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https://github.com/brain-hackers/u-boot-brain
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![Tom Rini](/assets/img/avatar_default.png)
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
176 lines
3.8 KiB
C
176 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* (C) Copyright 2002
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* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
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*
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* Influenced by code from:
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*/
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#include <common.h>
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#include <spi.h>
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#include <malloc.h>
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/*-----------------------------------------------------------------------
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* Definitions
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*/
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#ifdef DEBUG_SPI
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#define PRINTD(fmt,args...) printf (fmt ,##args)
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#else
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#define PRINTD(fmt,args...)
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#endif
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struct soft_spi_slave {
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struct spi_slave slave;
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unsigned int mode;
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};
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static inline struct soft_spi_slave *to_soft_spi(struct spi_slave *slave)
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{
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return container_of(slave, struct soft_spi_slave, slave);
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}
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/*=====================================================================*/
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/* Public Functions */
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/*=====================================================================*/
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/*-----------------------------------------------------------------------
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* Initialization
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*/
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void spi_init (void)
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{
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}
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struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
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unsigned int max_hz, unsigned int mode)
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{
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struct soft_spi_slave *ss;
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if (!spi_cs_is_valid(bus, cs))
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return NULL;
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ss = spi_alloc_slave(struct soft_spi_slave, bus, cs);
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if (!ss)
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return NULL;
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ss->mode = mode;
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/* TODO: Use max_hz to limit the SCK rate */
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return &ss->slave;
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}
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void spi_free_slave(struct spi_slave *slave)
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{
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struct soft_spi_slave *ss = to_soft_spi(slave);
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free(ss);
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}
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int spi_claim_bus(struct spi_slave *slave)
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{
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#ifdef CONFIG_SYS_IMMR
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volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
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#endif
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struct soft_spi_slave *ss = to_soft_spi(slave);
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/*
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* Make sure the SPI clock is in idle state as defined for
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* this slave.
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*/
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if (ss->mode & SPI_CPOL)
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SPI_SCL(1);
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else
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SPI_SCL(0);
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return 0;
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}
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void spi_release_bus(struct spi_slave *slave)
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{
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/* Nothing to do */
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}
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/*-----------------------------------------------------------------------
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* SPI transfer
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*
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* This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
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* "bitlen" bits in the SPI MISO port. That's just the way SPI works.
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*
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* The source of the outgoing bits is the "dout" parameter and the
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* destination of the input bits is the "din" parameter. Note that "dout"
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* and "din" can point to the same memory location, in which case the
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* input data overwrites the output data (since both are buffered by
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* temporary variables, this is OK).
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*/
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
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const void *dout, void *din, unsigned long flags)
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{
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#ifdef CONFIG_SYS_IMMR
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volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
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#endif
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struct soft_spi_slave *ss = to_soft_spi(slave);
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uchar tmpdin = 0;
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uchar tmpdout = 0;
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const u8 *txd = dout;
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u8 *rxd = din;
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int cpol = ss->mode & SPI_CPOL;
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int cpha = ss->mode & SPI_CPHA;
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unsigned int j;
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PRINTD("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
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slave->bus, slave->cs, *(uint *)txd, *(uint *)rxd, bitlen);
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if (flags & SPI_XFER_BEGIN)
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spi_cs_activate(slave);
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for(j = 0; j < bitlen; j++) {
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/*
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* Check if it is time to work on a new byte.
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*/
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if ((j % 8) == 0) {
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if (txd)
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tmpdout = *txd++;
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else
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tmpdout = 0;
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if(j != 0) {
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if (rxd)
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*rxd++ = tmpdin;
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}
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tmpdin = 0;
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}
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if (!cpha)
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SPI_SCL(!cpol);
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SPI_SDA(tmpdout & 0x80);
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SPI_DELAY;
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if (cpha)
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SPI_SCL(!cpol);
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else
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SPI_SCL(cpol);
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tmpdin <<= 1;
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tmpdin |= SPI_READ;
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tmpdout <<= 1;
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SPI_DELAY;
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if (cpha)
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SPI_SCL(cpol);
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}
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/*
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* If the number of bits isn't a multiple of 8, shift the last
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* bits over to left-justify them. Then store the last byte
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* read in.
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*/
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if (rxd) {
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if ((bitlen % 8) != 0)
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tmpdin <<= 8 - (bitlen % 8);
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*rxd++ = tmpdin;
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}
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if (flags & SPI_XFER_END)
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spi_cs_deactivate(slave);
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return(0);
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}
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