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From:   Punit Agrawal <punit1.agrawal@toshiba.co.jp>
To:     Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-gpio@vger.kernel.org, yuji2.ishikawa@toshiba.co.jp,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 2/4] gpio: visconti: Add Toshiba Visconti GPIO support
References: <20201201181406.2371881-1-nobuhiro1.iwamatsu@toshiba.co.jp>
        <20201201181406.2371881-3-nobuhiro1.iwamatsu@toshiba.co.jp>
Date:   Thu, 03 Dec 2020 19:03:27 +0900
In-Reply-To: <20201201181406.2371881-3-nobuhiro1.iwamatsu@toshiba.co.jp>
        (Nobuhiro Iwamatsu's message of "Wed, 2 Dec 2020 03:14:04 +0900")
Message-ID: <87mtyv4368.fsf@kokedama.swc.toshiba.co.jp>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux)
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Precedence: bulk

Hi Iwamatsu-san,

A couple of very minor comments below -

Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> writes:

> Add the GPIO driver for Toshiba Visconti ARM SoCs.
>
> Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
> ---
>  drivers/gpio/Kconfig                      |   9 +
>  drivers/gpio/Makefile                     |   1 +
>  drivers/gpio/gpio-visconti.c              | 232 ++++++++++++++++++++++
>  drivers/pinctrl/visconti/pinctrl-common.c |  23 +++
>  4 files changed, 265 insertions(+)
>  create mode 100644 drivers/gpio/gpio-visconti.c
>

[...]

> diff --git a/drivers/gpio/gpio-visconti.c b/drivers/gpio/gpio-visconti.c
> new file mode 100644
> index 000000000000..17e6da161f48
> --- /dev/null
> +++ b/drivers/gpio/gpio-visconti.c
> @@ -0,0 +1,232 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Toshiba Visconti GPIO Support
> + *
> + * (C) Copyright 2020 Toshiba Electronic Devices & Storage Corporation
> + * (C) Copyright 2020 Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
> + */
> +
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/of.h>
> +#include <linux/bitops.h>
> +
> +/* register offset */
> +#define GPIO_DIR	0x00
> +#define GPIO_IDATA	0x08
> +#define GPIO_ODATA	0x10
> +#define GPIO_OSET	0x18
> +#define GPIO_OCLR	0x20
> +#define GPIO_INTMODE	0x30
> +
> +#define VISCONTI_GPIO_NR	32

The macro doesn't seem to be used. Can we drop this? On the other hand
should there be a macro to indicate the maximum number of GPIO lines
that support interrupt (16)?

> +
> +struct visconti_gpio {
> +	void __iomem *base;
> +	int *irq;
> +	spinlock_t lock; /* protect gpio register */
> +	struct device *dev;
> +	struct gpio_chip gpio_chip;
> +	struct irq_chip irq_chip;
> +};
> +
> +static void visconti_gpio_irq_mask(struct irq_data *d)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct visconti_gpio *priv = gpiochip_get_data(gc);
> +
> +	disable_irq_nosync(priv->irq[irqd_to_hwirq(d)]);
> +}
> +
> +static void visconti_gpio_irq_unmask(struct irq_data *d)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct visconti_gpio *priv = gpiochip_get_data(gc);
> +
> +	enable_irq(priv->irq[irqd_to_hwirq(d)]);
> +}
> +
> +static int visconti_gpio_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct visconti_gpio *priv = gpiochip_get_data(gc);
> +	u32 offset = irqd_to_hwirq(d);
> +	u32 bit = BIT(offset);
> +	u32 intc_type = IRQ_TYPE_EDGE_RISING;
> +	u32 intmode, odata;
> +	int ret = 0;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	odata = readl(priv->base + GPIO_ODATA);
> +	intmode = readl(priv->base + GPIO_INTMODE);
> +
> +	switch (type) {
> +	case IRQ_TYPE_EDGE_RISING:
> +		odata &= ~bit;
> +		intmode &= ~bit;
> +		break;
> +	case IRQ_TYPE_EDGE_FALLING:
> +		odata |= bit;
> +		intmode &= ~bit;
> +		break;
> +	case IRQ_TYPE_EDGE_BOTH:
> +		intmode |= bit;
> +		break;
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		intc_type = IRQ_TYPE_LEVEL_HIGH;
> +		odata &= ~bit;
> +		intmode &= ~bit;
> +		break;
> +	case IRQ_TYPE_LEVEL_LOW:
> +		intc_type = IRQ_TYPE_LEVEL_HIGH;
> +		odata |= bit;
> +		intmode &= ~bit;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	writel(odata, priv->base + GPIO_ODATA);
> +	writel(intmode, priv->base + GPIO_INTMODE);
> +	irq_set_irq_type(priv->irq[offset], intc_type);
> +err:
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +}
> +
> +static irqreturn_t visconti_gpio_irq_handler(int irq, void *dev_id)
> +{
> +	struct visconti_gpio *priv = dev_id;
> +	u32 offset = irq - priv->irq[0];
> +
> +	generic_handle_irq(irq_find_mapping(priv->gpio_chip.irq.domain, offset));
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void visconti_init_irq_valid_mask(struct gpio_chip *chip, unsigned long *valid_mask,
> +					 unsigned int ngpios)
> +{
> +	int i;
> +
> +	/* Exclude GPIO pins 16-31 from irq */
> +	for (i = 16; i < ngpios; i++)
> +		clear_bit(i, valid_mask);
> +}
> +
> +static int visconti_gpio_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct visconti_gpio *priv;
> +	struct irq_chip *irq_chip;
> +	struct irq_desc *desc;
> +	struct gpio_irq_chip *girq;
> +	const char *name = dev_name(dev);
> +	int i, ret, num_irq;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +	spin_lock_init(&priv->lock);
> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	ret = platform_irq_count(pdev);
> +	if (!ret) {
> +		dev_err(dev, "Couldn't determine # GPIO banks\n");
> +		return -ENOENT;
> +	}

