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* omap_uwire.c -- MicroWire interface driver for OMAP
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* Copyright 2003 MontaVista Software Inc. <source@mvista.com>
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* Ported to 2.6 OMAP uwire interface.
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* Copyright (C) 2004 Texas Instruments.
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* Generalization patches by Juha Yrjola <juha.yrjola@nokia.com>
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* Copyright (C) 2005 David Brownell (ported to 2.6 SPI interface)
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* Copyright (C) 2006 Nokia
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* Many updates by Imre Deak <imre.deak@nokia.com>
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/workqueue.h>
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#include <linux/interrupt.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/slab.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <asm/system.h>
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#include <mach/hardware.h>
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#include <asm/mach-types.h>
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#include <plat/omap7xx.h> /* OMAP7XX_IO_CONF registers */
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/* FIXME address is now a platform device resource,
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* and irqs should show there too...
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#define UWIRE_BASE_PHYS 0xFFFB3000
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/* uWire Registers: */
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#define UWIRE_IO_SIZE 0x20
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#define UWIRE_TDR 0x00
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#define UWIRE_RDR 0x00
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#define UWIRE_CSR 0x01
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#define UWIRE_SR1 0x02
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#define UWIRE_SR2 0x03
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#define UWIRE_SR3 0x04
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#define UWIRE_SR4 0x05
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#define UWIRE_SR5 0x06
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#define RDRB (1 << 15)
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#define CSRB (1 << 14)
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#define START (1 << 13)
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#define CS_CMD (1 << 12)
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#define UWIRE_READ_FALLING_EDGE 0x0001
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#define UWIRE_READ_RISING_EDGE 0x0000
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#define UWIRE_WRITE_FALLING_EDGE 0x0000
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#define UWIRE_WRITE_RISING_EDGE 0x0002
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#define UWIRE_CS_ACTIVE_LOW 0x0000
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#define UWIRE_CS_ACTIVE_HIGH 0x0004
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#define UWIRE_FREQ_DIV_2 0x0000
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#define UWIRE_FREQ_DIV_4 0x0008
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#define UWIRE_FREQ_DIV_8 0x0010
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#define UWIRE_CHK_READY 0x0020
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#define UWIRE_CLK_INVERTED 0x0040
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struct spi_bitbang bitbang;
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unsigned bits_per_word;
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/* REVISIT compile time constant for idx_shift? */
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* Or, put it in a structure which is used throughout the driver;
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* that avoids having to issue two loads for each bit of static data.
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static unsigned int uwire_idx_shift;
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static void __iomem *uwire_base;
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static inline void uwire_write_reg(int idx, u16 val)
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__raw_writew(val, uwire_base + (idx << uwire_idx_shift));
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static inline u16 uwire_read_reg(int idx)
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return __raw_readw(uwire_base + (idx << uwire_idx_shift));
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static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags)
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if (flags & UWIRE_CLK_INVERTED)
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w = uwire_read_reg(reg);
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w &= ~(0x3f << shift);
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uwire_write_reg(reg, w);
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static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch)
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unsigned long max_jiffies = jiffies + HZ;
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w = uwire_read_reg(UWIRE_CSR);
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if ((w & mask) == val)
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if (time_after(jiffies, max_jiffies)) {
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printk(KERN_ERR "%s: timeout. reg=%#06x "
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"mask=%#06x val=%#06x\n",
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__func__, w, mask, val);
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if (might_not_catch && c > 64)
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static void uwire_set_clk1_div(int div1_idx)
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w = uwire_read_reg(UWIRE_SR3);
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uwire_write_reg(UWIRE_SR3, w);
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static void uwire_chipselect(struct spi_device *spi, int value)
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struct uwire_state *ust = spi->controller_state;
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BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0));
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w = uwire_read_reg(UWIRE_CSR);
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old_cs = (w >> 10) & 0x03;
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if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) {
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/* Deselect this CS, or the previous CS */
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uwire_write_reg(UWIRE_CSR, w);
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/* activate specfied chipselect */
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if (value == BITBANG_CS_ACTIVE) {
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uwire_set_clk1_div(ust->div1_idx);
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if (spi->mode & SPI_CPOL)
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uwire_write_reg(UWIRE_SR4, 1);
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uwire_write_reg(UWIRE_SR4, 0);
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w = spi->chip_select << 10;
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uwire_write_reg(UWIRE_CSR, w);
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static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
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struct uwire_state *ust = spi->controller_state;
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unsigned len = t->len;
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unsigned bits = ust->bits_per_word;
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if (!t->tx_buf && !t->rx_buf)
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/* Microwire doesn't read and write concurrently */
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if (t->tx_buf && t->rx_buf)
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w = spi->chip_select << 10;
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const u8 *buf = t->tx_buf;
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/* NOTE: DMA could be used for TX transfers */
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/* write one or two bytes at a time */
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/* tx bit 15 is first sent; we byteswap multibyte words
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* (msb-first) on the way out from memory.
