From 077253dd666a30ae5231c3748222d4b5b138593d Mon Sep 17 00:00:00 2001 From: Edoardo Scaglia Date: Fri, 1 Feb 2019 16:43:46 +0100 Subject: [PATCH] ar71xx: fix Arduino Yun enabling of level shifters outputs As show in Arduino Yun schematic [1] GPIO 21 and 22 are connected to output enable pin (OE) of two NTB01xx level shifters. NTB01xx datasheets [2] [3] states that OE pin are active-high therefore we should initialize GPIO 21 (DS_GPIO_OE) and GPIO 22 (DS_GPIO_OE2) accordingly to actually enable level shifters outputs. [1] https://www.arduino.cc/en/uploads/Main/arduino-Yun-schematic.pdf [2] https://www.nxp.com/docs/en/data-sheet/NTB0102.pdf [3] https://www.nxp.com/docs/en/data-sheet/NTB0104.pdf Signed-off-by: Edoardo Scaglia --- target/linux/ar71xx/files/arch/mips/ath79/mach-arduino-yun.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/target/linux/ar71xx/files/arch/mips/ath79/mach-arduino-yun.c b/target/linux/ar71xx/files/arch/mips/ath79/mach-arduino-yun.c index 5873248edf..e92f68f490 100644 --- a/target/linux/ar71xx/files/arch/mips/ath79/mach-arduino-yun.c +++ b/target/linux/ar71xx/files/arch/mips/ath79/mach-arduino-yun.c @@ -141,7 +141,7 @@ static void __init ds_setup(void) // enable OE of level shifter if (gpio_request_one(DS_GPIO_OE, - GPIOF_OUT_INIT_LOW | GPIOF_EXPORT_DIR_FIXED, "OE-1") != 0) + GPIOF_OUT_INIT_HIGH | GPIOF_EXPORT_DIR_FIXED, "OE-1") != 0) printk("Error setting GPIO OE\n"); if (gpio_request_one(DS_GPIO_UART_ENA, @@ -150,7 +150,7 @@ static void __init ds_setup(void) // enable OE of level shifter if (gpio_request_one(DS_GPIO_OE2, - GPIOF_OUT_INIT_LOW | GPIOF_EXPORT_DIR_FIXED, "OE-2") != 0) + GPIOF_OUT_INIT_HIGH | GPIOF_EXPORT_DIR_FIXED, "OE-2") != 0) printk("Error setting GPIO OE2\n"); } -- 2.30.2