volteer: stub in fan for Zephyr

Enable the PWM channel used for the cooling fan. This change forces
the fan speed to 50% to provide active cooling until temperature sensors
and a Zephyr fan API are available.

BUG=b:174851463
BRANCH=none
TEST=make buildall, zmake testall
TEST=Load zephyr on Volteer, verify fan turns on when the AP is powered.

Signed-off-by: Keith Short <keithshort@chromium.org>
Change-Id: Iaad82e4c83ccfcda3d4cc33be6fcd550930c4caa
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2637995
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>

5 files changed, 50 insertions, 0 deletions

diff --git a/zephyr/projects/volteer/CMakeLists.txt b/zephyr/projects/volteer/CMakeLists.txt
index 21a941ac0b..47c3d1def9 100644
--- a/zephyr/projects/volteer/CMakeLists.txt
+++ b/zephyr/projects/volteer/CMakeLists.txt
@@ -54,3 +54,8 @@ zephyr_sources_ifdef(CONFIG_PLATFORM_EC_LED_COMMON
   "${PLATFORM_EC_BOARD}/led.c")
 zephyr_sources_ifdef(CONFIG_PLATFORM_EC_USBC
   "${PLATFORM_EC_BOARD}/usbc_config.c")
+
+# TODO: b/177854276, b/174851465
+# Fan stub requires on PWM support.  Remove once full fan support
+# is available.
+zephyr_sources_ifdef(CONFIG_PLATFORM_EC_PWM  "src/fan.c")
diff --git a/zephyr/projects/volteer/boards/arm/volteer/volteer.dts b/zephyr/projects/volteer/boards/arm/volteer/volteer.dts
index 24b3610d95..c02bb8ff2f 100644
--- a/zephyr/projects/volteer/boards/arm/volteer/volteer.dts
+++ b/zephyr/projects/volteer/boards/arm/volteer/volteer.dts
@@ -85,6 +85,11 @@
 			label = "KBLIGHT";
 			frequency = <2400>;
 		};
+		fan {
+			pwms = <&pwm5 0 0>;
+			label = "FAN";
+			frequency = <25000>;
+		};
 	};
 
 	named-gpios {
@@ -518,6 +523,11 @@
 	status = "okay";
 };
 
+/* Fan control */
+&pwm5 {
+	status = "okay";
+};
+
 /* Side selection LED */
 &pwm7 {
 	status = "okay";
diff --git a/zephyr/projects/volteer/include/gpio_map.h b/zephyr/projects/volteer/include/gpio_map.h
index 77b8f10e3b..cc0afe5040 100644
--- a/zephyr/projects/volteer/include/gpio_map.h
+++ b/zephyr/projects/volteer/include/gpio_map.h
@@ -69,6 +69,9 @@
 #define GPIO_USB_C1_RT_RST_ODL \
 	NAMED_GPIO_NODELABEL(usb_c1_bb_retimer, reset_gpios)
 
+/* Fan control */
+#define GPIO_EN_PP5000_FAN         NAMED_GPIO(en_pp5000_fan)
+
 /* Don't have a load switch for retimer */
 /* TODO(b/176559881): How to do unimplemented GPIOs? */
 #define GPIO_USB_C1_LS_EN \
diff --git a/zephyr/projects/volteer/include/pwm_map.h b/zephyr/projects/volteer/include/pwm_map.h
index c15b820a86..2616bad589 100644
--- a/zephyr/projects/volteer/include/pwm_map.h
+++ b/zephyr/projects/volteer/include/pwm_map.h
@@ -23,4 +23,6 @@
 
 #define PWM_CH_KBLIGHT		NAMED_PWM(kblight)
 
+#define PWM_CH_FAN		NAMED_PWM(fan)
+
 #endif /* __ZEPHYR_CHROME_PWM_MAP_H */
diff --git a/zephyr/projects/volteer/src/fan.c b/zephyr/projects/volteer/src/fan.c
new file mode 100644
index 0000000000..5e683f1f2b
--- /dev/null
+++ b/zephyr/projects/volteer/src/fan.c
@@ -0,0 +1,30 @@
+/* Copyright 2021 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.
+ *
+ * Temporary fan stub for Zephyr running on Volteer.
+ * TODO: b/177854276, b/174851465
+ * Remove once temperature sensor and a Zephyr fan API are available.
+ */
+
+#include "common.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "pwm.h"
+
+static void board_fan_chipset_startup(void)
+{
+	gpio_set_level(GPIO_EN_PP5000_FAN, 1);
+	pwm_enable(PWM_CH_FAN, 1);
+	pwm_set_duty(PWM_CH_FAN, 50);
+}
+DECLARE_HOOK(HOOK_CHIPSET_STARTUP, board_fan_chipset_startup,
+	     HOOK_PRIO_DEFAULT);
+
+static void board_fan_chipset_shutdown(void)
+{
+	gpio_set_level(GPIO_EN_PP5000_FAN, 0);
+	pwm_enable(PWM_CH_FAN, 0);
+}
+DECLARE_HOOK(HOOK_CHIPSET_SHUTDOWN, board_fan_chipset_shutdown,
+	     HOOK_PRIO_DEFAULT);