Re: [PATCH v2] gpio: langwell: convert to use irq_domain

[Grant Likely <grant.likely@secretlab.ca>]

On Fri, 27 Apr 2012 09:53:52 +0300, Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> irq_domain already provides a facility to translate from hardware IRQ
> numbers to Linux IRQ numbers so use that instead of open-coding the logic
> in the driver.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Hi Mika,

Comments below...

> ---
> Changes to previous version:
> 	- use linear mapping instead of legacy as suggested by Grant.
> 
>  drivers/gpio/Kconfig         |    1 +
>  drivers/gpio/gpio-langwell.c |   45 +++++++++++++++++++++++++----------------
>  2 files changed, 28 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index e03653d..0a85d95 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -399,6 +399,7 @@ config GPIO_BT8XX
>  config GPIO_LANGWELL
>  	bool "Intel Langwell/Penwell GPIO support"
>  	depends on PCI && X86
> +	select IRQ_DOMAIN
>  	help
>  	  Say Y here to support Intel Langwell/Penwell GPIO.
>  
> diff --git a/drivers/gpio/gpio-langwell.c b/drivers/gpio/gpio-langwell.c
> index 52f00d3..4b3da8c 100644
> --- a/drivers/gpio/gpio-langwell.c
> +++ b/drivers/gpio/gpio-langwell.c
> @@ -36,6 +36,7 @@
>  #include <linux/gpio.h>
>  #include <linux/slab.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/irqdomain.h>
>  
>  /*
>   * Langwell chip has 64 pins and thus there are 2 32bit registers to control
> @@ -66,8 +67,8 @@ struct lnw_gpio {
>  	struct gpio_chip		chip;
>  	void				*reg_base;
>  	spinlock_t			lock;
> -	unsigned			irq_base;
>  	struct pci_dev			*pdev;
> +	struct irq_domain		*domain;
>  };
>  
>  static void __iomem *gpio_reg(struct gpio_chip *chip, unsigned offset,
> @@ -176,13 +177,13 @@ static int lnw_gpio_direction_output(struct gpio_chip *chip,
>  static int lnw_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
>  {
>  	struct lnw_gpio *lnw = container_of(chip, struct lnw_gpio, chip);
> -	return lnw->irq_base + offset;
> +	return irq_create_mapping(lnw->domain, offset);
>  }
>  
>  static int lnw_irq_type(struct irq_data *d, unsigned type)
>  {
>  	struct lnw_gpio *lnw = irq_data_get_irq_chip_data(d);
> -	u32 gpio = d->irq - lnw->irq_base;
> +	u32 gpio = irqd_to_hwirq(d);
>  	unsigned long flags;
>  	u32 value;
>  	void __iomem *grer = gpio_reg(&lnw->chip, gpio, GRER);
> @@ -256,7 +257,7 @@ static void lnw_irq_handler(unsigned irq, struct irq_desc *desc)
>  			pending &= ~mask;
>  			/* Clear before handling so we can't lose an edge */
>  			writel(mask, gedr);
> -			generic_handle_irq(lnw->irq_base + base + gpio);
> +			generic_handle_irq(gpio_to_irq(base + gpio));

Don't use gpio_to_irq() here. irq_find_mapping() is intended for this
purpose.

>  		}
>  	}
>  
> @@ -281,6 +282,24 @@ static void lnw_irq_init_hw(struct lnw_gpio *lnw)
>  	}
>  }
>  
> +static int lnw_gpio_irq_map(struct irq_domain *d, unsigned int virq,
> +			    irq_hw_number_t hw)
> +{
> +	struct lnw_gpio *lnw = d->host_data;
> +
> +	irq_set_chip_and_handler_name(virq, &lnw_irqchip, handle_simple_irq,
> +				      "demux");
> +	irq_set_chip_data(virq, lnw);
> +	irq_set_irq_type(virq, IRQ_TYPE_NONE);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops lnw_gpio_irq_ops = {
> +	.map = lnw_gpio_irq_map,
> +	.xlate = irq_domain_xlate_twocell,
> +};
> +
>  #ifdef CONFIG_PM
>  static int lnw_gpio_runtime_resume(struct device *dev)
>  {
> @@ -318,7 +337,6 @@ static int __devinit lnw_gpio_probe(struct pci_dev *pdev,
>  			const struct pci_device_id *id)
>  {
>  	void *base;
> -	int i;
>  	resource_size_t start, len;
>  	struct lnw_gpio *lnw;
>  	u32 irq_base;

There are stale references to irq_base in this file after applying
this patch.

I also wonder if gpio_base can also be removed and use dynamic
allocation of the gpio number too.

Otherwise the patch looks pretty good.

> @@ -364,12 +382,10 @@ static int __devinit lnw_gpio_probe(struct pci_dev *pdev,
>  		goto err3;
>  	}
>  
> -	retval = irq_alloc_descs(-1, irq_base, ngpio, 0);
> -	if (retval < 0) {
> -		dev_err(&pdev->dev, "can't allocate IRQ descs\n");
> +	lnw->domain = irq_domain_add_linear(pdev->dev.of_node, ngpio,
> +					    &lnw_gpio_irq_ops, lnw);
> +	if (!lnw->domain)
>  		goto err3;
> -	}
> -	lnw->irq_base = retval;
>  
>  	lnw->reg_base = base;
>  	lnw->chip.label = dev_name(&pdev->dev);
> @@ -387,18 +403,13 @@ static int __devinit lnw_gpio_probe(struct pci_dev *pdev,
>  	retval = gpiochip_add(&lnw->chip);
>  	if (retval) {
>  		dev_err(&pdev->dev, "langwell gpiochip_add error %d\n", retval);
> -		goto err4;
> +		goto err3;
>  	}
>  
>  	lnw_irq_init_hw(lnw);
>  
>  	irq_set_handler_data(pdev->irq, lnw);
>  	irq_set_chained_handler(pdev->irq, lnw_irq_handler);
> -	for (i = 0; i < lnw->chip.ngpio; i++) {
> -		irq_set_chip_and_handler_name(i + lnw->irq_base, &lnw_irqchip,
> -					      handle_simple_irq, "demux");
> -		irq_set_chip_data(i + lnw->irq_base, lnw);
> -	}
>  
>  	spin_lock_init(&lnw->lock);
>  
> @@ -407,8 +418,6 @@ static int __devinit lnw_gpio_probe(struct pci_dev *pdev,
>  
>  	return 0;
>  
> -err4:
> -	irq_free_descs(lnw->irq_base, ngpio);
>  err3:
>  	pci_release_regions(pdev);
>  err2:
> -- 
> 1.7.9.1
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.