[V2,6/8] phy: tegra: xusb: Add support for charger detect

Perform charger-detect operation if corresponding dt property is enabled.
Update usb-phy with the detected charger state and max current values.
Register charger-detect API's of usb-phy to provide needed functionalities.

Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com>
---
V2:
 - Patch re-based.
---
 drivers/phy/tegra/Makefile        |   2 +-
 drivers/phy/tegra/xusb-tegra-cd.c | 300 ++++++++++++++++++++++++++++++++++++++
 drivers/phy/tegra/xusb.c          |  80 ++++++++++
 drivers/phy/tegra/xusb.h          |   7 +
 4 files changed, 388 insertions(+), 1 deletion(-)
 create mode 100644 drivers/phy/tegra/xusb-tegra-cd.c

On Wed, Apr 15, 2020 at 01:55:06PM +0530, Nagarjuna Kristam wrote:
> Perform charger-detect operation if corresponding dt property is enabled.
> Update usb-phy with the detected charger state and max current values.
> Register charger-detect API's of usb-phy to provide needed functionalities.
> 
> Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com>
> ---
> V2:
>  - Patch re-based.
> ---
>  drivers/phy/tegra/Makefile        |   2 +-
>  drivers/phy/tegra/xusb-tegra-cd.c | 300 ++++++++++++++++++++++++++++++++++++++
>  drivers/phy/tegra/xusb.c          |  80 ++++++++++
>  drivers/phy/tegra/xusb.h          |   7 +
>  4 files changed, 388 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/phy/tegra/xusb-tegra-cd.c

Looks mostly good to me, just a few small nits.

> 
> diff --git a/drivers/phy/tegra/Makefile b/drivers/phy/tegra/Makefile
> index 89b8406..25ea9a9 100644
> --- a/drivers/phy/tegra/Makefile
> +++ b/drivers/phy/tegra/Makefile
> @@ -1,7 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  obj-$(CONFIG_PHY_TEGRA_XUSB) += phy-tegra-xusb.o
>  
> -phy-tegra-xusb-y += xusb.o
> +phy-tegra-xusb-y += xusb.o xusb-tegra-cd.o

Splitting this off into a separate file seems a little arbitrary. If
adding this to xusb.c is really making things too unwieldy, I'd suggest
a different name. Perhaps something like xusb-charger.c, or just cd.c.
This is already in a directory called "tegra" and it's obvious also that
this is part of the XUSB PHY driver.

>  phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_124_SOC) += xusb-tegra124.o
>  phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_132_SOC) += xusb-tegra124.o
>  phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_210_SOC) += xusb-tegra210.o
> diff --git a/drivers/phy/tegra/xusb-tegra-cd.c b/drivers/phy/tegra/xusb-tegra-cd.c
> new file mode 100644
> index 0000000..0fafc68
> --- /dev/null
> +++ b/drivers/phy/tegra/xusb-tegra-cd.c
> @@ -0,0 +1,300 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/phy/phy.h>
> +
> +#include "xusb.h"
> +
> +/* Data contact detection timeout */
> +#define TDCD_TIMEOUT_MS                         400
> +
> +#define USB2_BATTERY_CHRG_OTGPADX_CTL0(x)       (0x80 + (x) * 0x40)
> +#define  PD_CHG                                 (1 << 0)
> +#define  VDCD_DET_FILTER_EN                     (1 << 4)
> +#define  VDAT_DET                               (1 << 5)
> +#define  VDAT_DET_FILTER_EN                     (1 << 8)
> +#define  OP_SINK_EN                             (1 << 9)
> +#define  OP_SRC_EN                              (1 << 10)
> +#define  ON_SINK_EN                             (1 << 11)
> +#define  ON_SRC_EN                              (1 << 12)
> +#define  OP_I_SRC_EN                            (1 << 13)
> +#define  ZIP_FILTER_EN                          (1 << 21)
> +#define  ZIN_FILTER_EN                          (1 << 25)
> +#define  DCD_DETECTED                           (1 << 26)
> +
> +#define USB2_BATTERY_CHRG_OTGPADX_CTL1(x)       (0x84 + (x) * 0x40)
> +#define  PD_VREG                                (1 << 6)
> +#define  VREG_LEV(x)                            (((x) & 0x3) << 7)
> +#define  VREG_DIR(x)                            (((x) & 0x3) << 11)
> +#define  VREG_DIR_IN                            VREG_DIR(1)
> +#define  VREG_DIR_OUT                           VREG_DIR(2)
> +#define  USBOP_RPD_OVRD                         (1 << 16)
> +#define  USBOP_RPD_OVRD_VAL                     (1 << 17)
> +#define  USBOP_RPU_OVRD                         (1 << 18)
> +#define  USBOP_RPU_OVRD_VAL                     (1 << 19)
> +#define  USBON_RPD_OVRD                         (1 << 20)
> +#define  USBON_RPD_OVRD_VAL                     (1 << 21)
> +#define  USBON_RPU_OVRD                         (1 << 22)
> +#define  USBON_RPU_OVRD_VAL                     (1 << 23)
> +
> +#define XUSB_PADCTL_USB2_OTG_PADX_CTL0(x)	(0x88 + (x) * 0x40)

There's a bit of a mix of spaces and tabs for indentation here. Just
pick one and stick with it. I think checkpatch will want you to use tabs
first and then spaces if additional indentation is needed.

> +#define  USB2_OTG_PD2                           (1 << 27)
> +#define  USB2_OTG_PD2_OVRD_EN                   (1 << 28)
> +#define  USB2_OTG_PD_ZI                         (1 << 29)
> +
> +#define XUSB_PADCTL_USB2_BATTERY_CHRG_TDCD_DBNC_TIMER_0 (0x280)
> +#define   TDCD_DBNC(x)                          (((x) & 0x7ff) << 0)
> +
> +static void tegra_xusb_padctl_set_debounce_time(
> +				struct tegra_xusb_padctl *padctl, u32 val)

Perhaps rename "val" to something like "debounce", or "delay" or
something to avoid the "val" vs. "value" confusion. Also, wrapping
should be after the return type. Same for most functions below.

> +{
> +	u32 value;
> +
> +	value = padctl_readl(padctl,
> +		XUSB_PADCTL_USB2_BATTERY_CHRG_TDCD_DBNC_TIMER_0);
> +	value &= ~(TDCD_DBNC(0));
> +	value |= TDCD_DBNC(val);
> +	padctl_writel(padctl, value,
> +		XUSB_PADCTL_USB2_BATTERY_CHRG_TDCD_DBNC_TIMER_0);
> +}
> +
> +static void tegra_xusb_padctl_utmi_pad_charger_detect_on(
> +				struct tegra_xusb_padctl *padctl, u32 index)

In general these function names are a little long for my taste. Charger
detection can only happen on UTMI pads, right? So could we just drop the
_utmi_pad infix in these? That doesn't give us much, but at least it
should make splitting this across multiple lines less awkward.

