[ltp] [patch 04/12][2.6.18] ibm-acpi: prepare to cleanup fan_read and fan_write

[Henrique de Moraes Holschuh]

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>
Cc: borislav@users.sourceforge.net
---
 drivers/acpi/ibm_acpi.c |   78 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 76 insertions(+), 2 deletions(-)

Index: 2.6.18/drivers/acpi/ibm_acpi.c
===================================================================
--- 2.6.18.orig/drivers/acpi/ibm_acpi.c
+++ 2.6.18/drivers/acpi/ibm_acpi.c
@@ -225,6 +225,31 @@ enum thermal_access_mode {
 	IBMACPI_THERMAL_TPEC_16,	/* Use ACPI EC regs, 16 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 {
@@ -1608,8 +1633,56 @@ 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)
 {
@@ -1800,6 +1873,7 @@ static struct ibm_struct ibms[] = {
 	 .name = "fan",
 	 .read = fan_read,
 	 .write = fan_write,
+	 .init = fan_init,
 	 .experimental = 1,
 	 },
 };

--
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh