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https://github.com/AsahiLinux/u-boot
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451 lines
11 KiB
C
451 lines
11 KiB
C
/*
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* (C) Copyright 2012 SAMSUNG Electronics
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* Padmavathi Venna <padma.v@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <common.h>
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#include <malloc.h>
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#include <spi.h>
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#include <fdtdec.h>
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#include <asm/arch/clk.h>
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#include <asm/arch/clock.h>
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#include <asm/arch/cpu.h>
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#include <asm/arch/gpio.h>
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#include <asm/arch/pinmux.h>
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#include <asm/arch-exynos/spi.h>
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#include <asm/io.h>
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DECLARE_GLOBAL_DATA_PTR;
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/* Information about each SPI controller */
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struct spi_bus {
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enum periph_id periph_id;
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s32 frequency; /* Default clock frequency, -1 for none */
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struct exynos_spi *regs;
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int inited; /* 1 if this bus is ready for use */
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int node;
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};
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/* A list of spi buses that we know about */
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static struct spi_bus spi_bus[EXYNOS5_SPI_NUM_CONTROLLERS];
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static unsigned int bus_count;
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struct exynos_spi_slave {
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struct spi_slave slave;
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struct exynos_spi *regs;
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unsigned int freq; /* Default frequency */
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unsigned int mode;
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enum periph_id periph_id; /* Peripheral ID for this device */
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unsigned int fifo_size;
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};
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static struct spi_bus *spi_get_bus(unsigned dev_index)
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{
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if (dev_index < bus_count)
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return &spi_bus[dev_index];
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debug("%s: invalid bus %d", __func__, dev_index);
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return NULL;
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}
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static inline struct exynos_spi_slave *to_exynos_spi(struct spi_slave *slave)
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{
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return container_of(slave, struct exynos_spi_slave, slave);
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}
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/**
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* Setup the driver private data
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*
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* @param bus ID of the bus that the slave is attached to
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* @param cs ID of the chip select connected to the slave
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* @param max_hz Required spi frequency
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* @param mode Required spi mode (clk polarity, clk phase and
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* master or slave)
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* @return new device or NULL
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*/
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struct spi_slave *spi_setup_slave(unsigned int busnum, unsigned int cs,
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unsigned int max_hz, unsigned int mode)
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{
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struct exynos_spi_slave *spi_slave;
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struct spi_bus *bus;
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if (!spi_cs_is_valid(busnum, cs)) {
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debug("%s: Invalid bus/chip select %d, %d\n", __func__,
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busnum, cs);
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return NULL;
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}
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spi_slave = spi_alloc_slave(struct exynos_spi_slave, busnum, cs);
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if (!spi_slave) {
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debug("%s: Could not allocate spi_slave\n", __func__);
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return NULL;
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}
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bus = &spi_bus[busnum];
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spi_slave->regs = bus->regs;
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spi_slave->mode = mode;
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spi_slave->periph_id = bus->periph_id;
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if (bus->periph_id == PERIPH_ID_SPI1 ||
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bus->periph_id == PERIPH_ID_SPI2)
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spi_slave->fifo_size = 64;
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else
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spi_slave->fifo_size = 256;
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spi_slave->freq = bus->frequency;
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if (max_hz)
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spi_slave->freq = min(max_hz, spi_slave->freq);
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return &spi_slave->slave;
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}
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/**
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* Free spi controller
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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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 exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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free(spi_slave);
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}
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/**
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* Flush spi tx, rx fifos and reset the SPI controller
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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*/
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static void spi_flush_fifo(struct spi_slave *slave)
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{
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struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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struct exynos_spi *regs = spi_slave->regs;
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clrsetbits_le32(®s->ch_cfg, SPI_CH_HS_EN, SPI_CH_RST);
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clrbits_le32(®s->ch_cfg, SPI_CH_RST);
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setbits_le32(®s->ch_cfg, SPI_TX_CH_ON | SPI_RX_CH_ON);
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}
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/**
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* Initialize the spi base registers, set the required clock frequency and
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* initialize the gpios
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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* @return zero on success else a negative value
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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 exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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struct exynos_spi *regs = spi_slave->regs;
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u32 reg = 0;
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int ret;
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ret = set_spi_clk(spi_slave->periph_id,
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spi_slave->freq);
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if (ret < 0) {
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debug("%s: Failed to setup spi clock\n", __func__);
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return ret;
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}
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exynos_pinmux_config(spi_slave->periph_id, PINMUX_FLAG_NONE);
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spi_flush_fifo(slave);
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reg = readl(®s->ch_cfg);
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reg &= ~(SPI_CH_CPHA_B | SPI_CH_CPOL_L);
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if (spi_slave->mode & SPI_CPHA)
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reg |= SPI_CH_CPHA_B;
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if (spi_slave->mode & SPI_CPOL)
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reg |= SPI_CH_CPOL_L;
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writel(reg, ®s->ch_cfg);
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writel(SPI_FB_DELAY_180, ®s->fb_clk);
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return 0;
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}
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/**
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* Reset the spi H/W and flush the tx and rx fifos