> +{
> +	u32 value;
> +
> +	value = padctl_readl(padctl, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
> +	value &= ~USB2_OTG_PD_ZI;
> +	padctl_writel(padctl, value, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
> +
> +	value = padctl_readl(padctl, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
> +	value |= (USB2_OTG_PD2 | USB2_OTG_PD2_OVRD_EN);
> +	padctl_writel(padctl, value, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
> +
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value &= ~PD_CHG;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	/* Set DP/DN Pull up/down to zero by default */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +	value &= ~(USBOP_RPD_OVRD_VAL | USBOP_RPU_OVRD_VAL |
> +		USBON_RPD_OVRD_VAL | USBON_RPU_OVRD_VAL);
> +	value |= (USBOP_RPD_OVRD | USBOP_RPU_OVRD |
> +		USBON_RPD_OVRD | USBON_RPU_OVRD);
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +
> +	/* Disable DP/DN as src/sink */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value &= ~(OP_SRC_EN | ON_SINK_EN |
> +	ON_SRC_EN | OP_SINK_EN);
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +}
> +
> +static void tegra_xusb_padctl_utmi_pad_charger_detect_off(
> +				struct tegra_xusb_padctl *padctl, u32 index)
> +{
> +	u32 value;
> +
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +	value &= ~(USBOP_RPD_OVRD | USBOP_RPU_OVRD |
> +		 USBON_RPD_OVRD | USBON_RPU_OVRD);
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +
> +	/* power down necessary stuff */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value |= PD_CHG;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	value = padctl_readl(padctl, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
> +	value &= ~(USB2_OTG_PD2 | USB2_OTG_PD2_OVRD_EN);
> +	padctl_writel(padctl, value, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
> +}
> +
> +
> +static void tegra_xusb_padctl_detect_filters(
> +				struct tegra_xusb_padctl *padctl, u32 index,
> +				bool on)
> +{
> +	u32 value;
> +
> +	if (on) {
> +		value = padctl_readl(padctl,
> +				     USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +		value |= (VDCD_DET_FILTER_EN | VDAT_DET_FILTER_EN |
> +			  ZIP_FILTER_EN | ZIN_FILTER_EN);
> +		padctl_writel(padctl, value,
> +			      USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	} else {
> +		value = padctl_readl(padctl,
> +				     USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +		value &= ~(VDCD_DET_FILTER_EN | VDAT_DET_FILTER_EN |
> +			   ZIP_FILTER_EN | ZIN_FILTER_EN);
> +		padctl_writel(padctl, value,
> +			      USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	}
> +}
> +
> +static void tegra_xusb_padctl_utmi_pad_dcd(struct tegra_xusb_padctl *padctl,
> +					      u32 index)
> +{
> +	u32 value;
> +	int dcd_timeout_ms = 0;
> +	bool ret = false;
> +
> +	/* Turn on IDP_SRC */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value |= OP_I_SRC_EN;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	/* Turn on D- pull-down resistor */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +	value |= USBON_RPD_OVRD_VAL;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +
> +	/* Wait for TDCD_DBNC */
> +	usleep_range(10000, 120000);

From the comment this looks like we're waiting for some hardware
condition. Can we somehow obtain this rather than implementing a fixed
sleep? Especially since the range here is so large.

> +
> +	while (dcd_timeout_ms < TDCD_TIMEOUT_MS) {
> +		value = padctl_readl(padctl,
> +				     USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +		if (value & DCD_DETECTED) {
> +			dev_dbg(padctl->dev, "USB2 port %d DCD successful\n",
> +				index);
> +			ret = true;
> +			break;
> +		}
> +
> +		usleep_range(20000, 22000);
> +		dcd_timeout_ms += 22;
> +	}

Can we just use a timed loop instead? You should be able to use
something like:

		unsigned int offset = USB2_BATTERY_CHRG_OTGPADX_CTL0(index);

		err = readl_poll_timeout(padctl->regs + offset, value,
					 value & DCD_DETECTED,
					 22000, TDCD_TIMEOUT_MS * 1000);

That's slightly suboptimal because it doesn't let you use padctl_readl,
but at least it gives you a standard way of doing this kind of loop.

> +
> +	if (!ret)
> +		dev_info(padctl->dev, "%s: DCD timeout %d ms\n", __func__,
> +			 dcd_timeout_ms);

Should this be a dev_err() or dev_warn()? Is this expected to happen?

> +
> +	/* Turn off IP_SRC, clear DCD DETECTED*/
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value &= ~OP_I_SRC_EN;
> +	value |= DCD_DETECTED;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	/* Turn off D- pull-down resistor */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +	value &= ~USBON_RPD_OVRD_VAL;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> +
> +	dev_dbg(padctl->dev, "DCD: %d\n", ret);
> +}
> +
> +static bool tegra_xusb_padctl_utmi_pad_primary_charger_detect(
> +				struct tegra_xusb_padctl *padctl, u32 index)
> +{
> +	u32 value;
> +	int ret = false;

It doesn't look like there's a need to initialize this.

> +
> +	/* data contact detection */
> +	tegra_xusb_padctl_utmi_pad_dcd(padctl, index);
> +
> +	/* Source D+ to D- */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value |= OP_SRC_EN | ON_SINK_EN;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	/* Wait for TVDPSRC_ON */
> +	msleep(40);

Again, is this a hardware condition that we can wait on by polling a
register?

