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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-22 00:40:03 +00:00
458 lines
12 KiB
C
458 lines
12 KiB
C
/*
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* TXx9 SPI controller driver.
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*
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* Based on linux/arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c
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* Copyright (C) 2000-2001 Toshiba Corporation
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*
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* 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
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* terms of the GNU General Public License version 2. This program is
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* licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*
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* Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
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*
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* Convert to generic SPI framework - Atsushi Nemoto (anemo@mba.ocn.ne.jp)
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*/
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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#include <linux/spi/spi.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/gpio.h>
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#define SPI_FIFO_SIZE 4
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#define SPI_MAX_DIVIDER 0xff /* Max. value for SPCR1.SER */
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#define SPI_MIN_DIVIDER 1 /* Min. value for SPCR1.SER */
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#define TXx9_SPMCR 0x00
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#define TXx9_SPCR0 0x04
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#define TXx9_SPCR1 0x08
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#define TXx9_SPFS 0x0c
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#define TXx9_SPSR 0x14
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#define TXx9_SPDR 0x18
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/* SPMCR : SPI Master Control */
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#define TXx9_SPMCR_OPMODE 0xc0
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#define TXx9_SPMCR_CONFIG 0x40
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#define TXx9_SPMCR_ACTIVE 0x80
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#define TXx9_SPMCR_SPSTP 0x02
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#define TXx9_SPMCR_BCLR 0x01
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/* SPCR0 : SPI Control 0 */
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#define TXx9_SPCR0_TXIFL_MASK 0xc000
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#define TXx9_SPCR0_RXIFL_MASK 0x3000
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#define TXx9_SPCR0_SIDIE 0x0800
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#define TXx9_SPCR0_SOEIE 0x0400
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#define TXx9_SPCR0_RBSIE 0x0200
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#define TXx9_SPCR0_TBSIE 0x0100
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#define TXx9_SPCR0_IFSPSE 0x0010
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#define TXx9_SPCR0_SBOS 0x0004
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#define TXx9_SPCR0_SPHA 0x0002
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#define TXx9_SPCR0_SPOL 0x0001
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/* SPSR : SPI Status */
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#define TXx9_SPSR_TBSI 0x8000
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#define TXx9_SPSR_RBSI 0x4000
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#define TXx9_SPSR_TBS_MASK 0x3800
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#define TXx9_SPSR_RBS_MASK 0x0700
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#define TXx9_SPSR_SPOE 0x0080
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#define TXx9_SPSR_IFSD 0x0008
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#define TXx9_SPSR_SIDLE 0x0004
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#define TXx9_SPSR_STRDY 0x0002
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#define TXx9_SPSR_SRRDY 0x0001
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struct txx9spi {
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struct workqueue_struct *workqueue;
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struct work_struct work;
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spinlock_t lock; /* protect 'queue' */
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struct list_head queue;
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wait_queue_head_t waitq;
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void __iomem *membase;
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int baseclk;
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struct clk *clk;
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u32 max_speed_hz, min_speed_hz;
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int last_chipselect;
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int last_chipselect_val;
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};
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static u32 txx9spi_rd(struct txx9spi *c, int reg)
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{
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return __raw_readl(c->membase + reg);
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}
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static void txx9spi_wr(struct txx9spi *c, u32 val, int reg)
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{
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__raw_writel(val, c->membase + reg);
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}
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static void txx9spi_cs_func(struct spi_device *spi, struct txx9spi *c,
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int on, unsigned int cs_delay)
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{
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int val = (spi->mode & SPI_CS_HIGH) ? on : !on;
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if (on) {
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/* deselect the chip with cs_change hint in last transfer */
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if (c->last_chipselect >= 0)
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gpio_set_value(c->last_chipselect,
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!c->last_chipselect_val);
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c->last_chipselect = spi->chip_select;
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c->last_chipselect_val = val;
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} else {
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c->last_chipselect = -1;
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ndelay(cs_delay); /* CS Hold Time */
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}
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gpio_set_value(spi->chip_select, val);
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ndelay(cs_delay); /* CS Setup Time / CS Recovery Time */
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}
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static int txx9spi_setup(struct spi_device *spi)
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{
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struct txx9spi *c = spi_master_get_devdata(spi->master);
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if (!spi->max_speed_hz
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|| spi->max_speed_hz > c->max_speed_hz
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|| spi->max_speed_hz < c->min_speed_hz)
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return -EINVAL;
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if (gpio_direction_output(spi->chip_select,
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!(spi->mode & SPI_CS_HIGH))) {
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dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n");
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return -EINVAL;
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}
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/* deselect chip */
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spin_lock(&c->lock);
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txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz);
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spin_unlock(&c->lock);
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return 0;
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}
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static irqreturn_t txx9spi_interrupt(int irq, void *dev_id)
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{
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struct txx9spi *c = dev_id;
