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spi_mpc83xx: much improved driver

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The current driver may cause glitches on SPI CLK line since one must disable
the SPI controller before changing any HW settings.  Fix this by implementing
a local spi_transfer function that won't change speed and/or word size while
CS is active.

While doing that heavy lifting a few other issues were addressed too:
 - Make word size 16 and 32 work too.
 - Honor bits_per_word and speed_hz in spi transaction.
 - Optimize the common path.

This also stops using the "bitbang" framework (except for a few constants).

[Roel Kluin <12o3l@tiscali.nl>: "irq" needs to be signed]
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joakim Tjernlund 2008-05-12 14:02:30 -07:00 committed by Linus Torvalds
parent f4ed0deae8
commit c9bfcb3151
2 changed files with 288 additions and 136 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/spi/Kconfig
View File

@ -126,7 +126,6 @@ config SPI_MPC52xx_PSC
config SPI_MPC83xx
tristate "Freescale MPC83xx/QUICC Engine SPI controller"
depends on SPI_MASTER && (PPC_83xx || QUICC_ENGINE) && EXPERIMENTAL
select SPI_BITBANG
help
This enables using the Freescale MPC83xx and QUICC Engine SPI
controllers in master mode.

423
drivers/spi/spi_mpc83xx.c
View File

@ -49,6 +49,7 @@ struct mpc83xx_spi_reg {
#define SPMODE_LEN(x) ((x) << 20)
#define SPMODE_PM(x) ((x) << 16)
#define SPMODE_OP (1 << 14)
#define SPMODE_CG(x) ((x) << 7)
/*
* Default for SPI Mode:
@ -67,10 +68,6 @@ struct mpc83xx_spi_reg {
/* SPI Controller driver's private data. */
struct mpc83xx_spi {
/* bitbang has to be first */
struct spi_bitbang bitbang;
struct completion done;
struct mpc83xx_spi_reg __iomem *base;
/* rx & tx bufs from the spi_transfer */
@ -82,7 +79,7 @@ struct mpc83xx_spi {
u32(*get_tx) (struct mpc83xx_spi *);
unsigned int count;
u32 irq;
int irq;
unsigned nsecs; /* (clock cycle time)/2 */
@ -94,6 +91,25 @@ struct mpc83xx_spi {
void (*activate_cs) (u8 cs, u8 polarity);
void (*deactivate_cs) (u8 cs, u8 polarity);
u8 busy;
struct workqueue_struct *workqueue;
struct work_struct work;
struct list_head queue;
spinlock_t lock;
struct completion done;
};
struct spi_mpc83xx_cs {
/* functions to deal with different sized buffers */
void (*get_rx) (u32 rx_data, struct mpc83xx_spi *);
u32 (*get_tx) (struct mpc83xx_spi *);
u32 rx_shift; /* RX data reg shift when in qe mode */
u32 tx_shift; /* TX data reg shift when in qe mode */
u32 hw_mode; /* Holds HW mode register settings */
};
static inline void mpc83xx_spi_write_reg(__be32 __iomem * reg, u32 val)
@ -137,6 +153,7 @@ static void mpc83xx_spi_chipselect(struct spi_device *spi, int value)
{
struct mpc83xx_spi *mpc83xx_spi;
u8 pol = spi->mode & SPI_CS_HIGH ? 1 : 0;
struct spi_mpc83xx_cs *cs = spi->controller_state;
mpc83xx_spi = spi_master_get_devdata(spi->master);
@ -147,50 +164,26 @@ static void mpc83xx_spi_chipselect(struct spi_device *spi, int value)
if (value == BITBANG_CS_ACTIVE) {
u32 regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
u32 len = spi->bits_per_word;
u8 pm;
if (len == 32)
len = 0;
else
len = len - 1;
mpc83xx_spi->rx_shift = cs->rx_shift;
mpc83xx_spi->tx_shift = cs->tx_shift;
mpc83xx_spi->get_rx = cs->get_rx;
