linux-kernel - Re: [PATCH RFC 07/14] genirq: Introduce irq_chip_get/set_parent

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Date:   Thu, 05 Sep 2019 17:35:58 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Lina Iyer <ilina@...eaurora.org>, evgreen@...omium.org,
        linus.walleij@...aro.org, marc.zyngier@....com
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        bjorn.andersson@...aro.org, mkshah@...eaurora.org,
        linux-gpio@...r.kernel.org, rnayak@...eaurora.org
Subject: Re: [PATCH RFC 07/14] genirq: Introduce irq_chip_get/set_parent_state calls

Quoting Lina Iyer (2019-08-29 11:11:56)
> From: Maulik Shah <mkshah@...eaurora.org>
> 
> On certain QTI chipsets some GPIOs are direct-connect interrupts
> to the GIC.
> 
> Even when GPIOs are not used for interrupt generation and interrupt
> line is disabled, it does not prevent interrupt to get pending at
> GIC_ISPEND. When drivers call enable_irq unwanted interrupt occures.

Inidicate functions with parenthesis like enable_irq().

> 
> Introduce irq_chip_get/set_parent_state calls to clear pending irq
> which can get called within irq_enable of child irq chip to clear
> any pending irq before enabling.

This sentence is hard to read.

> 
> index b76703b2c0af..6bb5b22bb0a7 100644
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -1297,6 +1297,50 @@ EXPORT_SYMBOL_GPL(handle_fasteoi_mask_irq);
>  
>  #endif /* CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS */
>  
> +/**
> + *     irq_chip_set_parent_state - set the state of a parent interrupt.
> + *     @data: Pointer to interrupt specific data
> + *     @which: State to be restored (one of IRQCHIP_STATE_*)
> + *     @val: Value corresponding to @which
> + *
> + */
> +int irq_chip_set_parent_state(struct irq_data *data,
> +                             enum irqchip_irq_state which,
> +                             bool val)
> +{
> +       data = data->parent_data;
> +       if (!data)
> +               return 0;
> +
> +       if (data->chip->irq_set_irqchip_state)
> +               return data->chip->irq_set_irqchip_state(data, which, val);
> +
> +       return 0;

How about 

	if (!data || !data->chip->irq_set_irqchip_state)
		return 0;
	
	return data->chip->irq_set_irqchip_state(...)

> +}
> +EXPORT_SYMBOL(irq_chip_set_parent_state);
> +
> +/**
> + *     irq_chip_get_parent_state - get the state of a parent interrupt.

Why is this indented so much?

> + *     @data: Pointer to interrupt specific data
> + *     @which: one of IRQCHIP_STATE_* the caller wants to know
> + *     @state: a pointer to a boolean where the state is to be stored
> + *

Document return value?

> + */
> +int irq_chip_get_parent_state(struct irq_data *data,
> +                             enum irqchip_irq_state which,
> +                             bool *state)
> +{
> +       data = data->parent_data;
> +       if (!data)
> +               return 0;
> +
> +       if (data->chip->irq_get_irqchip_state)
> +               return data->chip->irq_get_irqchip_state(data, which, state);
> +

Same comment here about collapsing logic.

> +       return 0;
> +}
> +EXPORT_SYMBOL(irq_chip_get_parent_state);

Please make these symbols _GPL.

> +
>  /**
>   * irq_chip_enable_parent - Enable the parent interrupt (defaults to unmask if
>   * NULL)