> +
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	ret = !!(value & VDAT_DET);
> +
> +	/* Turn off OP_SRC, ON_SINK, clear VDAT, ZIN status change */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value &= ~(OP_SRC_EN | ON_SINK_EN);
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	return ret;
> +}
> +
> +static bool tegra_xusb_padctl_utmi_pad_secondary_charger_detect(
> +				struct tegra_xusb_padctl *padctl, u32 index)
> +{
> +	u32 value;
> +	bool ret = false;
> +
> +	/* Source D- to D+ */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value |= ON_SRC_EN | OP_SINK_EN;
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	/* Wait for TVDPSRC_ON */
> +	msleep(40);
> +
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	ret = !(value & VDAT_DET);
> +
> +	/* Turn off ON_SRC, OP_SINK, clear VDAT, ZIP status change */
> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +	value &= ~(ON_SRC_EN | OP_SINK_EN);
> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> +
> +	return ret;
> +}

This seems to be mostly identical to the primary charger detect, so
perhaps this can be parameterized instead? I'm not generally opposed to
splitting functions up like this if they are fairly small, but in this
particular case, splitting up could make the name a lot shorter, and in
this case it's really quite excessive (I count 51 characters...) =)

> +
> +enum usb_charger_type tegra_xusb_padctl_charger_detect(
> +					  struct tegra_xusb_port *port)
> +{
> +	struct tegra_xusb_padctl *padctl = port->padctl;
> +	struct phy *phy = port->lane->pad->lanes[port->index];
> +	struct tegra_xusb_usb2_lane *usb2 = to_usb2_lane(port->lane);
> +	u32 index = port->index;
> +	enum usb_charger_type chrg_type;
> +	bool pad_power_off = false;
> +
> +	mutex_lock(&padctl->lock);
> +
> +	if (!usb2->powered_on) {
> +		padctl->soc->ops->utmi_pad_power_on(phy);
> +		pad_power_off = true;
> +	}
> +
> +	tegra_xusb_padctl_utmi_pad_charger_detect_on(padctl, index);
> +	tegra_xusb_padctl_set_debounce_time(padctl, 0xa);

Perhaps use 10 here because that's how we're usually used to read time
values.

> +	tegra_xusb_padctl_detect_filters(padctl, index, true);
> +
> +	if (tegra_xusb_padctl_utmi_pad_primary_charger_detect(padctl,
> +								 index)) {
> +		/*
> +		 * wait 20ms (max of TVDMSRC_DIS) for D- to be disabled
> +		 * from host side, before we perform secondary detection.
> +		 * Some hosts may not respond well if we do secondary
> +		 * detection right after primary detection.
> +		 */
> +		msleep(20);

Could use a blank line after this for readability.

> +		if (tegra_xusb_padctl_utmi_pad_secondary_charger_detect(padctl,
> +									index))
> +			chrg_type = CDP_TYPE;
> +		else
> +			chrg_type = DCP_TYPE;
> +	} else {
> +		chrg_type = SDP_TYPE;
> +	}
> +
> +	dev_dbg(&port->dev, "charger detected of type %d", chrg_type);

Do we have a string representation of this?

> +
> +	tegra_xusb_padctl_detect_filters(padctl, index, false);
> +	tegra_xusb_padctl_utmi_pad_charger_detect_off(padctl, index);
> +
> +	if (pad_power_off)
> +		padctl->soc->ops->utmi_pad_power_down(phy);
> +
> +	mutex_unlock(&padctl->lock);
> +	return chrg_type;
> +}
> +
> +MODULE_AUTHOR("Nagarjuna Kristam <nkristam@nvidia.com>");
> +MODULE_DESCRIPTION("NVIDIA Tegra186 XUSB charger detect driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
> index de4a46f..e505ac4 100644
> --- a/drivers/phy/tegra/xusb.c
> +++ b/drivers/phy/tegra/xusb.c
> @@ -591,6 +591,50 @@ static enum usb_phy_events to_usb_phy_event(enum usb_role role)
>  	}
>  }
>  
> +#define VON_DIV2P0_DET BIT(0)
> +#define VON_DIV2P7_DET BIT(1)
> +#define VOP_DIV2P0_DET BIT(2)
> +#define VOP_DIV2P7_DET BIT(3)
> +
> +#define VREG_CUR_LEVEL_0        500
> +#define VREG_CUR_LEVEL_1        900
> +#define VREG_CUR_LEVEL_2        1500
> +#define VREG_CUR_LEVEL_3        2000
> +
> +#define IS_CUR_IN_RANGE(ma, low, high)  \
> +	((ma >= VREG_CUR_LEVEL_##low) && (ma <= (VREG_CUR_LEVEL_##high - 1)))
> +#define VREG_LVL(ma, level)     IS_CUR_IN_RANGE(ma, level, level + 1)
> +
> +static void tegra_xusb_padctl_vbus_pad_portection(struct tegra_xusb_port *port)
> +{
> +	struct tegra_xusb_padctl *padctl = port->padctl;
> +	int level = 0;
> +	enum tegra_vbus_dir dir = TEGRA_VBUS_SINK;
> +	int max_ua, min_ua;
> +
> +	if (!padctl->soc->ops->utmi_pad_set_protection_level)
> +		return;
> +
> +	usb_phy_get_charger_current(&port->usb_phy, &min_ua, &max_ua);
> +
> +	if (max_ua == 0) {
> +		level = -1;
> +		dir = TEGRA_VBUS_DEFAULT;
> +	} else if (VREG_LVL(max_ua, 0)) {
> +		level = 0;
> +	} else if (VREG_LVL(max_ua, 1)) {
> +		level = 1;
> +	} else if (VREG_LVL(max_ua, 2)) {
> +		level = 2;
> +	} else if (max_ua >= VREG_CUR_LEVEL_3) {
> +		level = 3;
> +	} else {
> +		return;
> +	}
> +
> +	padctl->soc->ops->utmi_pad_set_protection_level(port, max_ua, dir);
> +}

level seems to never be used in the above. Instead you just pass max_ua
to the set protection level callback.