mpc83xx_spi->get_tx = cs->get_tx;
/* mask out bits we are going to set */
regval &= ~(SPMODE_CP_BEGIN_EDGECLK | SPMODE_CI_INACTIVEHIGH
| SPMODE_LEN(0xF) | SPMODE_DIV16
| SPMODE_PM(0xF) | SPMODE_REV | SPMODE_LOOP);
if (cs->hw_mode != regval) {
unsigned long flags;
void *tmp_ptr = &mpc83xx_spi->base->mode;
if (spi->mode & SPI_CPHA)
regval |= SPMODE_CP_BEGIN_EDGECLK;
if (spi->mode & SPI_CPOL)
regval |= SPMODE_CI_INACTIVEHIGH;
if (!(spi->mode & SPI_LSB_FIRST))
regval |= SPMODE_REV;
if (spi->mode & SPI_LOOP)
regval |= SPMODE_LOOP;
regval |= SPMODE_LEN(len);
if ((mpc83xx_spi->spibrg / spi->max_speed_hz) >= 64) {
pm = mpc83xx_spi->spibrg / (spi->max_speed_hz * 64) - 1;
if (pm > 0x0f) {
dev_err(&spi->dev, "Requested speed is too "
"low: %d Hz. Will use %d Hz instead.\n",
spi->max_speed_hz,
mpc83xx_spi->spibrg / 1024);
pm = 0x0f;
}
regval |= SPMODE_PM(pm) | SPMODE_DIV16;
} else {
pm = mpc83xx_spi->spibrg / (spi->max_speed_hz * 4);
if (pm)
pm--;
regval |= SPMODE_PM(pm);
regval = cs->hw_mode;
/* Turn off IRQs locally to minimize time that
* SPI is disabled
*/
local_irq_save(flags);
/* Turn off SPI unit prior changing mode */
mpc83xx_spi_write_reg(tmp_ptr, regval & ~SPMODE_ENABLE);
mpc83xx_spi_write_reg(tmp_ptr, regval);
local_irq_restore(flags);
}
/* Turn off SPI unit prior changing mode */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, 0);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval);
if (mpc83xx_spi->activate_cs)
mpc83xx_spi->activate_cs(spi->chip_select, pol);
}
@ -201,8 +194,9 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct mpc83xx_spi *mpc83xx_spi;
u32 regval;
u8 bits_per_word;
u8 bits_per_word, pm;
u32 hz;
struct spi_mpc83xx_cs *cs = spi->controller_state;
mpc83xx_spi = spi_master_get_devdata(spi->master);
@ -223,122 +217,106 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
|| ((bits_per_word > 16) && (bits_per_word != 32)))
return -EINVAL;
mpc83xx_spi->rx_shift = 0;
mpc83xx_spi->tx_shift = 0;
if (!hz)
hz = spi->max_speed_hz;
cs->rx_shift = 0;
cs->tx_shift = 0;
if (bits_per_word <= 8) {
mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u8;
mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u8;
cs->get_rx = mpc83xx_spi_rx_buf_u8;
cs->get_tx = mpc83xx_spi_tx_buf_u8;
if (mpc83xx_spi->qe_mode) {
mpc83xx_spi->rx_shift = 16;
mpc83xx_spi->tx_shift = 24;
cs->rx_shift = 16;
cs->tx_shift = 24;
}
} else if (bits_per_word <= 16) {
mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u16;
mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u16;
cs->get_rx = mpc83xx_spi_rx_buf_u16;
cs->get_tx = mpc83xx_spi_tx_buf_u16;
if (mpc83xx_spi->qe_mode) {
mpc83xx_spi->rx_shift = 16;
mpc83xx_spi->tx_shift = 16;
cs->rx_shift = 16;
cs->tx_shift = 16;
}
} else if (bits_per_word <= 32) {
mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u32;
mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u32;
cs->get_rx = mpc83xx_spi_rx_buf_u32;
cs->get_tx = mpc83xx_spi_tx_buf_u32;
} else
return -EINVAL;
if (mpc83xx_spi->qe_mode && spi->mode & SPI_LSB_FIRST) {
mpc83xx_spi->tx_shift = 0;
cs->tx_shift = 0;
if (bits_per_word <= 8)
mpc83xx_spi->rx_shift = 8;
cs->rx_shift = 8;
else
mpc83xx_spi->rx_shift = 0;
cs->rx_shift = 0;
}
/* nsecs = (clock period)/2 */
if (!hz)
hz = spi->max_speed_hz;
