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linux-sg2042/drivers/spi/spi-bfin5xx.c

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/*
* Blackfin On-Chip SPI Driver
*
* Copyright 2004-2010 Analog Devices Inc.
*
* Enter bugs at http://blackfin.uclinux.org/
*
* Licensed under the GPL-2 or later.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <asm/dma.h>
#include <asm/portmux.h>
#include <asm/bfin5xx_spi.h>
#include <asm/cacheflush.h>
#define DRV_NAME "bfin-spi"
#define DRV_AUTHOR "Bryan Wu, Luke Yang"
#define DRV_DESC "Blackfin on-chip SPI Controller Driver"
#define DRV_VERSION "1.0"
MODULE_AUTHOR(DRV_AUTHOR);
MODULE_DESCRIPTION(DRV_DESC);
MODULE_LICENSE("GPL");
#define START_STATE ((void *)0)
#define RUNNING_STATE ((void *)1)
#define DONE_STATE ((void *)2)
#define ERROR_STATE ((void *)-1)
struct bfin_spi_master_data;
struct bfin_spi_transfer_ops {
void (*write) (struct bfin_spi_master_data *);
void (*read) (struct bfin_spi_master_data *);
void (*duplex) (struct bfin_spi_master_data *);
};
struct bfin_spi_master_data {
/* Driver model hookup */
struct platform_device *pdev;
/* SPI framework hookup */
struct spi_master *master;
/* Regs base of SPI controller */
struct bfin_spi_regs __iomem *regs;
/* Pin request list */
u16 *pin_req;
/* BFIN hookup */
struct bfin5xx_spi_master *master_info;
/* Driver message queue */
struct workqueue_struct *workqueue;
struct work_struct pump_messages;
spinlock_t lock;
struct list_head queue;
int busy;
bool running;
/* Message Transfer pump */
struct tasklet_struct pump_transfers;
/* Current message transfer state info */
struct spi_message *cur_msg;
struct spi_transfer *cur_transfer;
struct bfin_spi_slave_data *cur_chip;
size_t len_in_bytes;
size_t len;
void *tx;
void *tx_end;
void *rx;
void *rx_end;
/* DMA stuffs */
int dma_channel;
int dma_mapped;
int dma_requested;
dma_addr_t rx_dma;
dma_addr_t tx_dma;
int irq_requested;
int spi_irq;
size_t rx_map_len;
size_t tx_map_len;
u8 n_bytes;
u16 ctrl_reg;
u16 flag_reg;
int cs_change;
const struct bfin_spi_transfer_ops *ops;
};
struct bfin_spi_slave_data {
u16 ctl_reg;
u16 baud;
u16 flag;
u8 chip_select_num;
u8 enable_dma;
u16 cs_chg_udelay; /* Some devices require > 255usec delay */
u32 cs_gpio;
u16 idle_tx_val;
u8 pio_interrupt; /* use spi data irq */
const struct bfin_spi_transfer_ops *ops;
};
static void bfin_spi_enable(struct bfin_spi_master_data *drv_data)
{
bfin_write_or(&drv_data->regs->ctl, BIT_CTL_ENABLE);
}
static void bfin_spi_disable(struct bfin_spi_master_data *drv_data)
{
bfin_write_and(&drv_data->regs->ctl, ~BIT_CTL_ENABLE);
}
/* Caculate the SPI_BAUD register value based on input HZ */
static u16 hz_to_spi_baud(u32 speed_hz)
{
u_long sclk = get_sclk();
u16 spi_baud = (sclk / (2 * speed_hz));
if ((sclk % (2 * speed_hz)) > 0)
spi_baud++;
if (spi_baud < MIN_SPI_BAUD_VAL)
spi_baud = MIN_SPI_BAUD_VAL;
return spi_baud;
}
static int bfin_spi_flush(struct bfin_spi_master_data *drv_data)
{
unsigned long limit = loops_per_jiffy << 1;
/* wait for stop and clear stat */
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_SPIF) && --limit)
cpu_relax();
bfin_write(&drv_data->regs->stat, BIT_STAT_CLR);
return limit;
}
/* Chip select operation functions for cs_change flag */
static void bfin_spi_cs_active(struct bfin_spi_master_data *drv_data, struct bfin_spi_slave_data *chip)
{
if (likely(chip->chip_select_num < MAX_CTRL_CS))
bfin_write_and(&drv_data->regs->flg, ~chip->flag);
else
gpio_set_value(chip->cs_gpio, 0);
}
static void bfin_spi_cs_deactive(struct bfin_spi_master_data *drv_data,
struct bfin_spi_slave_data *chip)
{
if (likely(chip->chip_select_num < MAX_CTRL_CS))
bfin_write_or(&drv_data->regs->flg, chip->flag);
else
gpio_set_value(chip->cs_gpio, 1);
/* Move delay here for consistency */
if (chip->cs_chg_udelay)
udelay(chip->cs_chg_udelay);
}
/* enable or disable the pin muxed by GPIO and SPI CS to work as SPI CS */
static inline void bfin_spi_cs_enable(struct bfin_spi_master_data *drv_data,
struct bfin_spi_slave_data *chip)
{
if (chip->chip_select_num < MAX_CTRL_CS)
bfin_write_or(&drv_data->regs->flg, chip->flag >> 8);
}
static inline void bfin_spi_cs_disable(struct bfin_spi_master_data *drv_data,
struct bfin_spi_slave_data *chip)
{
if (chip->chip_select_num < MAX_CTRL_CS)
bfin_write_and(&drv_data->regs->flg, ~(chip->flag >> 8));
}
/* stop controller and re-config current chip*/
static void bfin_spi_restore_state(struct bfin_spi_master_data *drv_data)
{
struct bfin_spi_slave_data *chip = drv_data->cur_chip;
/* Clear status and disable clock */
bfin_write(&drv_data->regs->stat, BIT_STAT_CLR);
bfin_spi_disable(drv_data);
dev_dbg(&drv_data->pdev->dev, "restoring spi ctl state\n");
SSYNC();
/* Load the registers */
bfin_write(&drv_data->regs->ctl, chip->ctl_reg);
bfin_write(&drv_data->regs->baud, chip->baud);
bfin_spi_enable(drv_data);
bfin_spi_cs_active(drv_data, chip);
}
/* used to kick off transfer in rx mode and read unwanted RX data */
static inline void bfin_spi_dummy_read(struct bfin_spi_master_data *drv_data)
{
(void) bfin_read(&drv_data->regs->rdbr);
}
static void bfin_spi_u8_writer(struct bfin_spi_master_data *drv_data)
{
/* clear RXS (we check for RXS inside the loop) */
bfin_spi_dummy_read(drv_data);
while (drv_data->tx < drv_data->tx_end) {
bfin_write(&drv_data->regs->tdbr, (*(u8 *) (drv_data->tx++)));
/* wait until transfer finished.
