kernel-ark/drivers/spi/atmel_spi.c
Atsushi Nemoto f6febccd7f atmel_spi: fix clock polarity
The atmel_spi driver does not initialize clock polarity correctly (except for
at91rm9200 CS0 channel) in some case.

The atmel_spi driver uses gpio-controlled chipselect.  OTOH spi clock signal
is controlled by CSRn.CPOL bit, but this register controls clock signal
correctly only in 'real transfer' duration.  At the time of cs_activate()
call, CSRn.CPOL will be initialized correctly, but the controller do not know
which channel is to be used next, so clock signal will stay at the inactive
state of last transfer.  If clock polarity of new transfer and last transfer
was differ, new transfer will start with wrong clock signal state.

For example, if you started SPI MODE 2 or 3 transfer after SPI MODE 0 or 1
transfer, the clock signal state at the assertion of chipselect will be low.
Of course this will violates SPI transfer.

This patch is short term solution for this problem.  It makes all CSRn.CPOL
match for the transfer before activating chipselect.  For longer term, the
best fix might be to let NPCS0 stay selected permanently in MR and overwrite
CSR0 with to the new slave's settings before asserting CS.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:12:14 -08:00

866 lines
22 KiB
C

/*
* Driver for Atmel AT32 and AT91 SPI Controllers
*
* Copyright (C) 2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
#include <asm/io.h>
#include <asm/arch/board.h>
#include <asm/arch/gpio.h>
#include <asm/arch/cpu.h>
#include "atmel_spi.h"
/*
* The core SPI transfer engine just talks to a register bank to set up
* DMA transfers; transfer queue progress is driven by IRQs. The clock
* framework provides the base clock, subdivided for each spi_device.
*
* Newer controllers, marked with "new_1" flag, have:
* - CR.LASTXFER
* - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
* - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
* - SPI_CSRx.CSAAT
* - SPI_CSRx.SBCR allows faster clocking
*/
struct atmel_spi {
spinlock_t lock;
void __iomem *regs;
int irq;
struct clk *clk;
struct platform_device *pdev;
unsigned new_1:1;
struct spi_device *stay;
u8 stopping;
struct list_head queue;
struct spi_transfer *current_transfer;
unsigned long current_remaining_bytes;
struct spi_transfer *next_transfer;
unsigned long next_remaining_bytes;
void *buffer;
dma_addr_t buffer_dma;
};
#define BUFFER_SIZE PAGE_SIZE
#define INVALID_DMA_ADDRESS 0xffffffff
/*
* Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
* they assume that spi slave device state will not change on deselect, so
* that automagic deselection is OK. ("NPCSx rises if no data is to be
* transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer
* controllers have CSAAT and friends.
*
* Since the CSAAT functionality is a bit weird on newer controllers as
* well, we use GPIO to control nCSx pins on all controllers, updating
* MR.PCS to avoid confusing the controller. Using GPIOs also lets us
* support active-high chipselects despite the controller's belief that
* only active-low devices/systems exists.
*
* However, at91rm9200 has a second erratum whereby nCS0 doesn't work
* right when driven with GPIO. ("Mode Fault does not allow more than one
* Master on Chip Select 0.") No workaround exists for that ... so for
* nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
* and (c) will trigger that first erratum in some cases.
*/
static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
{
unsigned gpio = (unsigned) spi->controller_data;
unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;
int i;
u32 csr;
u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
/* Make sure clock polarity is correct */
for (i = 0; i < spi->master->num_chipselect; i++) {
csr = spi_readl(as, CSR0 + 4 * i);
if ((csr ^ cpol) & SPI_BIT(CPOL))
spi_writel(as, CSR0 + 4 * i, csr ^ SPI_BIT(CPOL));
}
mr = spi_readl(as, MR);
mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
gpio, active ? " (high)" : "",
mr);
if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
gpio_set_value(gpio, active);
spi_writel(as, MR, mr);
}
static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
{
unsigned gpio = (unsigned) spi->controller_data;
unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;
/* only deactivate *this* device; sometimes transfers to
* another device may be active when this routine is called.
