linux-kernel - Re: [PATCH V2 10/12] gpio: tegra: implement wake event support for Tegra210 and prior GPIO

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Date:   Sat, 1 Jun 2019 01:28:44 -0700
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Thierry Reding <thierry.reding@...il.com>
CC:     <jonathanh@...dia.com>, <tglx@...utronix.de>,
        <jason@...edaemon.net>, <marc.zyngier@....com>,
        <linus.walleij@...aro.org>, <stefan@...er.ch>,
        <mark.rutland@....com>, <pdeschrijver@...dia.com>,
        <pgaikwad@...dia.com>, <sboyd@...nel.org>,
        <linux-clk@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        <jckuo@...dia.com>, <josephl@...dia.com>, <talho@...dia.com>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <mperttunen@...dia.com>, <spatra@...dia.com>, <robh+dt@...nel.org>,
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH V2 10/12] gpio: tegra: implement wake event support for
 Tegra210 and prior GPIO


On 5/29/19 7:03 AM, Thierry Reding wrote:
> On Tue, May 28, 2019 at 04:08:54PM -0700, Sowjanya Komatineni wrote:
>> The GPIO controller doesn't have any controls to enable the system to
>> wake up from low power states based on activity on GPIO pins. An extra
>> hardware block that is part of the power management controller (PMC)
>> contains these controls. In order for the GPIO controller to be able
>> to cooperate with the PMC, obtain a reference to the PMC's IRQ domain
>> and make it a parent to the GPIO controller's IRQ domain. This way the
>> PMC gets an opportunity to program the additional registers required
>> to enable wakeup sources on suspend.
>>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>> ---
>>   drivers/gpio/gpio-tegra.c | 116 +++++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 110 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpio/gpio-tegra.c b/drivers/gpio/gpio-tegra.c
>> index 6d9b6906b9d0..5190129668d3 100644
>> --- a/drivers/gpio/gpio-tegra.c
>> +++ b/drivers/gpio/gpio-tegra.c
>> @@ -32,6 +32,8 @@
>>   #include <linux/pinctrl/consumer.h>
>>   #include <linux/pm.h>
>>   
>> +#include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>>   #define GPIO_BANK(x)		((x) >> 5)
>>   #define GPIO_PORT(x)		(((x) >> 3) & 0x3)
>>   #define GPIO_BIT(x)		((x) & 0x7)
>> @@ -275,8 +277,22 @@ static int tegra_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
>>   static int tegra_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
>>   {
>>   	struct tegra_gpio_info *tgi = gpiochip_get_data(chip);
>> +	struct irq_domain *domain = tgi->irq_domain;
>> +
>> +	if (!gpiochip_irqchip_irq_valid(chip, offset))
>> +		return -ENXIO;
>> +
>> +	if (irq_domain_is_hierarchy(domain)) {
>> +		struct irq_fwspec spec;
>> +
>> +		spec.fwnode = domain->fwnode;
>> +		spec.param_count = 2;
>> +		spec.param[0] = offset;
>> +		spec.param[1] = IRQ_TYPE_NONE;
>> +		return irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, &spec);
> This looks like it was copied from the equivalent Tegra186 patch. I have
> since then changed the implementation, based on feedback by Linus, to
> not call irq_domain_alloc_irqs() here and instead call
> irq_create_fwspec_mapping(). This has the advantage of not requiring the
> irq_domain_alloc_irqs() function to be exported. It ends up calling that
> function internally, but as discussed with Linus it's also a nicer way
> to create these mappings.
>
existing gpio-tegra driver maps hwirq to virtual interrupt number using 
irq_create_mapping during gpio probe

and irq_create_fwspec_mapping() will always return virq number as virq 
number exists already and irq_domain_alloc_irqs doesn't happen.

So I was using irq_domain_alloc_irqs().


>> +	}
>>   
>> -	return irq_find_mapping(tgi->irq_domain, offset);
>> +	return irq_find_mapping(domain, offset);
>>   }
>>   
>>   static void tegra_gpio_irq_ack(struct irq_data *d)
>> @@ -365,7 +381,10 @@ static int tegra_gpio_irq_set_type(struct irq_data *d, unsigned int type)
>>   	else if (type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
>>   		irq_set_handler_locked(d, handle_edge_irq);
>>   
>> -	return 0;
>> +	if (d->parent_data)
>> +		return irq_chip_set_type_parent(d, type);
>> +	else
>> +		return 0;
> There's no need for this final else. Just make it a regular "return 0;"
> at the end of the function, without the extra else branch.
>
>>   }
>>   
>>   static void tegra_gpio_irq_shutdown(struct irq_data *d)
>> @@ -503,6 +522,7 @@ static int tegra_gpio_irq_set_wake(struct irq_data *d, unsigned int enable)
>>   	struct tegra_gpio_bank *bank = irq_data_get_irq_chip_data(d);
>>   	unsigned int gpio = d->hwirq;
>>   	u32 port, bit, mask;
>> +	int ret;
>>   
>>   	port = GPIO_PORT(gpio);
>>   	bit = GPIO_BIT(gpio);
>> @@ -513,7 +533,14 @@ static int tegra_gpio_irq_set_wake(struct irq_data *d, unsigned int enable)
>>   	else
>>   		bank->wake_enb[port] &= ~mask;
>>   
>> -	return irq_set_irq_wake(bank->irq, enable);
>> +	ret = irq_set_irq_wake(bank->irq, enable);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (d->parent_data)
>> +		return irq_chip_set_wake_parent(d, enable);
>> +	else
>> +		return 0;
> Same here.
>
> Thierry