mpc83xx_spi->nsecs = (1000000000 / 2) / hz;
if (mpc83xx_spi->nsecs > MAX_UDELAY_MS * 1000)
return -EINVAL;
mpc83xx_spi->rx_shift = cs->rx_shift;
mpc83xx_spi->tx_shift = cs->tx_shift;
mpc83xx_spi->get_rx = cs->get_rx;
mpc83xx_spi->get_tx = cs->get_tx;
if (bits_per_word == 32)
bits_per_word = 0;
else
bits_per_word = bits_per_word - 1;
regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
/* mask out bits we are going to set */
regval &= ~(SPMODE_LEN(0xF) | SPMODE_REV);
regval |= SPMODE_LEN(bits_per_word);
if (!(spi->mode & SPI_LSB_FIRST))
regval |= SPMODE_REV;
cs->hw_mode &= ~(SPMODE_LEN(0xF) | SPMODE_DIV16
| SPMODE_PM(0xF));
/* Turn off SPI unit prior changing mode */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, 0);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval);
cs->hw_mode |= SPMODE_LEN(bits_per_word);
return 0;
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
| SPI_LSB_FIRST | SPI_LOOP)
static int mpc83xx_spi_setup(struct spi_device *spi)
{
struct spi_bitbang *bitbang;
struct mpc83xx_spi *mpc83xx_spi;
int retval;
if (spi->mode & ~MODEBITS) {
dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return -EINVAL;
if ((mpc83xx_spi->spibrg / hz) >= 64) {
pm = mpc83xx_spi->spibrg / (hz * 64) - 1;
if (pm > 0x0f) {
dev_err(&spi->dev, "Requested speed is too "
"low: %d Hz. Will use %d Hz instead.\n",
hz, mpc83xx_spi->spibrg / 1024);
pm = 0x0f;
}
cs->hw_mode |= SPMODE_PM(pm) | SPMODE_DIV16;
} else {
pm = mpc83xx_spi->spibrg / (hz * 4);
if (pm)
pm--;
cs->hw_mode |= SPMODE_PM(pm);
}
regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
if (cs->hw_mode != regval) {
unsigned long flags;
void *tmp_ptr = &mpc83xx_spi->base->mode;
if (!spi->max_speed_hz)
return -EINVAL;
bitbang = spi_master_get_devdata(spi->master);
mpc83xx_spi = spi_master_get_devdata(spi->master);
if (!spi->bits_per_word)
spi->bits_per_word = 8;
retval = mpc83xx_spi_setup_transfer(spi, NULL);
if (retval < 0)
return retval;
dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n",
__func__, spi->mode & (SPI_CPOL | SPI_CPHA),
spi->bits_per_word, 2 * mpc83xx_spi->nsecs);
/* NOTE we _need_ to call chipselect() early, ideally with adapter
* setup, unless the hardware defaults cooperate to avoid confusion
* between normal (active low) and inverted chipselects.
*/
/* deselect chip (low or high) */
spin_lock(&bitbang->lock);
if (!bitbang->busy) {
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(mpc83xx_spi->nsecs);
regval = cs->hw_mode;
/* Turn off IRQs locally to minimize time
* that SPI is disabled
*/
local_irq_save(flags);
/* Turn off SPI unit prior changing mode */
mpc83xx_spi_write_reg(tmp_ptr, regval & ~SPMODE_ENABLE);
mpc83xx_spi_write_reg(tmp_ptr, regval);
local_irq_restore(flags);
}
spin_unlock(&bitbang->lock);
return 0;
}
static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct mpc83xx_spi *mpc83xx_spi;
u32 word;
u32 word, len, bits_per_word;
mpc83xx_spi = spi_master_get_devdata(spi->master);
mpc83xx_spi->tx = t->tx_buf;
mpc83xx_spi->rx = t->rx_buf;
mpc83xx_spi->count = t->len;
bits_per_word = spi->bits_per_word;
if (t->bits_per_word)
bits_per_word = t->bits_per_word;
len = t->len;
if (bits_per_word > 8)
len /= 2;
if (bits_per_word > 16)
len /= 2;
mpc83xx_spi->count = len;
INIT_COMPLETION(mpc83xx_spi->done);