checking SPIF or TXS may not guarantee transfer completion */
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
/* discard RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
}
}
static void bfin_spi_u8_reader(struct bfin_spi_master_data *drv_data)
{
u16 tx_val = drv_data->cur_chip->idle_tx_val;
/* discard old RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
while (drv_data->rx < drv_data->rx_end) {
bfin_write(&drv_data->regs->tdbr, tx_val);
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
*(u8 *) (drv_data->rx++) = bfin_read(&drv_data->regs->rdbr);
}
}
static void bfin_spi_u8_duplex(struct bfin_spi_master_data *drv_data)
{
/* discard old RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
while (drv_data->rx < drv_data->rx_end) {
bfin_write(&drv_data->regs->tdbr, (*(u8 *) (drv_data->tx++)));
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
*(u8 *) (drv_data->rx++) = bfin_read(&drv_data->regs->rdbr);
}
}
static const struct bfin_spi_transfer_ops bfin_bfin_spi_transfer_ops_u8 = {
.write = bfin_spi_u8_writer,
.read = bfin_spi_u8_reader,
.duplex = bfin_spi_u8_duplex,
};
static void bfin_spi_u16_writer(struct bfin_spi_master_data *drv_data)
{
/* clear RXS (we check for RXS inside the loop) */
bfin_spi_dummy_read(drv_data);
while (drv_data->tx < drv_data->tx_end) {
bfin_write(&drv_data->regs->tdbr, (*(u16 *) (drv_data->tx)));
drv_data->tx += 2;
/* wait until transfer finished.
checking SPIF or TXS may not guarantee transfer completion */
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
/* discard RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
}
}
static void bfin_spi_u16_reader(struct bfin_spi_master_data *drv_data)
{
u16 tx_val = drv_data->cur_chip->idle_tx_val;
/* discard old RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
while (drv_data->rx < drv_data->rx_end) {
bfin_write(&drv_data->regs->tdbr, tx_val);
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
*(u16 *) (drv_data->rx) = bfin_read(&drv_data->regs->rdbr);
drv_data->rx += 2;
}
}
static void bfin_spi_u16_duplex(struct bfin_spi_master_data *drv_data)
{
/* discard old RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
while (drv_data->rx < drv_data->rx_end) {
bfin_write(&drv_data->regs->tdbr, (*(u16 *) (drv_data->tx)));
drv_data->tx += 2;
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
*(u16 *) (drv_data->rx) = bfin_read(&drv_data->regs->rdbr);
drv_data->rx += 2;
}
}
static const struct bfin_spi_transfer_ops bfin_bfin_spi_transfer_ops_u16 = {
.write = bfin_spi_u16_writer,
.read = bfin_spi_u16_reader,
.duplex = bfin_spi_u16_duplex,
};
/* test if there is more transfer to be done */
static void *bfin_spi_next_transfer(struct bfin_spi_master_data *drv_data)
{
struct spi_message *msg = drv_data->cur_msg;
struct spi_transfer *trans = drv_data->cur_transfer;
/* Move to next transfer */
if (trans->transfer_list.next != &msg->transfers) {
drv_data->cur_transfer =
list_entry(trans->transfer_list.next,
struct spi_transfer, transfer_list);
return RUNNING_STATE;
} else
return DONE_STATE;
}
/*
* caller already set message->status;
* dma and pio irqs are blocked give finished message back
*/
static void bfin_spi_giveback(struct bfin_spi_master_data *drv_data)
{
struct bfin_spi_slave_data *chip = drv_data->cur_chip;
struct spi_transfer *last_transfer;
unsigned long flags;
struct spi_message *msg;
spin_lock_irqsave(&drv_data->lock, flags);
msg = drv_data->cur_msg;
drv_data->cur_msg = NULL;
drv_data->cur_transfer = NULL;
drv_data->cur_chip = NULL;
queue_work(drv_data->workqueue, &drv_data->pump_messages);
spin_unlock_irqrestore(&drv_data->lock, flags);
last_transfer = list_entry(msg->transfers.prev,
struct spi_transfer, transfer_list);
msg->state = NULL;
if (!drv_data->cs_change)
bfin_spi_cs_deactive(drv_data, chip);
/* Not stop spi in autobuffer mode */
if (drv_data->tx_dma != 0xFFFF)
bfin_spi_disable(drv_data);
if (msg->complete)
msg->complete(msg->context);
}
/* spi data irq handler */
static irqreturn_t bfin_spi_pio_irq_handler(int irq, void *dev_id)
{
struct bfin_spi_master_data *drv_data = dev_id;
struct bfin_spi_slave_data *chip = drv_data->cur_chip;
struct spi_message *msg = drv_data->cur_msg;
int n_bytes = drv_data->n_bytes;
int loop = 0;
/* wait until transfer finished. */
