target/linux/mpc85xx/image/spi-loader/include/spi.h

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Common SPI Interface: Controller-specific definitions
   4  *
   5  * Copyright (c) 2022 Matthias Schiffer <mschiffer@universe-factory.net>
   6  *
   7  * Based on U-boot's spi.h:
   8  *
   9  * (C) Copyright 2001
  10  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
  11  */
  12
  13 #pragma once
  14
  15 #include <types.h>
  16
  17 /* SPI mode flags */
  18 #define SPI_CPHA        BIT(0)  /* clock phase (1 = SPI_CLOCK_PHASE_SECOND) */
  19 #define SPI_CPOL        BIT(1)  /* clock polarity (1 = SPI_POLARITY_HIGH) */
  20 #define SPI_MODE_0      (0|0)                   /* (original MicroWire) */
  21 #define SPI_MODE_1      (0|SPI_CPHA)
  22 #define SPI_MODE_2      (SPI_CPOL|0)
  23 #define SPI_MODE_3      (SPI_CPOL|SPI_CPHA)
  24
  25 struct spi_transfer {
  26         const void *tx_buf;
  27         void *rx_buf;
  28         size_t len;
  29 };
  30
  31 static inline size_t spi_message_len(const struct spi_transfer *msg, int n) {
  32         size_t total = 0;
  33         for (int i = 0; i < n; i++) {
  34                 total += msg[i].len;
  35         }
  36         return total;
  37 }
  38
  39 int spi_init(unsigned int cs, unsigned int max_hz, unsigned int mode);
  40 int spi_claim_bus(void);
  41 void spi_release_bus(void);
  42 int spi_xfer(const struct spi_transfer *msg, int n);
  43 size_t spi_max_xfer(void);