usb: typec: tcpm: Extend the matching rules on PPS APDO selection (c710d0bb) · Commits · 戴 / test

Current matching rules ensure that the voltage range of selected Source Capability is entirely within the range defined in one of the Sink Capabilities. This is reasonable but not practical because Sink may not support wide range of voltage when sinking power while Source could advertise its capabilities in relatively wider range. For example, a Source PDO advertising 3.3V-11V@3A (9V Prog of Fixed Nominal Voltage) will not be selected if the Sink requires 5V-12V@3A PPS power. However, the Sink could work well if the requested voltage range in RDOs is 5V-11V@3A. Currently accepted: |--------- source -----| |----------- sink ---------------| Currently not accepted: |--------- source -----| |----------- sink ---------------| |--------- source -----| |----------- sink ---------------| |--------- source -----------------| |------ sink -------| To improve the usability, change the matching rules to what listed below: a. The Source PDO is selectable if any portion of the voltage range overlaps one of the Sink PDO's voltage range. b. The maximum operational voltage will be the lower one between the selected Source PDO and the matching Sink PDO. c. The maximum power will be the maximum operational voltage times the maximum current defined in the selected Source PDO d. Select the Source PDO with the highest maximum power Signed-off-by:

Kyle Tso <kyletso@google.com> Acked-by:

Adam Thomson <Adam.Thomson.Opensource@diasemi.com> Reviewed-by:

Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/tcpm.c

+20 −15

Original line number	Diff line number	Diff line
		@@ -2213,7 +2213,8 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port)
		unsigned int i, j, max_mw = 0, max_mv = 0;
		unsigned int min_src_mv, max_src_mv, src_ma, src_mw;
		unsigned int min_snk_mv, max_snk_mv;
		u32 pdo;
		unsigned int max_op_mv;
		u32 pdo, src, snk;
		unsigned int src_pdo = 0, snk_pdo = 0;

		/*
		@@ -2263,16 +2264,18 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port)
		continue;
		}

		if (max_src_mv <= max_snk_mv &&
		min_src_mv >= min_snk_mv) {
		if (min_src_mv <= max_snk_mv &&
		max_src_mv >= min_snk_mv) {
		max_op_mv = min(max_src_mv, max_snk_mv);
		src_mw = (max_op_mv * src_ma) / 1000;
		/* Prefer higher voltages if available */
		if ((src_mw == max_mw &&
		min_src_mv > max_mv) \|\|
		max_op_mv > max_mv) \|\|
		src_mw > max_mw) {
		src_pdo = i;
		snk_pdo = j;
		max_mw = src_mw;
		max_mv = max_src_mv;
		max_mv = max_op_mv;
		}
		}
		}
		@@ -2285,16 +2288,18 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port)
		}

		if (src_pdo) {
		pdo = port->source_caps[src_pdo];

		port->pps_data.min_volt = pdo_pps_apdo_min_voltage(pdo);
		port->pps_data.max_volt = pdo_pps_apdo_max_voltage(pdo);
		port->pps_data.max_curr =
		min_pps_apdo_current(pdo, port->snk_pdo[snk_pdo]);
		port->pps_data.out_volt =
		min(pdo_pps_apdo_max_voltage(pdo), port->pps_data.out_volt);
		port->pps_data.op_curr =
		min(port->pps_data.max_curr, port->pps_data.op_curr);
		src = port->source_caps[src_pdo];
		snk = port->snk_pdo[snk_pdo];

		port->pps_data.min_volt = max(pdo_pps_apdo_min_voltage(src),
		pdo_pps_apdo_min_voltage(snk));
		port->pps_data.max_volt = min(pdo_pps_apdo_max_voltage(src),
		pdo_pps_apdo_max_voltage(snk));
		port->pps_data.max_curr = min_pps_apdo_current(src, snk);
		port->pps_data.out_volt = min(port->pps_data.max_volt,
		port->pps_data.out_volt);
		port->pps_data.op_curr = min(port->pps_data.max_curr,
		port->pps_data.op_curr);
		}

		return src_pdo;

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