Reset uncontrollable motor frequency to zero. (#72)

* Reset uncontrollable motor frequency to zero.

* Update readme

* Bump up to 3.2.0

Co-authored-by: Daisuke Sato <daisuke.sato@rt-net.jp>

Author: Shota Aoki

README.md

@@ -160,12 +160,16 @@ $ echo 1 > /dev/rtmotoren0
 
 ### PWM frequency for left/right motor driver (Output)
 
-Write 0 ~ 10000 to `/dev/rtmotor_raw_l0` or `/dev/rtmotor_raw_r0` to set PWM frequency for motor drivers.
+Write 0 ~ ±10000 to `/dev/rtmotor_raw_l0` or `/dev/rtmotor_raw_r0` to set PWM frequency for motor drivers.
 
-`/dev/rtmotor_raw_l0` または `/dev/rtmotor_raw_r0` に 0 ~ 10000 を書き込み、モータドライバへのPWM周波数を設定します。
+※ 0 ~ ±4 Hz will be reset to 0 Hz.
+
+`/dev/rtmotor_raw_l0` または `/dev/rtmotor_raw_r0` に 0 ~ ±10000 を書き込み、モータドライバへのPWM周波数を設定します。
+
+※ 0 ~ ±4 Hzは0Hzへリセットされます
 
 ```sh
-# echo 0 ~ 10000(Hz) > /dev/rtmotor_raw_[l0, r0]
+# echo 0 ~ ±10000(Hz) > /dev/rtmotor_raw_[l0, r0]
 $ echo 1 > /dev/rtmotoren0
 $ echo 400 > /dev/rtmotor_raw_l0
 ```

src/drivers/rtmouse.c

@@ -3,7 +3,7 @@
  * rtmouse.c
  * Raspberry Pi Mouse device driver
  *
- * Version: 3.1.1
+ * Version: 3.2.0
  *
  * Copyright (C) 2015-2021 RT Corporation <shop@rt-net.jp>
  *
@@ -55,7 +55,7 @@
 
 MODULE_AUTHOR("RT Corporation");
 MODULE_LICENSE("GPL");
-MODULE_VERSION("3.1.1");
+MODULE_VERSION("3.2.0");
 MODULE_DESCRIPTION("Raspberry Pi Mouse device driver");
 
 /* --- Device Numbers --- */
@@ -272,6 +272,9 @@ static struct mutex lock;
 #define CNT_ADDR_MSB 0x10
 #define CNT_ADDR_LSB 0x11
 
+/* Motor Parameter */
+#define MOTOR_UNCONTROLLABLE_FREQ 5
+
 /* --- Function Declarations --- */
 static void set_motor_r_freq(int freq);
 static void set_motor_l_freq(int freq);
@@ -467,6 +470,11 @@ static void set_motor_l_freq(int freq)
 
 	rpi_gpio_function_set(BUZZER_BASE, RPI_GPF_OUTPUT);
 
+	// Reset uncontrollable frequency to zero.
+	if (abs(freq) < MOTOR_UNCONTROLLABLE_FREQ) {
+		freq = 0;
+	}
+
 	if (freq == 0) {
 		rpi_gpio_function_set(MOTCLK_L_BASE, RPI_GPF_OUTPUT);
 		return;
@@ -498,6 +506,11 @@ static void set_motor_r_freq(int freq)
 
 	rpi_gpio_function_set(BUZZER_BASE, RPI_GPF_OUTPUT);
 
+	// Reset uncontrollable frequency to zero.
+	if (abs(freq) < MOTOR_UNCONTROLLABLE_FREQ) {
+		freq = 0;
+	}
+
 	if (freq == 0) {
 		rpi_gpio_function_set(MOTCLK_R_BASE, RPI_GPF_OUTPUT);
 		return;