Linux-USB Archive on lore.kernel.org
 help / color / Atom feed
From: Badhri Jagan Sridharan <badhri@google.com>
To: Guenter Roeck <linux@roeck-us.net>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Rob Herring <robh+dt@kernel.org>,
	Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org, Kyle Tso <kyletso@google.com>,
	Badhri Jagan Sridharan <badhri@google.com>
Subject: [PATCH v2 5/6] usb: typec: tcpm: Allow slow charging loops to comply to pSnkStby
Date: Wed,  7 Apr 2021 13:07:22 -0700
Message-ID: <20210407200723.1914388-5-badhri@google.com> (raw)
In-Reply-To: <20210407200723.1914388-1-badhri@google.com>

When a PD charger advertising Rp-3.0 is connected to a sink port, the
sink port current limit would 3A, during SNK_DISCOVERY, till power
negotiation starts. Once the negotiation starts the power limit needs
to drop down to pSnkStby(500mA @ 5V) and to negotiated current limit
once the explicit contract is in place. Not all charging loops can ramp
up to 3A and drop down to 500mA within tSnkStdby which is 15ms. The port
partner might hard reset if tSnkStdby is not met.

To solve this problem, this patch introduces slow-charger-loop which
when set makes the port request PD_P_SNK_STDBY_MW upon entering
SNK_DISCOVERY(instead of 3A or the 1.5A during SNK_DISCOVERY) and the
actual currrent limit after RX of PD_CTRL_PSRDY for PD link or during
SNK_READY for non-pd link.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 770b2edd9a04..b5bed6866a2b 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -459,6 +459,12 @@ struct tcpm_port {
 	/* Auto vbus discharge status */
 	bool auto_vbus_discharge_enabled;
 
+	/*
+	 * When set, port requests PD_P_SNK_STDBY_MW upon entering SNK_DISCOVERY and
+	 * the actual currrent limit after RX of PD_CTRL_PSRDY for PD link,
+	 * SNK_READY for non-pd link.
+	 */
+	bool slow_charger_loop;
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dentry;
 	struct mutex logbuffer_lock;	/* log buffer access lock */
@@ -4047,9 +4053,12 @@ static void run_state_machine(struct tcpm_port *port)
 		break;
 	case SNK_DISCOVERY:
 		if (port->vbus_present) {
-			tcpm_set_current_limit(port,
-					       tcpm_get_current_limit(port),
-					       5000);
+			u32 current_lim = (!port->slow_charger_loop ||
+					   (tcpm_get_current_limit(port) <=
+					    PD_P_SNK_STDBY_MW / 5)) ?
+				tcpm_get_current_limit(port) :
+				PD_P_SNK_STDBY_MW / 5;
+			tcpm_set_current_limit(port, current_lim, 5000);
 			tcpm_set_charge(port, true);
 			tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
 			break;
@@ -4161,6 +4170,8 @@ static void run_state_machine(struct tcpm_port *port)
 			port->pwr_opmode = TYPEC_PWR_MODE_PD;
 		}
 
+		if (!port->pd_capable && port->slow_charger_loop)
+			tcpm_set_current_limit(port, tcpm_get_current_limit(port), 5000);
 		tcpm_swap_complete(port, 0);
 		tcpm_typec_connect(port);
 		mod_enable_frs_delayed_work(port, 0);
@@ -5763,6 +5774,7 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
 	port->typec_caps.type = ret;
 	port->port_type = port->typec_caps.type;
 
+	port->slow_charger_loop = fwnode_property_read_bool(fwnode, "slow-charger-loop");
 	if (port->port_type == TYPEC_PORT_SNK)
 		goto sink;
 
-- 
2.31.1.295.g9ea45b61b8-goog


  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 20:07 [PATCH v2 1/6] usb: typec: tcpm: Address incorrect values of tcpm psy for fixed supply Badhri Jagan Sridharan
2021-04-07 20:07 ` [PATCH v2 2/6] usb: typec: tcpm: Address incorrect values of tcpm psy for pps supply Badhri Jagan Sridharan
2021-04-08  6:59   ` Heikki Krogerus
2021-04-10  2:10   ` Guenter Roeck
2021-04-07 20:07 ` [PATCH v2 3/6] usb: typec: tcpm: update power supply once partner accepts Badhri Jagan Sridharan
2021-04-08  7:09   ` Heikki Krogerus
2021-04-10  2:10   ` Guenter Roeck
2021-04-07 20:07 ` [PATCH v2 4/6] usb: typec: tcpm: Honour pSnkStdby requirement during negotiation Badhri Jagan Sridharan
2021-04-08  7:47   ` Heikki Krogerus
2021-04-14  0:58     ` Badhri Jagan Sridharan
2021-04-10  2:11   ` Guenter Roeck
2021-04-07 20:07 ` Badhri Jagan Sridharan [this message]
2021-04-08  8:14   ` [PATCH v2 5/6] usb: typec: tcpm: Allow slow charging loops to comply to pSnkStby Heikki Krogerus
2021-04-08  8:22     ` Heikki Krogerus
2021-04-14  0:59       ` Badhri Jagan Sridharan
2021-04-07 20:07 ` [PATCH v2 6/6] Documentation: connector: Add slow-charger-loop definition Badhri Jagan Sridharan
2021-04-09 18:38   ` Rob Herring
2021-04-14  1:27     ` Badhri Jagan Sridharan
2021-04-08  6:51 ` [PATCH v2 1/6] usb: typec: tcpm: Address incorrect values of tcpm psy for fixed supply Heikki Krogerus

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210407200723.1914388-5-badhri@google.com \
    --to=badhri@google.com \
    --cc=Adam.Thomson.Opensource@diasemi.com \
    --cc=devicetree@vger.kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=heikki.krogerus@linux.intel.com \
    --cc=kyletso@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=robh+dt@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-USB Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-usb/0 linux-usb/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-usb linux-usb/ https://lore.kernel.org/linux-usb \
		linux-usb@vger.kernel.org
	public-inbox-index linux-usb

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-usb


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git