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_RXS))
cpu_relax();
if ((drv_data->tx && drv_data->tx >= drv_data->tx_end) ||
(drv_data->rx && drv_data->rx >= (drv_data->rx_end - n_bytes))) {
/* last read */
if (drv_data->rx) {
dev_dbg(&drv_data->pdev->dev, "last read\n");
if (!(n_bytes % 2)) {
u16 *buf = (u16 *)drv_data->rx;
for (loop = 0; loop < n_bytes / 2; loop++)
*buf++ = bfin_read(&drv_data->regs->rdbr);
} else {
u8 *buf = (u8 *)drv_data->rx;
for (loop = 0; loop < n_bytes; loop++)
*buf++ = bfin_read(&drv_data->regs->rdbr);
}
drv_data->rx += n_bytes;
}
msg->actual_length += drv_data->len_in_bytes;
if (drv_data->cs_change)
bfin_spi_cs_deactive(drv_data, chip);
/* Move to next transfer */
msg->state = bfin_spi_next_transfer(drv_data);
disable_irq_nosync(drv_data->spi_irq);
/* Schedule transfer tasklet */
tasklet_schedule(&drv_data->pump_transfers);
return IRQ_HANDLED;
}
if (drv_data->rx && drv_data->tx) {
/* duplex */
dev_dbg(&drv_data->pdev->dev, "duplex: write_TDBR\n");
if (!(n_bytes % 2)) {
u16 *buf = (u16 *)drv_data->rx;
u16 *buf2 = (u16 *)drv_data->tx;
for (loop = 0; loop < n_bytes / 2; loop++) {
*buf++ = bfin_read(&drv_data->regs->rdbr);
bfin_write(&drv_data->regs->tdbr, *buf2++);
}
} else {
u8 *buf = (u8 *)drv_data->rx;
u8 *buf2 = (u8 *)drv_data->tx;
for (loop = 0; loop < n_bytes; loop++) {
*buf++ = bfin_read(&drv_data->regs->rdbr);
bfin_write(&drv_data->regs->tdbr, *buf2++);
}
}
} else if (drv_data->rx) {
/* read */
dev_dbg(&drv_data->pdev->dev, "read: write_TDBR\n");
if (!(n_bytes % 2)) {
u16 *buf = (u16 *)drv_data->rx;
for (loop = 0; loop < n_bytes / 2; loop++) {
*buf++ = bfin_read(&drv_data->regs->rdbr);
bfin_write(&drv_data->regs->tdbr, chip->idle_tx_val);
}
} else {
u8 *buf = (u8 *)drv_data->rx;
for (loop = 0; loop < n_bytes; loop++) {
*buf++ = bfin_read(&drv_data->regs->rdbr);
bfin_write(&drv_data->regs->tdbr, chip->idle_tx_val);
}
}
} else if (drv_data->tx) {
/* write */
dev_dbg(&drv_data->pdev->dev, "write: write_TDBR\n");
if (!(n_bytes % 2)) {
u16 *buf = (u16 *)drv_data->tx;
for (loop = 0; loop < n_bytes / 2; loop++) {
bfin_read(&drv_data->regs->rdbr);
bfin_write(&drv_data->regs->tdbr, *buf++);
}
} else {
u8 *buf = (u8 *)drv_data->tx;
for (loop = 0; loop < n_bytes; loop++) {
bfin_read(&drv_data->regs->rdbr);
bfin_write(&drv_data->regs->tdbr, *buf++);
}
}
}
if (drv_data->tx)
drv_data->tx += n_bytes;
if (drv_data->rx)
drv_data->rx += n_bytes;
return IRQ_HANDLED;
}
static irqreturn_t bfin_spi_dma_irq_handler(int irq, void *dev_id)
{
struct bfin_spi_master_data *drv_data = dev_id;
struct bfin_spi_slave_data *chip = drv_data->cur_chip;
struct spi_message *msg = drv_data->cur_msg;
unsigned long timeout;
unsigned short dmastat = get_dma_curr_irqstat(drv_data->dma_channel);
u16 spistat = bfin_read(&drv_data->regs->stat);
dev_dbg(&drv_data->pdev->dev,
"in dma_irq_handler dmastat:0x%x spistat:0x%x\n",
dmastat, spistat);
if (drv_data->rx != NULL) {
u16 cr = bfin_read(&drv_data->regs->ctl);
/* discard old RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
bfin_write(&drv_data->regs->ctl, cr & ~BIT_CTL_ENABLE); /* Disable SPI */
bfin_write(&drv_data->regs->ctl, cr & ~BIT_CTL_TIMOD); /* Restore State */
bfin_write(&drv_data->regs->stat, BIT_STAT_CLR); /* Clear Status */
}
clear_dma_irqstat(drv_data->dma_channel);
/*
* wait for the last transaction shifted out. HRM states:
* at this point there may still be data in the SPI DMA FIFO waiting
* to be transmitted ... software needs to poll TXS in the SPI_STAT
* register until it goes low for 2 successive reads
*/
if (drv_data->tx != NULL) {
while ((bfin_read(&drv_data->regs->stat) & BIT_STAT_TXS) ||
(bfin_read(&drv_data->regs->stat) & BIT_STAT_TXS))
cpu_relax();
}
dev_dbg(&drv_data->pdev->dev,
"in dma_irq_handler dmastat:0x%x spistat:0x%x\n",
dmastat, bfin_read(&drv_data->regs->stat));
timeout = jiffies + HZ;
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_SPIF))
if (!time_before(jiffies, timeout)) {
dev_warn(&drv_data->pdev->dev, "timeout waiting for SPIF\n");
break;
} else
cpu_relax();
if ((dmastat & DMA_ERR) && (spistat & BIT_STAT_RBSY)) {
msg->state = ERROR_STATE;
dev_err(&drv_data->pdev->dev, "dma receive: fifo/buffer overflow\n");
} else {
msg->actual_length += drv_data->len_in_bytes;
