1 /* 2 * Common SPI Interface: Controller-specific definitions 3 * 4 * (C) Copyright 2001 5 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com. 6 * 7 * SPDX-License-Identifier: GPL-2.0+ 8 */ 9 10 #ifndef _SPI_H_ 11 #define _SPI_H_ 12 13 /* SPI mode flags */ 14 #define SPI_CPHA 0x01 /* clock phase */ 15 #define SPI_CPOL 0x02 /* clock polarity */ 16 #define SPI_MODE_0 (0|0) /* (original MicroWire) */ 17 #define SPI_MODE_1 (0|SPI_CPHA) 18 #define SPI_MODE_2 (SPI_CPOL|0) 19 #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) 20 #define SPI_CS_HIGH 0x04 /* CS active high */ 21 #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ 22 #define SPI_3WIRE 0x10 /* SI/SO signals shared */ 23 #define SPI_LOOP 0x20 /* loopback mode */ 24 #define SPI_SLAVE 0x40 /* slave mode */ 25 #define SPI_PREAMBLE 0x80 /* Skip preamble bytes */ 26 27 /* SPI transfer flags */ 28 #define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */ 29 #define SPI_XFER_END 0x02 /* Deassert CS after transfer */ 30 #define SPI_XFER_MMAP 0x08 /* Memory Mapped start */ 31 #define SPI_XFER_MMAP_END 0x10 /* Memory Mapped End */ 32 #define SPI_XFER_ONCE (SPI_XFER_BEGIN | SPI_XFER_END) 33 #define SPI_XFER_U_PAGE (1 << 5) 34 35 /* SPI TX operation modes */ 36 #define SPI_OPM_TX_QPP 1 << 0 37 38 /* SPI RX operation modes */ 39 #define SPI_OPM_RX_AS 1 << 0 40 #define SPI_OPM_RX_DOUT 1 << 1 41 #define SPI_OPM_RX_DIO 1 << 2 42 #define SPI_OPM_RX_QOF 1 << 3 43 #define SPI_OPM_RX_QIOF 1 << 4 44 #define SPI_OPM_RX_EXTN SPI_OPM_RX_AS | SPI_OPM_RX_DOUT | \ 45 SPI_OPM_RX_DIO | SPI_OPM_RX_QOF | \ 46 SPI_OPM_RX_QIOF 47 48 /* SPI bus connection options */ 49 #define SPI_CONN_DUAL_SHARED 1 << 0 50 51 /* Header byte that marks the start of the message */ 52 #define SPI_PREAMBLE_END_BYTE 0xec 53 54 #define SPI_DEFAULT_WORDLEN 8 55 56 /** 57 * struct spi_slave - Representation of a SPI slave 58 * 59 * Drivers are expected to extend this with controller-specific data. 60 * 61 * @bus: ID of the bus that the slave is attached to. 62 * @cs: ID of the chip select connected to the slave. 63 * @op_mode_rx: SPI RX operation mode. 64 * @op_mode_tx: SPI TX operation mode. 65 * @wordlen: Size of SPI word in number of bits 66 * @max_write_size: If non-zero, the maximum number of bytes which can 67 * be written at once, excluding command bytes. 68 * @memory_map: Address of read-only SPI flash access. 69 * @option: Varies SPI bus options - separate bus. 70 * @flags: Indication of SPI flags. 71 */ 72 struct spi_slave { 73 unsigned int bus; 74 unsigned int cs; 75 u8 op_mode_rx; 76 u8 op_mode_tx; 77 unsigned int wordlen; 78 unsigned int max_write_size; 79 void *memory_map; 80 u8 option; 81 u8 flags; 82 }; 83 84 /** 85 * Initialization, must be called once on start up. 86 * 87 * TODO: I don't think we really need this. 88 */ 89 void spi_init(void); 90 91 /** 92 * spi_do_alloc_slave - Allocate a new SPI slave (internal) 93 * 94 * Allocate and zero all fields in the spi slave, and set the bus/chip 95 * select. Use the helper macro spi_alloc_slave() to call this. 96 * 97 * @offset: Offset of struct spi_slave within slave structure. 98 * @size: Size of slave structure. 99 * @bus: Bus ID of the slave chip. 100 * @cs: Chip select ID of the slave chip on the specified bus. 101 */ 102 void *spi_do_alloc_slave(int offset, int size, unsigned int bus, 103 unsigned int cs); 104 105 /** 106 * spi_alloc_slave - Allocate a new SPI slave 107 * 108 * Allocate and zero all fields in the spi slave, and set the bus/chip 109 * select. 110 * 111 * @_struct: Name of structure to allocate (e.g. struct tegra_spi). 112 * This structure must contain a member 'struct spi_slave *slave'. 113 * @bus: Bus ID of the slave chip. 114 * @cs: Chip select ID of the slave chip on the specified bus. 115 */ 116 #define spi_alloc_slave(_struct, bus, cs) \ 117 spi_do_alloc_slave(offsetof(_struct, slave), \ 118 sizeof(_struct), bus, cs) 119 120 /** 121 * spi_alloc_slave_base - Allocate a new SPI slave with no private data 122 * 123 * Allocate and zero all fields in the spi slave, and set the bus/chip 124 * select. 125 * 126 * @bus: Bus ID of the slave chip. 127 * @cs: Chip select ID of the slave chip on the specified bus. 128 */ 129 #define spi_alloc_slave_base(bus, cs) \ 130 spi_do_alloc_slave(0, sizeof(struct spi_slave), bus, cs) 131 132 /** 133 * Set up communications parameters for a SPI slave. 134 * 135 * This must be called once for each slave. Note that this function 136 * usually doesn't touch any actual hardware, it only initializes the 137 * contents of spi_slave so that the hardware can be easily 138 * initialized later. 139 * 140 * @bus: Bus ID of the slave chip. 141 * @cs: Chip select ID of the slave chip on the specified bus. 142 * @max_hz: Maximum SCK rate in Hz. 143 * @mode: Clock polarity, clock phase and other parameters. 144 * 145 * Returns: A spi_slave reference that can be used in subsequent SPI 146 * calls, or NULL if one or more of the parameters are not supported. 147 */ 148 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, 149 unsigned int max_hz, unsigned int mode); 150 151 /** 152 * Free any memory associated with a SPI slave. 