Hi, I'm implementing a user-space API that will give access to custom hardware features through sysfs. This library is here to hide the sysfs specifics.
This library must support multi-threaded accesses. I would like to know if something special must be done in this library to assure concurrent accesses. Here is an example : I want the users of my library to be able to switch-on/-off a LED using a simple function like the following : platform_led_on(0); //switches on led '0' platform_led_off(0); //switches on led '0' This led is declared in my platform_data in the board init file as a gpio_led and can be seen in sysfs under /sys/class/leds/led0 the platform_led_on/off(0) functions will : - build the sysfs path to the led0 based on the argument (0) - open the brightness file in the sysfs path - write to the brightness file a value != 0 to switch the led on or 0 to switch it off - close the brightness file - return Now what will happen if a thread tries to switch on the led while another thread tries to switch it off ? Thank your for your comments / help. Best regards, -- Christophe Aeschlimann Embedded Software Engineer Advanced Communications Networks S.A. Rue du Puits-Godet 8a 2000 Neuchâtel, Switzerland Tél. +41 32 724 74 31 [email protected] -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to [email protected] Please read the FAQ at http://kernelnewbies.org/FAQ