if (drv_data->cs_change)
bfin_spi_cs_deactive(drv_data, chip);
/* Move to next transfer */
msg->state = bfin_spi_next_transfer(drv_data);
}
/* Schedule transfer tasklet */
tasklet_schedule(&drv_data->pump_transfers);
/* free the irq handler before next transfer */
dev_dbg(&drv_data->pdev->dev,
"disable dma channel irq%d\n",
drv_data->dma_channel);
dma_disable_irq_nosync(drv_data->dma_channel);
return IRQ_HANDLED;
}
static void bfin_spi_pump_transfers(unsigned long data)
{
struct bfin_spi_master_data *drv_data = (struct bfin_spi_master_data *)data;
struct spi_message *message = NULL;
struct spi_transfer *transfer = NULL;
struct spi_transfer *previous = NULL;
struct bfin_spi_slave_data *chip = NULL;
unsigned int bits_per_word;
u16 cr, cr_width, dma_width, dma_config;
u32 tranf_success = 1;
u8 full_duplex = 0;
/* Get current state information */
message = drv_data->cur_msg;
transfer = drv_data->cur_transfer;
chip = drv_data->cur_chip;
/*
* if msg is error or done, report it back using complete() callback
*/
/* Handle for abort */
if (message->state == ERROR_STATE) {
dev_dbg(&drv_data->pdev->dev, "transfer: we've hit an error\n");
message->status = -EIO;
bfin_spi_giveback(drv_data);
return;
}
/* Handle end of message */
if (message->state == DONE_STATE) {
dev_dbg(&drv_data->pdev->dev, "transfer: all done!\n");
message->status = 0;
bfin_spi_flush(drv_data);
bfin_spi_giveback(drv_data);
return;
}
/* Delay if requested at end of transfer */
if (message->state == RUNNING_STATE) {
dev_dbg(&drv_data->pdev->dev, "transfer: still running ...\n");
previous = list_entry(transfer->transfer_list.prev,
struct spi_transfer, transfer_list);
if (previous->delay_usecs)
udelay(previous->delay_usecs);
}
/* Flush any existing transfers that may be sitting in the hardware */
if (bfin_spi_flush(drv_data) == 0) {
dev_err(&drv_data->pdev->dev, "pump_transfers: flush failed\n");
message->status = -EIO;
bfin_spi_giveback(drv_data);
return;
}
if (transfer->len == 0) {
/* Move to next transfer of this msg */
message->state = bfin_spi_next_transfer(drv_data);
/* Schedule next transfer tasklet */
tasklet_schedule(&drv_data->pump_transfers);
return;
}
if (transfer->tx_buf != NULL) {
drv_data->tx = (void *)transfer->tx_buf;
drv_data->tx_end = drv_data->tx + transfer->len;
dev_dbg(&drv_data->pdev->dev, "tx_buf is %p, tx_end is %p\n",
transfer->tx_buf, drv_data->tx_end);
} else {
drv_data->tx = NULL;
}
if (transfer->rx_buf != NULL) {
full_duplex = transfer->tx_buf != NULL;
drv_data->rx = transfer->rx_buf;
drv_data->rx_end = drv_data->rx + transfer->len;
dev_dbg(&drv_data->pdev->dev, "rx_buf is %p, rx_end is %p\n",
transfer->rx_buf, drv_data->rx_end);
} else {
drv_data->rx = NULL;
}
drv_data->rx_dma = transfer->rx_dma;
drv_data->tx_dma = transfer->tx_dma;
drv_data->len_in_bytes = transfer->len;
drv_data->cs_change = transfer->cs_change;
/* Bits per word setup */
bits_per_word = transfer->bits_per_word;
if (bits_per_word == 16) {
drv_data->n_bytes = bits_per_word/8;
drv_data->len = (transfer->len) >> 1;
cr_width = BIT_CTL_WORDSIZE;
drv_data->ops = &bfin_bfin_spi_transfer_ops_u16;
} else if (bits_per_word == 8) {
drv_data->n_bytes = bits_per_word/8;
drv_data->len = transfer->len;
cr_width = 0;
drv_data->ops = &bfin_bfin_spi_transfer_ops_u8;
}
cr = bfin_read(&drv_data->regs->ctl) & ~(BIT_CTL_TIMOD | BIT_CTL_WORDSIZE);
cr |= cr_width;
bfin_write(&drv_data->regs->ctl, cr);
dev_dbg(&drv_data->pdev->dev,
"transfer: drv_data->ops is %p, chip->ops is %p, u8_ops is %p\n",
drv_data->ops, chip->ops, &bfin_bfin_spi_transfer_ops_u8);
message->state = RUNNING_STATE;
dma_config = 0;
/* Speed setup (surely valid because already checked) */
if (transfer->speed_hz)
bfin_write(&drv_data->regs->baud, hz_to_spi_baud(transfer->speed_hz));
else
bfin_write(&drv_data->regs->baud, chip->baud);
bfin_write(&drv_data->regs->stat, BIT_STAT_CLR);
bfin_spi_cs_active(drv_data, chip);
dev_dbg(&drv_data->pdev->dev,
"now pumping a transfer: width is %d, len is %d\n",
cr_width, transfer->len);
/*
* Try to map dma buffer and do a dma transfer. If successful use,
* different way to r/w according to the enable_dma settings and if
* we are not doing a full duplex transfer (since the hardware does
* not support full duplex DMA transfers).
