• Alexis Lothoré's avatar
    wifi: wilc1000: revert reset line logic flip · f3ec6439
    Alexis Lothoré authored
    This reverts commit fcf690b0.
    
    When using a wilc1000 chip over a spi bus, users can optionally define a
    reset gpio and a chip enable gpio. The reset line of wilc1000 is active
    low, so to hold the chip in reset, a low (physical) value must be applied.
    
    The corresponding device tree binding documentation was introduced by
    commit f31ee3c0 ("wilc1000: Document enable-gpios and reset-gpios
    properties") and correctly indicates that the reset line is an active-low
    signal. The corresponding driver part, brought by commit ec031ac4
    ("wilc1000: Add reset/enable GPIO support to SPI driver") was applying the
    correct logic. But commit fcf690b0 ("wifi: wilc1000: use correct
    sequence of RESET for chip Power-UP/Down") eventually flipped this logic
    and started misusing the gpiod APIs, applying an inverted logic when
    powering up/down the chip (for example, setting the reset line to a logic
    "1" during power up, which in fact asserts the reset line when device tree
    describes the reset line as GPIO_ACTIVE_LOW). As a consequence, any
    platform currently using the driver in SPI mode must use a faulty reset
    line description in device tree, or else chip will be maintained in reset
    and will not even allow to bring up the chip.
    
    Fix reset line usage by inverting back the gpiod APIs usage, setting the
    reset line to the logic value "0" when powering the chip, and the logic
    value "1" when powering off the chip.
    
    Fixes: fcf690b0 ("wifi: wilc1000: use correct sequence of RESET for chip Power-UP/Down")
    Signed-off-by: default avatarAlexis Lothoré <alexis.lothore@bootlin.com>
    Acked-by: default avatarConor Dooley <conor.dooley@microchip.com>
    Acked-by: default avatarAjay Singh <ajay.kathat@microchip.com>
    Signed-off-by: default avatarKalle Valo <kvalo@kernel.org>
    Link: https://msgid.link/20240217-wilc_1000_reset_line-v2-1-b216f433d7d5@bootlin.com
    f3ec6439
spi.c 31.6 KB