*/
mr = spi_readl(as, MR);
if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
mr = SPI_BFINS(PCS, 0xf, mr);
spi_writel(as, MR, mr);
}
dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
gpio, active ? " (low)" : "",
mr);
if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
gpio_set_value(gpio, !active);
}
static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
struct spi_transfer *xfer)
{
return msg->transfers.prev == &xfer->transfer_list;
}
static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer)
{
return xfer->delay_usecs == 0 && !xfer->cs_change;
}
static void atmel_spi_next_xfer_data(struct spi_master *master,
struct spi_transfer *xfer,
dma_addr_t *tx_dma,
dma_addr_t *rx_dma,
u32 *plen)
{
struct atmel_spi *as = spi_master_get_devdata(master);
u32 len = *plen;
/* use scratch buffer only when rx or tx data is unspecified */
if (xfer->rx_buf)
*rx_dma = xfer->rx_dma + xfer->len - len;
else {
*rx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
}
if (xfer->tx_buf)
*tx_dma = xfer->tx_dma + xfer->len - len;
else {
*tx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
memset(as->buffer, 0, len);
dma_sync_single_for_device(&as->pdev->dev,
as->buffer_dma, len, DMA_TO_DEVICE);
}
*plen = len;
}
/*
* Submit next transfer for DMA.
* lock is held, spi irq is blocked
*/
static void atmel_spi_next_xfer(struct spi_master *master,
struct spi_message *msg)
{
struct atmel_spi *as = spi_master_get_devdata(master);
struct spi_transfer *xfer;
u32 len, remaining, total;
dma_addr_t tx_dma, rx_dma;
if (!as->current_transfer)
xfer = list_entry(msg->transfers.next,
struct spi_transfer, transfer_list);
else if (!as->next_transfer)
xfer = list_entry(as->current_transfer->transfer_list.next,
struct spi_transfer, transfer_list);
else
xfer = NULL;
if (xfer) {
len = xfer->len;
atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
remaining = xfer->len - len;
spi_writel(as, RPR, rx_dma);
spi_writel(as, TPR, tx_dma);
if (msg->spi->bits_per_word > 8)
len >>= 1;
spi_writel(as, RCR, len);
spi_writel(as, TCR, len);
dev_dbg(&msg->spi->dev,
" start xfer %p: len %u tx %p/%08x rx %p/%08x\n",
xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
xfer->rx_buf, xfer->rx_dma);
} else {
xfer = as->next_transfer;
remaining = as->next_remaining_bytes;
}
as->current_transfer = xfer;
as->current_remaining_bytes = remaining;
if (remaining > 0)
len = remaining;
else if (!atmel_spi_xfer_is_last(msg, xfer)
&& atmel_spi_xfer_can_be_chained(xfer)) {
xfer = list_entry(xfer->transfer_list.next,
struct spi_transfer, transfer_list);
len = xfer->len;
} else
xfer = NULL;
as->next_transfer = xfer;
if (xfer) {
total = len;
atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
as->next_remaining_bytes = total - len;
spi_writel(as, RNPR, rx_dma);
spi_writel(as, TNPR, tx_dma);
if (msg->spi->bits_per_word > 8)
len >>= 1;
spi_writel(as, RNCR, len);
spi_writel(as, TNCR, len);
dev_dbg(&msg->spi->dev,
" next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
xfer->rx_buf, xfer->rx_dma);
} else {
spi_writel(as, RNCR, 0);
spi_writel(as, TNCR, 0);
}
/* REVISIT: We're waiting for ENDRX before we start the next
* transfer because we need to handle some difficult timing
* issues otherwise. If we wait for ENDTX in one transfer and
* then starts waiting for ENDRX in the next, it's difficult
* to tell the difference between the ENDRX interrupt we're
* actually waiting for and the ENDRX interrupt of the
* previous transfer.
*
* It should be doable, though. Just not now...
*/
spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
}
static void atmel_spi_next_message(struct spi_master *master)
{
struct atmel_spi *as = spi_master_get_devdata(master);
struct spi_message *msg;
struct spi_device *spi;
BUG_ON(as->current_transfer);
msg = list_entry(as->queue.next, struct spi_message, queue);
spi = msg->spi;
dev_dbg(master->dev.parent, "start message %p for %s\n",
msg, spi->dev.bus_id);
/* select chip if it's not still active */
if (as->stay) {
if (as->stay != spi) {
cs_deactivate(as, as->stay);
cs_activate(as, spi);
}
as->stay = NULL;
} else
cs_activate(as, spi);
atmel_spi_next_xfer(master, msg);
}
/*
* For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
* - The buffer is either valid for CPU access, else NULL
* - If the buffer is valid, so is its DMA addresss
*
* This driver manages the dma addresss unless message->is_dma_mapped.