*/
if (!full_duplex && drv_data->cur_chip->enable_dma
&& drv_data->len > 6) {
unsigned long dma_start_addr, flags;
disable_dma(drv_data->dma_channel);
clear_dma_irqstat(drv_data->dma_channel);
/* config dma channel */
dev_dbg(&drv_data->pdev->dev, "doing dma transfer\n");
set_dma_x_count(drv_data->dma_channel, drv_data->len);
if (cr_width == BIT_CTL_WORDSIZE) {
set_dma_x_modify(drv_data->dma_channel, 2);
dma_width = WDSIZE_16;
} else {
set_dma_x_modify(drv_data->dma_channel, 1);
dma_width = WDSIZE_8;
}
/* poll for SPI completion before start */
while (!(bfin_read(&drv_data->regs->stat) & BIT_STAT_SPIF))
cpu_relax();
/* dirty hack for autobuffer DMA mode */
if (drv_data->tx_dma == 0xFFFF) {
dev_dbg(&drv_data->pdev->dev,
"doing autobuffer DMA out.\n");
/* no irq in autobuffer mode */
dma_config =
(DMAFLOW_AUTO | RESTART | dma_width | DI_EN);
set_dma_config(drv_data->dma_channel, dma_config);
set_dma_start_addr(drv_data->dma_channel,
(unsigned long)drv_data->tx);
enable_dma(drv_data->dma_channel);
/* start SPI transfer */
bfin_write(&drv_data->regs->ctl, cr | BIT_CTL_TIMOD_DMA_TX);
/* just return here, there can only be one transfer
* in this mode
*/
message->status = 0;
bfin_spi_giveback(drv_data);
return;
}
/* In dma mode, rx or tx must be NULL in one transfer */
dma_config = (RESTART | dma_width | DI_EN);
if (drv_data->rx != NULL) {
/* set transfer mode, and enable SPI */
dev_dbg(&drv_data->pdev->dev, "doing DMA in to %p (size %zx)\n",
drv_data->rx, drv_data->len_in_bytes);
/* invalidate caches, if needed */
if (bfin_addr_dcacheable((unsigned long) drv_data->rx))
invalidate_dcache_range((unsigned long) drv_data->rx,
(unsigned long) (drv_data->rx +
drv_data->len_in_bytes));
dma_config |= WNR;
dma_start_addr = (unsigned long)drv_data->rx;
cr |= BIT_CTL_TIMOD_DMA_RX | BIT_CTL_SENDOPT;
} else if (drv_data->tx != NULL) {
dev_dbg(&drv_data->pdev->dev, "doing DMA out.\n");
/* flush caches, if needed */
if (bfin_addr_dcacheable((unsigned long) drv_data->tx))
flush_dcache_range((unsigned long) drv_data->tx,
(unsigned long) (drv_data->tx +
drv_data->len_in_bytes));
dma_start_addr = (unsigned long)drv_data->tx;
cr |= BIT_CTL_TIMOD_DMA_TX;
} else
BUG();
/* oh man, here there be monsters ... and i dont mean the
* fluffy cute ones from pixar, i mean the kind that'll eat
* your data, kick your dog, and love it all. do *not* try
* and change these lines unless you (1) heavily test DMA
* with SPI flashes on a loaded system (e.g. ping floods),
* (2) know just how broken the DMA engine interaction with
* the SPI peripheral is, and (3) have someone else to blame
* when you screw it all up anyways.
*/
set_dma_start_addr(drv_data->dma_channel, dma_start_addr);
set_dma_config(drv_data->dma_channel, dma_config);
local_irq_save(flags);
SSYNC();
bfin_write(&drv_data->regs->ctl, cr);
enable_dma(drv_data->dma_channel);
dma_enable_irq(drv_data->dma_channel);
local_irq_restore(flags);
return;
}
/*
* We always use SPI_WRITE mode (transfer starts with TDBR write).
* SPI_READ mode (transfer starts with RDBR read) seems to have
* problems with setting up the output value in TDBR prior to the
* start of the transfer.
*/
bfin_write(&drv_data->regs->ctl, cr | BIT_CTL_TXMOD);
if (chip->pio_interrupt) {
/* SPI irq should have been disabled by now */
/* discard old RX data and clear RXS */
bfin_spi_dummy_read(drv_data);
/* start transfer */
if (drv_data->tx == NULL)
bfin_write(&drv_data->regs->tdbr, chip->idle_tx_val);
else {
int loop;
if (bits_per_word == 16) {
u16 *buf = (u16 *)drv_data->tx;
for (loop = 0; loop < bits_per_word / 16;
loop++) {
bfin_write(&drv_data->regs->tdbr, *buf++);
}
} else if (bits_per_word == 8) {
u8 *buf = (u8 *)drv_data->tx;
for (loop = 0; loop < bits_per_word / 8; loop++)
bfin_write(&drv_data->regs->tdbr, *buf++);
}
drv_data->tx += drv_data->n_bytes;
}
/* once TDBR is empty, interrupt is triggered */
enable_irq(drv_data->spi_irq);
return;
}
/* IO mode */
dev_dbg(&drv_data->pdev->dev, "doing IO transfer\n");
if (full_duplex) {
/* full duplex mode */
BUG_ON((drv_data->tx_end - drv_data->tx) !=
(drv_data->rx_end - drv_data->rx));
dev_dbg(&drv_data->pdev->dev,
"IO duplex: cr is 0x%x\n", cr);
drv_data->ops->duplex(drv_data);
if (drv_data->tx != drv_data->tx_end)
tranf_success = 0;
} else if (drv_data->tx != NULL) {
/* write only half duplex */
dev_dbg(&drv_data->pdev->dev,
"IO write: cr is 0x%x\n", cr);
drv_data->ops->write(drv_data);
if (drv_data->tx != drv_data->tx_end)
tranf_success = 0;
} else if (drv_data->rx != NULL) {
/* read only half duplex */
dev_dbg(&drv_data->pdev->dev,
"IO read: cr is 0x%x\n", cr);
drv_data->ops->read(drv_data);
if (drv_data->rx != drv_data->rx_end)
tranf_success = 0;
}
if (!tranf_success) {
dev_dbg(&drv_data->pdev->dev,
"IO write error!\n");
message->state = ERROR_STATE;
} else {
/* Update total byte transferred */
message->actual_length += drv_data->len_in_bytes;
/* Move to next transfer of this msg */
message->state = bfin_spi_next_transfer(drv_data);
if (drv_data->cs_change && message->state != DONE_STATE) {
bfin_spi_flush(drv_data);
bfin_spi_cs_deactive(drv_data, chip);
}
}
/* Schedule next transfer tasklet */
tasklet_schedule(&drv_data->pump_transfers);
}
/* pop a msg from queue and kick off real transfer */
static void bfin_spi_pump_messages(struct work_struct *work)
{
struct bfin_spi_master_data *drv_data;
unsigned long flags;
drv_data = container_of(work, struct bfin_spi_master_data, pump_messages);
/* Lock queue and check for queue work */
spin_lock_irqsave(&drv_data->lock, flags);
if (list_empty(&drv_data->queue) || !drv_data->running) {
/* pumper kicked off but no work to do */
drv_data->busy = 0;
spin_unlock_irqrestore(&drv_data->lock, flags);
return;
}
/* Make sure we are not already running a message */
if (drv_data->cur_msg) {
spin_unlock_irqrestore(&drv_data->lock, flags);
return;
}
/* Extract head of queue */
drv_data->cur_msg = list_entry(drv_data->queue.next,
struct spi_message, queue);
/* Setup the SSP using the per chip configuration */
drv_data->cur_chip = spi_get_ctldata(drv_data->cur_msg->spi);
bfin_spi_restore_state(drv_data);
list_del_init(&drv_data->cur_msg->queue);
/* Initial message state */
drv_data->cur_msg->state = START_STATE;
drv_data->cur_transfer = list_entry(drv_data->cur_msg->transfers.next,
struct spi_transfer, transfer_list);
dev_dbg(&drv_data->pdev->dev,
"got a message to pump, state is set to: baud "
"%d, flag 0x%x, ctl 0x%x\n",
drv_data->cur_chip->baud, drv_data->cur_chip->flag,
drv_data->cur_chip->ctl_reg);
dev_dbg(&drv_data->pdev->dev,
"the first transfer len is %d\n",
drv_data->cur_transfer->len);
/* Mark as busy and launch transfers */
tasklet_schedule(&drv_data->pump_transfers);
drv_data->busy = 1;
spin_unlock_irqrestore(&drv_data->lock, flags);
}
/*
* got a msg to transfer, queue it in drv_data->queue.