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pr_debug("%s: write-%d =%04x\n",
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dev_name(&spi->dev), bits, val);
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if (wait_uwire_csr_flag(CSRB, 0, 0))
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uwire_write_reg(UWIRE_TDR, val);
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val = START | w | (bits << 5);
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uwire_write_reg(UWIRE_CSR, val);
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/* Wait till write actually starts.
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* This is needed with MPU clock 60+ MHz.
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* REVISIT: we may not have time to catch it...
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if (wait_uwire_csr_flag(CSRB, CSRB, 1))
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/* REVISIT: save this for later to get more i/o overlap */
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if (wait_uwire_csr_flag(CSRB, 0, 0))
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} else if (t->rx_buf) {
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/* read one or two bytes at a time */
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val = START | w | (bits << 0);
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uwire_write_reg(UWIRE_CSR, val);
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/* Wait till read actually starts */
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(void) wait_uwire_csr_flag(CSRB, CSRB, 1);
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if (wait_uwire_csr_flag(RDRB | CSRB,
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/* rx bit 0 is last received; multibyte words will
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* be properly byteswapped on the way to memory.
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val = uwire_read_reg(UWIRE_RDR);
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val &= (1 << bits) - 1;
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pr_debug("%s: read-%d =%04x\n",
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dev_name(&spi->dev), bits, val);
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static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
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struct uwire_state *ust = spi->controller_state;
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struct uwire_spi *uwire;
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uwire = spi_master_get_devdata(spi->master);
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if (spi->chip_select > 3) {
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pr_debug("%s: cs%d?\n", dev_name(&spi->dev), spi->chip_select);
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bits = spi->bits_per_word;
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if (t != NULL && t->bits_per_word)
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bits = t->bits_per_word;
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pr_debug("%s: wordsize %d?\n", dev_name(&spi->dev), bits);
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ust->bits_per_word = bits;
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/* mode 0..3, clock inverted separately;
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* standard nCS signaling;
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* don't treat DI=high as "not ready"
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if (spi->mode & SPI_CS_HIGH)
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flags |= UWIRE_CS_ACTIVE_HIGH;
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if (spi->mode & SPI_CPOL)
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flags |= UWIRE_CLK_INVERTED;
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switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
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flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE;
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flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE;
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/* assume it's already enabled */
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rate = clk_get_rate(uwire->ck);
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hz = spi->max_speed_hz;
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if (t != NULL && t->speed_hz)
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pr_debug("%s: zero speed?\n", dev_name(&spi->dev));
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/* F_INT = mpu_xor_clk / DIV1 */
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for (div1_idx = 0; div1_idx < 4; div1_idx++) {
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div2 = (rate / div1 + hz - 1) / hz;
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pr_debug("%s: lowest clock %ld, need %d\n",
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dev_name(&spi->dev), rate / 10 / 8, hz);
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/* we have to cache this and reset in uwire_chipselect as this is a
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* global parameter and another uwire device can change it under
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ust->div1_idx = div1_idx;
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uwire_set_clk1_div(div1_idx);
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flags |= UWIRE_FREQ_DIV_2;
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flags |= UWIRE_FREQ_DIV_4;
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flags |= UWIRE_FREQ_DIV_8;
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omap_uwire_configure_mode(spi->chip_select, flags);
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pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n",
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clk_get_rate(uwire->ck) / 1000,
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static int uwire_setup(struct spi_device *spi)
