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![Sergey Kostanbaev](/assets/img/avatar_default.png)
This patch returns back support for old ep93xx processors family Signed-off-by: Sergey Kostanbaev <sergey.kostanbaev@gmail.com> Cc: albert.u.boot@aribaud.net
275 lines
5.4 KiB
C
275 lines
5.4 KiB
C
/*
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* SPI Driver for EP93xx
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*
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* Copyright (C) 2013 Sergey Kostanabev <sergey.kostanbaev <at> fairwaves.ru>
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*
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* Inspired form linux kernel driver and atmel uboot driver
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*
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* SPDX-License-Identifier: GPL-2.0+
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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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#include <asm/io.h>
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#include <asm/arch/ep93xx.h>
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#define BIT(x) (1<<(x))
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#define SSPBASE SPI_BASE
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#define SSPCR0 0x0000
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#define SSPCR0_MODE_SHIFT 6
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#define SSPCR0_SCR_SHIFT 8
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#define SSPCR0_SPH BIT(7)
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#define SSPCR0_SPO BIT(6)
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#define SSPCR0_FRF_SPI 0
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#define SSPCR0_DSS_8BIT 7
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#define SSPCR1 0x0004
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#define SSPCR1_RIE BIT(0)
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#define SSPCR1_TIE BIT(1)
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#define SSPCR1_RORIE BIT(2)
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#define SSPCR1_LBM BIT(3)
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#define SSPCR1_SSE BIT(4)
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#define SSPCR1_MS BIT(5)
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#define SSPCR1_SOD BIT(6)
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#define SSPDR 0x0008
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#define SSPSR 0x000c
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#define SSPSR_TFE BIT(0)
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#define SSPSR_TNF BIT(1)
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#define SSPSR_RNE BIT(2)
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#define SSPSR_RFF BIT(3)
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#define SSPSR_BSY BIT(4)
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#define SSPCPSR 0x0010
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#define SSPIIR 0x0014
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#define SSPIIR_RIS BIT(0)
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#define SSPIIR_TIS BIT(1)
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#define SSPIIR_RORIS BIT(2)
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#define SSPICR SSPIIR
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#define SSPCLOCK 14745600
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#define SSP_MAX_RATE (SSPCLOCK / 2)
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#define SSP_MIN_RATE (SSPCLOCK / (254 * 256))
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/* timeout in milliseconds */
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#define SPI_TIMEOUT 5
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/* maximum depth of RX/TX FIFO */
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#define SPI_FIFO_SIZE 8
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struct ep93xx_spi_slave {
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struct spi_slave slave;
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unsigned sspcr0;
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unsigned sspcpsr;
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};
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static inline struct ep93xx_spi_slave *to_ep93xx_spi(struct spi_slave *slave)
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{
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return container_of(slave, struct ep93xx_spi_slave, slave);
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}
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void spi_init()
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{
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}
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static inline void ep93xx_spi_write_u8(u16 reg, u8 value)
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{
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writel(value, (unsigned int *)(SSPBASE + reg));
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}
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static inline u8 ep93xx_spi_read_u8(u16 reg)
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{
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return readl((unsigned int *)(SSPBASE + reg));
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}
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static inline void ep93xx_spi_write_u16(u16 reg, u16 value)
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{
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writel(value, (unsigned int *)(SSPBASE + reg));
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}
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static inline u16 ep93xx_spi_read_u16(u16 reg)
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{
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return (u16)readl((unsigned int *)(SSPBASE + reg));
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}
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static int ep93xx_spi_init_hw(unsigned int rate, unsigned int mode,
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struct ep93xx_spi_slave *slave)
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{
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unsigned cpsr, scr;
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if (rate > SSP_MAX_RATE)
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rate = SSP_MAX_RATE;
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if (rate < SSP_MIN_RATE)
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return -1;
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/* Calculate divisors so that we can get speed according the
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* following formula:
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* rate = spi_clock_rate / (cpsr * (1 + scr))
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*
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* cpsr must be even number and starts from 2, scr can be any number
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* between 0 and 255.