* And kick off message pumper
*/
static int bfin_spi_transfer(struct spi_device *spi, struct spi_message *msg)
{
struct bfin_spi_master_data *drv_data = spi_master_get_devdata(spi->master);
unsigned long flags;
spin_lock_irqsave(&drv_data->lock, flags);
if (!drv_data->running) {
spin_unlock_irqrestore(&drv_data->lock, flags);
return -ESHUTDOWN;
}
msg->actual_length = 0;
msg->status = -EINPROGRESS;
msg->state = START_STATE;
dev_dbg(&spi->dev, "adding an msg in transfer() \n");
list_add_tail(&msg->queue, &drv_data->queue);
if (drv_data->running && !drv_data->busy)
queue_work(drv_data->workqueue, &drv_data->pump_messages);
spin_unlock_irqrestore(&drv_data->lock, flags);
return 0;
}
#define MAX_SPI_SSEL 7
static const u16 ssel[][MAX_SPI_SSEL] = {
{P_SPI0_SSEL1, P_SPI0_SSEL2, P_SPI0_SSEL3,
P_SPI0_SSEL4, P_SPI0_SSEL5,
P_SPI0_SSEL6, P_SPI0_SSEL7},
{P_SPI1_SSEL1, P_SPI1_SSEL2, P_SPI1_SSEL3,
P_SPI1_SSEL4, P_SPI1_SSEL5,
P_SPI1_SSEL6, P_SPI1_SSEL7},
{P_SPI2_SSEL1, P_SPI2_SSEL2, P_SPI2_SSEL3,
P_SPI2_SSEL4, P_SPI2_SSEL5,
P_SPI2_SSEL6, P_SPI2_SSEL7},
};
/* setup for devices (may be called multiple times -- not just first setup) */
static int bfin_spi_setup(struct spi_device *spi)
{
struct bfin5xx_spi_chip *chip_info;
struct bfin_spi_slave_data *chip = NULL;
struct bfin_spi_master_data *drv_data = spi_master_get_devdata(spi->master);
u16 bfin_ctl_reg;
int ret = -EINVAL;
/* Only alloc (or use chip_info) on first setup */
chip_info = NULL;
chip = spi_get_ctldata(spi);
if (chip == NULL) {
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (!chip) {
dev_err(&spi->dev, "cannot allocate chip data\n");
ret = -ENOMEM;
goto error;
}
chip->enable_dma = 0;
chip_info = spi->controller_data;
}
/* Let people set non-standard bits directly */
bfin_ctl_reg = BIT_CTL_OPENDRAIN | BIT_CTL_EMISO |
BIT_CTL_PSSE | BIT_CTL_GM | BIT_CTL_SZ;
/* chip_info isn't always needed */
if (chip_info) {
/* Make sure people stop trying to set fields via ctl_reg
* when they should actually be using common SPI framework.
* Currently we let through: WOM EMISO PSSE GM SZ.
* Not sure if a user actually needs/uses any of these,
* but let's assume (for now) they do.
*/
if (chip_info->ctl_reg & ~bfin_ctl_reg) {
dev_err(&spi->dev,
"do not set bits in ctl_reg that the SPI framework manages\n");
goto error;
}
chip->enable_dma = chip_info->enable_dma != 0
&& drv_data->master_info->enable_dma;
chip->ctl_reg = chip_info->ctl_reg;
chip->cs_chg_udelay = chip_info->cs_chg_udelay;
chip->idle_tx_val = chip_info->idle_tx_val;
chip->pio_interrupt = chip_info->pio_interrupt;
} else {
/* force a default base state */
chip->ctl_reg &= bfin_ctl_reg;
}
/* translate common spi framework into our register */
if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST)) {
dev_err(&spi->dev, "unsupported spi modes detected\n");
goto error;
}
if (spi->mode & SPI_CPOL)
chip->ctl_reg |= BIT_CTL_CPOL;
if (spi->mode & SPI_CPHA)
chip->ctl_reg |= BIT_CTL_CPHA;
if (spi->mode & SPI_LSB_FIRST)
chip->ctl_reg |= BIT_CTL_LSBF;
/* we dont support running in slave mode (yet?) */
chip->ctl_reg |= BIT_CTL_MASTER;
/*
* Notice: for blackfin, the speed_hz is the value of register
* SPI_BAUD, not the real baudrate
*/
chip->baud = hz_to_spi_baud(spi->max_speed_hz);
chip->chip_select_num = spi->chip_select;
if (chip->chip_select_num < MAX_CTRL_CS) {
if (!(spi->mode & SPI_CPHA))
dev_warn(&spi->dev,
"Warning: SPI CPHA not set: Slave Select not under software control!\n"
"See Documentation/blackfin/bfin-spi-notes.txt\n");
chip->flag = (1 << spi->chip_select) << 8;
} else
chip->cs_gpio = chip->chip_select_num - MAX_CTRL_CS;
if (chip->enable_dma && chip->pio_interrupt) {
dev_err(&spi->dev,
"enable_dma is set, do not set pio_interrupt\n");
goto error;
}
/*
* if any one SPI chip is registered and wants DMA, request the
* DMA channel for it
*/
if (chip->enable_dma && !drv_data->dma_requested) {
