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

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Date:   Wed, 13 Jul 2022 11:26:17 +0000
From:   <Conor.Dooley@...rochip.com>
To:     <Lewis.Hanly@...rochip.com>, <linux-gpio@...r.kernel.org>,
        <linux-riscv@...ts.infradead.org>, <linus.walleij@...aro.org>,
        <brgl@...ev.pl>, <linux-kernel@...r.kernel.org>,
        <palmer@...belt.com>, <maz@...nel.org>
CC:     <Conor.Dooley@...rochip.com>, <Daire.McNamara@...rochip.com>
Subject: Re: [PATCH v2 1/1] gpio: mpfs: add polarfire soc gpio support

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

> +		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?

> +		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

> +	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...

> +	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?

> +	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

> +};
> +
> +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?

Thanks,
Conor.