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Message-ID: <20201019134948.GH1667571@kuha.fi.intel.com>
Date: Mon, 19 Oct 2020 16:49:48 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Badhri Jagan Sridharan <badhri@...gle.com>
Cc: Guenter Roeck <linux@...ck-us.net>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Rob Herring <robh+dt@...nel.org>,
Lee Jones <lee.jones@...aro.org>,
Mark Brown <broonie@...nel.org>,
Maxime Ripard <mripard@...nel.org>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Thierry Reding <treding@...dia.com>,
Prashant Malani <pmalani@...omium.org>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-usb@...r.kernel.org, Amelie Delaunay <amelie.delaunay@...com>
Subject: Re: [PATCH v10 14/15] usb: typec: tcpci: Implement Auto discharge
disconnect callbacks
On Wed, Oct 07, 2020 at 11:15:55PM -0700, Badhri Jagan Sridharan wrote:
> vImplement callbacks for enabling/disabling
> POWER_CONTROL.AutoDischargeDisconnect.
>
> Programs VBUS_SINK_DISCONNECT_THRESHOLD based on the
> voltage requested as sink, mode of operation.
>
> The programmed threshold is based on vSinkDisconnect and
> vSinkDisconnectPD values.
>
> Add auto_discharge_disconnect to tdata to allow TCPC chip
> level drivers enable AutoDischargeDisconnect.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> ---
> Changes since v1:
> - Changing patch version to v6 to fix version number confusion.
>
> Changes since v6:
> - Rebase on usb-next.
>
> Changes since v7:
> Heikki's suggestion:
> - Moved the actual write to TCPC_VBUS_SINK_DISCONNECT_THRESH
> as it's common to all chip drivers.
> - Renaming the tcpci_data callback as
> get_auto_vbus_discharge_threshold
>
> Changes since v8:
> - Removed get_auto_vbus_discharge_threshold callback and moved the logic
> to program the default threshold for TCPC_VBUS_SINK_DISCONNECT_THRESH
> into the TCPCI code.
>
> Changes since v9:
> - none
> ---
> drivers/usb/typec/tcpm/tcpci.c | 63 +++++++++++++++++++++++++++++++++-
> drivers/usb/typec/tcpm/tcpci.h | 14 ++++++--
> 2 files changed, 74 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> index f91688e43991..12d983a75510 100644
> --- a/drivers/usb/typec/tcpm/tcpci.c
> +++ b/drivers/usb/typec/tcpm/tcpci.c
> @@ -18,7 +18,10 @@
>
> #include "tcpci.h"
>
> -#define PD_RETRY_COUNT 3
> +#define PD_RETRY_COUNT 3
> +#define AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV 3500
> +#define AUTO_DISCHARGE_PD_HEADROOM_MV 850
> +#define AUTO_DISCHARGE_PPS_HEADROOM_MV 1250
>
> struct tcpci {
> struct device *dev;
> @@ -268,6 +271,58 @@ static int tcpci_set_vconn(struct tcpc_dev *tcpc, bool enable)
> enable ? TCPC_POWER_CTRL_VCONN_ENABLE : 0);
> }
>
> +static int tcpci_enable_auto_vbus_discharge(struct tcpc_dev *dev, bool enable)
> +{
> + struct tcpci *tcpci = tcpc_to_tcpci(dev);
> + int ret;
> +
> + ret = regmap_update_bits(tcpci->regmap, TCPC_POWER_CTRL, TCPC_POWER_CTRL_AUTO_DISCHARGE,
> + enable ? TCPC_POWER_CTRL_AUTO_DISCHARGE : 0);
> + return ret;
> +}
> +
> +static int tcpci_set_auto_vbus_discharge_threshold(struct tcpc_dev *dev, enum typec_pwr_opmode mode,
> + bool pps_active, u32 requested_vbus_voltage_mv)
> +{
> + struct tcpci *tcpci = tcpc_to_tcpci(dev);
> + unsigned int pwr_ctrl, threshold = 0;
> + int ret;
> +
> + /*
> + * Indicates that vbus is going to go away due PR_SWAP, hard reset etc.
> + * Do not discharge vbus here.