platform_irq_count() can return -EPROBE_DEFER. Is that something that
should be handled?

With the above two comments addressed, feel free to add 

Reviewed-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp>

Thanks,
Punit


> +	num_irq = ret;
> +
> +	priv->irq = devm_kcalloc(dev, num_irq, sizeof(priv->irq), GFP_KERNEL);
> +	if (!priv->irq)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_irq; i++) {
> +		priv->irq[i] = platform_get_irq(pdev, i);
> +		if (priv->irq[i] < 0) {
> +			dev_err(dev, "invalid IRQ[%d]\n", i);
> +			return priv->irq[i];
> +		}
> +	}
> +
> +	ret = bgpio_init(&priv->gpio_chip, dev, 4,
> +			 priv->base + GPIO_IDATA,
> +			 priv->base + GPIO_OSET,
> +			 priv->base + GPIO_OCLR,
> +			 priv->base + GPIO_DIR,
> +			 NULL,
> +			 0);
> +	if (ret) {
> +		dev_err(dev, "unable to init generic GPIO\n");
> +		return ret;
> +	}
> +
> +	priv->gpio_chip.irq.init_valid_mask = visconti_init_irq_valid_mask;
> +
> +	irq_chip = &priv->irq_chip;
> +	irq_chip->name = "gpio-visconti";
> +	irq_chip->irq_mask = visconti_gpio_irq_mask;
> +	irq_chip->irq_unmask = visconti_gpio_irq_unmask;
> +	irq_chip->irq_set_type = visconti_gpio_irq_set_type;
> +	irq_chip->flags = IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND;
> +
> +	girq = &priv->gpio_chip.irq;
> +	girq->chip = irq_chip;
> +	/* This will let us handle the parent IRQ in the driver */
> +	girq->parent_handler = NULL;
> +	girq->num_parents = 0;
> +	girq->parents = NULL;
> +	girq->default_type = IRQ_TYPE_NONE;
> +	girq->handler = handle_level_irq;
> +
> +	ret = devm_gpiochip_add_data(dev, &priv->gpio_chip, priv);
> +	if (ret) {
> +		dev_err(dev, "failed to add GPIO chip\n");
> +		return ret;
> +	}
> +
> +	for (i = 0; i < num_irq; i++) {
> +		desc = irq_to_desc(priv->irq[i]);
> +		desc->status_use_accessors |= IRQ_NOAUTOEN;
> +		if (devm_request_irq(dev, priv->irq[i],
> +				     visconti_gpio_irq_handler, 0, name, priv)) {
> +			dev_err(dev, "failed to request IRQ[%d]\n", i);
> +			return -ENOENT;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id visconti_gpio_of_match[] = {
> +	{ .compatible = "toshiba,gpio-tmpv7708", },
> +	{ /* end of table */ }
> +};
> +MODULE_DEVICE_TABLE(of, visconti_gpio_of_match);
> +
> +static struct platform_driver visconti_gpio_driver = {
> +	.probe		= visconti_gpio_probe,
> +	.driver		= {
> +		.name	= "visconti_gpio",
> +		.of_match_table = of_match_ptr(visconti_gpio_of_match),
> +	}
> +};
> +module_platform_driver(visconti_gpio_driver);
> +
> +MODULE_AUTHOR("Toshiba Electronic Devices & Storage Corporation");
> +MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>");
> +MODULE_DESCRIPTION("Toshiba Visconti GPIO Driver");
> +MODULE_LICENSE("GPL v2");

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