> +
>  static void tegra_xusb_usb_phy_work(struct work_struct *work)
>  {
>  	struct tegra_xusb_port *port = container_of(work,
> @@ -598,6 +642,10 @@ static void tegra_xusb_usb_phy_work(struct work_struct *work)
>  						    usb_phy_work);
>  	enum usb_role role = usb_role_switch_get_role(port->usb_role_sw);
>  
> +	/* Set role to none, if charger is DCP type */
> +	if (port->chrg_type == DCP_TYPE)
> +		role = USB_ROLE_NONE;
> +
>  	usb_phy_set_event(&port->usb_phy, to_usb_phy_event(role));
>  
>  	dev_dbg(&port->dev, "%s(): calling notifier for role %s\n", __func__,
> @@ -610,9 +658,26 @@ static int tegra_xusb_role_sw_set(struct usb_role_switch *sw,
>  				  enum usb_role role)
>  {
>  	struct tegra_xusb_port *port = usb_role_switch_get_drvdata(sw);
> +	enum usb_charger_state charger_state;
>  
>  	dev_dbg(&port->dev, "%s(): role %s\n", __func__, usb_roles[role]);
>  
> +	/* Do charger detect if role is Device and charger detect is enabled */
> +	if (port->charger_detect) {
> +		if (role == USB_ROLE_DEVICE)
> +			port->chrg_type =
> +					 tegra_xusb_padctl_charger_detect(port);
> +		else
> +			port->chrg_type = UNKNOWN_TYPE;
> +
> +		charger_state = (port->chrg_type == UNKNOWN_TYPE) ?
> +				 USB_CHARGER_ABSENT : USB_CHARGER_PRESENT;
> +
> +		usb_phy_set_charger_state(&port->usb_phy, charger_state);
> +
> +		tegra_xusb_padctl_vbus_pad_portection(port);
> +	}
> +
>  	schedule_work(&port->usb_phy_work);
>  
>  	return 0;
> @@ -643,6 +708,14 @@ static int tegra_xusb_set_host(struct usb_otg *otg, struct usb_bus *host)
>  	return 0;
>  }
>  
> +static enum usb_charger_type tegra_xusb_charger_detect(struct usb_phy *usb_phy)
> +{
> +	struct tegra_xusb_port *port = container_of(usb_phy,
> +						    struct tegra_xusb_port,
> +						    usb_phy);
> +
> +	return port->chrg_type;
> +}
>  
>  static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
>  {
> @@ -693,6 +766,9 @@ static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
>  	port->usb_phy.otg->set_peripheral = tegra_xusb_set_peripheral;
>  	port->usb_phy.otg->set_host = tegra_xusb_set_host;
>  
> +	if (port->charger_detect)
> +		port->usb_phy.charger_detect = tegra_xusb_charger_detect;
> +
>  	err = usb_add_phy_dev(&port->usb_phy);
>  	if (err < 0) {
>  		dev_err(&port->dev, "Failed to add USB PHY: %d\n", err);
> @@ -727,6 +803,10 @@ static int tegra_xusb_usb2_port_parse_dt(struct tegra_xusb_usb2_port *usb2)
>  		usb2->mode = USB_DR_MODE_HOST;
>  	}
>  
> +	if (port->padctl->soc->charger_detect &&
> +	    of_property_read_bool(np, "nvidia,charger-detect"))
> +		port->charger_detect = true;
> +
>  	/* usb-role-switch property is mandatory for OTG/Peripheral modes */
>  	if (usb2->mode == USB_DR_MODE_PERIPHERAL ||
>  	    usb2->mode == USB_DR_MODE_OTG) {
> diff --git a/drivers/phy/tegra/xusb.h b/drivers/phy/tegra/xusb.h
> index 79e96b0..714bca2 100644
> --- a/drivers/phy/tegra/xusb.h
> +++ b/drivers/phy/tegra/xusb.h
> @@ -282,6 +282,9 @@ struct tegra_xusb_port {
>  	struct work_struct usb_phy_work;
>  	struct usb_phy usb_phy;
>  
> +	bool charger_detect;
> +	enum usb_charger_type chrg_type;
> +
>  	const struct tegra_xusb_port_ops *ops;
>  };
>  
> @@ -306,6 +309,9 @@ struct tegra_xusb_port *
>  tegra_xusb_find_port(struct tegra_xusb_padctl *padctl, const char *type,
>  		     unsigned int index);
>  
> +enum usb_charger_type tegra_xusb_padctl_charger_detect(
> +					  struct tegra_xusb_port *port);
> +
>  struct tegra_xusb_usb2_port {
>  	struct tegra_xusb_port base;
>  
> @@ -430,6 +436,7 @@ struct tegra_xusb_padctl_soc {
>  	unsigned int num_supplies;
>  	bool supports_gen2;
>  	bool need_fake_usb3_port;
> +	bool charger_detect;

Perhaps make this "supports_charger_detection" because it being in the
SoC structure means that it's a capability. "charger_detect" makes it
look like an option that we've enabled or not. That's what struct
tegra_xusb_port.charger_detect already is.

