linux-kernel - Re: [PATCH 2/2] irqchip: Add a driver for the Microsemi Ocelot controller

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Date:   Tue, 20 Mar 2018 15:03:14 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
cc:     Marc Zyngier <marc.zyngier@....com>,
        Jason Cooper <jason@...edaemon.net>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] irqchip: Add a driver for the Microsemi Ocelot
 controller

On Tue, 20 Mar 2018, Alexandre Belloni wrote:
> --- /dev/null
> +++ b/drivers/irqchip/irq-mscc-ocelot.c
> @@ -0,0 +1,109 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Microsemi Ocelot IRQ controller driver
> + *
> + * License: Dual MIT/GPL

The whole point of SPDX identifiers is to get rid of this kind of sloppy
and inexact license references. The SPDX identifier above is clear and
precise: The code is dual licensed under GPL V2 only or MIT.

Now looking again at your extra line:

> + * License: Dual MIT/GPL

It does not tell which version of GPL.

Please get rid of that.

> + * Copyright (c) 2017 Microsemi Corporation
> + */
> +#include <linux/bitops.h>
> +#include <linux/irq.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/interrupt.h>
> +
> +#define ICPU_CFG_INTR_INTR_STICKY	0x10
> +#define ICPU_CFG_INTR_INTR_ENA		0x18
> +#define ICPU_CFG_INTR_INTR_ENA_CLR	0x1c
> +#define ICPU_CFG_INTR_INTR_ENA_SET	0x20
> +#define ICPU_CFG_INTR_DST_INTR_IDENT(x)	(0x38 + 0x4 * (x))
> +#define ICPU_CFG_INTR_INTR_TRIGGER(x)	(0x5c + 0x4 * (x))
> +
> +#define OCELOT_NR_IRQ 24
> +
> +static void ocelot_irq_unmask(struct irq_data *data)
> +{
> +	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
> +	struct irq_chip_type *ct = irq_data_get_chip_type(data);
> +	unsigned int mask = data->mask;
> +	u32 val;
> +
> +	irq_gc_lock(gc);
> +	val = irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(0)) |
> +	      irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(1));
> +	if ((val & mask) == 0)

Usual kernel style is:

	if (!(val & mask))

> +		irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_STICKY);
> +
> +	*ct->mask_cache &= ~mask;
> +	irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_ENA_SET);
> +	irq_gc_unlock(gc);
> +}

> +
> +	irq_reg_writel(gc, 0, ICPU_CFG_INTR_INTR_ENA); /* Mask all */
> +	irq_reg_writel(gc, 0xffffffff, ICPU_CFG_INTR_INTR_STICKY); /* Ack pending */

Please do not use tail comments. They are annoying as they disturb the
visual parsing.

       /* Mask and ack all interrupts */
	irq_reg_writel(gc, 0, ICPU_CFG_INTR_INTR_ENA);
	irq_reg_writel(gc, 0xffffffff, ICPU_CFG_INTR_INTR_STICKY);

is way better to read.

Other than those nitpicks. Nice work!

Thanks,

	tglx