linux/drivers/spi/spi_mpc83xx.c
Joakim Tjernlund c9bfcb3151 spi_mpc83xx: much improved driver
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>
2008-05-13 08:02:25 -07:00

703 lines
17 KiB
C

/*
* MPC83xx SPI controller driver.
*
* Maintainer: Kumar Gala
*
* Copyright (C) 2006 Polycom, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/platform_device.h>
#include <linux/fsl_devices.h>
#include <asm/irq.h>
#include <asm/io.h>
/* SPI Controller registers */
struct mpc83xx_spi_reg {
u8 res1[0x20];
__be32 mode;
__be32 event;
__be32 mask;
__be32 command;
__be32 transmit;
__be32 receive;
};
/* SPI Controller mode register definitions */
#define SPMODE_LOOP (1 << 30)
#define SPMODE_CI_INACTIVEHIGH (1 << 29)
#define SPMODE_CP_BEGIN_EDGECLK (1 << 28)
#define SPMODE_DIV16 (1 << 27)
#define SPMODE_REV (1 << 26)
#define SPMODE_MS (1 << 25)
#define SPMODE_ENABLE (1 << 24)
#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:
* SPI MODE 0 (inactive low, phase middle, MSB, 8-bit length, slow clk
*/
#define SPMODE_INIT_VAL (SPMODE_CI_INACTIVEHIGH | SPMODE_DIV16 | SPMODE_REV | \
SPMODE_MS | SPMODE_LEN(7) | SPMODE_PM(0xf))
/* SPIE register values */
#define SPIE_NE 0x00000200 /* Not empty */
#define SPIE_NF 0x00000100 /* Not full */
/* SPIM register values */
#define SPIM_NE 0x00000200 /* Not empty */
#define SPIM_NF 0x00000100 /* Not full */
/* SPI Controller driver's private data. */
struct mpc83xx_spi {
struct mpc83xx_spi_reg __iomem *base;
/* rx & tx bufs from the spi_transfer */
const void *tx;
void *rx;
/* functions to deal with different sized buffers */
void (*get_rx) (u32 rx_data, struct mpc83xx_spi *);
u32(*get_tx) (struct mpc83xx_spi *);
unsigned int count;
int irq;
unsigned nsecs; /* (clock cycle time)/2 */
u32 spibrg; /* SPIBRG input clock */
u32 rx_shift; /* RX data reg shift when in qe mode */
u32 tx_shift; /* TX data reg shift when in qe mode */
bool qe_mode;
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)
{
out_be32(reg, val);
}
static inline u32 mpc83xx_spi_read_reg(__be32 __iomem * reg)
{
return in_be32(reg);
}
#define MPC83XX_SPI_RX_BUF(type) \
void mpc83xx_spi_rx_buf_##type(u32 data, struct mpc83xx_spi *mpc83xx_spi) \
{ \
type * rx = mpc83xx_spi->rx; \
*rx++ = (type)(data >> mpc83xx_spi->rx_shift); \
mpc83xx_spi->rx = rx; \
}
#define MPC83XX_SPI_TX_BUF(type) \
u32 mpc83xx_spi_tx_buf_##type(struct mpc83xx_spi *mpc83xx_spi) \
{ \
u32 data; \
const type * tx = mpc83xx_spi->tx; \
if (!tx) \
return 0; \
data = *tx++ << mpc83xx_spi->tx_shift; \
mpc83xx_spi->tx = tx; \
return data; \
}
MPC83XX_SPI_RX_BUF(u8)
MPC83XX_SPI_RX_BUF(u16)
MPC83XX_SPI_RX_BUF(u32)
MPC83XX_SPI_TX_BUF(u8)
MPC83XX_SPI_TX_BUF(u16)
MPC83XX_SPI_TX_BUF(u32)
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);
if (value == BITBANG_CS_INACTIVE) {
if (mpc83xx_spi->deactivate_cs)
mpc83xx_spi->deactivate_cs(spi->chip_select, pol);
}
if (value == BITBANG_CS_ACTIVE) {
u32 regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode);
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 (cs->hw_mode != regval) {
unsigned long flags;
void *tmp_ptr = &mpc83xx_spi->base->mode;
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);
}
if (mpc83xx_spi->activate_cs)
mpc83xx_spi->activate_cs(spi->chip_select, pol);
}
}
static
int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct mpc83xx_spi *mpc83xx_spi;
u32 regval;
u8 bits_per_word, pm;
u32 hz;
struct spi_mpc83xx_cs *cs = spi->controller_state;
mpc83xx_spi = spi_master_get_devdata(spi->master);
if (t) {
bits_per_word = t->bits_per_word;
hz = t->speed_hz;
} else {
bits_per_word = 0;
hz = 0;
}
/* spi_transfer level calls that work per-word */
if (!bits_per_word)
bits_per_word = spi->bits_per_word;
/* Make sure its a bit width we support [4..16, 32] */
if ((bits_per_word < 4)
|| ((bits_per_word > 16) && (bits_per_word != 32)))
return -EINVAL;
if (!hz)
hz = spi->max_speed_hz;
cs->rx_shift = 0;
cs->tx_shift = 0;
if (bits_per_word <= 8) {
cs->get_rx = mpc83xx_spi_rx_buf_u8;
cs->get_tx = mpc83xx_spi_tx_buf_u8;
if (mpc83xx_spi->qe_mode) {
cs->rx_shift = 16;
cs->tx_shift = 24;
}
} else if (bits_per_word <= 16) {
cs->get_rx = mpc83xx_spi_rx_buf_u16;
cs->get_tx = mpc83xx_spi_tx_buf_u16;
if (mpc83xx_spi->qe_mode) {
cs->rx_shift = 16;
cs->tx_shift = 16;
}
} else if (bits_per_word <= 32) {
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) {
cs->tx_shift = 0;
if (bits_per_word <= 8)
cs->rx_shift = 8;
else
cs->rx_shift = 0;
}
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;
/* mask out bits we are going to set */
cs->hw_mode &= ~(SPMODE_LEN(0xF) | SPMODE_DIV16
| SPMODE_PM(0xF));
cs->hw_mode |= SPMODE_LEN(bits_per_word);