/* enable rx ints */
@ -353,7 +331,147 @@ static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
/* disable rx ints */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0);
return t->len - mpc83xx_spi->count;
return mpc83xx_spi->count;
}
static void mpc83xx_spi_work(struct work_struct *work)
{
struct mpc83xx_spi *mpc83xx_spi =
container_of(work, struct mpc83xx_spi, work);
spin_lock_irq(&mpc83xx_spi->lock);
mpc83xx_spi->busy = 1;
while (!list_empty(&mpc83xx_spi->queue)) {
struct spi_message *m;
struct spi_device *spi;
struct spi_transfer *t = NULL;
unsigned cs_change;
int status, nsecs = 50;
m = container_of(mpc83xx_spi->queue.next,
struct spi_message, queue);
list_del_init(&m->queue);
spin_unlock_irq(&mpc83xx_spi->lock);
spi = m->spi;
cs_change = 1;
status = 0;
list_for_each_entry(t, &m->transfers, transfer_list) {
if (t->bits_per_word || t->speed_hz) {
/* Don't allow changes if CS is active */
status = -EINVAL;
if (cs_change)
status = mpc83xx_spi_setup_transfer(spi, t);
if (status < 0)
break;
}
if (cs_change)
mpc83xx_spi_chipselect(spi, BITBANG_CS_ACTIVE);
cs_change = t->cs_change;
if (t->len)
status = mpc83xx_spi_bufs(spi, t);
if (status) {
status = -EMSGSIZE;
break;
}
m->actual_length += t->len;
if (t->delay_usecs)
udelay(t->delay_usecs);
if (cs_change) {
ndelay(nsecs);
mpc83xx_spi_chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(nsecs);
}
}
m->status = status;
m->complete(m->context);
if (status || !cs_change) {
ndelay(nsecs);
mpc83xx_spi_chipselect(spi, BITBANG_CS_INACTIVE);
}
mpc83xx_spi_setup_transfer(spi, NULL);
spin_lock_irq(&mpc83xx_spi->lock);
}
mpc83xx_spi->busy = 0;
spin_unlock_irq(&mpc83xx_spi->lock);
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
| SPI_LSB_FIRST | SPI_LOOP)
static int mpc83xx_spi_setup(struct spi_device *spi)
{
struct mpc83xx_spi *mpc83xx_spi;
int retval;
u32 hw_mode;
struct spi_mpc83xx_cs *cs = spi->controller_state;
if (spi->mode & ~MODEBITS) {
dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return -EINVAL;
}
if (!spi->max_speed_hz)
return -EINVAL;
if (!cs) {
cs = kzalloc(sizeof *cs, GFP_KERNEL);
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
}
mpc83xx_spi = spi_master_get_devdata(spi->master);
if (!spi->bits_per_word)
spi->bits_per_word = 8;
hw_mode = cs->hw_mode; /* Save orginal settings */
cs->hw_mode = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
/* mask out bits we are going to set */
cs->hw_mode &= ~(SPMODE_CP_BEGIN_EDGECLK | SPMODE_CI_INACTIVEHIGH
| SPMODE_REV | SPMODE_LOOP);
if (spi->mode & SPI_CPHA)
cs->hw_mode |= SPMODE_CP_BEGIN_EDGECLK;
if (spi->mode & SPI_CPOL)
cs->hw_mode |= SPMODE_CI_INACTIVEHIGH;
if (!(spi->mode & SPI_LSB_FIRST))
cs->hw_mode |= SPMODE_REV;
if (spi->mode & SPI_LOOP)
cs->hw_mode |= SPMODE_LOOP;
retval = mpc83xx_spi_setup_transfer(spi, NULL);
if (retval < 0) {
cs->hw_mode = hw_mode; /* Restore settings */
return retval;
}
dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u Hz\n",
__func__, spi->mode & (SPI_CPOL | SPI_CPHA),
spi->bits_per_word, spi->max_speed_hz);
#if 0 /* Don't think this is needed */
/* NOTE we _need_ to call chipselect() early, ideally with adapter
* setup, unless the hardware defaults cooperate to avoid confusion
* between normal (active low) and inverted chipselects.
