Fix: Rework pull-configuration for ehrpwm and eqep based on schematics.

The previous Fix was a mistake!

TB6612 has pull-downs, so disable pulls on all pins going there.

EQEP1 has external pull-downs, so disable pulls there again.
EQEP0,2 and the PRU emulated Encoder should mimic EQEP1 electrical
behaviour, so set pull-downs there.

Signed-off-by: Patrick Menschel <menschel.p@posteo.de>

src/arm/am335x-boneblue.dts

@@ -160,7 +160,9 @@
 		>;
 	};
 
-	/* PWM1 for Motor 1 and 2 */
+	/* PWM1 for Motor 1 and 2
+	 * Note: The Motor driver TB6612FNG has internal pull-downs, therefore disable internal pulls.
+	 */
 	ehrpwm1_pins: pinmux_ehrpwm1_pins {
 		pinctrl-single,pins = <
 			AM33XX_PADCONF(AM335X_PIN_GPMC_A2, PIN_OUTPUT, MUX_MODE6)		/* (U14) gpmc_a2.ehrpwm1a - PWM_1A */
@@ -168,7 +170,9 @@
 		>;
 	};
 
-	/* PWM2 for Motor 3 and 4 */
+	/* PWM2 for Motor 3 and 4 
+	 * Note: The Motor driver TB6612FNG has internal pull-downs, therefore disable internal pulls.
+	 */
 	ehrpwm2_pins: pinmux_ehrpwm2_pins {
 		pinctrl-single,pins = <
 			AM33XX_PADCONF(AM335X_PIN_GPMC_AD8, PIN_OUTPUT, MUX_MODE4)		/* (U10) gpmc_ad8.ehrpwm2a - PWM_2A */
@@ -176,15 +180,20 @@
 		>;
 	};
 
-	/* E1 */
+	/* E1
+	 * Note: No external pull-down, therefore enable internal pull-down.
+	 */
 	eqep0_pins: pinmux_eqep0_pins {
 		pinctrl-single,pins = <
-			AM33XX_PADCONF(AM335X_PIN_MCASP0_ACLKR, PIN_INPUT, MUX_MODE1)		/* (B12) mcasp0_aclkr.eQEP0A_in */
-			AM33XX_PADCONF(AM335X_PIN_MCASP0_FSR, PIN_INPUT, MUX_MODE1)		/* (C13) mcasp0_fsr.eQEP0B_in */
+			AM33XX_PADCONF(AM335X_PIN_MCASP0_ACLKR, PIN_INPUT_PULLDOWN, MUX_MODE1)	/* (B12) mcasp0_aclkr.eQEP0A_in */
+			AM33XX_PADCONF(AM335X_PIN_MCASP0_FSR, PIN_INPUT_PULLDOWN, MUX_MODE1)	/* (C13) mcasp0_fsr.eQEP0B_in */
 		>;
 	};
 
-	/* E2 */
+	/* E2
+	 * Note: according to schematics, both pins have external 100k pull-down resistors,
+	 *       therefore disable the internal pull.
+	 */
 	eqep1_pins: pinmux_eqep1_pins {
 		pinctrl-single,pins = <
 			AM33XX_PADCONF(AM335X_PIN_LCD_DATA12, PIN_INPUT, MUX_MODE2)		/* (V2) lcd_data12.eQEP1A_in */
@@ -192,18 +201,25 @@
 		>;
 	};
 
-	/* E3 */
+	/* E3
+	 * Note: No external pull-down, therefore enable internal pull-down,
+         *       mimic E2 behaviour.
+	 */
 	eqep2_pins: pinmux_eqep2_pins {
 		pinctrl-single,pins = <
-			AM33XX_PADCONF(AM335X_PIN_GPMC_AD12, PIN_INPUT, MUX_MODE4)		/* (T12) gpmc_ad12.eQEP2A_in */
-			AM33XX_PADCONF(AM335X_PIN_GPMC_AD13, PIN_INPUT, MUX_MODE4)		/* (R12) gpmc_ad13.eQEP2B_in */
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD12, PIN_INPUT_PULLDOWN, MUX_MODE4)	/* (T12) gpmc_ad12.eQEP2A_in */
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD13, PIN_INPUT_PULLDOWN, MUX_MODE4)	/* (R12) gpmc_ad13.eQEP2B_in */
 		>;
 	};
 
-	/* E4 - Fake Encoder using PRU */
+	/* E4
+	 * Note: Emulated Encoder by using PRU,
+	 *       no external pull-down, therefore enable internal pull-down,
+         *       mimic E2 behaviour.
+	 */
 	pru_encoder_pins: pinmux_pru_encoder_pins {
 		pinctrl-single,pins = <
-			AM33XX_PADCONF(AM335X_PIN_GPMC_AD14, PIN_INPUT_PULLUP, MUX_MODE6)		/* (V13) gpmc_ad14.pr1_pru0_pru_r31_14 */
+			AM33XX_PADCONF(AM335X_PIN_GPMC_AD14, PIN_INPUT_PULLDOWN, MUX_MODE6)	/* (V13) gpmc_ad14.pr1_pru0_pru_r31_14 */
 			/* Note: That is only PRU_E_A. PRU_E_B is nowhere to be found in 4.14 dts but it's (U13) */
 		>;
 	};
@@ -256,7 +272,9 @@
 		>;
 	};
 
-	/* Onboard Motor Driver Control Pins */
+	/* Onboard Motor Driver Control Pins
+	 * Note: The Motor driver TB6612FNG has internal pull-downs, therefore disable internal pulls.
+	 */
 	motor_pins: pinmux_motor_pins {
 		pinctrl-single,pins = <
 			AM33XX_PADCONF(AM335X_PIN_GPMC_CSN3, PIN_OUTPUT, MUX_MODE7)		/* (T13) gpmc_csn3.gpio2[0] - MDIR_1A */