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/* disable rx intr */
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txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE,
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TXx9_SPCR0);
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wake_up(&c->waitq);
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return IRQ_HANDLED;
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}
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static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
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{
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struct spi_device *spi = m->spi;
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struct spi_transfer *t;
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unsigned int cs_delay;
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unsigned int cs_change = 1;
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int status = 0;
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u32 mcr;
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u32 prev_speed_hz = 0;
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u8 prev_bits_per_word = 0;
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/* CS setup/hold/recovery time in nsec */
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cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz;
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mcr = txx9spi_rd(c, TXx9_SPMCR);
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if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) {
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dev_err(&spi->dev, "Bad mode.\n");
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status = -EIO;
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goto exit;
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}
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mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
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/* enter config mode */
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txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
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txx9spi_wr(c, TXx9_SPCR0_SBOS
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| ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0)
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| ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0)
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| 0x08,
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TXx9_SPCR0);
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list_for_each_entry(t, &m->transfers, transfer_list) {
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const void *txbuf = t->tx_buf;
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void *rxbuf = t->rx_buf;
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u32 data;
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unsigned int len = t->len;
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unsigned int wsize;
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u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
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u8 bits_per_word = t->bits_per_word;
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wsize = bits_per_word >> 3; /* in bytes */
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if (prev_speed_hz != speed_hz
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|| prev_bits_per_word != bits_per_word) {
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int n = DIV_ROUND_UP(c->baseclk, speed_hz) - 1;
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n = clamp(n, SPI_MIN_DIVIDER, SPI_MAX_DIVIDER);
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/* enter config mode */
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txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR,
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TXx9_SPMCR);
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txx9spi_wr(c, (n << 8) | bits_per_word, TXx9_SPCR1);
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/* enter active mode */
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txx9spi_wr(c, mcr | TXx9_SPMCR_ACTIVE, TXx9_SPMCR);
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prev_speed_hz = speed_hz;
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prev_bits_per_word = bits_per_word;
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}
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if (cs_change)
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txx9spi_cs_func(spi, c, 1, cs_delay);
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cs_change = t->cs_change;
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while (len) {
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unsigned int count = SPI_FIFO_SIZE;
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int i;
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u32 cr0;
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if (len < count * wsize)
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count = len / wsize;
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/* now tx must be idle... */
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while (!(txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_SIDLE))
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cpu_relax();
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cr0 = txx9spi_rd(c, TXx9_SPCR0);
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cr0 &= ~TXx9_SPCR0_RXIFL_MASK;
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cr0 |= (count - 1) << 12;
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/* enable rx intr */
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cr0 |= TXx9_SPCR0_RBSIE;
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txx9spi_wr(c, cr0, TXx9_SPCR0);
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/* send */
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for (i = 0; i < count; i++) {
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if (txbuf) {
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data = (wsize == 1)
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? *(const u8 *)txbuf
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: *(const u16 *)txbuf;
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txx9spi_wr(c, data, TXx9_SPDR);
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txbuf += wsize;
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} else
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txx9spi_wr(c, 0, TXx9_SPDR);
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}
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/* wait all rx data */
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wait_event(c->waitq,
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txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_RBSI);
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/* receive */
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for (i = 0; i < count; i++) {
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data = txx9spi_rd(c, TXx9_SPDR);
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if (rxbuf) {
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if (wsize == 1)
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*(u8 *)rxbuf = data;
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else
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*(u16 *)rxbuf = data;
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rxbuf += wsize;
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}
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}
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len -= count * wsize;
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}
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m->actual_length += t->len;
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if (t->delay_usecs)
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udelay(t->delay_usecs);
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if (!cs_change)
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continue;
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if (t->transfer_list.next == &m->transfers)
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break;
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/* sometimes a short mid-message deselect of the chip
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* may be needed to terminate a mode or command
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*/
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txx9spi_cs_func(spi, c, 0, cs_delay);
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}
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exit:
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m->status = status;
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m->complete(m->context);
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/* normally deactivate chipselect ... unless no error and
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* cs_change has hinted that the next message will probably
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* be for this chip too.
