include/linux/mfd/cros_ec_lpc_reg.h

   1 /*
   2  * cros_ec_lpc_reg - LPC access to the Chrome OS Embedded Controller
   3  *
   4  * Copyright (C) 2016 Google, Inc
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * This driver uses the Chrome OS EC byte-level message-based protocol for
  16  * communicating the keyboard state (which keys are pressed) from a keyboard EC
  17  * to the AP over some bus (such as i2c, lpc, spi).  The EC does debouncing,
  18  * but everything else (including deghosting) is done here.  The main
  19  * motivation for this is to keep the EC firmware as simple as possible, since
  20  * it cannot be easily upgraded and EC flash/IRAM space is relatively
  21  * expensive.
  22  */
  23
  24 #ifndef __LINUX_MFD_CROS_EC_REG_H
  25 #define __LINUX_MFD_CROS_EC_REG_H
  26
  27 /**
  28  * cros_ec_lpc_read_bytes - Read bytes from a given LPC-mapped address.
  29  * Returns 8-bit checksum of all bytes read.
  30  *
  31  * @offset: Base read address
  32  * @length: Number of bytes to read
  33  * @dest: Destination buffer
  34  */
  35 u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest);
  36
  37 /**
  38  * cros_ec_lpc_write_bytes - Write bytes to a given LPC-mapped address.
  39  * Returns 8-bit checksum of all bytes written.
  40  *
  41  * @offset: Base write address
  42  * @length: Number of bytes to write
  43  * @msg: Write data buffer
  44  */
  45 u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg);
  46
  47 /**
  48  * cros_ec_lpc_reg_init
  49  *
  50  * Initialize register I/O.
  51  */
  52 void cros_ec_lpc_reg_init(void);
  53
  54 /**
  55  * cros_ec_lpc_reg_destroy
  56  *
  57  * Cleanup reg I/O.
  58  */
  59 void cros_ec_lpc_reg_destroy(void);
  60
  61 #endif /* __LINUX_MFD_CROS_EC_REG_H */