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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*/
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void spi_release_bus(struct spi_slave *slave)
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{
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spi_flush_fifo(slave);
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}
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static void spi_get_fifo_levels(struct exynos_spi *regs,
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int *rx_lvl, int *tx_lvl)
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{
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uint32_t spi_sts = readl(®s->spi_sts);
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*rx_lvl = (spi_sts >> SPI_RX_LVL_OFFSET) & SPI_FIFO_LVL_MASK;
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*tx_lvl = (spi_sts >> SPI_TX_LVL_OFFSET) & SPI_FIFO_LVL_MASK;
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}
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/**
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* If there's something to transfer, do a software reset and set a
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* transaction size.
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*
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* @param regs SPI peripheral registers
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* @param count Number of bytes to transfer
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*/
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static void spi_request_bytes(struct exynos_spi *regs, int count)
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{
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assert(count && count < (1 << 16));
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setbits_le32(®s->ch_cfg, SPI_CH_RST);
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clrbits_le32(®s->ch_cfg, SPI_CH_RST);
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writel(count | SPI_PACKET_CNT_EN, ®s->pkt_cnt);
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}
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static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
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void **dinp, void const **doutp)
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{
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struct exynos_spi *regs = spi_slave->regs;
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uchar *rxp = *dinp;
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const uchar *txp = *doutp;
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int rx_lvl, tx_lvl;
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uint out_bytes, in_bytes;
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out_bytes = in_bytes = todo;
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/*
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* If there's something to send, do a software reset and set a
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* transaction size.
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*/
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spi_request_bytes(regs, todo);
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/*
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* Bytes are transmitted/received in pairs. Wait to receive all the
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* data because then transmission will be done as well.
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*/
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while (in_bytes) {
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int temp;
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/* Keep the fifos full/empty. */
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spi_get_fifo_levels(regs, &rx_lvl, &tx_lvl);
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if (tx_lvl < spi_slave->fifo_size && out_bytes) {
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temp = txp ? *txp++ : 0xff;
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writel(temp, ®s->tx_data);
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out_bytes--;
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}
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if (rx_lvl > 0 && in_bytes) {
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temp = readl(®s->rx_data);
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if (rxp)
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*rxp++ = temp;
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in_bytes--;
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}
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}
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*dinp = rxp;
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*doutp = txp;
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}
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/**
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* Transfer and receive data
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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* @param bitlen No of bits to tranfer or receive
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* @param dout Pointer to transfer buffer
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* @param din Pointer to receive buffer
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* @param flags Flags for transfer begin and end
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* @return zero on success else a negative value
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*/
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
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void *din, unsigned long flags)
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{
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struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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int upto, todo;
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int bytelen;
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/* spi core configured to do 8 bit transfers */
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if (bitlen % 8) {
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debug("Non byte aligned SPI transfer.\n");
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return -1;
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}
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/* Start the transaction, if necessary. */
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if ((flags & SPI_XFER_BEGIN))
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spi_cs_activate(slave);
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/* Exynos SPI limits each transfer to 65535 bytes */
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bytelen = bitlen / 8;
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for (upto = 0; upto < bytelen; upto += todo) {
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todo = min(bytelen - upto, (1 << 16) - 1);
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spi_rx_tx(spi_slave, todo, &din, &dout);
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}
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/* Stop the transaction, if necessary. */
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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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/**
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* Validates the bus and chip select numbers
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*
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* @param bus ID of the bus that the slave is attached to
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* @param cs ID of the chip select connected to the slave
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* @return one on success else zero
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*/
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int spi_cs_is_valid(unsigned int bus, unsigned int cs)
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{
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return spi_get_bus(bus) && cs == 0;
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}
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/**
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* Activate the CS by driving it LOW
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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*/
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void spi_cs_activate(struct spi_slave *slave)
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{
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struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
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debug("Activate CS, bus %d\n", spi_slave->slave.bus);
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}
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/**
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* Deactivate the CS by driving it HIGH
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*
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* @param slave Pointer to spi_slave to which controller has to
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* communicate with
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*/
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void spi_cs_deactivate(struct spi_slave *slave)
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{
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struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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setbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
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debug("Deactivate CS, bus %d\n", spi_slave->slave.bus);
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}
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static inline struct exynos_spi *get_spi_base(int dev_index)
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{
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if (dev_index < 3)
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return (struct exynos_spi *)samsung_get_base_spi() + dev_index;
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else
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return (struct exynos_spi *)samsung_get_base_spi_isp() +
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(dev_index - 3);
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}
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/*
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* Read the SPI config from the device tree node.