Thierry

>On 28-04-2020 16:25, Thierry Reding wrote:
>> On Wed, Apr 15, 2020 at 01:55:06PM +0530, Nagarjuna Kristam wrote:
>> Perform charger-detect operation if corresponding dt property is enabled.
>> Update usb-phy with the detected charger state and max current values.
>> Register charger-detect API's of usb-phy to provide needed functionalities.
>>
>> Signed-off-by: Nagarjuna Kristam<nkristam@nvidia.com>
>> ---
>> V2:
>>   - Patch re-based.
>> ---
>>   drivers/phy/tegra/Makefile        |   2 +-
>>   drivers/phy/tegra/xusb-tegra-cd.c | 300 ++++++++++++++++++++++++++++++++++++++
>>   drivers/phy/tegra/xusb.c          |  80 ++++++++++
>>   drivers/phy/tegra/xusb.h          |   7 +
>>   4 files changed, 388 insertions(+), 1 deletion(-)
>>   create mode 100644 drivers/phy/tegra/xusb-tegra-cd.c
> Looks mostly good to me, just a few small nits.
> 
>> diff --git a/drivers/phy/tegra/Makefile b/drivers/phy/tegra/Makefile
>> index 89b8406..25ea9a9 100644
>> --- a/drivers/phy/tegra/Makefile
>> +++ b/drivers/phy/tegra/Makefile
>> @@ -1,7 +1,7 @@
>>   # SPDX-License-Identifier: GPL-2.0-only
>>   obj-$(CONFIG_PHY_TEGRA_XUSB) += phy-tegra-xusb.o
>>   
>> -phy-tegra-xusb-y += xusb.o
>> +phy-tegra-xusb-y += xusb.o xusb-tegra-cd.o
> Splitting this off into a separate file seems a little arbitrary. If
> adding this to xusb.c is really making things too unwieldy, I'd suggest
> a different name. Perhaps something like xusb-charger.c, or just cd.c.
> This is already in a directory called "tegra" and it's obvious also that
> this is part of the XUSB PHY driver.
> 
Will add as cd.c
>>   phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_124_SOC) += xusb-tegra124.o
>>   phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_132_SOC) += xusb-tegra124.o
>>   phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_210_SOC) += xusb-tegra210.o
>> diff --git a/drivers/phy/tegra/xusb-tegra-cd.c b/drivers/phy/tegra/xusb-tegra-cd.c
>> new file mode 100644
>> index 0000000..0fafc68
>> --- /dev/null
>> +++ b/drivers/phy/tegra/xusb-tegra-cd.c
>> @@ -0,0 +1,300 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/phy/phy.h>
>> +
>> +#include "xusb.h"
>> +
>> +/* Data contact detection timeout */
>> +#define TDCD_TIMEOUT_MS                         400
>> +
>> +#define USB2_BATTERY_CHRG_OTGPADX_CTL0(x)       (0x80 + (x) * 0x40)
>> +#define  PD_CHG                                 (1 << 0)
>> +#define  VDCD_DET_FILTER_EN                     (1 << 4)
>> +#define  VDAT_DET                               (1 << 5)
>> +#define  VDAT_DET_FILTER_EN                     (1 << 8)
>> +#define  OP_SINK_EN                             (1 << 9)
>> +#define  OP_SRC_EN                              (1 << 10)
>> +#define  ON_SINK_EN                             (1 << 11)
>> +#define  ON_SRC_EN                              (1 << 12)
>> +#define  OP_I_SRC_EN                            (1 << 13)
>> +#define  ZIP_FILTER_EN                          (1 << 21)
>> +#define  ZIN_FILTER_EN                          (1 << 25)
>> +#define  DCD_DETECTED                           (1 << 26)
>> +
>> +#define USB2_BATTERY_CHRG_OTGPADX_CTL1(x)       (0x84 + (x) * 0x40)
>> +#define  PD_VREG                                (1 << 6)
>> +#define  VREG_LEV(x)                            (((x) & 0x3) << 7)
>> +#define  VREG_DIR(x)                            (((x) & 0x3) << 11)
>> +#define  VREG_DIR_IN                            VREG_DIR(1)
>> +#define  VREG_DIR_OUT                           VREG_DIR(2)
>> +#define  USBOP_RPD_OVRD                         (1 << 16)
>> +#define  USBOP_RPD_OVRD_VAL                     (1 << 17)
>> +#define  USBOP_RPU_OVRD                         (1 << 18)
>> +#define  USBOP_RPU_OVRD_VAL                     (1 << 19)
>> +#define  USBON_RPD_OVRD                         (1 << 20)
>> +#define  USBON_RPD_OVRD_VAL                     (1 << 21)
>> +#define  USBON_RPU_OVRD                         (1 << 22)
>> +#define  USBON_RPU_OVRD_VAL                     (1 << 23)
>> +
>> +#define XUSB_PADCTL_USB2_OTG_PADX_CTL0(x)	(0x88 + (x) * 0x40)
> There's a bit of a mix of spaces and tabs for indentation here. Just
> pick one and stick with it. I think checkpatch will want you to use tabs
> first and then spaces if additional indentation is needed.
> 
Will update accordingly
>> +#define  USB2_OTG_PD2                           (1 << 27)
>> +#define  USB2_OTG_PD2_OVRD_EN                   (1 << 28)
>> +#define  USB2_OTG_PD_ZI                         (1 << 29)
>> +
>> +#define XUSB_PADCTL_USB2_BATTERY_CHRG_TDCD_DBNC_TIMER_0 (0x280)
>> +#define   TDCD_DBNC(x)                          (((x) & 0x7ff) << 0)
>> +
>> +static void tegra_xusb_padctl_set_debounce_time(
>> +				struct tegra_xusb_padctl *padctl, u32 val)
> Perhaps rename "val" to something like "debounce", or "delay" or
> something to avoid the "val" vs. "value" confusion. Also, wrapping
> should be after the return type. Same for most functions below.
> 
Will update accordingly
>> +{
>> +	u32 value;
>> +
>> +	value = padctl_readl(padctl,
>> +		XUSB_PADCTL_USB2_BATTERY_CHRG_TDCD_DBNC_TIMER_0);
>> +	value &= ~(TDCD_DBNC(0));
>> +	value |= TDCD_DBNC(val);
>> +	padctl_writel(padctl, value,
>> +		XUSB_PADCTL_USB2_BATTERY_CHRG_TDCD_DBNC_TIMER_0);
>> +}
>> +
>> +static void tegra_xusb_padctl_utmi_pad_charger_detect_on(
>> +				struct tegra_xusb_padctl *padctl, u32 index)
> In general these function names are a little long for my taste. Charger
> detection can only happen on UTMI pads, right? So could we just drop the
> _utmi_pad infix in these? That doesn't give us much, but at least it
> should make splitting this across multiple lines less awkward.
> 
will remove utmi_pad_ and shorten the functions.
>> +{
>> +	u32 value;
>> +
>> +	value = padctl_readl(padctl, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
>> +	value &= ~USB2_OTG_PD_ZI;
>> +	padctl_writel(padctl, value, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
>> +
>> +	value = padctl_readl(padctl, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
>> +	value |= (USB2_OTG_PD2 | USB2_OTG_PD2_OVRD_EN);
>> +	padctl_writel(padctl, value, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
>> +
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value &= ~PD_CHG;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	/* Set DP/DN Pull up/down to zero by default */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +	value &= ~(USBOP_RPD_OVRD_VAL | USBOP_RPU_OVRD_VAL |
>> +		USBON_RPD_OVRD_VAL | USBON_RPU_OVRD_VAL);
>> +	value |= (USBOP_RPD_OVRD | USBOP_RPU_OVRD |
>> +		USBON_RPD_OVRD | USBON_RPU_OVRD);
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +
>> +	/* Disable DP/DN as src/sink */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value &= ~(OP_SRC_EN | ON_SINK_EN |
>> +	ON_SRC_EN | OP_SINK_EN);
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +}
>> +
>> +static void tegra_xusb_padctl_utmi_pad_charger_detect_off(
>> +				struct tegra_xusb_padctl *padctl, u32 index)
>> +{
>> +	u32 value;
>> +
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +	value &= ~(USBOP_RPD_OVRD | USBOP_RPU_OVRD |
>> +		 USBON_RPD_OVRD | USBON_RPU_OVRD);
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +
>> +	/* power down necessary stuff */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value |= PD_CHG;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	value = padctl_readl(padctl, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
>> +	value &= ~(USB2_OTG_PD2 | USB2_OTG_PD2_OVRD_EN);
>> +	padctl_writel(padctl, value, XUSB_PADCTL_USB2_OTG_PADX_CTL0(index));
>> +}
>> +
>> +
>> +static void tegra_xusb_padctl_detect_filters(
>> +				struct tegra_xusb_padctl *padctl, u32 index,
>> +				bool on)
>> +{
>> +	u32 value;
>> +
>> +	if (on) {
>> +		value = padctl_readl(padctl,
>> +				     USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +		value |= (VDCD_DET_FILTER_EN | VDAT_DET_FILTER_EN |
>> +			  ZIP_FILTER_EN | ZIN_FILTER_EN);
>> +		padctl_writel(padctl, value,
>> +			      USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	} else {
>> +		value = padctl_readl(padctl,
>> +				     USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +		value &= ~(VDCD_DET_FILTER_EN | VDAT_DET_FILTER_EN |
>> +			   ZIP_FILTER_EN | ZIN_FILTER_EN);
>> +		padctl_writel(padctl, value,
>> +			      USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	}
>> +}
>> +
>> +static void tegra_xusb_padctl_utmi_pad_dcd(struct tegra_xusb_padctl *padctl,
>> +					      u32 index)
>> +{
>> +	u32 value;
>> +	int dcd_timeout_ms = 0;
>> +	bool ret = false;
>> +
>> +	/* Turn on IDP_SRC */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value |= OP_I_SRC_EN;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	/* Turn on D- pull-down resistor */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +	value |= USBON_RPD_OVRD_VAL;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +
>> +	/* Wait for TDCD_DBNC */
>> +	usleep_range(10000, 120000);
>  From the comment this looks like we're waiting for some hardware
> condition. Can we somehow obtain this rather than implementing a fixed
> sleep? Especially since the range here is so large.
> 
As per data sheet we need to wait for 10 micro seconds as settle time.
>> +
>> +	while (dcd_timeout_ms < TDCD_TIMEOUT_MS) {
>> +		value = padctl_readl(padctl,
>> +				     USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +		if (value & DCD_DETECTED) {
>> +			dev_dbg(padctl->dev, "USB2 port %d DCD successful\n",
>> +				index);
>> +			ret = true;
>> +			break;
>> +		}
>> +
>> +		usleep_range(20000, 22000);
>> +		dcd_timeout_ms += 22;
>> +	}
> Can we just use a timed loop instead? You should be able to use
> something like:
Will update using single API accordingly
> 
> 		unsigned int offset = USB2_BATTERY_CHRG_OTGPADX_CTL0(index);
> 
> 		err = readl_poll_timeout(padctl->regs + offset, value,
> 					 value & DCD_DETECTED,
> 					 22000, TDCD_TIMEOUT_MS * 1000);
> 
> That's slightly suboptimal because it doesn't let you use padctl_readl,
> but at least it gives you a standard way of doing this kind of loop.
> 
>> +
>> +	if (!ret)
>> +		dev_info(padctl->dev, "%s: DCD timeout %d ms\n", __func__,
>> +			 dcd_timeout_ms);
> Should this be a dev_err() or dev_warn()? Is this expected to happen?
> 
In general shouldnot happen, will mark as warn.
>> +
>> +	/* Turn off IP_SRC, clear DCD DETECTED*/
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value &= ~OP_I_SRC_EN;
