ACPI: ibm-acpi: fix and extend fan control functions

This patch extend fan control functions, implementing enable/disable for
all write access modes, implementing level control for all level-capable
write access modes.

The patch also updates the documentation, explaining levels auto and
disengaged.

ABI changes:
	1. Support level 0 as an equivalent to disable
	2. Add support for level auto and level disengaged when doing
	   EC 0x2f fan control
	3. Support enable/disable for all level-based write access modes
	4. Add support for level command on FANS thinkpads, as per
	   thinkwiki reports

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>

1 files changed, 34 insertions, 5 deletions

diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index ecb5ece79a37..4001ad193ddc 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -1833,10 +1833,13 @@ static int fan_init(void)
                                     IBMACPI_FAN_WR_ACPI_FANS;
                                 fan_control_commands |=
                                     IBMACPI_FAN_CMD_SPEED |
+                                    IBMACPI_FAN_CMD_LEVEL |
                                     IBMACPI_FAN_CMD_ENABLE;
                         } else {
                                 fan_control_access_mode = IBMACPI_FAN_WR_TPEC;
-                                fan_control_commands |= IBMACPI_FAN_CMD_ENABLE;
+                                fan_control_commands |=
+                                    IBMACPI_FAN_CMD_LEVEL |
+                                    IBMACPI_FAN_CMD_ENABLE;
                         }
                 }
         }
@@ -1948,9 +1951,20 @@ static int fan_read(char *p)
                 len += sprintf(p + len, "status:\t\tnot supported\n");
         }
 
-        if (fan_control_commands & IBMACPI_FAN_CMD_LEVEL)
-                len += sprintf(p + len, "commands:\tlevel <level>"
-                               " (<level> is 0-7)\n");
+        if (fan_control_commands & IBMACPI_FAN_CMD_LEVEL) {
+                len += sprintf(p + len, "commands:\tlevel <level>");
+
+                switch (fan_control_access_mode) {
+                case IBMACPI_FAN_WR_ACPI_SFAN:
+                        len += sprintf(p + len, " (<level> is 0-7)\n");
+                        break;
+
+                default:
+                        len += sprintf(p + len, " (<level> is 0-7, "
+                                       "auto, disengaged)\n");
+                        break;
+                }
+        }
 
         if (fan_control_commands & IBMACPI_FAN_CMD_ENABLE)
                 len += sprintf(p + len, "commands:\tenable, disable\n");
@@ -1973,6 +1987,17 @@ static int fan_set_level(int level)
                         return -EINVAL;
                 break;
 
+        case IBMACPI_FAN_WR_ACPI_FANS:
+        case IBMACPI_FAN_WR_TPEC:
+                if ((level != IBMACPI_FAN_EC_AUTO) &&
+                    (level != IBMACPI_FAN_EC_DISENGAGED) &&
+                    ((level < 0) || (level > 7)))
+                        return -EINVAL;
+
+                if (!acpi_ec_write(fan_status_offset, level))
+                        return -EIO;
+                break;
+
         default:
                 return -ENXIO;
         }
@@ -2060,7 +2085,11 @@ static int fan_write_cmd_level(const char *cmd, int *rc)
 {
         int level;
 
-        if (sscanf(cmd, "level %d", &level) != 1)
+        if (strlencmp(cmd, "level auto") == 0)
+                level = IBMACPI_FAN_EC_AUTO;
+        else if (strlencmp(cmd, "level disengaged") == 0)
+                level = IBMACPI_FAN_EC_DISENGAGED;
+        else if (sscanf(cmd, "level %d", &level) != 1)
                 return 0;
 
         if ((*rc = fan_set_level(level)) == -ENXIO)