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*
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* @param blob FDT blob to read from
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* @param node Node offset to read from
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* @param bus SPI bus structure to fill with information
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* @return 0 if ok, or -FDT_ERR_NOTFOUND if something was missing
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*/
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#ifdef CONFIG_OF_CONTROL
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static int spi_get_config(const void *blob, int node, struct spi_bus *bus)
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{
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bus->node = node;
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bus->regs = (struct exynos_spi *)fdtdec_get_addr(blob, node, "reg");
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bus->periph_id = pinmux_decode_periph_id(blob, node);
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if (bus->periph_id == PERIPH_ID_NONE) {
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debug("%s: Invalid peripheral ID %d\n", __func__,
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bus->periph_id);
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return -FDT_ERR_NOTFOUND;
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}
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/* Use 500KHz as a suitable default */
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bus->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
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500000);
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return 0;
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}
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/*
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* Process a list of nodes, adding them to our list of SPI ports.
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*
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* @param blob fdt blob
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* @param node_list list of nodes to process (any <=0 are ignored)
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* @param count number of nodes to process
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* @param is_dvc 1 if these are DVC ports, 0 if standard I2C
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* @return 0 if ok, -1 on error
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*/
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static int process_nodes(const void *blob, int node_list[], int count)
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{
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int i;
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/* build the i2c_controllers[] for each controller */
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for (i = 0; i < count; i++) {
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int node = node_list[i];
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struct spi_bus *bus;
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if (node <= 0)
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continue;
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bus = &spi_bus[i];
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if (spi_get_config(blob, node, bus)) {
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printf("exynos spi_init: failed to decode bus %d\n",
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i);
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return -1;
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}
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debug("spi: controller bus %d at %p, periph_id %d\n",
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i, bus->regs, bus->periph_id);
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bus->inited = 1;
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bus_count++;
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}
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return 0;
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}
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#endif
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/* Sadly there is no error return from this function */
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void spi_init(void)
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{
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int count;
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#ifdef CONFIG_OF_CONTROL
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int node_list[EXYNOS5_SPI_NUM_CONTROLLERS];
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const void *blob = gd->fdt_blob;
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count = fdtdec_find_aliases_for_id(blob, "spi",
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COMPAT_SAMSUNG_EXYNOS_SPI, node_list,
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EXYNOS5_SPI_NUM_CONTROLLERS);
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if (process_nodes(blob, node_list, count))
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return;
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#else
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struct spi_bus *bus;
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for (count = 0; count < EXYNOS5_SPI_NUM_CONTROLLERS; count++) {
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bus = &spi_bus[count];
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bus->regs = get_spi_base(count);
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bus->periph_id = PERIPH_ID_SPI0 + count;
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/* Although Exynos5 supports upto 50Mhz speed,
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* we are setting it to 10Mhz for safe side
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*/
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bus->frequency = 10000000;
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bus->inited = 1;
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bus->node = 0;
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bus_count = EXYNOS5_SPI_NUM_CONTROLLERS;
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}
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#endif
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}
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