linux-kernel - Re: [PATCH v3 2/2] gpio: davinci: Do not assume continuous IRQ numbering

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Date:   Tue, 12 Jun 2018 15:06:24 -0500
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Keerthy <j-keerthy@...com>, <linus.walleij@...aro.org>
CC:     <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <t-kristo@...com>
Subject: Re: [PATCH v3 2/2] gpio: davinci: Do not assume continuous IRQ
 numbering



On 06/12/2018 02:59 AM, Keerthy wrote:
> Currently the driver assumes that the interrupts are continuous
> and does platform_get_irq only once and assumes the rest are continuous,
> instead call platform_get_irq for all the interrupts and store them
> in an array for later use.
> 
> Signed-off-by: Keerthy <j-keerthy@...com>
> ---
> 
> Tested for GPIO Interrupts on da850-lcdk board.
> 
> Changes in v3:
> 
>    * Changed irqs type from unsigned to int
> 
> Changes in v2:
> 
>    * Extended the logic of using saved IRQs to unbanked IRQs
>      as per Grygorii's suggestion.
> 
>   drivers/gpio/gpio-davinci.c                | 54 +++++++++++++++++++-----------
>   include/linux/platform_data/gpio-davinci.h |  3 +-
>   2 files changed, 36 insertions(+), 21 deletions(-)
> 

[...]

>   
> @@ -383,7 +396,7 @@ static int gpio_to_irq_unbanked(struct gpio_chip *chip, unsigned offset)
>   	 * can provide direct-mapped IRQs to AINTC (up to 32 GPIOs).
>   	 */
>   	if (offset < d->gpio_unbanked)
> -		return d->base_irq + offset;
> +		return d->irqs[offset];

this one seems right

>   	else
>   		return -ENODEV;
>   }
> @@ -396,7 +409,7 @@ static int gpio_irq_type_unbanked(struct irq_data *data, unsigned trigger)
>   
>   	d = (struct davinci_gpio_controller *)irq_data_get_irq_handler_data(data);
>   	g = (struct davinci_gpio_regs __iomem *)d->regs[0];
> -	mask = __gpio_mask(data->irq - d->base_irq);
> +	mask = __gpio_mask(data->irq - d->irqs[0]);

but this one is not. You can't do "base + offset" or "irq - base" ops
if Irqs range is not sequential. So, in my opinion, here you need to
convert irq to gpio bank offset (hwirq value in irq_data is not offset
- gic specific value) which means - walk through d->irqs[x] and find
item with d->irqs[x] == irq which will give gpio bank offset.
Than offset can be used to build mask.

>   
>   	if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
>   		return -EINVAL;
> @@ -458,7 +471,7 @@ static struct irq_chip *keystone_gpio_get_irq_chip(unsigned int irq)
>    * (dm6446) can be set appropriately for GPIOV33 pins.
>    */
>   
> -static int davinci_gpio_irq_setup(struct platform_device *pdev, int bank_irq)


[...]

>   #include <asm-generic/gpio.h>
>   
>   #define MAX_REGS_BANKS		5
> +#define MAX_INT_PER_BANK 32
>   
>   struct davinci_gpio_platform_data {
>   	u32	ngpio;
> @@ -41,7 +42,7 @@ struct davinci_gpio_controller {
>   	spinlock_t		lock;
>   	void __iomem		*regs[MAX_REGS_BANKS];
>   	int			gpio_unbanked;
> -	unsigned int		base_irq;
> +	int			irqs[MAX_INT_PER_BANK];
>   	unsigned int		base;
>   };
>   
> 

-- 
regards,
-grygorii