>> +	value |= DCD_DETECTED;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	/* Turn off D- pull-down resistor */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +	value &= ~USBON_RPD_OVRD_VAL;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>> +
>> +	dev_dbg(padctl->dev, "DCD: %d\n", ret);
>> +}
>> +
>> +static bool tegra_xusb_padctl_utmi_pad_primary_charger_detect(
>> +				struct tegra_xusb_padctl *padctl, u32 index)
>> +{
>> +	u32 value;
>> +	int ret = false;
> It doesn't look like there's a need to initialize this.
> 
will remove.
>> +
>> +	/* data contact detection */
>> +	tegra_xusb_padctl_utmi_pad_dcd(padctl, index);
>> +
>> +	/* Source D+ to D- */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value |= OP_SRC_EN | ON_SINK_EN;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	/* Wait for TVDPSRC_ON */
>> +	msleep(40);
> Again, is this a hardware condition that we can wait on by polling a
> register?
> 
It HW settle time before reading registers.
>> +
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	ret = !!(value & VDAT_DET);
>> +
>> +	/* Turn off OP_SRC, ON_SINK, clear VDAT, ZIN status change */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value &= ~(OP_SRC_EN | ON_SINK_EN);
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	return ret;
>> +}
>> +
>> +static bool tegra_xusb_padctl_utmi_pad_secondary_charger_detect(
>> +				struct tegra_xusb_padctl *padctl, u32 index)
>> +{
>> +	u32 value;
>> +	bool ret = false;
>> +
>> +	/* Source D- to D+ */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value |= ON_SRC_EN | OP_SINK_EN;
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	/* Wait for TVDPSRC_ON */
>> +	msleep(40);
>> +
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	ret = !(value & VDAT_DET);
>> +
>> +	/* Turn off ON_SRC, OP_SINK, clear VDAT, ZIP status change */
>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +	value &= ~(ON_SRC_EN | OP_SINK_EN);
>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>> +
>> +	return ret;
>> +}
> This seems to be mostly identical to the primary charger detect, so
> perhaps this can be parameterized instead? I'm not generally opposed to
> splitting functions up like this if they are fairly small, but in this
> particular case, splitting up could make the name a lot shorter, and in
> this case it's really quite excessive (I count 51 characters...) =)
> Will update accordingly
>> +
>> +enum usb_charger_type tegra_xusb_padctl_charger_detect(
>> +					  struct tegra_xusb_port *port)
>> +{
>> +	struct tegra_xusb_padctl *padctl = port->padctl;
>> +	struct phy *phy = port->lane->pad->lanes[port->index];
>> +	struct tegra_xusb_usb2_lane *usb2 = to_usb2_lane(port->lane);
>> +	u32 index = port->index;
>> +	enum usb_charger_type chrg_type;
>> +	bool pad_power_off = false;
>> +
>> +	mutex_lock(&padctl->lock);
>> +
>> +	if (!usb2->powered_on) {
>> +		padctl->soc->ops->utmi_pad_power_on(phy);
>> +		pad_power_off = true;
>> +	}
>> +
>> +	tegra_xusb_padctl_utmi_pad_charger_detect_on(padctl, index);
>> +	tegra_xusb_padctl_set_debounce_time(padctl, 0xa);
> Perhaps use 10 here because that's how we're usually used to read time
> values.
> 
Will update accordingly
>> +	tegra_xusb_padctl_detect_filters(padctl, index, true);
>> +
>> +	if (tegra_xusb_padctl_utmi_pad_primary_charger_detect(padctl,
>> +								 index)) {
>> +		/*
>> +		 * wait 20ms (max of TVDMSRC_DIS) for D- to be disabled
>> +		 * from host side, before we perform secondary detection.
>> +		 * Some hosts may not respond well if we do secondary
>> +		 * detection right after primary detection.
>> +		 */
>> +		msleep(20);
> Could use a blank line after this for readability.
> 
Will update accordingly
>> +		if (tegra_xusb_padctl_utmi_pad_secondary_charger_detect(padctl,
>> +									index))
>> +			chrg_type = CDP_TYPE;
>> +		else
>> +			chrg_type = DCP_TYPE;
>> +	} else {
>> +		chrg_type = SDP_TYPE;
>> +	}
>> +
>> +	dev_dbg(&port->dev, "charger detected of type %d", chrg_type);
> Do we have a string representation of this?
> 
No String representation available. Shall i add one for wasy reading ?
>> +
>> +	tegra_xusb_padctl_detect_filters(padctl, index, false);
>> +	tegra_xusb_padctl_utmi_pad_charger_detect_off(padctl, index);
>> +
>> +	if (pad_power_off)
>> +		padctl->soc->ops->utmi_pad_power_down(phy);
>> +
>> +	mutex_unlock(&padctl->lock);
>> +	return chrg_type;
>> +}
>> +
>> +MODULE_AUTHOR("Nagarjuna Kristam<nkristam@nvidia.com>");
>> +MODULE_DESCRIPTION("NVIDIA Tegra186 XUSB charger detect driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
>> index de4a46f..e505ac4 100644
>> --- a/drivers/phy/tegra/xusb.c
>> +++ b/drivers/phy/tegra/xusb.c
>> @@ -591,6 +591,50 @@ static enum usb_phy_events to_usb_phy_event(enum usb_role role)
>>   	}
>>   }
>>   
>> +#define VON_DIV2P0_DET BIT(0)
>> +#define VON_DIV2P7_DET BIT(1)
>> +#define VOP_DIV2P0_DET BIT(2)
>> +#define VOP_DIV2P7_DET BIT(3)
>> +
>> +#define VREG_CUR_LEVEL_0        500
>> +#define VREG_CUR_LEVEL_1        900
>> +#define VREG_CUR_LEVEL_2        1500
>> +#define VREG_CUR_LEVEL_3        2000
>> +
>> +#define IS_CUR_IN_RANGE(ma, low, high)  \
>> +	((ma >= VREG_CUR_LEVEL_##low) && (ma <= (VREG_CUR_LEVEL_##high - 1)))
>> +#define VREG_LVL(ma, level)     IS_CUR_IN_RANGE(ma, level, level + 1)
>> +
>> +static void tegra_xusb_padctl_vbus_pad_portection(struct tegra_xusb_port *port)
>> +{
>> +	struct tegra_xusb_padctl *padctl = port->padctl;
>> +	int level = 0;
>> +	enum tegra_vbus_dir dir = TEGRA_VBUS_SINK;
>> +	int max_ua, min_ua;
>> +
>> +	if (!padctl->soc->ops->utmi_pad_set_protection_level)
>> +		return;
>> +
>> +	usb_phy_get_charger_current(&port->usb_phy, &min_ua, &max_ua);
>> +
>> +	if (max_ua == 0) {
>> +		level = -1;
>> +		dir = TEGRA_VBUS_DEFAULT;
>> +	} else if (VREG_LVL(max_ua, 0)) {
>> +		level = 0;
>> +	} else if (VREG_LVL(max_ua, 1)) {
>> +		level = 1;
>> +	} else if (VREG_LVL(max_ua, 2)) {
>> +		level = 2;
>> +	} else if (max_ua >= VREG_CUR_LEVEL_3) {
>> +		level = 3;
>> +	} else {
>> +		return;
>> +	}
>> +
>> +	padctl->soc->ops->utmi_pad_set_protection_level(port, max_ua, dir);
>> +}
> level seems to never be used in the above. Instead you just pass max_ua
> to the set protection level callback.
> 
Will remove accordingly
>> +
>>   static void tegra_xusb_usb_phy_work(struct work_struct *work)
>>   {
>>   	struct tegra_xusb_port *port = container_of(work,
>> @@ -598,6 +642,10 @@ static void tegra_xusb_usb_phy_work(struct work_struct *work)
>>   						    usb_phy_work);
>>   	enum usb_role role = usb_role_switch_get_role(port->usb_role_sw);
>>   
>> +	/* Set role to none, if charger is DCP type */
>> +	if (port->chrg_type == DCP_TYPE)
>> +		role = USB_ROLE_NONE;
>> +
>>   	usb_phy_set_event(&port->usb_phy, to_usb_phy_event(role));
>>   
>>   	dev_dbg(&port->dev, "%s(): calling notifier for role %s\n", __func__,
>> @@ -610,9 +658,26 @@ static int tegra_xusb_role_sw_set(struct usb_role_switch *sw,
>>   				  enum usb_role role)
>>   {
>>   	struct tegra_xusb_port *port = usb_role_switch_get_drvdata(sw);
>> +	enum usb_charger_state charger_state;
>>   
>>   	dev_dbg(&port->dev, "%s(): role %s\n", __func__, usb_roles[role]);
>>   
>> +	/* Do charger detect if role is Device and charger detect is enabled */
>> +	if (port->charger_detect) {
>> +		if (role == USB_ROLE_DEVICE)
>> +			port->chrg_type =
>> +					 tegra_xusb_padctl_charger_detect(port);
>> +		else
>> +			port->chrg_type = UNKNOWN_TYPE;
>> +
>> +		charger_state = (port->chrg_type == UNKNOWN_TYPE) ?
>> +				 USB_CHARGER_ABSENT : USB_CHARGER_PRESENT;
>> +
>> +		usb_phy_set_charger_state(&port->usb_phy, charger_state);
>> +
>> +		tegra_xusb_padctl_vbus_pad_portection(port);
>> +	}
>> +
>>   	schedule_work(&port->usb_phy_work);
>>   
>>   	return 0;
>> @@ -643,6 +708,14 @@ static int tegra_xusb_set_host(struct usb_otg *otg, struct usb_bus *host)
>>   	return 0;
>>   }
>>   
>> +static enum usb_charger_type tegra_xusb_charger_detect(struct usb_phy *usb_phy)
>> +{
>> +	struct tegra_xusb_port *port = container_of(usb_phy,
>> +						    struct tegra_xusb_port,
>> +						    usb_phy);
>> +
>> +	return port->chrg_type;
>> +}
>>   
>>   static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
>>   {
>> @@ -693,6 +766,9 @@ static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
>>   	port->usb_phy.otg->set_peripheral = tegra_xusb_set_peripheral;
>>   	port->usb_phy.otg->set_host = tegra_xusb_set_host;
>>   
>> +	if (port->charger_detect)
>> +		port->usb_phy.charger_detect = tegra_xusb_charger_detect;
>> +
>>   	err = usb_add_phy_dev(&port->usb_phy);
>>   	if (err < 0) {
>>   		dev_err(&port->dev, "Failed to add USB PHY: %d\n", err);
>> @@ -727,6 +803,10 @@ static int tegra_xusb_usb2_port_parse_dt(struct tegra_xusb_usb2_port *usb2)
>>   		usb2->mode = USB_DR_MODE_HOST;
>>   	}
>>   
>> +	if (port->padctl->soc->charger_detect &&
>> +	    of_property_read_bool(np, "nvidia,charger-detect"))
>> +		port->charger_detect = true;
>> +
>>   	/* usb-role-switch property is mandatory for OTG/Peripheral modes */
>>   	if (usb2->mode == USB_DR_MODE_PERIPHERAL ||
>>   	    usb2->mode == USB_DR_MODE_OTG) {
>> diff --git a/drivers/phy/tegra/xusb.h b/drivers/phy/tegra/xusb.h
>> index 79e96b0..714bca2 100644
>> --- a/drivers/phy/tegra/xusb.h
>> +++ b/drivers/phy/tegra/xusb.h
>> @@ -282,6 +282,9 @@ struct tegra_xusb_port {
>>   	struct work_struct usb_phy_work;
>>   	struct usb_phy usb_phy;
>>   
>> +	bool charger_detect;
>> +	enum usb_charger_type chrg_type;
>> +
>>   	const struct tegra_xusb_port_ops *ops;
>>   };
>>   
>> @@ -306,6 +309,9 @@ struct tegra_xusb_port *
>>   tegra_xusb_find_port(struct tegra_xusb_padctl *padctl, const char *type,
>>   		     unsigned int index);
>>   
>> +enum usb_charger_type tegra_xusb_padctl_charger_detect(
>> +					  struct tegra_xusb_port *port);
>> +
>>   struct tegra_xusb_usb2_port {
>>   	struct tegra_xusb_port base;
>>   
>> @@ -430,6 +436,7 @@ struct tegra_xusb_padctl_soc {
>>   	unsigned int num_supplies;
>>   	bool supports_gen2;
>>   	bool need_fake_usb3_port;
>> +	bool charger_detect;
> Perhaps make this "supports_charger_detection" because it being in the
> SoC structure means that it's a capability. "charger_detect" makes it
> look like an option that we've enabled or not. That's what struct
> tegra_xusb_port.charger_detect already is.
> 
Will update accordingly
-Nagarjuna
> Thierry
>

