Re: [PATCH RfC v4 5/6] pinctrl: meson: add support for GPIO interrupts

[Heiner Kallweit <hkallweit1@xxxxxxxxx>]

Am 29.05.2017 um 10:43 schrieb Neil Armstrong:
> Hi Heiner,
> 
> On 05/28/2017 09:12 PM, Heiner Kallweit wrote:
>> Add support for GPIO interrupts and make use of the just introduced
>> irqchip driver handling the GPIO interrupt-controller.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
>> ---
>>  drivers/pinctrl/Kconfig               |   2 +
>>  drivers/pinctrl/meson/pinctrl-meson.c | 164 +++++++++++++++++++++++++++++++++-
>>  2 files changed, 165 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
>> index abc1cef7..d8c92809 100644
>> --- a/drivers/pinctrl/Kconfig
>> +++ b/drivers/pinctrl/Kconfig
>> @@ -166,8 +166,10 @@ config PINCTRL_MESON
>>  	select PINCONF
>>  	select GENERIC_PINCONF
>>  	select GPIOLIB
>> +	select GPIOLIB_IRQCHIP
>>  	select OF_GPIO
>>  	select REGMAP_MMIO
>> +	select MESON_GPIO_INTC
> 
> This should not be here, there is not "compile-time" dependency.
> 
>>  
>>  config PINCTRL_OXNAS
>>  	bool
>> diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
>> index 66ed70c1..7fb98c71 100644
>> --- a/drivers/pinctrl/meson/pinctrl-meson.c
>> +++ b/drivers/pinctrl/meson/pinctrl-meson.c
>> @@ -62,6 +62,8 @@
>>  #include "../pinctrl-utils.h"
>>  #include "pinctrl-meson.h"
>>  
>> +static struct irq_domain *meson_pinctrl_irq_domain;
>> +
>>  /**
>>   * meson_get_bank() - find the bank containing a given pin
>>   *
>> @@ -497,6 +499,150 @@ static int meson_gpio_get(struct gpio_chip *chip, unsigned gpio)
>>  	return !!(val & BIT(bit));
>>  }
>>  
>> +static struct meson_pinctrl *meson_gpio_data_to_pc(struct irq_data *data)
>> +{
>> +        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
>> +
>> +        return gpiochip_get_data(chip);
>> +}
>> +
>> +static int meson_gpio_bank_hwirq(struct meson_bank *bank, unsigned int offset)
>> +{
>> +        int hwirq;
>> +
>> +        if (bank->irq_first < 0)
>> +                /* this bank cannot generate irqs */
>> +                return 0;
>> +
>> +        hwirq = offset - bank->first + bank->irq_first;
>> +
>> +        if (hwirq > bank->irq_last)
>> +                /* this pin cannot generate irqs */
>> +                return 0;
>> +
>> +        return hwirq;
>> +}
>> +
>> +static int meson_gpio_to_hwirq(struct irq_data *data)
>> +{
>> +	struct meson_pinctrl *pc = meson_gpio_data_to_pc(data);
>> +	unsigned int offset = data->hwirq;
>> +        struct meson_bank *bank;
>> +        int hwirq, ret;
>> +
>> +        offset += pc->data->pin_base;
>> +
>> +        ret = meson_get_bank(pc, offset, &bank);
>> +        if (ret)
>> +                return ret;
>> +
>> +        hwirq = meson_gpio_bank_hwirq(bank, offset);
>> +        if (!hwirq)
>> +                dev_dbg(pc->dev, "no interrupt for pin %u\n", offset);
>> +
>> +        return hwirq;
>> +}
>> +
>> +static void meson_gpio_irq_handler(struct irq_desc *desc)
>> +{
>> +        struct irq_chip *chip = irq_desc_get_chip(desc);
>> +        struct irq_data *gpio_irq_data = irq_desc_get_handler_data(desc);
>> +
>> +        chained_irq_enter(chip, desc);
>> +
>> +        if (gpio_irq_data)
>> +                generic_handle_irq(gpio_irq_data->irq);
>> +
>> +        chained_irq_exit(chip, desc);
>> +}
>> +
>> +static void meson_gpio_irq_unmask(struct irq_data *data) {}
>> +static void meson_gpio_irq_mask(struct irq_data *data) {}
>> +
>> +static void meson_gpio_irq_shutdown(struct irq_data *data)
>> +{
>> +	int hwirq = meson_gpio_to_hwirq(data);
>> +	int irq;
>> +
>> +	if (hwirq <= 0)
>> +		return;
>> +
>> +	irq = irq_find_mapping(meson_pinctrl_irq_domain, hwirq * 2);
>> +	if (irq) {
>> +		irq_set_chained_handler_and_data(irq, handle_bad_irq, NULL);
>> +		irq_domain_free_irqs(irq, 1);
>> +	}
>> +	irq = irq_find_mapping(meson_pinctrl_irq_domain, hwirq * 2 + 1);
>> +	if (irq) {
>> +		irq_set_chained_handler_and_data(irq, handle_bad_irq, NULL);
>> +		irq_domain_free_irqs(irq, 1);
>> +	}
> 
> Same as irqchip, please add paragraph explaining why you use *2 here to handle the
> IRQ_BOTH situation.
> 
>> +}
>> +
>> +static int meson_gpio_irq_set_type(struct irq_data *data, unsigned int type)
>> +{
>> +	int hwirq = meson_gpio_to_hwirq(data);
>> +	struct irq_fwspec fwspec;
>> +        int irq, irq2, num_slots;
>> +
>> +	if (irqd_is_activated(data))
>> +		return -EBUSY;
>> +
>> +	if (hwirq < 0)
>> +		return hwirq;
>> +
>> +	if (!hwirq)
>> +		return -ENXIO;
>> +
>> +	fwspec.fwnode = meson_pinctrl_irq_domain->fwnode;
>> +	fwspec.param_count = 2;
>> +
>> +        /*
>> +         * The chip can create an interrupt for either rising or falling edge
>> +         * only. Therefore use two interrupts in case of IRQ_TYPE_EDGE_BOTH,
>> +         * first for falling edge and second one for rising edge.
>> +         */
>> +        num_slots = (type == IRQ_TYPE_EDGE_BOTH) ? 2 : 1;
>> +
>> +        /*
> 
> Please correct indentation.
> 
>> +	 * Add one bit to hwirq to allow for
>> +	 * - using the same gpio hwirq twice
>> +	 * - decoding the gpio hwirq in the interrupt controller driver
>> +         */
>> +	fwspec.param[0] = hwirq << 1;
>> +	if (num_slots == 1)
>> +		fwspec.param[1] = type;
>> +	else
>> +		fwspec.param[1] = IRQ_TYPE_EDGE_FALLING;
>> +
>> +	irq = irq_create_fwspec_mapping(&fwspec);
>> +	if (!irq)
>> +		return -EINVAL;
>> +
>> +	irq_set_chained_handler_and_data(irq, meson_gpio_irq_handler, data);
>> +
>> +	if (num_slots > 1) {
>> +		fwspec.param[0]++;
>> +		fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
>> +		irq2 = irq_create_fwspec_mapping(&fwspec);
>> +		if (!irq2) {
>> +			irq_domain_free_irqs(irq, 1);
>> +			return -EINVAL;
>> +		}
>> +		irq_set_chained_handler_and_data(irq2, meson_gpio_irq_handler, data);
>> +	}
>> +
>> +        return 0;
>> +}
> 
> You will have an irq leak if you chance twice of type in the same GPIO from BOTH to Edge/Level.
> 
I'm not sure I get your point.
This function is called once for a GPIO IRQ, typically within request_irq()
based on the type flags (provided that gpio_to_irq is used).
And I don't change the type from BOTH to something, I create two parent irq's
with type RISING/FALLING.

