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linux-next/drivers/spi/mpc52xx_psc_spi.c
Stefano Babic b7d271df87 spi: mpc52xx_psc_spi chipselect bugfix
According to the manual the "tdfOnExit" flag must be set on the last byte
we want to send.  The PSC controller holds SS low until the flag is set.

However, the flag was set always on the last byte of the FIFO,
independently if it is the last byte of the transfer.  This generates
spurious toggling of the SS signals that breaks the protocol of some
peripherals.  Fix.

Signed-off-by: Stefano Babic <sbabic@denx.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
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>
2008-12-01 19:55:24 -08:00

542 lines
14 KiB
C

/*
* MPC52xx PSC in SPI mode driver.
*
* Maintainer: Dragos Carp
*
* Copyright (C) 2006 TOPTICA Photonics AG.
*
* 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/errno.h>
#include <linux/interrupt.h>
#include <linux/of_platform.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/spi/spi.h>
#include <linux/fsl_devices.h>
#include <asm/mpc52xx.h>
#include <asm/mpc52xx_psc.h>
#define MCLK 20000000 /* PSC port MClk in hz */
struct mpc52xx_psc_spi {
/* fsl_spi_platform data */
void (*activate_cs)(u8, u8);
void (*deactivate_cs)(u8, u8);
u32 sysclk;
/* driver internal data */
struct mpc52xx_psc __iomem *psc;
struct mpc52xx_psc_fifo __iomem *fifo;
unsigned int irq;
u8 bits_per_word;
u8 busy;
struct workqueue_struct *workqueue;
struct work_struct work;
struct list_head queue;
spinlock_t lock;
struct completion done;
};
/* controller state */
struct mpc52xx_psc_spi_cs {
int bits_per_word;
int speed_hz;
};
/* set clock freq, clock ramp, bits per work
* if t is NULL then reset the values to the default values
*/
static int mpc52xx_psc_spi_transfer_setup(struct spi_device *spi,
struct spi_transfer *t)
{
struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
cs->speed_hz = (t && t->speed_hz)
? t->speed_hz : spi->max_speed_hz;
cs->bits_per_word = (t && t->bits_per_word)
? t->bits_per_word : spi->bits_per_word;
cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
return 0;
}
static void mpc52xx_psc_spi_activate_cs(struct spi_device *spi)
{
struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
struct mpc52xx_psc __iomem *psc = mps->psc;
u32 sicr;
u16 ccr;
sicr = in_be32(&psc->sicr);
/* Set clock phase and polarity */
if (spi->mode & SPI_CPHA)
sicr |= 0x00001000;
else
sicr &= ~0x00001000;
if (spi->mode & SPI_CPOL)
sicr |= 0x00002000;
else
sicr &= ~0x00002000;
if (spi->mode & SPI_LSB_FIRST)
sicr |= 0x10000000;
else
sicr &= ~0x10000000;
out_be32(&psc->sicr, sicr);
/* Set clock frequency and bits per word
* Because psc->ccr is defined as 16bit register instead of 32bit
* just set the lower byte of BitClkDiv
*/
ccr = in_be16((u16 __iomem *)&psc->ccr);
ccr &= 0xFF00;
if (cs->speed_hz)
ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
else /* by default SPI Clk 1MHz */
ccr |= (MCLK / 1000000 - 1) & 0xFF;
out_be16((u16 __iomem *)&psc->ccr, ccr);
mps->bits_per_word = cs->bits_per_word;
if (mps->activate_cs)
mps->activate_cs(spi->chip_select,
(spi->mode & SPI_CS_HIGH) ? 1 : 0);
}
static void mpc52xx_psc_spi_deactivate_cs(struct spi_device *spi)
{
struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
if (mps->deactivate_cs)
mps->deactivate_cs(spi->chip_select,
(spi->mode & SPI_CS_HIGH) ? 1 : 0);
}
