[PATCH v2] dell-laptop: Add debugfs support

[Keng-Yu Lin <keng-yu.lin@canonical.com>]

Export the status of RF killswitch through debugfs.

The killswitch status is obtained by the SMI to BIOS. Exporting this status
through debugfs can help identify the issue with the misbehaving firmware.

Signed-off-by: Keng-Yu Lin <keng-yu.lin@canonical.com>
---
 drivers/platform/x86/dell-laptop.c |   83 ++++++++++++++++++++++++++++++++++++
 1 files changed, 83 insertions(+), 0 deletions(-)

diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index 4413975..1536dd5 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -25,6 +25,8 @@
 #include <linux/mm.h>
 #include <linux/i8042.h>
 #include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 #include "../../firmware/dcdbas.h"
 
 #define BRIGHTNESS_TOKEN 0x7d
@@ -325,6 +327,77 @@ static const struct rfkill_ops dell_rfkill_ops = {
 	.query = dell_rfkill_query,
 };
 
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *dell_laptop_dir;
+
+static int dell_debugfs_show(struct seq_file *s, void *data)
+{
+	int status;
+
+	get_buffer();
+	dell_send_request(buffer, 17, 11);
+	status = buffer->output[1];
+	release_buffer();
+
+	seq_printf(s, "status:\t0x%X\n", status);
+	seq_printf(s, "Hardware switch supported:   %lu\n",
+		   status & BIT(0));
+	seq_printf(s, "Wifi locator supported:      %lu\n",
+		  (status & BIT(1)) >> 1);
+	seq_printf(s, "Wifi is supported:           %lu\n",
+		  (status & BIT(2)) >> 2);
+	seq_printf(s, "Bluetooth is supported:      %lu\n",
+		  (status & BIT(3)) >> 3);
+	seq_printf(s, "WWAN is supported:           %lu\n",
+		  (status & BIT(4)) >> 4);
+	seq_printf(s, "Wireless keyboard supported: %lu\n",
+		  (status & BIT(5)) >> 5);
+	seq_printf(s, "Wifi is installed:           %lu\n",
+		  (status & BIT(8)) >> 8);
+	seq_printf(s, "Bluetooth is installed:      %lu\n",
+		  (status & BIT(9)) >> 9);
+	seq_printf(s, "WWAN is installed:           %lu\n",
+		  (status & BIT(10)) >> 10);
+	seq_printf(s, "Hardware switch is on:       %lu\n",
+		  (status & BIT(16)) >> 16);
+	seq_printf(s, "Wifi is blocked:             %lu\n",
+		  (status & BIT(17)) >> 17);
+	seq_printf(s, "Bluetooth is blocked:        %lu\n",
+		  (status & BIT(18)) >> 18);
+	seq_printf(s, "WWAN is blocked:             %lu\n",
+		  (status & BIT(19)) >> 19);
+
+	seq_printf(s, "\nhwswitch_state:\t0x%X\n", hwswitch_state);
+	seq_printf(s, "Wifi controlled by switch:      %lu\n",
+		   hwswitch_state & BIT(0));
+	seq_printf(s, "Bluetooth controlled by switch: %lu\n",
+		   hwswitch_state & BIT(0) >> 1);
+	seq_printf(s, "WWAN controlled by switch:      %lu\n",
+		   hwswitch_state & BIT(0) >> 2);
+	seq_printf(s, "Wireless switch config locked:  %lu\n",
+		   hwswitch_state & BIT(0) >> 7);
+	seq_printf(s, "Wifi locator enabled:           %lu\n",
+		   hwswitch_state & BIT(0) >> 8);
+	seq_printf(s, "Wifi locator setting locked:    %lu\n",
+		   hwswitch_state & BIT(0) >> 15);
+
+	return 0;
+}
+
+static int dell_debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, dell_debugfs_show, inode->i_private);
+}
+
+static const struct file_operations dell_debugfs_fops = {
+	.owner = THIS_MODULE,
+	.open = dell_debugfs_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+#endif
+
 static void dell_update_rfkill(struct work_struct *ignored)
 {
 	if (wifi_rfkill)
@@ -556,6 +629,13 @@ static int __init dell_init(void)
 		goto fail_filter;
 	}
 
+#ifdef CONFIG_DEBUG_FS
+	dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
+	if (dell_laptop_dir != NULL)
+		debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
+				    &dell_debugfs_fops);
+#endif
+
 #ifdef CONFIG_ACPI
 	/* In the event of an ACPI backlight being available, don't
 	 * register the platform controller.
@@ -615,6 +695,9 @@ fail_platform_driver:
 
 static void __exit dell_exit(void)
 {
+#ifdef CONFIG_DEBUG_FS
+	debugfs_remove_recursive(dell_laptop_dir);
+#endif
 	i8042_remove_filter(dell_laptop_i8042_filter);
 	cancel_delayed_work_sync(&dell_rfkill_work);
 	backlight_device_unregister(dell_backlight_device);
-- 
1.7.1