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;
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);
}
return 0;
}
static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct mpc83xx_spi *mpc83xx_spi;
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;
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 */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, SPIM_NE);
/* transmit word */
word = mpc83xx_spi->get_tx(mpc83xx_spi);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, word);
wait_for_completion(&mpc83xx_spi->done);
/* disable rx ints */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0);
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)
{
struct mpc83xx_spi *mpc83xx_spi = context_data;
u32 event;
irqreturn_t ret = IRQ_NONE;
/* Get interrupt events(tx/rx) */
event = mpc83xx_spi_read_reg(&mpc83xx_spi->base->event);
/* We need handle RX first */
if (event & SPIE_NE) {
u32 rx_data = mpc83xx_spi_read_reg(&mpc83xx_spi->base->receive);
if (mpc83xx_spi->rx)
mpc83xx_spi->get_rx(rx_data, mpc83xx_spi);
ret = IRQ_HANDLED;
}
if ((event & SPIE_NF) == 0)
/* spin until TX is done */
while (((event =
mpc83xx_spi_read_reg(&mpc83xx_spi->base->event)) &
SPIE_NF) == 0)
cpu_relax();
mpc83xx_spi->count -= 1;
if (mpc83xx_spi->count) {
u32 word = mpc83xx_spi->get_tx(mpc83xx_spi);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, word);
} else {
complete(&mpc83xx_spi->done);
}
/* Clear the events */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->event, event);
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)
{
struct spi_master *master;
struct mpc83xx_spi *mpc83xx_spi;
struct fsl_spi_platform_data *pdata;
struct resource *r;
u32 regval;
int ret = 0;
/* Get resources(memory, IRQ) associated with the device */
master = spi_alloc_master(&dev->dev, sizeof(struct mpc83xx_spi));
if (master == NULL) {
ret = -ENOMEM;
goto err;
}
platform_set_drvdata(dev, master);
pdata = dev->dev.platform_data;
if (pdata == NULL) {
ret = -ENODEV;
goto free_master;
}
r = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (r == NULL) {
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->activate_cs = pdata->activate_cs;
mpc83xx_spi->deactivate_cs = pdata->deactivate_cs;
mpc83xx_spi->qe_mode = pdata->qe_mode;
mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u8;
mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u8;
mpc83xx_spi->spibrg = pdata->sysclk;
mpc83xx_spi->rx_shift = 0;
mpc83xx_spi->tx_shift = 0;
if (mpc83xx_spi->qe_mode) {
mpc83xx_spi->rx_shift = 16;
mpc83xx_spi->tx_shift = 24;
}
init_completion(&mpc83xx_spi->done);
mpc83xx_spi->base = ioremap(r->start, r->end - r->start + 1);
if (mpc83xx_spi->base == NULL) {
ret = -ENOMEM;
goto put_master;
}
mpc83xx_spi->irq = platform_get_irq(dev, 0);
if (mpc83xx_spi->irq < 0) {
ret = -ENXIO;
goto unmap_io;
}
/* Register for SPI Interrupt */
ret = request_irq(mpc83xx_spi->irq, mpc83xx_spi_irq,
0, "mpc83xx_spi", mpc83xx_spi);
if (ret != 0)
goto unmap_io;
master->bus_num = pdata->bus_num;
master->num_chipselect = pdata->max_chipselect;
/* SPI controller initializations */
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, 0);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->command, 0);
mpc83xx_spi_write_reg(&mpc83xx_spi->base->event, 0xffffffff);
/* Enable SPI interface */
regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
if (pdata->qe_mode)
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);
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",
dev->dev.bus_id, mpc83xx_spi->base, mpc83xx_spi->irq);
return ret;
unreg_master:
destroy_workqueue(mpc83xx_spi->workqueue);
free_irq:
free_irq(mpc83xx_spi->irq, mpc83xx_spi);
unmap_io:
iounmap(mpc83xx_spi->base);
put_master:
spi_master_put(master);
free_master:
kfree(master);
err:
return ret;
}
static int __exit mpc83xx_spi_remove(struct platform_device *dev)
{
struct mpc83xx_spi *mpc83xx_spi;
struct spi_master *master;
master = platform_get_drvdata(dev);
mpc83xx_spi = spi_master_get_devdata(master);
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);
return 0;
}
MODULE_ALIAS("platform:mpc83xx_spi");
static struct platform_driver mpc83xx_spi_driver = {
.remove = __exit_p(mpc83xx_spi_remove),
.driver = {
.name = "mpc83xx_spi",
.owner = THIS_MODULE,
},
};
static int __init mpc83xx_spi_init(void)
{
return platform_driver_probe(&mpc83xx_spi_driver, mpc83xx_spi_probe);
}
static void __exit mpc83xx_spi_exit(void)
{
platform_driver_unregister(&mpc83xx_spi_driver);
}
module_init(mpc83xx_spi_init);
module_exit(mpc83xx_spi_exit);
MODULE_AUTHOR("Kumar Gala");
MODULE_DESCRIPTION("Simple MPC83xx SPI Driver");
MODULE_LICENSE("GPL");