ACPI: Provide /sys/kernel/debug/ec/...

This patch provides the same information through debugfs, which previously was
provided through /proc/acpi/embedded_controller/*/info

This is the gpe the EC is connected to and whether the global lock
gets used.
The io ports used are added to /proc/ioports in another patch.
Beside the fact that /proc/acpi is deprecated for quite some time,
this info is not needed for applications and thus can be moved
to debugfs instead of a public interface like /sys.

Signed-off-by: Thomas Renninger <trenn@suse.de>

CC: Alexey Starikovskiy <astarikovskiy@suse.de>
CC: Len Brown <lenb@kernel.org>
CC: linux-kernel@vger.kernel.org
CC: linux-acpi@vger.kernel.org
CC: Bjorn Helgaas <bjorn.helgaas@hp.com>
CC: platform-driver-x86@vger.kernel.org
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/acpi/ec_sys.c

@@ -0,0 +1,57 @@
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/debugfs.h>
+#include "internal.h"
+
+MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");
+MODULE_DESCRIPTION("ACPI EC sysfs access driver");
+MODULE_LICENSE("GPL");
+
+struct sysdev_class acpi_ec_sysdev_class = {
+	.name = "ec",
+};
+
+static struct dentry *acpi_ec_debugfs_dir;
+
+int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
+{
+	struct dentry *dev_dir;
+	char name[64];
+	if (ec_device_count == 0) {
+		acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
+		if (!acpi_ec_debugfs_dir)
+			return -ENOMEM;
+	}
+
+	sprintf(name, "ec%u", ec_device_count);
+	dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
+	if (!dev_dir) {
+		if (ec_device_count == 0)
+			debugfs_remove_recursive(acpi_ec_debugfs_dir);
+		/* TBD: Proper cleanup for multiple ECs */
+		return -ENOMEM;
+	}
+
+	debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe);
+	debugfs_create_bool("use_global_lock", 0444, dev_dir,
+			    (u32 *)&first_ec->global_lock);
+	return 0;
+}
+
+static int __init acpi_ec_sys_init(void)
+{
+	int err = 0;
+	if (first_ec)
+		err = acpi_ec_add_debugfs(first_ec, 0);
+	else
+		err = -ENODEV;
+	return err;
+}
+
+static void __exit acpi_ec_sys_exit(void)
+{
+	debugfs_remove_recursive(acpi_ec_debugfs_dir);
+}
+
+module_init(acpi_ec_sys_init);
+module_exit(acpi_ec_sys_exit);