#define MPC52xx_PSC_BUFSIZE (MPC52xx_PSC_RFNUM_MASK + 1)
/* wake up when 80% fifo full */
#define MPC52xx_PSC_RFALARM (MPC52xx_PSC_BUFSIZE * 20 / 100)
static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
struct spi_transfer *t)
{
struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
struct mpc52xx_psc __iomem *psc = mps->psc;
struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
unsigned rb = 0; /* number of bytes receieved */
unsigned sb = 0; /* number of bytes sent */
unsigned char *rx_buf = (unsigned char *)t->rx_buf;
unsigned char *tx_buf = (unsigned char *)t->tx_buf;
unsigned rfalarm;
unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
unsigned recv_at_once;
int last_block = 0;
if (!t->tx_buf && !t->rx_buf && t->len)
return -EINVAL;
/* enable transmiter/receiver */
out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
while (rb < t->len) {
if (t->len - rb > MPC52xx_PSC_BUFSIZE) {
rfalarm = MPC52xx_PSC_RFALARM;
last_block = 0;
} else {
send_at_once = t->len - sb;
rfalarm = MPC52xx_PSC_BUFSIZE - (t->len - rb);
last_block = 1;
}
dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
for (; send_at_once; sb++, send_at_once--) {
/* set EOF flag before the last word is sent */
if (send_at_once == 1 && last_block)
out_8(&psc->ircr2, 0x01);
if (tx_buf)
out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
else
out_8(&psc->mpc52xx_psc_buffer_8, 0);
}
/* enable interrupts and wait for wake up
* if just one byte is expected the Rx FIFO genererates no
* FFULL interrupt, so activate the RxRDY interrupt
*/
out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
if (t->len - rb == 1) {
out_8(&psc->mode, 0);
} else {
out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
out_be16(&fifo->rfalarm, rfalarm);
}
out_be16(&psc->mpc52xx_psc_imr, MPC52xx_PSC_IMR_RXRDY);
wait_for_completion(&mps->done);
recv_at_once = in_be16(&fifo->rfnum);
dev_dbg(&spi->dev, "%d bytes received\n", recv_at_once);
send_at_once = recv_at_once;
if (rx_buf) {
for (; recv_at_once; rb++, recv_at_once--)
rx_buf[rb] = in_8(&psc->mpc52xx_psc_buffer_8);
} else {
for (; recv_at_once; rb++, recv_at_once--)
in_8(&psc->mpc52xx_psc_buffer_8);
}
}
/* disable transmiter/receiver */
out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
return 0;
}
static void mpc52xx_psc_spi_work(struct work_struct *work)
{
struct mpc52xx_psc_spi *mps =
container_of(work, struct mpc52xx_psc_spi, work);
spin_lock_irq(&mps->lock);
mps->busy = 1;
while (!list_empty(&mps->queue)) {
struct spi_message *m;
struct spi_device *spi;
struct spi_transfer *t = NULL;
unsigned cs_change;
int status;
m = container_of(mps->queue.next, struct spi_message, queue);
list_del_init(&m->queue);
spin_unlock_irq(&mps->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) {
status = mpc52xx_psc_spi_transfer_setup(spi, t);
if (status < 0)
break;
}
if (cs_change)
mpc52xx_psc_spi_activate_cs(spi);
cs_change = t->cs_change;
status = mpc52xx_psc_spi_transfer_rxtx(spi, t);
if (status)
break;
m->actual_length += t->len;
if (t->delay_usecs)
udelay(t->delay_usecs);
if (cs_change)
mpc52xx_psc_spi_deactivate_cs(spi);
}
m->status = status;
m->complete(m->context);
if (status || !cs_change)
mpc52xx_psc_spi_deactivate_cs(spi);
mpc52xx_psc_spi_transfer_setup(spi, NULL);
spin_lock_irq(&mps->lock);
}
mps->busy = 0;
spin_unlock_irq(&mps->lock);
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)