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*/
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for (cpsr = 2; cpsr <= 254; cpsr += 2) {
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for (scr = 0; scr <= 255; scr++) {
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if ((SSPCLOCK / (cpsr * (scr + 1))) <= rate) {
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/* Set CHPA and CPOL, SPI format and 8bit */
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unsigned sspcr0 = (scr << SSPCR0_SCR_SHIFT) |
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SSPCR0_FRF_SPI | SSPCR0_DSS_8BIT;
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if (mode & SPI_CPHA)
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sspcr0 |= SSPCR0_SPH;
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if (mode & SPI_CPOL)
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sspcr0 |= SSPCR0_SPO;
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slave->sspcr0 = sspcr0;
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slave->sspcpsr = cpsr;
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return 0;
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}
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}
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}
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return -1;
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}
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void spi_set_speed(struct spi_slave *slave, unsigned int hz)
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{
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struct ep93xx_spi_slave *as = to_ep93xx_spi(slave);
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unsigned int mode = 0;
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if (as->sspcr0 & SSPCR0_SPH)
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mode |= SPI_CPHA;
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if (as->sspcr0 & SSPCR0_SPO)
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mode |= SPI_CPOL;
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ep93xx_spi_init_hw(hz, mode, as);
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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 ep93xx_spi_slave *as;
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if (!spi_cs_is_valid(bus, cs))
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return NULL;
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as = spi_alloc_slave(struct ep93xx_spi_slave, bus, cs);
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if (!as)
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return NULL;
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if (ep93xx_spi_init_hw(max_hz, mode, as)) {
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free(as);
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return NULL;
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}
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return &as->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 ep93xx_spi_slave *as = to_ep93xx_spi(slave);
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free(as);
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}
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int spi_claim_bus(struct spi_slave *slave)
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{
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struct ep93xx_spi_slave *as = to_ep93xx_spi(slave);
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/* Enable the SPI hardware */
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ep93xx_spi_write_u8(SSPCR1, SSPCR1_SSE);
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ep93xx_spi_write_u8(SSPCPSR, as->sspcpsr);
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ep93xx_spi_write_u16(SSPCR0, as->sspcr0);
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debug("Select CS:%d SSPCPSR=%02x SSPCR0=%04x\n",
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slave->cs, as->sspcpsr, as->sspcr0);
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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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/* Disable the SPI hardware */
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ep93xx_spi_write_u8(SSPCR1, 0);
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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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unsigned int len_tx;
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unsigned int len_rx;
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unsigned int len;
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u32 status;
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const u8 *txp = dout;
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u8 *rxp = din;
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u8 value;
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debug("spi_xfer: slave %u:%u dout %p din %p bitlen %u\n",
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slave->bus, slave->cs, (uint *)dout, (uint *)din, bitlen);
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if (bitlen == 0)
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/* Finish any previously submitted transfers */
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goto out;
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if (bitlen % 8) {
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/* Errors always terminate an ongoing transfer */
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flags |= SPI_XFER_END;
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goto out;
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}
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len = bitlen / 8;
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if (flags & SPI_XFER_BEGIN) {
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/* Empty RX FIFO */
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while ((ep93xx_spi_read_u8(SSPSR) & SSPSR_RNE))
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ep93xx_spi_read_u8(SSPDR);
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spi_cs_activate(slave);
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}
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for (len_tx = 0, len_rx = 0; len_rx < len; ) {
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status = ep93xx_spi_read_u8(SSPSR);
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if ((len_tx < len) && (status & SSPSR_TNF)) {
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if (txp)
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value = *txp++;
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else
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value = 0xff;
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ep93xx_spi_write_u8(SSPDR, value);
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len_tx++;
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}
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if (status & SSPSR_RNE) {
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value = ep93xx_spi_read_u8(SSPDR);
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if (rxp)
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*rxp++ = value;
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len_rx++;
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}
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}
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out:
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if (flags & SPI_XFER_END) {
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/*
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* Wait until the transfer is completely done before
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* we deactivate CS.
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*/
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do {
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status = ep93xx_spi_read_u8(SSPSR);
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} while (status & SSPSR_BSY);
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spi_cs_deactivate(slave);
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}
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return 0;
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}
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