PNP: add CONFIG_PNP_DEBUG_MESSAGES and pnp_dbg()

This adds the core function pnp_dbg() and a new config option to
enable it.

The PNP core debugging messages can be enabled at boot-time with the
"pnp.debug" kernel parameter.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

4 files changed, 39 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1150444a21ab..7164d4e4136b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1660,6 +1660,10 @@ and is between 256 and 4096 characters. It is defined in the file
                         Override pmtimer IOPort with a hex value.
                         e.g. pmtmr=0x508
 
+        pnp.debug       [PNP]
+                        Enable PNP debug messages.  This depends on the
+                        CONFIG_PNP_DEBUG_MESSAGES option.
+
         pnpacpi=        [ACPI]
                         { off }
 
diff --git a/drivers/pnp/Kconfig b/drivers/pnp/Kconfig
index 821933f9aa57..8a3237f9f2a7 100644
--- a/drivers/pnp/Kconfig
+++ b/drivers/pnp/Kconfig
@@ -20,6 +20,20 @@ menuconfig PNP
 
           If unsure, say Y.
 
+config PNP_DEBUG_MESSAGES
+        default y
+        bool "PNP debugging messages"
+        depends on PNP
+        help
+          Say Y here if you want the PNP layer to be able to produce debugging
+          messages if needed.  The messages can be enabled at boot-time with
+          the pnp.debug kernel parameter.
+
+          This option allows you to save a bit of space if you do not want
+          the messages to even be built into the kernel.
+
+          If you have any doubts about this, say Y here.
+
 if PNP
 
 config PNP_DEBUG
diff --git a/drivers/pnp/base.h b/drivers/pnp/base.h
index 9fd7bb9b7dce..5e4e82c82659 100644
--- a/drivers/pnp/base.h
+++ b/drivers/pnp/base.h
@@ -166,3 +166,13 @@ struct pnp_resource *pnp_add_io_resource(struct pnp_dev *dev,
 struct pnp_resource *pnp_add_mem_resource(struct pnp_dev *dev,
                                           resource_size_t start,
                                           resource_size_t end, int flags);
+
+extern int pnp_debug;
+
+#if defined(CONFIG_PNP_DEBUG_MESSAGES)
+#define pnp_dbg(dev, format, arg...)                                    \
+        ({ if (pnp_debug) dev_printk(KERN_DEBUG, dev, format, ## arg); 0; })
+#else
+#define pnp_dbg(dev, format, arg...)                                    \
+        ({ if (0) dev_printk(KERN_DEBUG, dev, format, ## arg); 0; })
+#endif
diff --git a/drivers/pnp/core.c b/drivers/pnp/core.c
index 7cb1ffc14d4e..61291b5bfe12 100644
--- a/drivers/pnp/core.c
+++ b/drivers/pnp/core.c
@@ -221,3 +221,14 @@ static int __init pnp_init(void)
 }
 
 subsys_initcall(pnp_init);
+
+int pnp_debug;
+
+#if defined(CONFIG_PNP_DEBUG_MESSAGES)
+static int __init pnp_debug_setup(char *__unused)
+{
+        pnp_debug = 1;
+        return 1;
+}
+__setup("pnp.debug", pnp_debug_setup);
+#endif