linux-kernel - Re: [PATCH v2 1/1] gpio: mpfs: add polarfire soc gpio support

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Message-ID: <9e00e2cca641b735fe56988ca1eec1aef183f481.camel@microchip.com>
Date:   Wed, 13 Jul 2022 21:00:45 +0000
From:   <Lewis.Hanly@...rochip.com>
To:     <linux-riscv@...ts.infradead.org>, <Conor.Dooley@...rochip.com>,
        <brgl@...ev.pl>, <linux-gpio@...r.kernel.org>,
        <linus.walleij@...aro.org>, <palmer@...belt.com>, <maz@...nel.org>,
        <linux-kernel@...r.kernel.org>
CC:     <Daire.McNamara@...rochip.com>, <Lewis.Hanly@...rochip.com>
Subject: Re: [PATCH v2 1/1] gpio: mpfs: add polarfire soc gpio support

Thanks Conor.

On Wed, 2022-07-13 at 11:26 +0000, Conor Dooley - M52691 wrote:
> Hey Lewis,
> Couple comments.
> 
> On 13/07/2022 11:59, lewis.hanly@...rochip.com wrote:
> > From: Lewis Hanly <lewis.hanly@...rochip.com>
> > 
> > Add a driver to support the Polarfire SoC gpio controller.
> > 
> > Signed-off-by: Lewis Hanly <lewis.hanly@...rochip.com>
> > ---
> >   drivers/gpio/Kconfig     |   9 +
> >   drivers/gpio/Makefile    |   1 +
> >   drivers/gpio/gpio-mpfs.c | 379
> > +++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 389 insertions(+)
> >   create mode 100644 drivers/gpio/gpio-mpfs.c
> > 
> > +
> > +static int mpfs_gpio_probe(struct platform_device *pdev)
> > +{
> > +	struct clk *clk;
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *node = pdev->dev.of_node;
> > +	struct device_node *irq_parent;
> > +	struct gpio_irq_chip *girq;
> > +	struct irq_domain *parent;
> > +	struct mpfs_gpio_chip *mpfs_gpio;
> > +	int i, ret, ngpio;
> > +
> > +	mpfs_gpio = devm_kzalloc(dev, sizeof(*mpfs_gpio), GFP_KERNEL);
> > +	if (!mpfs_gpio)
> > +		return -ENOMEM;
> > +
> > +	mpfs_gpio->base = devm_platform_ioremap_resource(pdev, 0);
> > +	if (IS_ERR(mpfs_gpio->base))
> > +		return PTR_ERR(mpfs_gpio->base);
> > +
> > +	clk = devm_clk_get(&pdev->dev, NULL);
> > +	if (IS_ERR(clk)) {
> > +		dev_err(&pdev->dev, "devm_clk_get failed\n");
> > +		return PTR_ERR(clk);
> > +	}
> > +
> > +	ret = clk_prepare_enable(clk);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "failed to enable clock\n");
> > +		return ret;
> > +	}
> > +
> > +	mpfs_gpio->clk = clk;
> > +
> > +	ngpio = of_irq_count(node);
> > +	if (ngpio > NUM_GPIO) {
> > +		dev_err(dev, "Too many GPIO interrupts (max=%d)\n",
> > +			NUM_GPIO);
> 
> This should fit on one line
Can do.
> 
> > +		ret = -ENXIO;
> > +		goto cleanup_clock;
> > +	}
> > +
> > +	irq_parent = of_irq_find_parent(node);
> > +	if (!irq_parent) {
> > +		dev_err(dev, "no IRQ parent node\n");
> > +		ret = -ENODEV;
> > +		goto cleanup_clock;
> > +	}
> > +	parent = irq_find_host(irq_parent);
> > +	if (!parent) {
> > +		dev_err(dev, "no IRQ parent domain\n");
> > +		ret = -ENODEV;
> > +		goto cleanup_clock;
> > +	}
