src/ec/lenovo/h8/sense.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <ec/acpi/ec.h>
   4
   5 #include "h8.h"
   6
   7 /**
   8  * Return the EC sense status register state.
   9  *
  10  * Observations showed the sense registers are all zero until the EC populates
  11  * them after some time. Likely the EC sets all bits to it's valid state at
  12  * once, but there's no prove as the firmware isn't available.
  13  *
  14  * Wait for any register having at least one bit set.
  15  * Unlikely that all register will be zero after booting has finished.
  16  *
  17  * @return 1 if the EC provides valid data in sense status registers
  18  */
  19 int h8_get_sense_ready(void)
  20 {
  21         static const u8 regs[] = { H8_STATUS0, H8_STATUS1, H8_STATUS2,
  22                         H8_STATUS3};
  23
  24         for (size_t i = 0; i < ARRAY_SIZE(regs); i++) {
  25                 if (ec_read(regs[i]))
  26                         return 1;
  27         }
  28
  29         return 0;
  30 }
  31
  32 /**
  33  * Return the state of Fn key.
  34  * Only valid if h8_get_sense_ready (see above) returns true.
  35  *
  36  * @return 1 if the key is pressed.
  37  */
  38 int h8_get_fn_key(void)
  39 {
  40         return ec_read(H8_STATUS0) & H8_STATUS0_FN_KEY_DOWN;
  41 }