1. 08 Dec, 2017 1 commit
    • Linus Walleij's avatar
      w1: w1-gpio: Convert to use GPIO descriptors · e0fc62a6
      Linus Walleij authored
      The w1 master driver includes a complete open drain emulation
      reimplementation among other things.
      
      This converts the driver and all board files using it to use
      GPIO descriptors associated with the device to look up the
      GPIO wire, as well ass the optional pull-up GPIO line.
      
      When probed from the device tree, the driver will just pick
      descriptors and use them right off. For the two board files
      in the kernel, we add descriptor lookups so we do not need
      to keep any old platform data handling around for the GPIO
      lines.
      
      As the platform data is also a state container for this driver,
      we augment it to contain the GPIO descriptors.
      
      w1_gpio_write_bit_dir() and w1_gpio_write_bit_val() are gone
      since this pair was a reimplementation of open drain emulation
      which is now handled by gpiolib.
      
      The special "linux,open-drain" flag is a bit of mishap here:
      it has the same semantic as the same flags in I2C: it means
      that something in the platform is setting up the line as
      open drain behind our back. We handle this the same way as
      in I2C.
      
      To drive the pull-up, we need to bypass open drain emulation
      in gpiolib for the line, and this is done by driving it high
      using gpiod_set_raw_value() which has been augmented to have
      the semantic of overriding the open drain emulation.
      
      We also augment the documentation to reflect the way to pass
      GPIO descriptors from the machine.
      Acked-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
      Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      e0fc62a6
  2. 07 Dec, 2017 9 commits
  3. 02 Dec, 2017 26 commits
  4. 30 Nov, 2017 4 commits