• Geert Uytterhoeven's avatar
    gpio: Add missing open drain/source handling to gpiod_set_value_cansleep() · 1e77fc82
    Geert Uytterhoeven authored
    Since commit f11a0446 ("i2c: gpio: Enable working over slow
    can_sleep GPIOs"), probing the i2c RTC connected to an i2c-gpio bus on
    r8a7740/armadillo fails with:
    
        rtc-s35390a 0-0030: error resetting chip
        rtc-s35390a: probe of 0-0030 failed with error -5
    
    More debug code reveals:
    
        i2c i2c-0: master_xfer[0] R, addr=0x30, len=1
        i2c i2c-0: NAK from device addr 0x30 msg #0
        s35390a_get_reg: ret = -6
    
    Commit 02e47980 ("gpio: Alter semantics of *raw* operations to
    actually be raw") moved open drain/source handling from
    gpiod_set_raw_value_commit() to gpiod_set_value(), but forgot to take
    into account that gpiod_set_value_cansleep() also needs this handling.
    The i2c protocol mandates that i2c signals are open drain, hence i2c
    communication fails.
    
    Fix this by adding the missing handling to gpiod_set_value_cansleep(),
    using a new common helper gpiod_set_value_nocheck().
    
    Fixes: 02e47980 ("gpio: Alter semantics of *raw* operations to actually be raw")
    Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
    [removed underscore syntax, added kerneldoc]
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    1e77fc82
gpiolib.c 109 KB