[PATCH v10 12/15] usb: typec: tcpm: Parse frs type-c current from device tree

[Badhri Jagan Sridharan]

New source's current capability is now defined as string based
device tree property through new-source-frs-typec-current.
Refactor tcpm code to parse new-source-frs-typec-current and
infer local port's new source current capability during frs.

Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
---
v9 is the first version of this patch in this series to rebase
TCPM code to read new source frs current from
new-source-frs-typec-current. No changes since v9.
---
 drivers/usb/typec/tcpm/tcpm.c | 41 +++++++++++++++++++----------------
 include/linux/usb/typec.h     | 12 ++++++++++
 2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 02b7f623f584..d5a3e2b3bea2 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -180,16 +180,11 @@ enum adev_actions {
 	ADEV_ATTENTION,
 };
 
-/*
- * Initial current capability of the new source when vSafe5V is applied during PD3.0 Fast Role Swap.
- * Based on "Table 6-14 Fixed Supply PDO - Sink" of "USB Power Delivery Specification Revision 3.0,
- * Version 1.2"
- */
-enum frs_typec_current {
-	FRS_NOT_SUPPORTED,
-	FRS_DEFAULT_POWER,
-	FRS_5V_1P5A,
-	FRS_5V_3A,
+static const char * const typec_new_source_frs_current[] = {
+	[FRS_NOT_SUPPORTED]	= "not-supported",
+	[FRS_DEFAULT_POWER]	= "default",
+	[FRS_5V_1P5A]		= "1.5A",
+	[FRS_5V_3A]		= "3.0A",
 };
 
 /* Events from low level driver */
@@ -364,7 +359,7 @@ struct tcpm_port {
 	bool self_powered;
 
 	/* FRS */
-	enum frs_typec_current frs_current;
+	enum typec_new_source_frs_current new_source_frs_current;
 
 	/* Sink caps have been queried */
 	bool sink_cap_done;
@@ -1713,7 +1708,7 @@ static void tcpm_pd_data_request(struct tcpm_port *port,
 	unsigned int cnt = pd_header_cnt_le(msg->header);
 	unsigned int rev = pd_header_rev_le(msg->header);
 	unsigned int i;
-	enum frs_typec_current frs_current;
+	enum typec_new_source_frs_current partner_frs_current;
 	bool frs_enable;
 	int ret;
 
@@ -1786,12 +1781,13 @@ static void tcpm_pd_data_request(struct tcpm_port *port,
 		for (i = 0; i < cnt; i++)
 			port->sink_caps[i] = le32_to_cpu(msg->payload[i]);
 
-		frs_current = (port->sink_caps[0] & PDO_FIXED_FRS_CURR_MASK) >>
+		partner_frs_current = (port->sink_caps[0] & PDO_FIXED_FRS_CURR_MASK) >>
 			PDO_FIXED_FRS_CURR_SHIFT;
-		frs_enable = frs_current && (frs_current <= port->frs_current);
+		frs_enable = partner_frs_current && (partner_frs_current <=
+						     port->new_source_frs_current);
 		tcpm_log(port,
 			 "Port partner FRS capable partner_frs_current:%u port_frs_current:%u enable:%c",
-			 frs_current, port->frs_current, frs_enable ? 'y' : 'n');
+			 partner_frs_current, port->new_source_frs_current, frs_enable ? 'y' : 'n');
 		if (frs_enable) {
 			ret  = port->tcpc->enable_frs(port->tcpc, true);
 			tcpm_log(port, "Enable FRS %s, ret:%d\n", ret ? "fail" : "success", ret);
@@ -4746,7 +4742,8 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
 {
 	const char *cap_str;
 	int ret;
-	u32 mw, frs_current;
+	u32 mw;
+	const char *new_source_frs_current;
 
 	if (!fwnode)
 		return -EINVAL;
@@ -4817,9 +4814,15 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
 
 	/* FRS can only be supported byb DRP ports */
 	if (port->port_type == TYPEC_PORT_DRP) {
-		ret = fwnode_property_read_u32(fwnode, "frs-typec-current", &frs_current);
-		if (ret >= 0 && frs_current <= FRS_5V_3A)
-			port->frs_current = frs_current;
+		ret = fwnode_property_read_string(fwnode, "new-source-frs-typec-current",
+						  &new_source_frs_current);
+		if (!ret) {
+			ret = match_string(typec_new_source_frs_current,
+					   ARRAY_SIZE(typec_new_source_frs_current),
+					   new_source_frs_current);
+			if (ret >= 0)
+				port->new_source_frs_current = ret;
+		}
 	}
 
 	return 0;
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 6be558045942..3198b89fa451 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -72,6 +72,18 @@ enum typec_orientation {
 	TYPEC_ORIENTATION_REVERSE,
 };
 
+/*
+ * Based on "Table 6-14 Fixed Supply PDO - Sink" of "USB Power Delivery Specification Revision 3.0,
+ * Version 1.2"
+ * Initial current capability of the new source when vSafe5V is applied.
+ */
+enum typec_new_source_frs_current {
+	FRS_NOT_SUPPORTED,
+	FRS_DEFAULT_POWER,
+	FRS_5V_1P5A,
+	FRS_5V_3A,
+};
+
 /*
  * struct enter_usb_data - Enter_USB Message details
  * @eudo: Enter_USB Data Object
-- 
2.28.0.806.g8561365e88-goog