1 /* 2 * (C) Copyright 2002 3 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. 4 * 5 * Influenced by code from: 6 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 7 * 8 * SPDX-License-Identifier: GPL-2.0+ 9 */ 10 11 #include <common.h> 12 #include <spi.h> 13 14 #include <malloc.h> 15 16 /*----------------------------------------------------------------------- 17 * Definitions 18 */ 19 20 #ifdef DEBUG_SPI 21 #define PRINTD(fmt,args...) printf (fmt ,##args) 22 #else 23 #define PRINTD(fmt,args...) 24 #endif 25 26 struct soft_spi_slave { 27 struct spi_slave slave; 28 unsigned int mode; 29 }; 30 31 static inline struct soft_spi_slave *to_soft_spi(struct spi_slave *slave) 32 { 33 return container_of(slave, struct soft_spi_slave, slave); 34 } 35 36 /*=====================================================================*/ 37 /* Public Functions */ 38 /*=====================================================================*/ 39 40 /*----------------------------------------------------------------------- 41 * Initialization 42 */ 43 void spi_init (void) 44 { 45 #ifdef SPI_INIT 46 volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; 47 48 SPI_INIT; 49 #endif 50 } 51 52 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, 53 unsigned int max_hz, unsigned int mode) 54 { 55 struct soft_spi_slave *ss; 56 57 if (!spi_cs_is_valid(bus, cs)) 58 return NULL; 59 60 ss = spi_alloc_slave(struct soft_spi_slave, bus, cs); 61 if (!ss) 62 return NULL; 63 64 ss->mode = mode; 65 66 /* TODO: Use max_hz to limit the SCK rate */ 67 68 return &ss->slave; 69 } 70 71 void spi_free_slave(struct spi_slave *slave) 72 { 73 struct soft_spi_slave *ss = to_soft_spi(slave); 74 75 free(ss); 76 } 77 78 int spi_claim_bus(struct spi_slave *slave) 79 { 80 #ifdef CONFIG_SYS_IMMR 81 volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; 82 #endif 83 struct soft_spi_slave *ss = to_soft_spi(slave); 84 85 /* 86 * Make sure the SPI clock is in idle state as defined for 87 * this slave. 88 */ 89 if (ss->mode & SPI_CPOL) 90 SPI_SCL(1); 91 else 92 SPI_SCL(0); 93 94 return 0; 95 } 96 97 void spi_release_bus(struct spi_slave *slave) 98 { 99 /* Nothing to do */ 100 } 101 102 /*----------------------------------------------------------------------- 103 * SPI transfer 104 * 105 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks 106 * "bitlen" bits in the SPI MISO port. That's just the way SPI works. 107 * 108 * The source of the outgoing bits is the "dout" parameter and the 109 * destination of the input bits is the "din" parameter. Note that "dout" 110 * and "din" can point to the same memory location, in which case the 111 * input data overwrites the output data (since both are buffered by 112 * temporary variables, this is OK). 113 */ 114 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, 115 const void *dout, void *din, unsigned long flags) 116 { 117 #ifdef CONFIG_SYS_IMMR 118 volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; 119 #endif 120 struct soft_spi_slave *ss = to_soft_spi(slave); 121 uchar tmpdin = 0; 122 uchar tmpdout = 0; 123 const u8 *txd = dout; 124 u8 *rxd = din; 125 int cpol = ss->mode & SPI_CPOL; 126 int cpha = ss->mode & SPI_CPHA; 127 unsigned int j; 128 129 PRINTD("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n", 130 slave->bus, slave->cs, *(uint *)txd, *(uint *)rxd, bitlen); 131 132 if (flags & SPI_XFER_BEGIN) 133 spi_cs_activate(slave); 134 135 for(j = 0; j < bitlen; j++) { 136 /* 137 * Check if it is time to work on a new byte. 138 */ 139 if ((j % 8) == 0) { 140 if (txd) 141 tmpdout = *txd++; 142 else 143 tmpdout = 0; 144 if(j != 0) { 145 if (rxd) 146 *rxd++ = tmpdin; 147 } 148 tmpdin = 0; 149 } 150 151 if (!cpha) 152 SPI_SCL(!cpol); 153 SPI_SDA(tmpdout & 0x80); 154 SPI_DELAY; 155 if (cpha) 156 SPI_SCL(!cpol); 157 else 158 SPI_SCL(cpol); 159 tmpdin <<= 1; 160 tmpdin |= SPI_READ; 161 tmpdout <<= 1; 162 SPI_DELAY; 163 if (cpha) 164 SPI_SCL(cpol); 165 } 166 /* 167 * If the number of bits isn't a multiple of 8, shift the last 168 * bits over to left-justify them. Then store the last byte 169 * read in. 170 */ 171 if (rxd) { 172 if ((bitlen % 8) != 0) 173 tmpdin <<= 8 - (bitlen % 8); 174 *rxd++ = tmpdin; 175 } 176 177 if (flags & SPI_XFER_END) 178 spi_cs_deactivate(slave); 179 180 return(0); 181 } 182