thunderbolt: Add helper to check if CL states are enabled on port

We will need this when enabling lane margining support.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/switch.c

@@ -1330,6 +1330,34 @@ static int tb_port_clx_enable(struct tb_port *port, enum tb_clx clx)
 	return __tb_port_clx_set(port, clx, true);
 }
 
+/**
+ * tb_port_is_clx_enabled() - Is given CL state enabled
+ * @port: USB4 port to check
+ * @clx_mask: Mask of CL states to check
+ *
+ * Returns true if any of the given CL states is enabled for @port.
+ */
+bool tb_port_is_clx_enabled(struct tb_port *port, unsigned int clx_mask)
+{
+	u32 val, mask = 0;
+	int ret;
+
+	if (!tb_port_clx_supported(port, clx_mask))
+		return false;
+
+	if (clx_mask & TB_CL1)
+		mask |= LANE_ADP_CS_1_CL0S_ENABLE | LANE_ADP_CS_1_CL1_ENABLE;
+	if (clx_mask & TB_CL2)
+		mask |= LANE_ADP_CS_1_CL2_ENABLE;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_phy + LANE_ADP_CS_1, 1);
+	if (ret)
+		return false;
+
+	return !!(val & mask);
+}
+
 static int tb_port_start_lane_initialization(struct tb_port *port)
 {
 	int ret;

drivers/thunderbolt/tb.h

@@ -1035,6 +1035,7 @@ void tb_port_lane_bonding_disable(struct tb_port *port);
 int tb_port_wait_for_link_width(struct tb_port *port, int width,
 				int timeout_msec);
 int tb_port_update_credits(struct tb_port *port);
+bool tb_port_is_clx_enabled(struct tb_port *port, enum tb_clx clx);
 
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec);
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap);

drivers/thunderbolt/tb_regs.h

@@ -334,6 +334,7 @@ struct tb_regs_port_header {
 #define LANE_ADP_CS_1_TARGET_WIDTH_DUAL		0x3
 #define LANE_ADP_CS_1_CL0S_ENABLE		BIT(10)
 #define LANE_ADP_CS_1_CL1_ENABLE		BIT(11)
+#define LANE_ADP_CS_1_CL2_ENABLE		BIT(12)
 #define LANE_ADP_CS_1_LD			BIT(14)
 #define LANE_ADP_CS_1_LB			BIT(15)
 #define LANE_ADP_CS_1_CURRENT_SPEED_MASK	GENMASK(19, 16)