On Mon, May 04, 2020 at 02:32:51PM +0530, Nagarjuna Kristam wrote:
> >On 28-04-2020 16:25, Thierry Reding wrote:
> > > On Wed, Apr 15, 2020 at 01:55:06PM +0530, Nagarjuna Kristam wrote:
[...]
> > > diff --git a/drivers/phy/tegra/xusb-tegra-cd.c b/drivers/phy/tegra/xusb-tegra-cd.c
> > > +static void tegra_xusb_padctl_utmi_pad_dcd(struct tegra_xusb_padctl *padctl,
> > > +					      u32 index)
> > > +{
> > > +	u32 value;
> > > +	int dcd_timeout_ms = 0;
> > > +	bool ret = false;
> > > +
> > > +	/* Turn on IDP_SRC */
> > > +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> > > +	value |= OP_I_SRC_EN;
> > > +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
> > > +
> > > +	/* Turn on D- pull-down resistor */
> > > +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> > > +	value |= USBON_RPD_OVRD_VAL;
> > > +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
> > > +
> > > +	/* Wait for TDCD_DBNC */
> > > +	usleep_range(10000, 120000);
> >  From the comment this looks like we're waiting for some hardware
> > condition. Can we somehow obtain this rather than implementing a fixed
> > sleep? Especially since the range here is so large.
> > 
> As per data sheet we need to wait for 10 micro seconds as settle time.

