linux-kernel - [PATCH v2] usb: typec: intel_pmc_mux: Expose IOM port status to debugfs

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Message-Id: <20230414081910.1336405-1-rajat.khandelwal@linux.intel.com>
Date:   Fri, 14 Apr 2023 13:49:10 +0530
From:   Rajat Khandelwal <rajat.khandelwal@...ux.intel.com>
To:     heikki.krogerus@...ux.intel.com, gregkh@...uxfoundation.org
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rajat Khandelwal <rajat.khandelwal@...ux.intel.com>
Subject: [PATCH v2] usb: typec: intel_pmc_mux: Expose IOM port status to debugfs

IOM status has a crucial role during debugging to check the
current state of the type-C port.
There are ways to fetch the status, but all those require the
IOM port status offset, which could change with platform.

Make a debugfs directory for intel_pmc_mux and expose the status
under it per port basis.

Signed-off-by: Rajat Khandelwal <rajat.khandelwal@...ux.intel.com>
---

v2:
1. Remove static declaration of the debugfs root for 'intel_pmc_mux'
2. Remove explicitly defined one-liner functions

 drivers/usb/typec/mux/intel_pmc_mux.c | 34 +++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index 34e4188a40ff..1d43b111781e 100644
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -15,6 +15,7 @@
 #include <linux/usb/typec_mux.h>
 #include <linux/usb/typec_dp.h>
 #include <linux/usb/typec_tbt.h>
+#include <linux/debugfs.h>
 
 #include <asm/intel_scu_ipc.h>
 
@@ -639,9 +640,34 @@ static int pmc_usb_probe_iom(struct pmc_usb *pmc)
 	return 0;
 }
 
+static int port_iom_status_show(struct seq_file *s, void *unused)
+{
+	struct pmc_usb_port *port = s->private;
+
+	update_port_status(port);
+	seq_printf(s, "0x%08x\n", port->iom_status);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(port_iom_status);
+
+static void pmc_mux_port_debugfs_init(struct pmc_usb_port *port,
+				      struct dentry *pmc_mux_debugfs_root)
+{
+	struct dentry *debugfs_dir;
+	char name[6];
+
+	snprintf(name, sizeof(name), "port%d", port->usb3_port - 1);
+
+	debugfs_dir = debugfs_create_dir(name, pmc_mux_debugfs_root);
+	debugfs_create_file("iom_status", 0400, debugfs_dir, port,
+			    &port_iom_status_fops);
+}
+
 static int pmc_usb_probe(struct platform_device *pdev)
 {
 	struct fwnode_handle *fwnode = NULL;
+	struct dentry *pmc_mux_debugfs_root;
 	struct pmc_usb *pmc;
 	int i = 0;
 	int ret;
@@ -674,6 +700,8 @@ static int pmc_usb_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	pmc_mux_debugfs_root = debugfs_create_dir("intel_pmc_mux", NULL);
+
 	/*
 	 * For every physical USB connector (USB2 and USB3 combo) there is a
 	 * child ACPI device node under the PMC mux ACPI device object.
@@ -688,6 +716,8 @@ static int pmc_usb_probe(struct platform_device *pdev)
 			fwnode_handle_put(fwnode);
 			goto err_remove_ports;
 		}
+
+		pmc_mux_port_debugfs_init(&pmc->port[i], pmc_mux_debugfs_root);
 	}
 
 	platform_set_drvdata(pdev, pmc);
@@ -703,6 +733,8 @@ static int pmc_usb_probe(struct platform_device *pdev)
 
 	acpi_dev_put(pmc->iom_adev);
 
+	debugfs_lookup_and_remove("intel_pmc_mux", NULL);
+
 	return ret;
 }
 
@@ -719,6 +751,8 @@ static int pmc_usb_remove(struct platform_device *pdev)
 
 	acpi_dev_put(pmc->iom_adev);
 
+	debugfs_lookup_and_remove("intel_pmc_mux", NULL);
+
 	return 0;
 }
 
-- 
2.34.1