ACPI: ibm-acpi: prepare to cleanup fan_read and fan_write

This patch lays some groundwork for a fan_read and fan_write cleanup in the
next patches.  To do so, it provides a new fan_init initializer, and also some
constants (through enums).

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

1 files changed, 79 insertions, 2 deletions

diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index 1703c617c0e8..7d0bd61eebc7 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -231,6 +231,31 @@ struct ibm_thermal_sensors_struct {
         s32 temp[IBMACPI_MAX_THERMAL_SENSORS];
 };
 
+enum fan_status_access_mode {
+        IBMACPI_FAN_NONE = 0,           /* No fan status or control */
+        IBMACPI_FAN_RD_ACPI_GFAN,       /* Use ACPI GFAN */
+        IBMACPI_FAN_RD_TPEC,            /* Use ACPI EC regs 0x2f, 0x84-0x85 */
+};
+
+enum fan_control_access_mode {
+        IBMACPI_FAN_WR_NONE = 0,        /* No fan control */
+        IBMACPI_FAN_WR_ACPI_SFAN,       /* Use ACPI SFAN */
+        IBMACPI_FAN_WR_TPEC,            /* Use ACPI EC reg 0x2f */
+        IBMACPI_FAN_WR_ACPI_FANS,       /* Use ACPI FANS and EC reg 0x2f */
+};
+
+enum fan_control_commands {
+        IBMACPI_FAN_CMD_SPEED   = 0x0001,       /* speed command */
+        IBMACPI_FAN_CMD_LEVEL   = 0x0002,       /* level command  */
+        IBMACPI_FAN_CMD_ENABLE  = 0x0004,       /* enable/disable cmd */
+};
+
+enum {                                  /* Fan control constants */
+        fan_status_offset = 0x2f,       /* EC register 0x2f */
+        fan_rpm_offset = 0x84,          /* EC register 0x84: LSB, 0x85 MSB (RPM)
+                                         * 0x84 must be read before 0x85 */
+};
+
 static int ibm_thinkpad_ec_found;
 
 struct ibm_struct {
@@ -1659,8 +1684,59 @@ static int volume_write(char *buf)
         return 0;
 }
 
-static int fan_status_offset = 0x2f;
-static int fan_rpm_offset = 0x84;
+static enum fan_status_access_mode fan_status_access_mode;
+static enum fan_control_access_mode fan_control_access_mode;
+static enum fan_control_commands fan_control_commands;
+
+static int fan_init(void)
+{
+        u8 status;
+
+        fan_status_access_mode = IBMACPI_FAN_NONE;
+        fan_control_access_mode = IBMACPI_FAN_WR_NONE;
+        fan_control_commands = 0;
+
+        if (gfan_handle) {
+                /* 570, 600e/x, 770e, 770x */
+                fan_status_access_mode = IBMACPI_FAN_RD_ACPI_GFAN;
+        } else {
+                /* all other ThinkPads: note that even old-style
+                 * ThinkPad ECs supports the fan control register */
+                if (likely(acpi_ec_read(fan_status_offset, &status))) {
+                        fan_status_access_mode = IBMACPI_FAN_RD_TPEC;
+                } else {
+                        printk(IBM_ERR
+                               "ThinkPad ACPI EC access misbehaving, "
+                               "fan status and control unavailable\n");
+                        return 0;
+                }
+        }
+
+        if (sfan_handle) {
+                /* 570, 770x-JL */
+                fan_control_access_mode = IBMACPI_FAN_WR_ACPI_SFAN;
+                fan_control_commands |= IBMACPI_FAN_CMD_LEVEL;
+        } else {
+                if (!gfan_handle) {
+                        /* gfan without sfan means no fan control */
+                        /* all other models implement TP EC 0x2f control */
+
+                        if (fans_handle) {
+                                /* X31, X40 */
+                                fan_control_access_mode =
+                                    IBMACPI_FAN_WR_ACPI_FANS;
+                                fan_control_commands |=
+                                    IBMACPI_FAN_CMD_SPEED |
+                                    IBMACPI_FAN_CMD_ENABLE;
+                        } else {
+                                fan_control_access_mode = IBMACPI_FAN_WR_TPEC;
+                                fan_control_commands |= IBMACPI_FAN_CMD_ENABLE;
+                        }
+                }
+        }
+
+        return 0;
+}
 
 static int fan_read(char *p)
 {
@@ -1849,6 +1925,7 @@ static struct ibm_struct ibms[] = {
          .name = "fan",
          .read = fan_read,
          .write = fan_write,
+         .init = fan_init,
          .experimental = 1,
          },
 };