static int mpc52xx_psc_spi_setup(struct spi_device *spi)
{
struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
unsigned long flags;
if (spi->bits_per_word%8)
return -EINVAL;
if (spi->mode & ~MODEBITS) {
dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return -EINVAL;
}
if (!cs) {
cs = kzalloc(sizeof *cs, GFP_KERNEL);
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
}
cs->bits_per_word = spi->bits_per_word;
cs->speed_hz = spi->max_speed_hz;
spin_lock_irqsave(&mps->lock, flags);
if (!mps->busy)
mpc52xx_psc_spi_deactivate_cs(spi);
spin_unlock_irqrestore(&mps->lock, flags);
return 0;
}
static int mpc52xx_psc_spi_transfer(struct spi_device *spi,
struct spi_message *m)
{
struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
unsigned long flags;
m->actual_length = 0;
m->status = -EINPROGRESS;
spin_lock_irqsave(&mps->lock, flags);
list_add_tail(&m->queue, &mps->queue);
queue_work(mps->workqueue, &mps->work);
spin_unlock_irqrestore(&mps->lock, flags);
return 0;
}
static void mpc52xx_psc_spi_cleanup(struct spi_device *spi)
{
kfree(spi->controller_state);
}
static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)
{
struct mpc52xx_psc __iomem *psc = mps->psc;
struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
u32 mclken_div;
int ret = 0;
/* default sysclk is 512MHz */
mclken_div = (mps->sysclk ? mps->sysclk : 512000000) / MCLK;
mpc52xx_set_psc_clkdiv(psc_id, mclken_div);
/* Reset the PSC into a known state */
out_8(&psc->command, MPC52xx_PSC_RST_RX);
out_8(&psc->command, MPC52xx_PSC_RST_TX);
out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
/* Disable interrupts, interrupts are based on alarm level */
out_be16(&psc->mpc52xx_psc_imr, 0);
out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
out_8(&fifo->rfcntl, 0);
out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
/* Configure 8bit codec mode as a SPI master and use EOF flags */
/* SICR_SIM_CODEC8|SICR_GENCLK|SICR_SPI|SICR_MSTR|SICR_USEEOF */
out_be32(&psc->sicr, 0x0180C800);
out_be16((u16 __iomem *)&psc->ccr, 0x070F); /* default SPI Clk 1MHz */
/* Set 2ms DTL delay */
out_8(&psc->ctur, 0x00);
out_8(&psc->ctlr, 0x84);
mps->bits_per_word = 8;
return ret;
}
static irqreturn_t mpc52xx_psc_spi_isr(int irq, void *dev_id)
{
struct mpc52xx_psc_spi *mps = (struct mpc52xx_psc_spi *)dev_id;
struct mpc52xx_psc __iomem *psc = mps->psc;
/* disable interrupt and wake up the work queue */
if (in_be16(&psc->mpc52xx_psc_isr) & MPC52xx_PSC_IMR_RXRDY) {
out_be16(&psc->mpc52xx_psc_imr, 0);
complete(&mps->done);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
/* bus_num is used only for the case dev->platform_data == NULL */
static int __init mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
u32 size, unsigned int irq, s16 bus_num)
{
struct fsl_spi_platform_data *pdata = dev->platform_data;
struct mpc52xx_psc_spi *mps;
struct spi_master *master;
int ret;
master = spi_alloc_master(dev, sizeof *mps);
if (master == NULL)
return -ENOMEM;
dev_set_drvdata(dev, master);
mps = spi_master_get_devdata(master);
mps->irq = irq;
if (pdata == NULL) {
dev_warn(dev, "probe called without platform data, no "
"(de)activate_cs function will be called\n");
mps->activate_cs = NULL;
mps->deactivate_cs = NULL;
mps->sysclk = 0;
master->bus_num = bus_num;
master->num_chipselect = 255;
} else {
mps->activate_cs = pdata->activate_cs;
mps->deactivate_cs = pdata->deactivate_cs;
