linux-kernel - Re: [PATCH v4 2/3] reset: Add USB2PHY port reset driver for Renesas RZ/V2H(P)

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Message-ID: <9c32c9aa-3895-4969-8a33-059c4ad93143@oracle.com>
Date: Mon, 14 Apr 2025 19:16:15 +0530
From: ALOK TIWARI <alok.a.tiwari@...cle.com>
To: Prabhakar <prabhakar.csengg@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>
Cc: linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Biju Das <biju.das.jz@...renesas.com>,
        Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v4 2/3] reset: Add USB2PHY port reset driver for Renesas
 RZ/V2H(P)


> +static int rzv2h_usbphy_reset_assert(struct reset_controller_dev *rcdev,
> +				     unsigned long id)
> +{
> +	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
> +	struct device *dev = priv->dev;
> +	int ret;
> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret) {

nit: it will good if we check similar to reset-rzg2l-usbphy-ctrl.c
pm_runtime_resume_and_get -> 0 on success, or a negative error code 
otherwise.
1 → if the device was resumed and incremented usage count
0 → if the device was already active or successfully resumed
if (ret < 0)

> +		dev_err(dev, "pm_runtime_resume_and_get failed\n");
> +		return ret;
> +	}
> +
> +	rzv2h_usbphy_assert_helper(priv);
> +
> +	pm_runtime_put(dev);
> +
> +	return 0;
> +}
> +
> +static int rzv2h_usbphy_reset_deassert(struct reset_controller_dev *rcdev,
> +				       unsigned long id)
> +{
> +	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
> +	const struct rzv2h_usb2phy_reset_of_data *data = priv->data;
> +	struct device *dev = priv->dev;
> +	int ret;
> +
> +	ret = pm_runtime_resume_and_get(dev);

pm_runtime_resume_and_get -> 0 on success, or a negative error code 
otherwise.
if (ret < 0)

> +	if (ret) {
> +		dev_err(dev, "pm_runtime_resume_and_get failed\n");
> +		return ret;
> +	}
> +
> +	scoped_guard(spinlock, &priv->lock) {
> +		writel(data->reset_deassert_val, priv->base + data->reset_reg);
> +		writel(data->reset2_release_val, priv->base + data->reset2_reg);
> +		writel(data->reset_release_val, priv->base + data->reset_reg);
> +	}
> +
> +	pm_runtime_put(dev);
> +
> +	return 0;
> +}
> +
> +static int rzv2h_usbphy_reset_status(struct reset_controller_dev *rcdev,
> +				     unsigned long id)
> +{
> +	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
> +	struct device *dev = priv->dev;
> +	int ret;
> +	u32 reg;
> +
> +	ret = pm_runtime_resume_and_get(dev);

pm_runtime_resume_and_get -> 0 on success, or a negative error code 
otherwise.
if (ret < 0)

> +	if (ret) {
> +		dev_err(dev, "pm_runtime_resume_and_get failed\n");
> +		return ret;
> +	}
> +
> +	reg = readl(priv->base + priv->data->reset_reg);
> +
> +	pm_runtime_put(dev);
> +
> +	return (reg & priv->data->reset_status_bits) == priv->data->reset_status_bits;
> +}
> +
> +static const struct reset_control_ops rzv2h_usbphy_reset_ops = {
> +	.assert = rzv2h_usbphy_reset_assert,
> +	.deassert = rzv2h_usbphy_reset_deassert,
> +	.status = rzv2h_usbphy_reset_status,
> +};
> +
> +static int rzv2h_usb2phy_reset_of_xlate(struct reset_controller_dev *rcdev,
> +					const struct of_phandle_args *reset_spec)
> +{
> +	/* No special handling needed, we have only one reset line per device */
> +	return 0;
> +}
> +
> +static int rzv2h_usb2phy_reset_probe(struct platform_device *pdev)
> +{
> +	const struct rzv2h_usb2phy_reset_of_data *data;
> +	struct rzv2h_usb2phy_reset_priv *priv;
> +	struct device *dev = &pdev->dev;
> +	struct reset_control *rstc;
> +	int error;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	data = of_device_get_match_data(dev);
> +	if (!data)
> +		return dev_err_probe(dev, -ENODEV,
> +				     "failed to match device\n");
> +
> +	priv->data = data;
> +	priv->dev = dev;
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	rstc = devm_reset_control_get_shared_deasserted(dev, NULL);
> +	if (IS_ERR(rstc))
> +		return dev_err_probe(dev, PTR_ERR(rstc),
> +				     "failed to get deasserted reset\n");
> +
> +	spin_lock_init(&priv->lock);
> +	dev_set_drvdata(dev, priv);
> +
> +	error = devm_pm_runtime_enable(dev);
> +	if (error)
> +		return dev_err_probe(dev, error, "Failed to enable pm_runtime\n");
> +
> +	error = pm_runtime_resume_and_get(dev); 

nit: it will good if we check similar to reset-rzg2l-usbphy-ctrl.c
pm_runtime_resume_and_get -> 0 on success, or a negative error code 
otherwise.
if (error < 0)

> +	if (error)
> +		return dev_err_probe(dev, error, "pm_runtime_resume_and_get failed\n");
> +
> +	for (unsigned int i = 0; i < data->init_val_count; i++)
> +		writel(data->init_vals[i].val, priv->base + data->init_vals[i].reg);
> +
> +	/* keep usb2phy in asserted state */
> +	rzv2h_usbphy_assert_helper(priv);
> +
> +	pm_runtime_put(dev);
> +
> +	priv->rcdev.ops = &rzv2h_usbphy_reset_ops;
> +	priv->rcdev.of_reset_n_cells = 0;
> +	priv->rcdev.nr_resets = 1;
> +	priv->rcdev.of_xlate = rzv2h_usb2phy_reset_of_xlate;
> +	priv->rcdev.of_node = dev->of_node;
> +	priv->rcdev.dev = dev;
> +
> +	return devm_reset_controller_register(dev, &priv->rcdev);
> +}
> +


Thanks
Alok