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

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Date:   Wed, 13 Jun 2018 06:48:32 +0530
From:   "J, KEERTHY" <j-keerthy@...com>
To:     Grygorii Strashko <grygorii.strashko@...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 6/13/2018 6:36 AM, J, KEERTHY wrote:
> 
> 
> On 6/13/2018 1:36 AM, Grygorii Strashko wrote:
>>
>>
>> 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.
> 
> Agreed.

-       mask = __gpio_mask(data->irq - d->base_irq);
+       for (i = 0; i < MAX_INT_PER_BANK; i++)
+               if (data->irq == d->irqs[i])
+                       break;
+
+       if (i == MAX_INT_PER_BANK)
+               return -EINVAL;
+
+       mask = __gpio_mask(i);

I believe the above snippet works for non-sequential IRQs.

> 
>>
>>>        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;
>>>    };
>>>
>>