Okay, so TDCD_DBNC is a value that comes from a timing diagram in a
datasheet? Seems fine to leave it as-is then. Perhaps add parentheses
and mention which exact datasheet that's from, and perhaps which figure
so that people can more easily reference it. Provided there is a
publicly available datasheet, of course.

Actually, one other thing: If the data sheet says to wait 10 us, why do
you use an upper range of 120 us? Shouldn't a range of 10-20 us be good
enough?

> > > +	/* Wait for TVDPSRC_ON */
> > > +	msleep(40);
> > Again, is this a hardware condition that we can wait on by polling a
> > register?
> > 
> It HW settle time before reading registers.

Again, perhaps link to the datasheet, or alternatively describe in the
comment what this is waiting for. That is, something like:

	/* wait for TVDPSRC_ON (wait for hardware to settle) */

or similar.

> > > +		if (tegra_xusb_padctl_utmi_pad_secondary_charger_detect(padctl,
> > > +									index))
> > > +			chrg_type = CDP_TYPE;
> > > +		else
> > > +			chrg_type = DCP_TYPE;
> > > +	} else {
> > > +		chrg_type = SDP_TYPE;
> > > +	}
> > > +
> > > +	dev_dbg(&port->dev, "charger detected of type %d", chrg_type);
> > Do we have a string representation of this?
> > 
> No String representation available. Shall i add one for wasy reading ?

Yeah, I think that'd be nice.

Thierry

On 04-05-2020 21:20, Thierry Reding wrote:
> 
> On Mon, May 04, 2020 at 02:32:51PM +0530, Nagarjuna Kristam wrote:
>>> On 28-04-2020 16:25, Thierry Reding wrote:
>>>> On Wed, Apr 15, 2020 at 01:55:06PM +0530, Nagarjuna Kristam wrote:
> [...]
>>>> diff --git a/drivers/phy/tegra/xusb-tegra-cd.c b/drivers/phy/tegra/xusb-tegra-cd.c
>>>> +static void tegra_xusb_padctl_utmi_pad_dcd(struct tegra_xusb_padctl *padctl,
>>>> +					      u32 index)
>>>> +{
>>>> +	u32 value;
>>>> +	int dcd_timeout_ms = 0;
>>>> +	bool ret = false;
>>>> +
>>>> +	/* Turn on IDP_SRC */
>>>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>>>> +	value |= OP_I_SRC_EN;
>>>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>>>> +
>>>> +	/* Turn on D- pull-down resistor */
>>>> +	value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>>>> +	value |= USBON_RPD_OVRD_VAL;
>>>> +	padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>>>> +
>>>> +	/* Wait for TDCD_DBNC */
>>>> +	usleep_range(10000, 120000);
>>>   From the comment this looks like we're waiting for some hardware
>>> condition. Can we somehow obtain this rather than implementing a fixed
>>> sleep? Especially since the range here is so large.
>>>
>> As per data sheet we need to wait for 10 micro seconds as settle time.
> Okay, so TDCD_DBNC is a value that comes from a timing diagram in a
> datasheet? Seems fine to leave it as-is then. Perhaps add parentheses
> and mention which exact datasheet that's from, and perhaps which figure
> so that people can more easily reference it. Provided there is a
> publicly available datasheet, of course.
> 
Will update reference to table in the data sheet where these values are 
recommended. ITs part of BC 1.2 spec from USB.

> Actually, one other thing: If the data sheet says to wait 10 us, why do
> you use an upper range of 120 us? Shouldn't a range of 10-20 us be good
> enough?
> Yes, will reduce it to 20ms.

-Nagarjuna