Re: [RESEND PATCH v8 2/2] phy: Add USB3 PHY support for Intel LGM SoC

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Hi Vinod,

  Thank you for the review comments...

On 24/8/2020 12:06 am, Vinod Koul wrote:
On 17-08-20, 15:05, Ramuthevar,Vadivel MuruganX wrote:
From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>

Add support for USB PHY on Intel LGM SoC.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
  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?
Good catch, it's not required.

+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?
Noted.

+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?
Yes, it's required during the reboot and already device is connected status update to controller, well tested.

+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
Sure, we can handle it separately.

+	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
Noted.

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

here too
Noted.

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

empty notifier, why bother?
Let me check and double confirm if it's required or not.

+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?
yes you're right but not required for Intel LGM SoC, it's working fine.

Regards
Vadivel

+	/*
+	 * 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..?




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