> > +
> > +	/* Get the interrupt numbers.
> 
> netdev style comment
> 
> > +	 * Clear/Disable All interrupts before enabling parent
> > interrupts.
> > +	 */
> > +	for (i = 0; i < ngpio; i++) {
> > +		mpfs_gpio->irq_number[i] = platform_get_irq(pdev, i);
> 
> You need to handle the case where platform_get_irq returns an error
> right?
Was not going to as I don't think it breaks if error. I will do a
little more checking if required.
> 
> > +		mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, i,
> > 1);
> > +		mpfs_gpio_assign_bit(mpfs_gpio->base + (i *
> > BYTE_BOUNDARY),
> > +				     MPFS_GPIO_EN_INT, 0);
> > +	}
> > +
> > +	raw_spin_lock_init(&mpfs_gpio->lock);
> > +
> > +	mpfs_gpio->gc.direction_input = mpfs_gpio_direction_input;
> > +	mpfs_gpio->gc.direction_output = mpfs_gpio_direction_output;
> > +	mpfs_gpio->gc.get_direction = mpfs_gpio_get_direction;
> > +	mpfs_gpio->gc.get = mpfs_gpio_get;
> > +	mpfs_gpio->gc.set = mpfs_gpio_set;
> > +	mpfs_gpio->gc.base = -1;
> > +	mpfs_gpio->gc.ngpio = ngpio;
> > +	mpfs_gpio->gc.label = dev_name(dev);
> > +	mpfs_gpio->gc.parent = dev;
> > +	mpfs_gpio->gc.owner = THIS_MODULE;
> > +
> > +	/* Get a pointer to the gpio_irq_chip */
> 
> I doubt this comment is needed
OK.
> 
> > +	girq = &mpfs_gpio->gc.irq;
> > +	gpio_irq_chip_set_chip(girq, &mpfs_gpio_irqchip);
> > +	girq->fwnode = of_node_to_fwnode(node);
> > +	girq->parent_domain = parent;
> > +	girq->child_to_parent_hwirq = mpfs_gpio_child_to_parent_hwirq;
> > +	girq->handler = handle_bad_irq;
> > +	girq->default_type = IRQ_TYPE_NONE;
> > +
> > +	ret = gpiochip_add_data(&mpfs_gpio->gc, mpfs_gpio);
> 
> Can we use a devm_ variant instead here...
Maybe, will check.
> 
> > +	if (ret)
> > +		goto cleanup_clock;
> > +
> > +	platform_set_drvdata(pdev, mpfs_gpio);
> > +	dev_info(dev, "Microchip MPFS GPIO registered, ngpio=%d\n",
> > ngpio);
> > +
> > +	return 0;
> > +
> > +cleanup_clock:
> > +	clk_disable_unprepare(mpfs_gpio->clk);
> > +	return ret;
> > +}
> > +
> > +static int mpfs_gpio_remove(struct platform_device *pdev)
> > +{
> > +	struct mpfs_gpio_chip *mpfs_gpio = platform_get_drvdata(pdev);
> > +
> > +	gpiochip_remove(&mpfs_gpio->gc);
> 
> ... and drop this?
eh, OK.
> 
> > +	clk_disable_unprepare(mpfs_gpio->clk);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id mpfs_gpio_match[] = {
> > +	{ .compatible = "microchip,mpfs-gpio", },
> > +	{ /* end of list */ },
> 
> Don't need a comma after the sentinel
OK.
> 
> > +};
> > +
> > +static struct platform_driver mpfs_gpio_driver = {
> > +	.probe = mpfs_gpio_probe,
> > +	.driver = {
> > +		.name = "microchip,mpfs-gpio",
> > +		.of_match_table = of_match_ptr(mpfs_gpio_match),
> > +	},
> > +	.remove = mpfs_gpio_remove,
> > +};
> > +builtin_platform_driver(mpfs_gpio_driver)
> 
> Mising semicolon?
Can add..
> 
> Thanks,
> Conor.