/* register dma irq handler */
ret = request_dma(drv_data->dma_channel, "BFIN_SPI_DMA");
if (ret) {
dev_err(&spi->dev,
"Unable to request BlackFin SPI DMA channel\n");
goto error;
}
drv_data->dma_requested = 1;
ret = set_dma_callback(drv_data->dma_channel,
bfin_spi_dma_irq_handler, drv_data);
if (ret) {
dev_err(&spi->dev, "Unable to set dma callback\n");
goto error;
}
dma_disable_irq(drv_data->dma_channel);
}
if (chip->pio_interrupt && !drv_data->irq_requested) {
ret = request_irq(drv_data->spi_irq, bfin_spi_pio_irq_handler,
0, "BFIN_SPI", drv_data);
if (ret) {
dev_err(&spi->dev, "Unable to register spi IRQ\n");
goto error;
}
drv_data->irq_requested = 1;
/* we use write mode, spi irq has to be disabled here */
disable_irq(drv_data->spi_irq);
}
if (chip->chip_select_num >= MAX_CTRL_CS) {
/* Only request on first setup */
if (spi_get_ctldata(spi) == NULL) {
ret = gpio_request(chip->cs_gpio, spi->modalias);
if (ret) {
dev_err(&spi->dev, "gpio_request() error\n");
goto pin_error;
}
gpio_direction_output(chip->cs_gpio, 1);
}
}
dev_dbg(&spi->dev, "setup spi chip %s, width is %d, dma is %d\n",
spi->modalias, spi->bits_per_word, chip->enable_dma);
dev_dbg(&spi->dev, "ctl_reg is 0x%x, flag_reg is 0x%x\n",
chip->ctl_reg, chip->flag);
spi_set_ctldata(spi, chip);
dev_dbg(&spi->dev, "chip select number is %d\n", chip->chip_select_num);
if (chip->chip_select_num < MAX_CTRL_CS) {
ret = peripheral_request(ssel[spi->master->bus_num]
[chip->chip_select_num-1], spi->modalias);
if (ret) {
dev_err(&spi->dev, "peripheral_request() error\n");
goto pin_error;
}
}
bfin_spi_cs_enable(drv_data, chip);
bfin_spi_cs_deactive(drv_data, chip);
return 0;
pin_error:
if (chip->chip_select_num >= MAX_CTRL_CS)
gpio_free(chip->cs_gpio);
else
peripheral_free(ssel[spi->master->bus_num]
[chip->chip_select_num - 1]);
error:
if (chip) {
if (drv_data->dma_requested)
free_dma(drv_data->dma_channel);
drv_data->dma_requested = 0;
kfree(chip);
/* prevent free 'chip' twice */
spi_set_ctldata(spi, NULL);
}
return ret;
}
/*
* callback for spi framework.
* clean driver specific data
*/
static void bfin_spi_cleanup(struct spi_device *spi)
{
struct bfin_spi_slave_data *chip = spi_get_ctldata(spi);
struct bfin_spi_master_data *drv_data = spi_master_get_devdata(spi->master);
if (!chip)
return;
if (chip->chip_select_num < MAX_CTRL_CS) {
peripheral_free(ssel[spi->master->bus_num]
[chip->chip_select_num-1]);
bfin_spi_cs_disable(drv_data, chip);
} else
gpio_free(chip->cs_gpio);
kfree(chip);
/* prevent free 'chip' twice */
spi_set_ctldata(spi, NULL);
}
static int bfin_spi_init_queue(struct bfin_spi_master_data *drv_data)
{
INIT_LIST_HEAD(&drv_data->queue);
spin_lock_init(&drv_data->lock);
drv_data->running = false;
drv_data->busy = 0;
/* init transfer tasklet */
tasklet_init(&drv_data->pump_transfers,
bfin_spi_pump_transfers, (unsigned long)drv_data);
/* init messages workqueue */
INIT_WORK(&drv_data->pump_messages, bfin_spi_pump_messages);
drv_data->workqueue = create_singlethread_workqueue(
dev_name(drv_data->master->dev.parent));
if (drv_data->workqueue == NULL)
return -EBUSY;
return 0;
}
static int bfin_spi_start_queue(struct bfin_spi_master_data *drv_data)
{
unsigned long flags;
spin_lock_irqsave(&drv_data->lock, flags);
if (drv_data->running || drv_data->busy) {
spin_unlock_irqrestore(&drv_data->lock, flags);
return -EBUSY;
}
drv_data->running = true;
drv_data->cur_msg = NULL;
drv_data->cur_transfer = NULL;
drv_data->cur_chip = NULL;
spin_unlock_irqrestore(&drv_data->lock, flags);
queue_work(drv_data->workqueue, &drv_data->pump_messages);
return 0;
}
static int bfin_spi_stop_queue(struct bfin_spi_master_data *drv_data)
{
unsigned long flags;
unsigned limit = 500;
int status = 0;
spin_lock_irqsave(&drv_data->lock, flags);
/*
* This is a bit lame, but is optimized for the common execution path.
