Dne 20.8.2015 v 22:01 Robert Jarzmik napsal(a): > Petr Cvek <petr.cvek@xxxxxx> writes: > >> Add support for alternative LCD backlight with GPIO (no brightness). > Here, I don't understand, the commit message is too short. > > Are there 2 brightness controls on magician, or are these 2 different magicians > (hardware wise), each having a different backlight control ? Or is it there is a > GPIO to light up the screen and a PWM backlight ? > > I have to understand first. > I have aimed for a configuration, where user can use PWM xor GPIO backlight. As pin mux can set GPIO or PWM (or UART :-D) on PWM pin, you can choose if you spare few kB (as magician has only 64MB RAM and 64MB flash) on GPIO or will have smooth backlight with PWM. I have tested both (I think I have added the gpio backlight for debugging a regression in pwm_bl). Only ugly thing is the GPIO definition: #if IS_ENABLED(CONFIG_PWM_PXA) /* PWM 0 - LCD backlight */ GPIO16_PWM0_OUT, #else /* Ensure static backlight without any driver */ MFP_CFG_OUT(GPIO16, AF0, DRIVE_LOW), /* Backlight enabled */ #endif Hmmm.. I think I can do this better in pwm-backlight init/exit (same way as pxa_ficp). During init the pin mux will switch to Alternate Function (PWM) and during exit it will switch to GPIO (which can be used by gpio-backlight). This will remove ugly ifdef. Best regards, Petr -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