> + */
> + if (requested_vbus_voltage_mv == 0)
> + goto write_thresh;
> +
> + ret = regmap_read(tcpci->regmap, TCPC_POWER_CTRL, &pwr_ctrl);
> + if (ret < 0)
> + return ret;
> +
> + if (pwr_ctrl & TCPC_FAST_ROLE_SWAP_EN) {
> + /* To prevent disconnect when the source is fast role swap is capable. */
> + threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
> + } else if (mode == TYPEC_PWR_MODE_PD) {
> + if (pps_active)
> + threshold = (95 * requested_vbus_voltage_mv / 100) -
> + AUTO_DISCHARGE_PD_HEADROOM_MV;
> + else
> + threshold = (95 * requested_vbus_voltage_mv / 100) -
> + AUTO_DISCHARGE_PPS_HEADROOM_MV;
> + } else {
> + /* 3.5V for non-pd sink */
> + threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
> + }
> +
> + threshold = threshold / TCPC_VBUS_SINK_DISCONNECT_THRESH_LSB_MV;
> +
> + if (threshold > TCPC_VBUS_SINK_DISCONNECT_THRESH_MAX)
> + return -EINVAL;
> +
> +write_thresh:
> + return tcpci_write16(tcpci, TCPC_VBUS_SINK_DISCONNECT_THRESH, threshold);
> +}
> +
> static int tcpci_enable_frs(struct tcpc_dev *dev, bool enable)
> {
> struct tcpci *tcpci = tcpc_to_tcpci(dev);
> @@ -638,6 +693,12 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
> tcpci->tcpc.enable_frs = tcpci_enable_frs;
> tcpci->tcpc.frs_sourcing_vbus = tcpci_frs_sourcing_vbus;
>
> + if (tcpci->data->auto_discharge_disconnect) {
> + tcpci->tcpc.enable_auto_vbus_discharge = tcpci_enable_auto_vbus_discharge;
> + tcpci->tcpc.set_auto_vbus_discharge_threshold =
> + tcpci_set_auto_vbus_discharge_threshold;
> + }
> +
> err = tcpci_parse_config(tcpci);
> if (err < 0)
> return ERR_PTR(err);
> diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h
> index b418fe11b527..3fe313655f0c 100644
> --- a/drivers/usb/typec/tcpm/tcpci.h
> +++ b/drivers/usb/typec/tcpm/tcpci.h
> @@ -8,6 +8,8 @@
> #ifndef __LINUX_USB_TCPCI_H
> #define __LINUX_USB_TCPCI_H
>
> +#include <linux/usb/typec.h>
> +
> #define TCPC_VENDOR_ID 0x0
> #define TCPC_PRODUCT_ID 0x2
> #define TCPC_BCD_DEV 0x4
> @@ -67,6 +69,7 @@
>
> #define TCPC_POWER_CTRL 0x1c
> #define TCPC_POWER_CTRL_VCONN_ENABLE BIT(0)
> +#define TCPC_POWER_CTRL_AUTO_DISCHARGE BIT(4)
> #define TCPC_FAST_ROLE_SWAP_EN BIT(7)
>
> #define TCPC_CC_STATUS 0x1d
> @@ -133,6 +136,8 @@
>
> #define TCPC_VBUS_VOLTAGE 0x70
> #define TCPC_VBUS_SINK_DISCONNECT_THRESH 0x72
> +#define TCPC_VBUS_SINK_DISCONNECT_THRESH_LSB_MV 25
> +#define TCPC_VBUS_SINK_DISCONNECT_THRESH_MAX 0x3ff
> #define TCPC_VBUS_STOP_DISCHARGE_THRESH 0x74
> #define TCPC_VBUS_VOLTAGE_ALARM_HI_CFG 0x76
> #define TCPC_VBUS_VOLTAGE_ALARM_LO_CFG 0x78
> @@ -140,17 +145,22 @@
> /* I2C_WRITE_BYTE_COUNT + 1 when TX_BUF_BYTE_x is only accessible I2C_WRITE_BYTE_COUNT */
> #define TCPC_TRANSMIT_BUFFER_MAX_LEN 31
>
> +struct tcpci;
> +
> /*
> - * @TX_BUF_BYTE_x_hidden
> + * @TX_BUF_BYTE_x_hidden:
> * optional; Set when TX_BUF_BYTE_x can only be accessed through I2C_WRITE_BYTE_COUNT.
> * @frs_sourcing_vbus:
> * Optional; Callback to perform chip specific operations when FRS
> * is sourcing vbus.
> + * @auto_discharge_disconnect:
> + * Optional; Enables TCPC to autonously discharge vbus on disconnect.
> */
> -struct tcpci;
> struct tcpci_data {
> struct regmap *regmap;
> unsigned char TX_BUF_BYTE_x_hidden:1;
> + unsigned char auto_discharge_disconnect:1;
> +
> int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
> int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,
> bool enable);
> --
> 2.28.0.806.g8561365e88-goog
--
heikki
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