*/
/* deselect chip (low or high) */
spin_lock(&mpc83xx_spi->lock);
if (!mpc83xx_spi->busy)
mpc83xx_spi_chipselect(spi, BITBANG_CS_INACTIVE);
spin_unlock(&mpc83xx_spi->lock);
#endif
return 0;
}
irqreturn_t mpc83xx_spi_irq(s32 irq, void *context_data)
@ -395,6 +513,28 @@ irqreturn_t mpc83xx_spi_irq(s32 irq, void *context_data)
return ret;
}
static int mpc83xx_spi_transfer(struct spi_device *spi,
struct spi_message *m)
{
struct mpc83xx_spi *mpc83xx_spi = spi_master_get_devdata(spi->master);
unsigned long flags;
m->actual_length = 0;
m->status = -EINPROGRESS;
spin_lock_irqsave(&mpc83xx_spi->lock, flags);
list_add_tail(&m->queue, &mpc83xx_spi->queue);
queue_work(mpc83xx_spi->workqueue, &mpc83xx_spi->work);
spin_unlock_irqrestore(&mpc83xx_spi->lock, flags);
return 0;
}
static void mpc83xx_spi_cleanup(struct spi_device *spi)
{
kfree(spi->controller_state);
}
static int __init mpc83xx_spi_probe(struct platform_device *dev)
{
@ -426,11 +566,11 @@ static int __init mpc83xx_spi_probe(struct platform_device *dev)
ret = -ENODEV;
goto free_master;
}
master->setup = mpc83xx_spi_setup;
master->transfer = mpc83xx_spi_transfer;
master->cleanup = mpc83xx_spi_cleanup;
mpc83xx_spi = spi_master_get_devdata(master);
mpc83xx_spi->bitbang.master = spi_master_get(master);
mpc83xx_spi->bitbang.chipselect = mpc83xx_spi_chipselect;
mpc83xx_spi->bitbang.setup_transfer = mpc83xx_spi_setup_transfer;
mpc83xx_spi->bitbang.txrx_bufs = mpc83xx_spi_bufs;
mpc83xx_spi->activate_cs = pdata->activate_cs;
mpc83xx_spi->deactivate_cs = pdata->deactivate_cs;
mpc83xx_spi->qe_mode = pdata->qe_mode;
@ -445,7 +585,6 @@ static int __init mpc83xx_spi_probe(struct platform_device *dev)
mpc83xx_spi->tx_shift = 24;
}
mpc83xx_spi->bitbang.master->setup = mpc83xx_spi_setup;
init_completion(&mpc83xx_spi->done);
mpc83xx_spi->base = ioremap(r->start, r->end - r->start + 1);
@ -483,11 +622,21 @@ static int __init mpc83xx_spi_probe(struct platform_device *dev)
regval |= SPMODE_OP;
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval);
spin_lock_init(&mpc83xx_spi->lock);
init_completion(&mpc83xx_spi->done);
INIT_WORK(&mpc83xx_spi->work, mpc83xx_spi_work);
INIT_LIST_HEAD(&mpc83xx_spi->queue);
ret = spi_bitbang_start(&mpc83xx_spi->bitbang);
if (ret != 0)
mpc83xx_spi->workqueue = create_singlethread_workqueue(
master->dev.parent->bus_id);
if (mpc83xx_spi->workqueue == NULL) {
ret = -EBUSY;
goto free_irq;
}
ret = spi_register_master(master);
if (ret < 0)
goto unreg_master;
printk(KERN_INFO
"%s: MPC83xx SPI Controller driver at 0x%p (irq = %d)\n",
@ -495,6 +644,8 @@ static int __init mpc83xx_spi_probe(struct platform_device *dev)
return ret;
unreg_master:
destroy_workqueue(mpc83xx_spi->workqueue);
free_irq:
free_irq(mpc83xx_spi->irq, mpc83xx_spi);
unmap_io:
@ -515,10 +666,12 @@ static int __exit mpc83xx_spi_remove(struct platform_device *dev)
master = platform_get_drvdata(dev);
mpc83xx_spi = spi_master_get_devdata(master);
spi_bitbang_stop(&mpc83xx_spi->bitbang);
flush_workqueue(mpc83xx_spi->workqueue);
destroy_workqueue(mpc83xx_spi->workqueue);
spi_unregister_master(master);
free_irq(mpc83xx_spi->irq, mpc83xx_spi);
iounmap(mpc83xx_spi->base);
spi_master_put(mpc83xx_spi->bitbang.master);
return 0;
}