From 62a33ef405f54182627b2a1244856df18017f7d6 Mon Sep 17 00:00:00 2001
From: coolneng <akasroua@gmail.com>
Date: Mon, 16 May 2022 23:30:06 +0200
Subject: [PATCH] Incomplete: Enable HW PWM timers for the HDD fan

---
 scripts/SATA-hat.sh | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/scripts/SATA-hat.sh b/scripts/SATA-hat.sh
index 8d879e1..71822ca 100755
--- a/scripts/SATA-hat.sh
+++ b/scripts/SATA-hat.sh
@@ -2,14 +2,12 @@
 
 BASE_PATH=/sys/class
 GPIO_PATH="$BASE_PATH"/gpio
-PWM_PATH="$BASE_PATH"/pwm
+PWM_PATH="$BASE_PATH"/pwm/pwmchip0
 
 # GPIO pins
 SATA0=26
 SATA1=25
-# PWM pins
 CPU_FAN=12
-HDD_FAN=13
 
 # Values
 LOW=0
@@ -27,7 +25,7 @@ unexport_pin() {
     fi
 }
 
-set_mode() {
+set_gpio() {
     export_pin "$1"
     echo "out" >$GPIO_PATH/gpio"$1"/direction
     echo "$2" >$GPIO_PATH/gpio"$1"/value
@@ -36,17 +34,33 @@ set_mode() {
     fi
 }
 
+enable_pwm_channel() {
+    echo "$1" >$PWM_PATH/export
+    echo 40000 >$PWM_PATH/pwm"$1"/period
+    echo 30000 >$PWM_PATH/pwm"$1"/duty_cycle
+    echo 1 >$PWM_PATH/pwm"$1"/enable
+}
+
+set_pwm() {
+    enable_pwm_channel 1
+    if [ "$1" = "clean" ]; then
+        echo 0 >$PWM_PATH/unexport
+    fi
+}
+
 turn_on() {
-    set_mode $SATA0 $HIGH
+    set_gpio $SATA0 $HIGH
     sleep 1
-    set_mode $SATA1 $HIGH
-    set_mode $CPU_FAN $HIGH
+    set_gpio $SATA1 $HIGH
+    set_gpio $CPU_FAN $HIGH
+    set_pwm
 }
 
 turn_off() {
-    set_mode $SATA0 $LOW clean
-    set_mode $SATA1 $LOW clean
-    set_mode $CPU_FAN $LOW clean
+    set_gpio $SATA0 $LOW clean
+    set_gpio $SATA1 $LOW clean
+    set_gpio $CPU_FAN $LOW clean
+    set_pwm clean
 }
 
 trap turn_off INT