• Geert Uytterhoeven's avatar
    pwm: Fix period and polarity in pwm_get() for non-perfect matches · d717ea73
    Geert Uytterhoeven authored
    If pwm_get() finds a look-up entry with a perfect match (both dev_id and
    con_id match), the loop is aborted, and "p" still points to the correct
    struct pwm_lookup.
    
    If only an entry with a matching dev_id or con_id is found, the loop
    terminates after traversing the whole list, and "p" now points to
    arbitrary memory, not part of the pwm_lookup list.
    Then pwm_set_period() and pwm_set_polarity() will set random values for
    period resp. polarity.
    
    To fix this, save period and polarity when finding a new best match,
    just like is done for chip (for the provider) and index.
    
    This fixes the LCD backlight on r8a7740/armadillo-legacy, which was fed
    period 0 and polarity -1068821144 instead of 33333 resp. 1.
    
    Fixes: 3796ce1d
    
     ("pwm: add period and polarity to struct pwm_lookup")
    Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
    d717ea73
core.c 19.3 KB