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*/
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if (!(status == 0 && cs_change))
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txx9spi_cs_func(spi, c, 0, cs_delay);
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/* enter config mode */
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txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
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}
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static void txx9spi_work(struct work_struct *work)
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{
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struct txx9spi *c = container_of(work, struct txx9spi, work);
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unsigned long flags;
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spin_lock_irqsave(&c->lock, flags);
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while (!list_empty(&c->queue)) {
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struct spi_message *m;
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m = container_of(c->queue.next, struct spi_message, queue);
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list_del_init(&m->queue);
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spin_unlock_irqrestore(&c->lock, flags);
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txx9spi_work_one(c, m);
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spin_lock_irqsave(&c->lock, flags);
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}
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spin_unlock_irqrestore(&c->lock, flags);
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}
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static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m)
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{
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struct spi_master *master = spi->master;
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struct txx9spi *c = spi_master_get_devdata(master);
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struct spi_transfer *t;
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unsigned long flags;
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m->actual_length = 0;
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/* check each transfer's parameters */
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list_for_each_entry(t, &m->transfers, transfer_list) {
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u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
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u8 bits_per_word = t->bits_per_word;
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if (!t->tx_buf && !t->rx_buf && t->len)
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return -EINVAL;
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if (t->len & ((bits_per_word >> 3) - 1))
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return -EINVAL;
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if (speed_hz < c->min_speed_hz || speed_hz > c->max_speed_hz)
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return -EINVAL;
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}
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spin_lock_irqsave(&c->lock, flags);
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list_add_tail(&m->queue, &c->queue);
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queue_work(c->workqueue, &c->work);
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spin_unlock_irqrestore(&c->lock, flags);
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return 0;
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}
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static int txx9spi_probe(struct platform_device *dev)
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{
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struct spi_master *master;
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struct txx9spi *c;
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struct resource *res;
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int ret = -ENODEV;
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u32 mcr;
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int irq;
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master = spi_alloc_master(&dev->dev, sizeof(*c));
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if (!master)
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return ret;
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c = spi_master_get_devdata(master);
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platform_set_drvdata(dev, master);
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INIT_WORK(&c->work, txx9spi_work);
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spin_lock_init(&c->lock);
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INIT_LIST_HEAD(&c->queue);
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init_waitqueue_head(&c->waitq);
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c->clk = devm_clk_get(&dev->dev, "spi-baseclk");
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if (IS_ERR(c->clk)) {
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ret = PTR_ERR(c->clk);
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c->clk = NULL;
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goto exit;
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}
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ret = clk_enable(c->clk);
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if (ret) {
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c->clk = NULL;
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goto exit;
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}
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c->baseclk = clk_get_rate(c->clk);
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c->min_speed_hz = DIV_ROUND_UP(c->baseclk, SPI_MAX_DIVIDER + 1);
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c->max_speed_hz = c->baseclk / (SPI_MIN_DIVIDER + 1);
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res = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (!res)
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goto exit_busy;
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if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
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"spi_txx9"))
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goto exit_busy;
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c->membase = devm_ioremap(&dev->dev, res->start, resource_size(res));
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if (!c->membase)
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goto exit_busy;
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/* enter config mode */
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mcr = txx9spi_rd(c, TXx9_SPMCR);
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mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
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txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
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irq = platform_get_irq(dev, 0);
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if (irq < 0)
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goto exit_busy;
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ret = devm_request_irq(&dev->dev, irq, txx9spi_interrupt, 0,
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"spi_txx9", c);
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if (ret)
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goto exit;
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c->workqueue = create_singlethread_workqueue(
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dev_name(master->dev.parent));
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if (!c->workqueue)
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goto exit_busy;
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c->last_chipselect = -1;
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dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n",
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(unsigned long long)res->start, irq,
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(c->baseclk + 500000) / 1000000);
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/* the spi->mode bits understood by this driver: */
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master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA;
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master->bus_num = dev->id;
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master->setup = txx9spi_setup;
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master->transfer = txx9spi_transfer;
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master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */
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master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
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ret = devm_spi_register_master(&dev->dev, master);
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if (ret)
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goto exit;
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return 0;
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exit_busy:
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ret = -EBUSY;
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exit:
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if (c->workqueue)
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destroy_workqueue(c->workqueue);
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if (c->clk)
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clk_disable(c->clk);
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spi_master_put(master);
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return ret;
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}
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static int txx9spi_remove(struct platform_device *dev)
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{
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struct spi_master *master = platform_get_drvdata(dev);
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struct txx9spi *c = spi_master_get_devdata(master);
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destroy_workqueue(c->workqueue);
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clk_disable(c->clk);
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return 0;
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}
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/* work with hotplug and coldplug */
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MODULE_ALIAS("platform:spi_txx9");
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static struct platform_driver txx9spi_driver = {
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.probe = txx9spi_probe,
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.remove = txx9spi_remove,
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.driver = {
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.name = "spi_txx9",
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.owner = THIS_MODULE,
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},
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};
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static int __init txx9spi_init(void)
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{
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return platform_driver_register(&txx9spi_driver);
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}
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subsys_initcall(txx9spi_init);
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static void __exit txx9spi_exit(void)
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{
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platform_driver_unregister(&txx9spi_driver);
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}
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module_exit(txx9spi_exit);
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MODULE_DESCRIPTION("TXx9 SPI Driver");
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MODULE_LICENSE("GPL");
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