mps->sysclk = pdata->sysclk;
master->bus_num = pdata->bus_num;
master->num_chipselect = pdata->max_chipselect;
}
master->setup = mpc52xx_psc_spi_setup;
master->transfer = mpc52xx_psc_spi_transfer;
master->cleanup = mpc52xx_psc_spi_cleanup;
mps->psc = ioremap(regaddr, size);
if (!mps->psc) {
dev_err(dev, "could not ioremap I/O port range\n");
ret = -EFAULT;
goto free_master;
}
/* On the 5200, fifo regs are immediately ajacent to the psc regs */
mps->fifo = ((void __iomem *)mps->psc) + sizeof(struct mpc52xx_psc);
ret = request_irq(mps->irq, mpc52xx_psc_spi_isr, 0, "mpc52xx-psc-spi",
mps);
if (ret)
goto free_master;
ret = mpc52xx_psc_spi_port_config(master->bus_num, mps);
if (ret < 0)
goto free_irq;
spin_lock_init(&mps->lock);
init_completion(&mps->done);
INIT_WORK(&mps->work, mpc52xx_psc_spi_work);
INIT_LIST_HEAD(&mps->queue);
mps->workqueue = create_singlethread_workqueue(
master->dev.parent->bus_id);
if (mps->workqueue == NULL) {
ret = -EBUSY;
goto free_irq;
}
ret = spi_register_master(master);
if (ret < 0)
goto unreg_master;
return ret;
unreg_master:
destroy_workqueue(mps->workqueue);
free_irq:
free_irq(mps->irq, mps);
free_master:
if (mps->psc)
iounmap(mps->psc);
spi_master_put(master);
return ret;
}
static int __exit mpc52xx_psc_spi_do_remove(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct mpc52xx_psc_spi *mps = spi_master_get_devdata(master);
flush_workqueue(mps->workqueue);
destroy_workqueue(mps->workqueue);
spi_unregister_master(master);
free_irq(mps->irq, mps);
if (mps->psc)
iounmap(mps->psc);
return 0;
}
static int __init mpc52xx_psc_spi_of_probe(struct of_device *op,
const struct of_device_id *match)
{
const u32 *regaddr_p;
u64 regaddr64, size64;
s16 id = -1;
regaddr_p = of_get_address(op->node, 0, &size64, NULL);
if (!regaddr_p) {
printk(KERN_ERR "Invalid PSC address\n");
return -EINVAL;
}
regaddr64 = of_translate_address(op->node, regaddr_p);
/* get PSC id (1..6, used by port_config) */
if (op->dev.platform_data == NULL) {
const u32 *psc_nump;
psc_nump = of_get_property(op->node, "cell-index", NULL);
if (!psc_nump || *psc_nump > 5) {
printk(KERN_ERR "mpc52xx_psc_spi: Device node %s has invalid "
"cell-index property\n", op->node->full_name);
return -EINVAL;
}
id = *psc_nump + 1;
}
return mpc52xx_psc_spi_do_probe(&op->dev, (u32)regaddr64, (u32)size64,
irq_of_parse_and_map(op->node, 0), id);
}
static int __exit mpc52xx_psc_spi_of_remove(struct of_device *op)
{
return mpc52xx_psc_spi_do_remove(&op->dev);
}
static struct of_device_id mpc52xx_psc_spi_of_match[] = {
{ .compatible = "fsl,mpc5200-psc-spi", },
{ .compatible = "mpc5200-psc-spi", }, /* old */
{}
};
MODULE_DEVICE_TABLE(of, mpc52xx_psc_spi_of_match);
static struct of_platform_driver mpc52xx_psc_spi_of_driver = {
.owner = THIS_MODULE,
.name = "mpc52xx-psc-spi",
.match_table = mpc52xx_psc_spi_of_match,
.probe = mpc52xx_psc_spi_of_probe,
.remove = __exit_p(mpc52xx_psc_spi_of_remove),
.driver = {
.name = "mpc52xx-psc-spi",
.owner = THIS_MODULE,
},
};
static int __init mpc52xx_psc_spi_init(void)
{
return of_register_platform_driver(&mpc52xx_psc_spi_of_driver);
}
module_init(mpc52xx_psc_spi_init);
static void __exit mpc52xx_psc_spi_exit(void)
{
of_unregister_platform_driver(&mpc52xx_psc_spi_of_driver);
}
module_exit(mpc52xx_psc_spi_exit);
MODULE_AUTHOR("Dragos Carp");
MODULE_DESCRIPTION("MPC52xx PSC SPI Driver");
MODULE_LICENSE("GPL");