153 * 154 * @slave: The SPI slave 155 */ 156 void spi_free_slave(struct spi_slave *slave); 157 158 /** 159 * Claim the bus and prepare it for communication with a given slave. 160 * 161 * This must be called before doing any transfers with a SPI slave. It 162 * will enable and initialize any SPI hardware as necessary, and make 163 * sure that the SCK line is in the correct idle state. It is not 164 * allowed to claim the same bus for several slaves without releasing 165 * the bus in between. 166 * 167 * @slave: The SPI slave 168 * 169 * Returns: 0 if the bus was claimed successfully, or a negative value 170 * if it wasn't. 171 */ 172 int spi_claim_bus(struct spi_slave *slave); 173 174 /** 175 * Release the SPI bus 176 * 177 * This must be called once for every call to spi_claim_bus() after 178 * all transfers have finished. It may disable any SPI hardware as 179 * appropriate. 180 * 181 * @slave: The SPI slave 182 */ 183 void spi_release_bus(struct spi_slave *slave); 184 185 /** 186 * Set the word length for SPI transactions 187 * 188 * Set the word length (number of bits per word) for SPI transactions. 189 * 190 * @slave: The SPI slave 191 * @wordlen: The number of bits in a word 192 * 193 * Returns: 0 on success, -1 on failure. 194 */ 195 int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen); 196 197 /** 198 * SPI transfer 199 * 200 * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks 201 * "bitlen" bits in the SPI MISO port. That's just the way SPI works. 202 * 203 * The source of the outgoing bits is the "dout" parameter and the 204 * destination of the input bits is the "din" parameter. Note that "dout" 205 * and "din" can point to the same memory location, in which case the 206 * input data overwrites the output data (since both are buffered by 207 * temporary variables, this is OK). 208 * 209 * spi_xfer() interface: 210 * @slave: The SPI slave which will be sending/receiving the data. 211 * @bitlen: How many bits to write and read. 212 * @dout: Pointer to a string of bits to send out. The bits are 213 * held in a byte array and are sent MSB first. 214 * @din: Pointer to a string of bits that will be filled in. 215 * @flags: A bitwise combination of SPI_XFER_* flags. 216 * 217 * Returns: 0 on success, not 0 on failure 218 */ 219 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, 220 void *din, unsigned long flags); 221 222 /** 223 * Determine if a SPI chipselect is valid. 224 * This function is provided by the board if the low-level SPI driver 225 * needs it to determine if a given chipselect is actually valid. 226 * 227 * Returns: 1 if bus:cs identifies a valid chip on this board, 0 228 * otherwise. 229 */ 230 int spi_cs_is_valid(unsigned int bus, unsigned int cs); 231 232 /** 233 * Activate a SPI chipselect. 234 * This function is provided by the board code when using a driver 235 * that can't control its chipselects automatically (e.g. 236 * common/soft_spi.c). When called, it should activate the chip select 237 * to the device identified by "slave". 238 */ 239 void spi_cs_activate(struct spi_slave *slave); 240 241 /** 242 * Deactivate a SPI chipselect. 243 * This function is provided by the board code when using a driver 244 * that can't control its chipselects automatically (e.g. 245 * common/soft_spi.c). When called, it should deactivate the chip 246 * select to the device identified by "slave". 247 */ 248 void spi_cs_deactivate(struct spi_slave *slave); 249 250 /** 251 * Set transfer speed. 252 * This sets a new speed to be applied for next spi_xfer(). 253 * @slave: The SPI slave 254 * @hz: The transfer speed 255 */ 256 void spi_set_speed(struct spi_slave *slave, uint hz); 257 258 /** 259 * Write 8 bits, then read 8 bits. 260 * @slave: The SPI slave we're communicating with 261 * @byte: Byte to be written 262 * 263 * Returns: The value that was read, or a negative value on error. 264 * 265 * TODO: This function probably shouldn't be inlined. 266 */ 267 static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte) 268 { 269 unsigned char dout[2]; 270 unsigned char din[2]; 271 int ret; 272 273 dout[0] = byte; 274 dout[1] = 0; 275 276 ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END); 277 return ret < 0 ? ret : din[1]; 278 } 279 280 /** 281 * Set up a SPI slave for a particular device tree node 282 * 283 * This calls spi_setup_slave() with the correct bus number. Call 284 * spi_free_slave() to free it later. 285 * 286 * @param blob: Device tree blob 287 * @param slave_node: Slave node to use 288 * @param spi_node: SPI peripheral node to use 289 * @return pointer to new spi_slave structure 290 */ 291 struct spi_slave *spi_setup_slave_fdt(const void *blob, int slave_node, 292 int spi_node); 293 294 /** 295 * spi_base_setup_slave_fdt() - helper function to set up a SPI slace 296 * 297 * This decodes SPI properties from the slave node to determine the 298 * chip select and SPI parameters. 299 * 300 * @blob: Device tree blob 301 * @busnum: Bus number to use 302 * @node: Device tree node for the SPI bus 303 */ 304 struct spi_slave *spi_base_setup_slave_fdt(const void *blob, int busnum, 305 int node); 306 307 #endif /* _SPI_H_ */ 308