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@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Message-ID: <20230531105050.638250-1-rajat.khandelwal@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index e049ead..5e8edf3 100644 (file)
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -15,6 +15,8 @@
 #include <linux/usb/typec_mux.h>
 #include <linux/usb/typec_dp.h>
 #include <linux/usb/typec_tbt.h>
+#include <linux/debugfs.h>
+#include <linux/usb.h>
 
 #include <asm/intel_scu_ipc.h>
 
@@ -143,8 +145,12 @@ struct pmc_usb {
        struct acpi_device *iom_adev;
        void __iomem *iom_base;
        u32 iom_port_status_offset;
+
+       struct dentry *dentry;
 };
 
+static struct dentry *pmc_mux_debugfs_root;
+
 static void update_port_status(struct pmc_usb_port *port)
 {
        u8 port_num;
@@ -639,6 +645,29 @@ 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 *debugfs_dir;
+       char name[6];
+
+       snprintf(name, sizeof(name), "port%d", port->usb3_port - 1);
+
+       debugfs_dir = debugfs_create_dir(name, port->pmc->dentry);
+       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;
@@ -674,6 +703,8 @@ static int pmc_usb_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
+       pmc->dentry = debugfs_create_dir(dev_name(pmc->dev), pmc_mux_debugfs_root);
+
        /*
         * 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 +719,8 @@ 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]);
        }
 
        platform_set_drvdata(pdev, pmc);
@@ -703,6 +736,8 @@ err_remove_ports:
 
        acpi_dev_put(pmc->iom_adev);
 
+       debugfs_remove(pmc->dentry);
+
        return ret;
 }
 
@@ -718,6 +753,8 @@ static void pmc_usb_remove(struct platform_device *pdev)
        }
 
        acpi_dev_put(pmc->iom_adev);
+
+       debugfs_remove(pmc->dentry);
 }
 
 static const struct acpi_device_id pmc_usb_acpi_ids[] = {
@@ -735,7 +772,20 @@ static struct platform_driver pmc_usb_driver = {
        .remove_new = pmc_usb_remove,
 };
 
-module_platform_driver(pmc_usb_driver);
+static int __init pmc_usb_init(void)
+{
+       pmc_mux_debugfs_root = debugfs_create_dir("intel_pmc_mux", usb_debug_root);
+
+       return platform_driver_register(&pmc_usb_driver);
+}
+module_init(pmc_usb_init);
+
+static void __exit pmc_usb_exit(void)
+{
+       platform_driver_unregister(&pmc_usb_driver);
+       debugfs_remove(pmc_mux_debugfs_root);
+}
+module_exit(pmc_usb_exit);
 
 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
 MODULE_LICENSE("GPL v2");