Hi all. I have been configuring and compiling kernels to get /sys/class/gpio without success. I'm starting a new thread since I have exhausted the existing ones and they mostly have 3 year old comments. I have read all the postings and set all the config options. gpio does not show up. I'm looking for any advice, like is there something that might be blocking this? Linux 220.127.116.11 FriendlyARM source and .config is for W35i. Tools 4.4.3 Compiler output has lots of gpio related object files and nothing called sysfs_gpio or similar - don't know if it should. I need to get this working (or extend leds.c to include pins 0 and 1 or GPB).
Mini2440 GPIO Again
Have you enabled sys filesystem (somewhere in the kernel config)? Did you get other /sys/class entries?
I think CONFIG_GPIO_SYSFS is the one. I see the Pengutronix BSP also has: CONFIG_ARCH_HAVE_CUSTOM_GPIO CONFIG_ARCH_REQUIRE_GPIOLIB CONFIG_GPIOLIB CONFIG_LEDS_GPIO and CONFIG_GENERIC_GPIO CONFIG_NEED_MACH_GPIO_H set. There are others.
I enabled all the GPIO options in config including one for sysfs gpio. It is in Device Drivers, GPIO support, and called /sys/class/gpio... (sysfs interface) /sys/class has lots. BDI, BLOCK, FIRMWARE, I2C-dev, leds, spi-master, etc. The .config has 5 or 6 gpio related items set to yes, including the sysfs.
I was referring to Linux kernel 3.7 this may not help you a lot, trying to get 18.104.22.168 to work. Attached find a config for 22.214.171.124 that was floating around the net by Eric Brombaugh.
Got it going. I was using a command line with an error (up arrow failure) and copying an old zImage instead of my new uImage to SD every time. SO it works. Unfortunately, GPB0 on the GPIO header is also the piezo buzzer and my simplest test script just turns the buzzer on and off. Apparently not disabling the timer/PWM on that pin. GPB1 not responding so back to the schematic.