ACPI: thinkpad-acpi: add CMOS NVRAM polling for hot keys (v9)

Older ThinkPad models do not export some of the hot keys over the
event-based ACPI hot key interface.  For these models, one has to poll
the CMOS NVRAM to check the key state at a rate faster than the expected
rate at which the user might repeatedly press the same hot key.

This patch implements this functionality for many of the hotkeys in a
transparent way: hot keys will now Just Work, and the driver knows the
best approach (events or NVRAM polling) to employ, based on the
HKEY.MHKA ACPI method.

Also, the driver can turn off the polling when there are no users for
the hot keys that need such polling.

The NVRAM-based hot keys of the A3x series that have never been
implemented by later models are not supported, to avoid changes in the
keymap of the input devices that could cause headaches in the future.

There is a Kconfig option to avoid compiling the NVRAM polling code, as
it is not very small, and unlikely to be useful on any ThinkPad newer
than a T40, X31 or R52.

This feature is based on a previous effort by Richard Hughes.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Richard Hughes <hughsient@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 56 insertions, 4 deletions

diff --git a/drivers/misc/thinkpad_acpi.h b/drivers/misc/thinkpad_acpi.h
index 3b0313443138..582184dc4543 100644
--- a/drivers/misc/thinkpad_acpi.h
+++ b/drivers/misc/thinkpad_acpi.h
@@ -31,6 +31,9 @@
 #include <linux/string.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/delay.h>
 
 #include <linux/nvram.h>
 #include <linux/proc_fs.h>
@@ -82,10 +85,31 @@
 #define TP_CMOS_BRIGHTNESS_UP   4
 #define TP_CMOS_BRIGHTNESS_DOWN 5
 
-/* ThinkPad CMOS NVRAM constants */
-#define TP_NVRAM_ADDR_BRIGHTNESS       0x5e
-#define TP_NVRAM_MASK_LEVEL_BRIGHTNESS 0x0f
-#define TP_NVRAM_POS_LEVEL_BRIGHTNESS 0
+/* NVRAM Addresses */
+enum tp_nvram_addr {
+        TP_NVRAM_ADDR_HK2               = 0x57,
+        TP_NVRAM_ADDR_THINKLIGHT        = 0x58,
+        TP_NVRAM_ADDR_VIDEO             = 0x59,
+        TP_NVRAM_ADDR_BRIGHTNESS        = 0x5e,
+        TP_NVRAM_ADDR_MIXER             = 0x60,
+};
+
+/* NVRAM bit masks */
+enum {
+        TP_NVRAM_MASK_HKT_THINKPAD      = 0x08,
+        TP_NVRAM_MASK_HKT_ZOOM          = 0x20,
+        TP_NVRAM_MASK_HKT_DISPLAY       = 0x40,
+        TP_NVRAM_MASK_HKT_HIBERNATE     = 0x80,
+        TP_NVRAM_MASK_THINKLIGHT        = 0x10,
+        TP_NVRAM_MASK_HKT_DISPEXPND     = 0x30,
+        TP_NVRAM_MASK_HKT_BRIGHTNESS    = 0x20,
+        TP_NVRAM_MASK_LEVEL_BRIGHTNESS  = 0x0f,
+        TP_NVRAM_POS_LEVEL_BRIGHTNESS   = 0,
+        TP_NVRAM_MASK_MUTE              = 0x40,
+        TP_NVRAM_MASK_HKT_VOLUME        = 0x80,
+        TP_NVRAM_MASK_LEVEL_VOLUME      = 0x0f,
+        TP_NVRAM_POS_LEVEL_VOLUME       = 0,
+};
 
 #define onoff(status,bit) ((status) & (1 << (bit)) ? "on" : "off")
 #define enabled(status,bit) ((status) & (1 << (bit)) ? "enabled" : "disabled")
@@ -255,6 +279,7 @@ static struct {
         u32 sensors_pdrv_registered:1;
         u32 sensors_pdrv_attrs_registered:1;
         u32 sensors_pdev_attrs_registered:1;
+        u32 hotkey_poll_active:1;
 } tp_features;
 
 struct thinkpad_id_data {
@@ -454,6 +479,33 @@ static int fan_write_cmd_watchdog(const char *cmd, int *rc);
  * Hotkey subdriver
  */
 
+enum {  /* hot key scan codes (derived from ACPI DSDT) */
+        TP_ACPI_HOTKEYSCAN_FNF1         = 0,
+        TP_ACPI_HOTKEYSCAN_FNF2,
+        TP_ACPI_HOTKEYSCAN_FNF3,
+        TP_ACPI_HOTKEYSCAN_FNF4,
+        TP_ACPI_HOTKEYSCAN_FNF5,
+        TP_ACPI_HOTKEYSCAN_FNF6,
+        TP_ACPI_HOTKEYSCAN_FNF7,
+        TP_ACPI_HOTKEYSCAN_FNF8,
+        TP_ACPI_HOTKEYSCAN_FNF9,
+        TP_ACPI_HOTKEYSCAN_FNF10,
+        TP_ACPI_HOTKEYSCAN_FNF11,
+        TP_ACPI_HOTKEYSCAN_FNF12,
+        TP_ACPI_HOTKEYSCAN_FNBACKSPACE,
+        TP_ACPI_HOTKEYSCAN_FNINSERT,
+        TP_ACPI_HOTKEYSCAN_FNDELETE,
+        TP_ACPI_HOTKEYSCAN_FNHOME,
+        TP_ACPI_HOTKEYSCAN_FNEND,
+        TP_ACPI_HOTKEYSCAN_FNPAGEUP,
+        TP_ACPI_HOTKEYSCAN_FNPAGEDOWN,
+        TP_ACPI_HOTKEYSCAN_FNSPACE,
+        TP_ACPI_HOTKEYSCAN_VOLUMEUP,
+        TP_ACPI_HOTKEYSCAN_VOLUMEDOWN,
+        TP_ACPI_HOTKEYSCAN_MUTE,
+        TP_ACPI_HOTKEYSCAN_THINKPAD,
+};
+
 static int hotkey_orig_status;
 static u32 hotkey_orig_mask;