Add DPTF interface for fan duty

This adds include/dptf.h to define the DPTF interface functions.

As the first DPTF feature, it also adds a register to the EC's ACPI
interface block. Register 0x04 is used to get and set the fan's target duty
cycle, as a percentage value. Writing a 0 to this register will set the
target duty cycle to 0, writing a 100 (0x64) will set it to 100%. Writing
any other value will return the fan control to the EC, rather than driving
it manually from the host.

Likewise, reading from this register returns the current fan target duty
cycle, as a percentage. If the EC is controlling the fan automatically, the
returned value will be 0xFF.

BUG=chrome-os-partner:23972
BRANCH=none
TEST=manual

You can monitor the fan state from the EC console with the "faninfo"
command. From the host side, test this interface from a root shell.

Read fan duty:

  iotools io_write8 0x66 0x80
  iotools io_write8 0x62 4
  iotools io_read8 0x62

Set fan duty to 100%:

  iotools io_write8 0x66 0x81
  iotools io_write8 0x62 4
  iotools io_write8 0x62 100

Set fan duty to 50%:

  iotools io_write8 0x66 0x81
  iotools io_write8 0x62 4
  iotools io_write8 0x62 50

Set fan duty to 0%:

  iotools io_write8 0x66 0x81
  iotools io_write8 0x62 4
  iotools io_write8 0x62 0

Set fan control back to automatic:

  iotools io_write8 0x66 0x81
  iotools io_write8 0x62 4
  iotools io_write8 0x62 -1

Change-Id: I91ec463095cfd17adf452f0967da3944b254d558
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/177423
Reviewed-by: Randall Spangler <rspangler@chromium.org>

4 files changed, 63 insertions, 1 deletions

diff --git a/chip/lm4/lpc.c b/chip/lm4/lpc.c
index afbe31f717..0b9ec2771a 100644
--- a/chip/lm4/lpc.c
+++ b/chip/lm4/lpc.c
@@ -8,6 +8,7 @@
 #include "clock.h"
 #include "common.h"
 #include "console.h"
+#include "dptf.h"
 #include "gpio.h"
 #include "hooks.h"
 #include "host_command.h"
@@ -412,7 +413,7 @@ static void handle_acpi_write(int is_cmd)
 	/* Process complete commands */
 	if (acpi_cmd == EC_CMD_ACPI_READ && acpi_data_count == 1) {
 		/* ACPI read cmd + addr */
-		int result = 0;
+		int result = 0xff;		/* value for bogus read */
 
 		switch (acpi_addr) {
 		case EC_ACPI_MEM_VERSION:
@@ -437,6 +438,12 @@ static void handle_acpi_write(int is_cmd)
 			result = pwm_get_duty(PWM_CH_KBLIGHT);
 			break;
 #endif
+#ifdef CONFIG_FANS
+		case EC_ACPI_MEM_FAN_DUTY:
+			/** TODO(crosbug.com/p/23774): Fix this too */
+			result = dptf_get_fan_duty_target();
+			break;
+#endif
 		default:
 			break;
 		}
@@ -463,6 +470,12 @@ static void handle_acpi_write(int is_cmd)
 			pwm_set_duty(PWM_CH_KBLIGHT, data);
 			break;
 #endif
+#ifdef CONFIG_FANS
+		case EC_ACPI_MEM_FAN_DUTY:
+			/** TODO(crosbug.com/p/23774): Fix this too */
+			dptf_set_fan_duty_target(data);
+			break;
+#endif
 		default:
 			CPRINTF("[%T ACPI write 0x%02x = 0x%02x]\n",
 				acpi_addr, data);
diff --git a/common/fan.c b/common/fan.c
index 9d9c0f68fc..520d6fe03b 100644
--- a/common/fan.c
+++ b/common/fan.c
@@ -259,6 +259,36 @@ DECLARE_CONSOLE_COMMAND(fanduty, cc_fanduty,
 			NULL);
 
 /*****************************************************************************/
+/* DPTF interface functions */
+
+/* 0-100% if in duty mode. -1 if not */
+int dptf_get_fan_duty_target(void)
+{
+	int fan = 0;				/* TODO(crosbug.com/p/23803) */
+
+	if (thermal_control_enabled[fan] || fan_get_rpm_mode(fan))
+		return -1;
+
+	return fan_get_duty(fan);
+}
+
+/* 0-100% sets duty, out of range means let the EC drive */
+void dptf_set_fan_duty_target(int pct)
+{
+	int fan;
+
+	if (pct < 0 || pct > 100) {
+		/* TODO(crosbug.com/p/23803) */
+		for (fan = 0; fan < CONFIG_FANS; fan++)
+			set_thermal_control_enabled(fan, 1);
+	} else {
+		/* TODO(crosbug.com/p/23803) */
+		for (fan = 0; fan < CONFIG_FANS; fan++)
+			set_duty_cycle(fan, pct);
+	}
+}
+
+/*****************************************************************************/
 /* Host commands */
 
 static int hc_pwm_get_fan_target_rpm(struct host_cmd_handler_args *args)
diff --git a/include/dptf.h b/include/dptf.h
new file mode 100644
index 0000000000..48be860f2d
--- /dev/null
+++ b/include/dptf.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* Functions used to provide the Intel DPTF interface over ACPI */
+
+#ifndef __CROS_EC_DPTF_H
+#define __CROS_EC_DPTF_H
+
+/* 0-100% sets fixed duty cycle, out of range means let the EC drive */
+void dptf_set_fan_duty_target(int pct);
+
+/*  0-100% if in duty mode. -1 if not */
+int dptf_get_fan_duty_target(void);
+
+#endif	/* __CROS_EC_DPTF_H */
diff --git a/include/ec_commands.h b/include/ec_commands.h
index b1e3ed887b..b97ef7dc48 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -1866,6 +1866,8 @@ struct ec_params_reboot_ec {
 #define EC_ACPI_MEM_TEST_COMPLIMENT    0x02
 /* Keyboard backlight brightness percent (0 - 100) */
 #define EC_ACPI_MEM_KEYBOARD_BACKLIGHT 0x03
+/* Target Fan Duty (0-100, 0xff for auto/none) */
+#define EC_ACPI_MEM_FAN_DUTY 0x04
 
 /* Current version of ACPI memory address space */
 #define EC_ACPI_MEM_VERSION_CURRENT 1