*/
static int
atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
{
struct device *dev = &as->pdev->dev;
xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
if (xfer->tx_buf) {
xfer->tx_dma = dma_map_single(dev,
(void *) xfer->tx_buf, xfer->len,
DMA_TO_DEVICE);
if (dma_mapping_error(xfer->tx_dma))
return -ENOMEM;
}
if (xfer->rx_buf) {
xfer->rx_dma = dma_map_single(dev,
xfer->rx_buf, xfer->len,
DMA_FROM_DEVICE);
if (dma_mapping_error(xfer->rx_dma)) {
if (xfer->tx_buf)
dma_unmap_single(dev,
xfer->tx_dma, xfer->len,
DMA_TO_DEVICE);
return -ENOMEM;
}
}
return 0;
}
static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
struct spi_transfer *xfer)
{
if (xfer->tx_dma != INVALID_DMA_ADDRESS)
dma_unmap_single(master->dev.parent, xfer->tx_dma,
xfer->len, DMA_TO_DEVICE);
if (xfer->rx_dma != INVALID_DMA_ADDRESS)
dma_unmap_single(master->dev.parent, xfer->rx_dma,
xfer->len, DMA_FROM_DEVICE);
}
static void
atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
struct spi_message *msg, int status, int stay)
{
if (!stay || status < 0)
cs_deactivate(as, msg->spi);
else
as->stay = msg->spi;
list_del(&msg->queue);
msg->status = status;
dev_dbg(master->dev.parent,
"xfer complete: %u bytes transferred\n",
msg->actual_length);
spin_unlock(&as->lock);
msg->complete(msg->context);
spin_lock(&as->lock);
as->current_transfer = NULL;
as->next_transfer = NULL;
/* continue if needed */
if (list_empty(&as->queue) || as->stopping)
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
else
atmel_spi_next_message(master);
}
static irqreturn_t
atmel_spi_interrupt(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct atmel_spi *as = spi_master_get_devdata(master);
struct spi_message *msg;
struct spi_transfer *xfer;
u32 status, pending, imr;
int ret = IRQ_NONE;
spin_lock(&as->lock);
xfer = as->current_transfer;
msg = list_entry(as->queue.next, struct spi_message, queue);
imr = spi_readl(as, IMR);
status = spi_readl(as, SR);
pending = status & imr;
if (pending & SPI_BIT(OVRES)) {
int timeout;
ret = IRQ_HANDLED;
spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
| SPI_BIT(OVRES)));
/*
* When we get an overrun, we disregard the current
* transfer. Data will not be copied back from any
* bounce buffer and msg->actual_len will not be
* updated with the last xfer.
*
* We will also not process any remaning transfers in
* the message.
*
* First, stop the transfer and unmap the DMA buffers.
*/
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
if (!msg->is_dma_mapped)
atmel_spi_dma_unmap_xfer(master, xfer);
/* REVISIT: udelay in irq is unfriendly */
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
dev_warn(master->dev.parent, "fifo overrun (%u/%u remaining)\n",
spi_readl(as, TCR), spi_readl(as, RCR));
/*
* Clean up DMA registers and make sure the data
* registers are empty.
*/
spi_writel(as, RNCR, 0);
spi_writel(as, TNCR, 0);
spi_writel(as, RCR, 0);
spi_writel(as, TCR, 0);
for (timeout = 1000; timeout; timeout--)
if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
break;
if (!timeout)
dev_warn(master->dev.parent,
"timeout waiting for TXEMPTY");
while (spi_readl(as, SR) & SPI_BIT(RDRF))
spi_readl(as, RDR);
/* Clear any overrun happening while cleaning up */
spi_readl(as, SR);
atmel_spi_msg_done(master, as, msg, -EIO, 0);
} else if (pending & SPI_BIT(ENDRX)) {
ret = IRQ_HANDLED;
spi_writel(as, IDR, pending);
if (as->current_remaining_bytes == 0) {
msg->actual_length += xfer->len;
if (!msg->is_dma_mapped)
atmel_spi_dma_unmap_xfer(master, xfer);
/* REVISIT: udelay in irq is unfriendly */
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
if (atmel_spi_xfer_is_last(msg, xfer)) {
/* report completed message */
atmel_spi_msg_done(master, as, msg, 0,
xfer->cs_change);
} else {
if (xfer->cs_change) {
cs_deactivate(as, msg->spi);
udelay(1);
cs_activate(as, msg->spi);
}
/*
* Not done yet. Submit the next transfer.
*
* FIXME handle protocol options for xfer
*/
atmel_spi_next_xfer(master, msg);
}
} else {
/*
* Keep going, we still have data to send in
* the current transfer.
