• Gregory Bean's avatar
    msm: add gpiomux api for gpio multiplex & configuration. · 1963a2af
    Gregory Bean authored
    Add the 'gpiomux' api, which addresses the following shortcomings
    of existing tlmm api:
    
    - gpio power-collapse, which is managed by a peripheral processor on
      other targets, must be managed by the application processor on the 8x60.
    - The enable/disable flag of the legacy gpio_tlmm_config api
      is not applicable on the 8x60, and causes confusion.
    - The gpio 'direction' bits are meaningless for all func_sel
      configurations except for generic-gpio mode (func_sel 0), in which
      case the gpio_direction_* functions should be used.  Having these
      bits in the tlmm api leads to confusion and misuse of the gpiolib
      api, and they have been removed in gpiomux.
    - The functional api of the legacy system ran contrary to the typical
      use-case, which is a single massive configuration at boot.  Rather
      than forcing hundreds of 'config' function calls, the new api
      allows data to be configured with a single table.
    
    gpiomux_get and gpiomux_put are meant to be called automatically
    when gpio_request and gpio_free are called, giving automatic
    gpiomux/tlmm control to those drivers/lines with simple
    power profiles - in the simplest cases, an entry in the gpiomux table
    and the correct usage of gpiolib is all that is required to get proper
    gpio power control.
    Signed-off-by: default avatarGregory Bean <gbean@codeaurora.org>
    Signed-off-by: default avatarDaniel Walker <dwalker@codeaurora.org>
    1963a2af
gpiomux.h 3.24 KB