* A wait_queue on the drv_data->busy could be used, but then the common
* execution path (pump_messages) would be required to call wake_up or
* friends on every SPI message. Do this instead
*/
drv_data->running = false;
while ((!list_empty(&drv_data->queue) || drv_data->busy) && limit--) {
spin_unlock_irqrestore(&drv_data->lock, flags);
msleep(10);
spin_lock_irqsave(&drv_data->lock, flags);
}
if (!list_empty(&drv_data->queue) || drv_data->busy)
status = -EBUSY;
spin_unlock_irqrestore(&drv_data->lock, flags);
return status;
}
static int bfin_spi_destroy_queue(struct bfin_spi_master_data *drv_data)
{
int status;
status = bfin_spi_stop_queue(drv_data);
if (status != 0)
return status;
destroy_workqueue(drv_data->workqueue);
return 0;
}
static int bfin_spi_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct bfin5xx_spi_master *platform_info;
struct spi_master *master;
struct bfin_spi_master_data *drv_data;
struct resource *res;
int status = 0;
platform_info = dev_get_platdata(dev);
/* Allocate master with space for drv_data */
master = spi_alloc_master(dev, sizeof(*drv_data));
if (!master) {
dev_err(&pdev->dev, "can not alloc spi_master\n");
return -ENOMEM;
}
drv_data = spi_master_get_devdata(master);
drv_data->master = master;
drv_data->master_info = platform_info;
drv_data->pdev = pdev;
drv_data->pin_req = platform_info->pin_req;
/* the spi->mode bits supported by this driver: */
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
master->bus_num = pdev->id;
master->num_chipselect = platform_info->num_chipselect;
master->cleanup = bfin_spi_cleanup;
master->setup = bfin_spi_setup;
master->transfer = bfin_spi_transfer;
/* Find and map our resources */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(dev, "Cannot get IORESOURCE_MEM\n");
status = -ENOENT;
goto out_error_get_res;
}
drv_data->regs = ioremap(res->start, resource_size(res));
if (drv_data->regs == NULL) {
dev_err(dev, "Cannot map IO\n");
status = -ENXIO;
goto out_error_ioremap;
}
res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (res == NULL) {
dev_err(dev, "No DMA channel specified\n");
status = -ENOENT;
goto out_error_free_io;
}
drv_data->dma_channel = res->start;
drv_data->spi_irq = platform_get_irq(pdev, 0);
if (drv_data->spi_irq < 0) {
dev_err(dev, "No spi pio irq specified\n");
status = -ENOENT;
goto out_error_free_io;
}
/* Initial and start queue */
status = bfin_spi_init_queue(drv_data);
if (status != 0) {
dev_err(dev, "problem initializing queue\n");
goto out_error_queue_alloc;
}
status = bfin_spi_start_queue(drv_data);
if (status != 0) {
dev_err(dev, "problem starting queue\n");
goto out_error_queue_alloc;
}
status = peripheral_request_list(drv_data->pin_req, DRV_NAME);
if (status != 0) {
dev_err(&pdev->dev, ": Requesting Peripherals failed\n");
goto out_error_queue_alloc;
}
/* Reset SPI registers. If these registers were used by the boot loader,
* the sky may fall on your head if you enable the dma controller.
*/
bfin_write(&drv_data->regs->ctl, BIT_CTL_CPHA | BIT_CTL_MASTER);
bfin_write(&drv_data->regs->flg, 0xFF00);
/* Register with the SPI framework */
platform_set_drvdata(pdev, drv_data);
status = spi_register_master(master);
if (status != 0) {
dev_err(dev, "problem registering spi master\n");
goto out_error_queue_alloc;
}
dev_info(dev, "%s, Version %s, regs@%p, dma channel@%d\n",
DRV_DESC, DRV_VERSION, drv_data->regs,
drv_data->dma_channel);
return status;
out_error_queue_alloc:
bfin_spi_destroy_queue(drv_data);
out_error_free_io:
iounmap(drv_data->regs);
out_error_ioremap:
out_error_get_res:
spi_master_put(master);
return status;
}
/* stop hardware and remove the driver */
static int bfin_spi_remove(struct platform_device *pdev)
{
struct bfin_spi_master_data *drv_data = platform_get_drvdata(pdev);
int status = 0;
if (!drv_data)
return 0;
/* Remove the queue */
status = bfin_spi_destroy_queue(drv_data);
if (status != 0)
return status;
/* Disable the SSP at the peripheral and SOC level */
bfin_spi_disable(drv_data);
/* Release DMA */
if (drv_data->master_info->enable_dma) {
if (dma_channel_active(drv_data->dma_channel))
free_dma(drv_data->dma_channel);
}
if (drv_data->irq_requested) {
free_irq(drv_data->spi_irq, drv_data);
drv_data->irq_requested = 0;
}
/* Disconnect from the SPI framework */
spi_unregister_master(drv_data->master);
peripheral_free_list(drv_data->pin_req);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int bfin_spi_suspend(struct device *dev)
{
struct bfin_spi_master_data *drv_data = dev_get_drvdata(dev);
int status = 0;
status = bfin_spi_stop_queue(drv_data);
if (status != 0)
return status;
drv_data->ctrl_reg = bfin_read(&drv_data->regs->ctl);
drv_data->flag_reg = bfin_read(&drv_data->regs->flg);
/*
* reset SPI_CTL and SPI_FLG registers
*/
bfin_write(&drv_data->regs->ctl, BIT_CTL_CPHA | BIT_CTL_MASTER);
bfin_write(&drv_data->regs->flg, 0xFF00);
return 0;
}
static int bfin_spi_resume(struct device *dev)
{
struct bfin_spi_master_data *drv_data = dev_get_drvdata(dev);
int status = 0;
bfin_write(&drv_data->regs->ctl, drv_data->ctrl_reg);
bfin_write(&drv_data->regs->flg, drv_data->flag_reg);
/* Start the queue running */
status = bfin_spi_start_queue(drv_data);
if (status != 0) {
dev_err(dev, "problem starting queue (%d)\n", status);
return status;
}
return 0;
}
static SIMPLE_DEV_PM_OPS(bfin_spi_pm_ops, bfin_spi_suspend, bfin_spi_resume);
#define BFIN_SPI_PM_OPS (&bfin_spi_pm_ops)
#else
#define BFIN_SPI_PM_OPS NULL
#endif
MODULE_ALIAS("platform:bfin-spi");
static struct platform_driver bfin_spi_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
.pm = BFIN_SPI_PM_OPS,
},
.probe = bfin_spi_probe,
.remove = bfin_spi_remove,
};
static int __init bfin_spi_init(void)
{
return platform_driver_register(&bfin_spi_driver);
}
subsys_initcall(bfin_spi_init);
static void __exit bfin_spi_exit(void)
{
platform_driver_unregister(&bfin_spi_driver);
}
module_exit(bfin_spi_exit);
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