*/
atmel_spi_next_xfer(master, msg);
}
}
spin_unlock(&as->lock);
return ret;
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
static int atmel_spi_setup(struct spi_device *spi)
{
struct atmel_spi *as;
u32 scbr, csr;
unsigned int bits = spi->bits_per_word;
unsigned long bus_hz, sck_hz;
unsigned int npcs_pin;
int ret;
as = spi_master_get_devdata(spi->master);
if (as->stopping)
return -ESHUTDOWN;
if (spi->chip_select > spi->master->num_chipselect) {
dev_dbg(&spi->dev,
"setup: invalid chipselect %u (%u defined)\n",
spi->chip_select, spi->master->num_chipselect);
return -EINVAL;
}
if (bits == 0)
bits = 8;
if (bits < 8 || bits > 16) {
dev_dbg(&spi->dev,
"setup: invalid bits_per_word %u (8 to 16)\n",
bits);
return -EINVAL;
}
if (spi->mode & ~MODEBITS) {
dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return -EINVAL;
}
/* see notes above re chipselect */
if (cpu_is_at91rm9200()
&& spi->chip_select == 0
&& (spi->mode & SPI_CS_HIGH)) {
dev_dbg(&spi->dev, "setup: can't be active-high\n");
return -EINVAL;
}
/* speed zero convention is used by some upper layers */
bus_hz = clk_get_rate(as->clk);
if (spi->max_speed_hz) {
/* assume div32/fdiv/mbz == 0 */
if (!as->new_1)
bus_hz /= 2;
scbr = ((bus_hz + spi->max_speed_hz - 1)
/ spi->max_speed_hz);
if (scbr >= (1 << SPI_SCBR_SIZE)) {
dev_dbg(&spi->dev,
"setup: %d Hz too slow, scbr %u; min %ld Hz\n",
spi->max_speed_hz, scbr, bus_hz/255);
return -EINVAL;
}
} else
scbr = 0xff;
sck_hz = bus_hz / scbr;
csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
if (spi->mode & SPI_CPOL)
csr |= SPI_BIT(CPOL);
if (!(spi->mode & SPI_CPHA))
csr |= SPI_BIT(NCPHA);
/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
*
* DLYBCT would add delays between words, slowing down transfers.
* It could potentially be useful to cope with DMA bottlenecks, but
* in those cases it's probably best to just use a lower bitrate.
*/
csr |= SPI_BF(DLYBS, 0);
csr |= SPI_BF(DLYBCT, 0);
/* chipselect must have been muxed as GPIO (e.g. in board setup) */
npcs_pin = (unsigned int)spi->controller_data;
if (!spi->controller_state) {
ret = gpio_request(npcs_pin, spi->dev.bus_id);
if (ret)
return ret;
spi->controller_state = (void *)npcs_pin;
gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
} else {
unsigned long flags;
spin_lock_irqsave(&as->lock, flags);
if (as->stay == spi)
as->stay = NULL;
cs_deactivate(as, spi);
spin_unlock_irqrestore(&as->lock, flags);
}
dev_dbg(&spi->dev,
"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
sck_hz, bits, spi->mode, spi->chip_select, csr);
spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
return 0;
}
static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
{
struct atmel_spi *as;
struct spi_transfer *xfer;
unsigned long flags;
struct device *controller = spi->master->dev.parent;
as = spi_master_get_devdata(spi->master);
dev_dbg(controller, "new message %p submitted for %s\n",
msg, spi->dev.bus_id);
if (unlikely(list_empty(&msg->transfers)
|| !spi->max_speed_hz))
return -EINVAL;
if (as->stopping)
return -ESHUTDOWN;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (!(xfer->tx_buf || xfer->rx_buf)) {
dev_dbg(&spi->dev, "missing rx or tx buf\n");
return -EINVAL;
}
/* FIXME implement these protocol options!! */
if (xfer->bits_per_word || xfer->speed_hz) {
dev_dbg(&spi->dev, "no protocol options yet\n");
return -ENOPROTOOPT;
}
/*
* DMA map early, for performance (empties dcache ASAP) and
* better fault reporting. This is a DMA-only driver.
*
* NOTE that if dma_unmap_single() ever starts to do work on
* platforms supported by this driver, we would need to clean
* up mappings for previously-mapped transfers.
