 bmc machine:

# gpio-event-mon -n gpiochip0 -o 123 -r -f &
# cat /proc/interrupts |grep gpio-event-mon
60: 0 0 1e780800.gpio 123 Edge gpio-event-mon

> + if (rc)
> + return;
> +
> + seq_printf(p, dev_name(gpio->dev));
> +}
> +
> +static const struct irq_chip aspeed_gpio_irq_chip = {
> + .irq_ack = aspeed_gpio_irq_ack,
> + .irq_mask = aspeed_gpio_irq_mask,
> + .irq_unmask = aspeed_gpio_irq_unmask,
> + .irq_set_type = aspeed_gpio_set_type,
> + .irq_print_chip = aspeed_gpio_irq_print_chip,
> + .flags = IRQCHIP_IMMUTABLE,
> + GPIOCHIP_IRQ_RESOURCE_HELPERS,
> +};
> +
> /*
> * Any banks not specified in a struct aspeed_bank_props array are assumed to
> * have the properties:
> @@ -1149,6 +1182,8 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
> if (IS_ERR(gpio->base))
> return PTR_ERR(gpio->base);
>
> + gpio->dev = &pdev->dev;
> +
> raw_spin_lock_init(&gpio->lock);
>
> gpio_id = of_match_node(aspeed_gpio_of_table, pdev->dev.of_node);
> @@ -1208,12 +1243,9 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
>
> gpio->irq = rc;
> girq = &gpio->chip.irq;
> - girq->chip = &gpio->irqc;
> + gpio_irq_chip_set_chip(girq, &aspeed_gpio_irq_chip);
> girq->chip->name = dev_name(&pdev->dev);
> - girq->chip->irq_ack = aspeed_gpio_irq_ack;
> - girq->chip->irq_mask = aspeed_gpio_irq_mask;
> - girq->chip->irq_unmask = aspeed_gpio_irq_unmask;
> - girq->chip->irq_set_type = aspeed_gpio_set_type;
> +

I was thinking we could make the interrupt registration unconditional,
as there's always an irq in the device tree. Happy to send a follow
up, or for you to fold in a change along the lines of this:

--- a/drivers/gpio/gpio-aspeed.c
+++ b/drivers/gpio/gpio-aspeed.c
@@ -1091,14 +1091,7 @@ EXPORT_SYMBOL_GPL(aspeed_gpio_copro_release_gpio);

static void aspeed_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
{
- const struct aspeed_gpio_bank *bank;
- struct aspeed_gpio *gpio;
- u32 bit;
- int rc, offset;
-
- rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit, &offset);
- if (rc)
- return;
+ struct aspeed_gpio *gpio = irq_data_get_irq_chip_data(d);

seq_printf(p, dev_name(gpio->dev));
}
@@ -1108,7 +1101,7 @@ static const struct irq_chip aspeed_gpio_irq_chip = {
.irq_mask = aspeed_gpio_irq_mask,
.irq_unmask = aspeed_gpio_irq_unmask,
.irq_set_type = aspeed_gpio_set_type,
- .irq_print_chip = aspeed_gpio_irq_print_chip,
+// .irq_print_chip = aspeed_gpio_irq_print_chip,
.flags = IRQCHIP_IMMUTABLE,
GPIOCHIP_IRQ_RESOURCE_HELPERS,
};
@@ -1170,6 +1163,7 @@ MODULE_DEVICE_TABLE(of, aspeed_gpio_of_table);
static int __init aspeed_gpio_probe(struct platform_device *pdev)
{
const struct of_device_id *gpio_id;
+ struct gpio_irq_chip *girq;
struct aspeed_gpio *gpio;
int rc, i, banks, err;
u32 ngpio;
@@ -1238,27 +1232,25 @@ static int __init aspeed_gpio_probe(struct
platform_device *pdev)

/* Optionally set up an irqchip if there is an IRQ */
rc = platform_get_irq(pdev, 0);
- if (rc > 0) {
- struct gpio_irq_chip *girq;
-
- gpio->irq = rc;
- girq = &gpio->chip.irq;
- gpio_irq_chip_set_chip(girq, &aspeed_gpio_irq_chip);
- girq->chip->name = dev_name(&pdev->dev);
-
- girq->parent_handler = aspeed_gpio_irq_handler;
- girq->num_parents = 1;
- girq->parents = devm_kcalloc(&pdev->dev, 1,
- sizeof(*girq->parents),
- GFP_KERNEL);
- if (!girq->parents)
- return -ENOMEM;
- girq->parents[0] = gpio->irq;
- girq->default_type = IRQ_TYPE_NONE;
- girq->handler = handle_bad_irq;
- girq->init_valid_mask = aspeed_init_irq_valid_mask;
+ if (rc < 0) {
+ return rc;
}

+ gpio->irq = rc;
+ girq = &gpio->chip.irq;
+ gpio_irq_chip_set_chip(girq, &aspeed_gpio_irq_chip);
+ girq->chip->name = dev_name(&pdev->dev);
+
+ girq->parent_handler = aspeed_gpio_irq_handler;
+ girq->num_parents = 1;
+ girq->parents = devm_kcalloc(&pdev->dev, 1,
sizeof(*girq->parents), GFP_KERNEL);
+ if (!girq->parents)
+ return -ENOMEM;
+ girq->parents[0] = gpio->irq;
+ girq->default_type = IRQ_TYPE_NONE;
+ girq->handler = handle_bad_irq;
+ girq->init_valid_mask = aspeed_init_irq_valid_mask;
+
gpio->offset_timer =
devm_kzalloc(&pdev->dev, gpio->chip.ngpio, GFP_KERNEL);
if (!gpio->offset_timer)

> girq->parent_handler = aspeed_gpio_irq_handler;
> girq->num_parents = 1;
> girq->parents = devm_kcalloc(&pdev->dev, 1,
>
> --
> 2.34.1
>