>> +
>> +static struct irq_chip meson_gpio_irq_chip = {
>> +        .name = "GPIO",
>> +        .irq_set_type = meson_gpio_irq_set_type,
>> +        .irq_mask = meson_gpio_irq_mask,
>> +        .irq_unmask = meson_gpio_irq_unmask,
>> +        .irq_shutdown = meson_gpio_irq_shutdown,
>> +};
>> +
>>  static const struct of_device_id meson_pinctrl_dt_match[] = {
>>  	{
>>  		.compatible = "amlogic,meson8-cbus-pinctrl",
>> @@ -558,7 +704,8 @@ static int meson_gpiolib_register(struct meson_pinctrl *pc)
>>  		return ret;
>>  	}
>>  
>> -	return 0;
>> +	return gpiochip_irqchip_add(&pc->chip, &meson_gpio_irq_chip, 0,
>> +				    handle_simple_irq, IRQ_TYPE_NONE);
>>  }
>>  
>>  static struct regmap_config meson_regmap_config = {
>> @@ -637,6 +784,21 @@ static int meson_pinctrl_parse_dt(struct meson_pinctrl *pc,
>>  		return PTR_ERR(pc->reg_gpio);
>>  	}
>>  
>> +	if (!meson_pinctrl_irq_domain) {
>> +		np = of_find_compatible_node(NULL, NULL, "amlogic,meson-gpio-intc");
>> +		if (!np) {
>> +			dev_err(pc->dev, "interrupt controller DT node not found\n");
>> +			return -EINVAL;
>> +		}
>> +		meson_pinctrl_irq_domain = irq_find_host(np);
>> +		if (!meson_pinctrl_irq_domain) {
>> +			dev_err(pc->dev, "interrupt controller not found\n");
>> +			of_node_put(np);
>> +			return -EINVAL;
>> +		}
>> +		of_node_put(np);
>> +	}
> 
> Please add some blank lines between logical sections of the code.
> 
>> +
>>  	return 0;
>>  }
>>  
>>
> 
> Thanks,
> Neil
> 

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