*/
if (!msg->is_dma_mapped) {
if (atmel_spi_dma_map_xfer(as, xfer) < 0)
return -ENOMEM;
}
}
#ifdef VERBOSE
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
dev_dbg(controller,
" xfer %p: len %u tx %p/%08x rx %p/%08x\n",
xfer, xfer->len,
xfer->tx_buf, xfer->tx_dma,
xfer->rx_buf, xfer->rx_dma);
}
#endif
msg->status = -EINPROGRESS;
msg->actual_length = 0;
spin_lock_irqsave(&as->lock, flags);
list_add_tail(&msg->queue, &as->queue);
if (!as->current_transfer)
atmel_spi_next_message(spi->master);
spin_unlock_irqrestore(&as->lock, flags);
return 0;
}
static void atmel_spi_cleanup(struct spi_device *spi)
{
struct atmel_spi *as = spi_master_get_devdata(spi->master);
unsigned gpio = (unsigned) spi->controller_data;
unsigned long flags;
if (!spi->controller_state)
return;
spin_lock_irqsave(&as->lock, flags);
if (as->stay == spi) {
as->stay = NULL;
cs_deactivate(as, spi);
}
spin_unlock_irqrestore(&as->lock, flags);
gpio_free(gpio);
}
/*-------------------------------------------------------------------------*/
static int __init atmel_spi_probe(struct platform_device *pdev)
{
struct resource *regs;
int irq;
struct clk *clk;
int ret;
struct spi_master *master;
struct atmel_spi *as;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs)
return -ENXIO;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
clk = clk_get(&pdev->dev, "spi_clk");
if (IS_ERR(clk))
return PTR_ERR(clk);
/* setup spi core then atmel-specific driver state */
ret = -ENOMEM;
master = spi_alloc_master(&pdev->dev, sizeof *as);
if (!master)
goto out_free;
master->bus_num = pdev->id;
master->num_chipselect = 4;
master->setup = atmel_spi_setup;
master->transfer = atmel_spi_transfer;
master->cleanup = atmel_spi_cleanup;
platform_set_drvdata(pdev, master);
as = spi_master_get_devdata(master);
/*
* Scratch buffer is used for throwaway rx and tx data.
* It's coherent to minimize dcache pollution.
*/
as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
&as->buffer_dma, GFP_KERNEL);
if (!as->buffer)
goto out_free;
spin_lock_init(&as->lock);
INIT_LIST_HEAD(&as->queue);
as->pdev = pdev;
as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
if (!as->regs)
goto out_free_buffer;
as->irq = irq;
as->clk = clk;
if (!cpu_is_at91rm9200())
as->new_1 = 1;
ret = request_irq(irq, atmel_spi_interrupt, 0,
pdev->dev.bus_id, master);
if (ret)
goto out_unmap_regs;
/* Initialize the hardware */
clk_enable(clk);
spi_writel(as, CR, SPI_BIT(SWRST));
spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
spi_writel(as, CR, SPI_BIT(SPIEN));
/* go! */
dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
(unsigned long)regs->start, irq);
ret = spi_register_master(master);
if (ret)
goto out_reset_hw;
return 0;
out_reset_hw:
spi_writel(as, CR, SPI_BIT(SWRST));
clk_disable(clk);
free_irq(irq, master);
out_unmap_regs:
iounmap(as->regs);
out_free_buffer:
dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
as->buffer_dma);
out_free:
clk_put(clk);
spi_master_put(master);
return ret;
}
static int __exit atmel_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct atmel_spi *as = spi_master_get_devdata(master);
struct spi_message *msg;
/* reset the hardware and block queue progress */
spin_lock_irq(&as->lock);
as->stopping = 1;
spi_writel(as, CR, SPI_BIT(SWRST));
spi_readl(as, SR);
spin_unlock_irq(&as->lock);
/* Terminate remaining queued transfers */
list_for_each_entry(msg, &as->queue, queue) {
/* REVISIT unmapping the dma is a NOP on ARM and AVR32
* but we shouldn't depend on that...
*/
msg->status = -ESHUTDOWN;
msg->complete(msg->context);
}
dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
as->buffer_dma);
clk_disable(as->clk);
clk_put(as->clk);
free_irq(as->irq, master);
iounmap(as->regs);
spi_unregister_master(master);
return 0;
}
#ifdef CONFIG_PM
static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct atmel_spi *as = spi_master_get_devdata(master);
clk_disable(as->clk);
return 0;
}
static int atmel_spi_resume(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct atmel_spi *as = spi_master_get_devdata(master);
clk_enable(as->clk);
return 0;
}
#else
#define atmel_spi_suspend NULL
#define atmel_spi_resume NULL
#endif
static struct platform_driver atmel_spi_driver = {
.driver = {
.name = "atmel_spi",
.owner = THIS_MODULE,
},
.suspend = atmel_spi_suspend,
.resume = atmel_spi_resume,
.remove = __exit_p(atmel_spi_remove),
};
static int __init atmel_spi_init(void)
{
return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
}
module_init(atmel_spi_init);
static void __exit atmel_spi_exit(void)
{
platform_driver_unregister(&atmel_spi_driver);
}
module_exit(atmel_spi_exit);
MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
MODULE_LICENSE("GPL");