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struct uwire_state *ust = spi->controller_state;
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ust = kzalloc(sizeof(*ust), GFP_KERNEL);
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spi->controller_state = ust;
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return uwire_setup_transfer(spi, NULL);
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static void uwire_cleanup(struct spi_device *spi)
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kfree(spi->controller_state);
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static void uwire_off(struct uwire_spi *uwire)
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uwire_write_reg(UWIRE_SR3, 0);
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clk_disable(uwire->ck);
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spi_master_put(uwire->bitbang.master);
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static int __init uwire_probe(struct platform_device *pdev)
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struct spi_master *master;
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struct uwire_spi *uwire;
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master = spi_alloc_master(&pdev->dev, sizeof *uwire);
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uwire = spi_master_get_devdata(master);
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uwire_base = ioremap(UWIRE_BASE_PHYS, UWIRE_IO_SIZE);
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dev_dbg(&pdev->dev, "can't ioremap UWIRE\n");
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spi_master_put(master);
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dev_set_drvdata(&pdev->dev, uwire);
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uwire->ck = clk_get(&pdev->dev, "fck");
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if (IS_ERR(uwire->ck)) {
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status = PTR_ERR(uwire->ck);
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dev_dbg(&pdev->dev, "no functional clock?\n");
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spi_master_put(master);
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clk_enable(uwire->ck);
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if (cpu_is_omap7xx())
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uwire_write_reg(UWIRE_SR3, 1);
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/* the spi->mode bits understood by this driver: */
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master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
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master->flags = SPI_MASTER_HALF_DUPLEX;
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master->bus_num = 2; /* "official" */
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master->num_chipselect = 4;
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master->setup = uwire_setup;
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master->cleanup = uwire_cleanup;
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uwire->bitbang.master = master;
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uwire->bitbang.chipselect = uwire_chipselect;
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uwire->bitbang.setup_transfer = uwire_setup_transfer;
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uwire->bitbang.txrx_bufs = uwire_txrx;
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status = spi_bitbang_start(&uwire->bitbang);
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static int __exit uwire_remove(struct platform_device *pdev)
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struct uwire_spi *uwire = dev_get_drvdata(&pdev->dev);
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// FIXME remove all child devices, somewhere ...
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status = spi_bitbang_stop(&uwire->bitbang);
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/* work with hotplug and coldplug */
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MODULE_ALIAS("platform:omap_uwire");
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static struct platform_driver uwire_driver = {
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.name = "omap_uwire",
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.owner = THIS_MODULE,
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.remove = __exit_p(uwire_remove),
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// suspend ... unuse ck
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static int __init omap_uwire_init(void)
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/* FIXME move these into the relevant board init code. also, include
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* H3 support; it uses tsc2101 like H2 (on a different chipselect).
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if (machine_is_omap_h2()) {
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/* defaults: W21 SDO, U18 SDI, V19 SCL */
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omap_cfg_reg(N14_1610_UWIRE_CS0);
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omap_cfg_reg(N15_1610_UWIRE_CS1);
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if (machine_is_omap_perseus2()) {
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/* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */
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int val = omap_readl(OMAP7XX_IO_CONF_9) & ~0x00EEE000;
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omap_writel(val | 0x00AAA000, OMAP7XX_IO_CONF_9);
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return platform_driver_probe(&uwire_driver, uwire_probe);
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static void __exit omap_uwire_exit(void)
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platform_driver_unregister(&uwire_driver);
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subsys_initcall(omap_uwire_init);
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module_exit(omap_uwire_exit);
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MODULE_LICENSE("GPL");