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Date:   Sun, 23 Aug 2020 21:36:37 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     "Ramuthevar,Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, kishon@...com,
        devicetree@...r.kernel.org, robh+dt@...nel.org,
        gregkh@...uxfoundation.org, p.zabel@...gutronix.de,
        balbi@...nel.org, andriy.shevchenko@...el.com,
        cheol.yong.kim@...el.com, qi-ming.wu@...el.com, yin1.li@...el.com
Subject: Re: [RESEND PATCH v8 2/2] phy: Add USB3 PHY support for Intel LGM SoC

On 17-08-20, 15:05, Ramuthevar,Vadivel MuruganX wrote:
> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
> 
> Add support for USB PHY on Intel LGM SoC.
> 
> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
> Reviewed-by: Philipp Zabel <p.zabel@...gutronix.de>
> ---
>  drivers/phy/Kconfig       |  11 ++
>  drivers/phy/Makefile      |   1 +
>  drivers/phy/phy-lgm-usb.c | 278 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 290 insertions(+)
>  create mode 100644 drivers/phy/phy-lgm-usb.c
> 
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index de9362c25c07..01b53f86004c 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -49,6 +49,17 @@ config PHY_XGENE
>  	help
>  	  This option enables support for APM X-Gene SoC multi-purpose PHY.
>  
> +config USB_LGM_PHY
> +	tristate "INTEL Lightning Mountain USB PHY Driver"
> +	depends on USB_SUPPORT

Why is the dependent on USB..? Should that not be other way around?

> +static int get_flipped(struct tca_apb *ta, bool *flipped)
> +{
> +	union extcon_property_value property;
> +	int ret;
> +
> +	ret = extcon_get_property(ta->phy.edev, EXTCON_USB_HOST,
> +				  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
> +	if (ret) {
> +		dev_err(ta->phy.dev, "no polarity property from extcon\n");
> +		return ret;
> +	}
> +
> +	*flipped = property.intval;
> +
> +	return ret;

return 0 here?

> +static int phy_init(struct usb_phy *phy)
> +{
> +	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
> +	void __iomem *ctrl1 = phy->io_priv + CTRL1_OFFSET;
> +	int val, ret, i;
> +
> +	if (ta->phy_initialized)
> +		return 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
> +		reset_control_deassert(ta->resets[i]);
> +
> +	ret = readl_poll_timeout(ctrl1, val, val & SRAM_INIT_DONE, 10, 10 * 1000);
> +	if (ret) {
> +		dev_err(ta->phy.dev, "SRAM init failed, 0x%x\n", val);
> +		return ret;
> +	}
> +
> +	writel(readl(ctrl1) | SRAM_EXT_LD_DONE, ctrl1);
> +
> +	ta->phy_initialized = true;
> +	if (!ta->phy.edev) {
> +		writel(TCPC_CONN, ta->phy.io_priv + TCPC_OFFSET);
> +		return phy->set_vbus(phy, true);
> +	}
> +
> +	schedule_work(&ta->wk);

why work for init?

> +static void tca_work(struct work_struct *work)
> +{
> +	struct tca_apb *ta = container_of(work, struct tca_apb, wk);
> +	bool connected;
> +	bool flipped = false;
> +	u32 val;
> +	int ret;
> +
> +	ret = get_flipped(ta, &flipped);

so every time this work is scheduled you are reading from firmware, why..
Typically we should read in probe and store it..

> +	connected = extcon_get_state(ta->phy.edev, EXTCON_USB_HOST) && !ret;

lets handle ret and extcon_get_state separately please

> +	if (connected == ta->connected)
> +		return;
> +
> +	ta->connected = connected;
> +	if (connected) {
> +		val = TCPC_CONN;
> +		if (flipped)
> +			val |= TCPC_FLIPPED;
> +		dev_info(ta->phy.dev, "connected%s\n", flipped ? " flipped" : "");

debug perhaps

> +	} else {
> +		val = TCPC_DISCONN;
> +		dev_info(ta->phy.dev, "disconnected\n");

here too

> +static int vbus_notifier(struct notifier_block *nb, unsigned long evnt, void *ptr)
> +{
> +	return NOTIFY_DONE;
> +}

empty notifier, why bother?

> +static int phy_probe(struct platform_device *pdev)
> +{
> +	struct reset_control *resets[ARRAY_SIZE(CTL_RESETS)];
> +	struct device *dev = &pdev->dev;
> +	struct usb_phy *phy;
> +	struct tca_apb *ta;
> +	int i;
> +
> +	ta = devm_kzalloc(dev, sizeof(*ta), GFP_KERNEL);
> +	if (!ta)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, ta);
> +	INIT_WORK(&ta->wk, tca_work);
> +
> +	phy = &ta->phy;
> +	phy->dev = dev;
> +	phy->label = dev_name(dev);
> +	phy->type = USB_PHY_TYPE_USB3;
> +	phy->init = phy_init;
> +	phy->shutdown = phy_shutdown;
> +	phy->set_vbus = phy_set_vbus;
> +	phy->id_nb.notifier_call = id_notifier;
> +	phy->vbus_nb.notifier_call = vbus_notifier;
> +
> +	phy->io_priv = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(phy->io_priv))
> +		return PTR_ERR(phy->io_priv);
> +
> +	ta->vbus = devm_regulator_get(dev, "vbus");
> +	if (IS_ERR(ta->vbus))
> +		return PTR_ERR(ta->vbus);
> +
> +	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++) {
> +		resets[i] = devm_reset_control_get_exclusive(dev, CTL_RESETS[i]);
> +		if (IS_ERR(resets[i])) {
> +			dev_err(dev, "%s reset not found\n", CTL_RESETS[i]);
> +			return PTR_ERR(resets[i]);
> +		}
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++) {
> +		ta->resets[i] = devm_reset_control_get_exclusive(dev, PHY_RESETS[i]);
> +		if (IS_ERR(ta->resets[i])) {
> +			dev_err(dev, "%s reset not found\n", PHY_RESETS[i]);
> +			return PTR_ERR(ta->resets[i]);
> +		}
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
> +		reset_control_assert(resets[i]);
> +
> +	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
> +		reset_control_assert(ta->resets[i]);

no time lag b/w assert and dessert below?

> +	/*
> +	 * Out-of-band reset of the controller after PHY reset will cause
> +	 * controller malfunctioning, so we should use in-band controller
> +	 * reset only and leave the controller de-asserted here.
> +	 */
> +	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
> +		reset_control_deassert(resets[i]);
> +
> +	/* Need to wait at least 20us after de-assert the controller */
> +	usleep_range(20, 100);
> +
> +	return usb_add_phy_dev(phy);

aha, this is usb_phy stuff. 

Kishon this is not really a generic phy driver, should it be in
drivers/phy..?

-- 
~Vinod

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