Fix bug in Samus DPTF fan control

It worked on Link because the fan number and the fan channel were both 0.
Samus has two fans, connected to different GPIOs.

In 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=samus
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: I3a133b0b16e2a5e1ce04b16cb2bf035a04a83daf
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179373
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 13 insertions, 8 deletions

diff --git a/common/fan.c b/common/fan.c
index 520d6fe03b..d61eba67d9 100644
--- a/common/fan.c
+++ b/common/fan.c
@@ -266,10 +266,10 @@ 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))
+	if (thermal_control_enabled[fan] || fan_get_rpm_mode(fans[fan].ch))
 		return -1;
 
-	return fan_get_duty(fan);
+	return fan_get_duty(fans[fan].ch);
 }
 
 /* 0-100% sets duty, out of range means let the EC drive */
@@ -367,6 +367,7 @@ BUILD_ASSERT(CONFIG_FANS <= EC_FAN_SPEED_ENTRIES);
 #define PWM_HOOK_VERSION 1
 /* Saved PWM state across sysjumps */
 struct pwm_fan_state {
+	/* TODO(crosbug.com/p/23530): Still treating all fans as one. */
 	uint16_t fan_rpm;
 	uint8_t fan_en;
 };
@@ -381,21 +382,25 @@ static void pwm_fan_init(void)
 
 	gpio_config_module(MODULE_PWM_FAN, 1);
 
-	for (i = 0; i < CONFIG_FANS; i++)
-		fan_channel_setup(fans[i].ch, fans[i].flags);
+	for (fan = 0; fan < CONFIG_FANS; fan++)
+		fan_channel_setup(fans[fan].ch, fans[fan].flags);
 
 	prev = (const struct pwm_fan_state *)
 		system_get_jump_tag(PWMFAN_SYSJUMP_TAG, &version, &size);
 	if (prev && version == PWM_HOOK_VERSION && size == sizeof(*prev)) {
 		/* Restore previous state. */
-		fan_set_enabled(fans[fan].ch, prev->fan_en);
-		fan_set_rpm_target(fans[fan].ch, prev->fan_rpm);
+		for (fan = 0; fan < CONFIG_FANS; fan++) {
+			fan_set_enabled(fans[fan].ch, prev->fan_en);
+			fan_set_rpm_target(fans[fan].ch, prev->fan_rpm);
+		}
 	} else {
 		/* Set initial fan speed to maximum */
-		fan_set_duty(fans[fan].ch, 100);
+		for (fan = 0; fan < CONFIG_FANS; fan++)
+			fan_set_duty(fans[fan].ch, 100);
 	}
 
-	set_thermal_control_enabled(fan, 1);
+	for (fan = 0; fan < CONFIG_FANS; fan++)
+		set_thermal_control_enabled(fan, 1);
 
 	/* Initialize memory-mapped data */
 	mapped = (uint16_t *)host_get_memmap(EC_MEMMAP_FAN);