- 根目录:
- drivers
- spi
- spi-bcm63xx.c
/*
* Broadcom BCM63xx SPI controller support
*
* Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
* Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/pm_runtime.h>
#include <bcm63xx_dev_spi.h>
#define BCM63XX_SPI_MAX_PREPEND 15
struct bcm63xx_spi {
struct completion done;
void __iomem *regs;
int irq;
/* Platform data */
unsigned fifo_size;
unsigned int msg_type_shift;
unsigned int msg_ctl_width;
/* data iomem */
u8 __iomem *tx_io;
const u8 __iomem *rx_io;
struct clk *clk;
struct platform_device *pdev;
};
static inline u8 bcm_spi_readb(struct bcm63xx_spi *bs,
unsigned int offset)
{
return bcm_readb(bs->regs + bcm63xx_spireg(offset));
}
static inline u16 bcm_spi_readw(struct bcm63xx_spi *bs,
unsigned int offset)
{
return bcm_readw(bs->regs + bcm63xx_spireg(offset));
}
static inline void bcm_spi_writeb(struct bcm63xx_spi *bs,
u8 value, unsigned int offset)
{
bcm_writeb(value, bs->regs + bcm63xx_spireg(offset));
}
static inline void bcm_spi_writew(struct bcm63xx_spi *bs,
u16 value, unsigned int offset)
{
bcm_writew(value, bs->regs + bcm63xx_spireg(offset));
}
static const unsigned bcm63xx_spi_freq_table[SPI_CLK_MASK][2] = {
{ 20000000, SPI_CLK_20MHZ },
{ 12500000, SPI_CLK_12_50MHZ },
{ 6250000, SPI_CLK_6_250MHZ },
{ 3125000, SPI_CLK_3_125MHZ },
{ 1563000, SPI_CLK_1_563MHZ },
{ 781000, SPI_CLK_0_781MHZ },
{ 391000, SPI_CLK_0_391MHZ }
};
static void bcm63xx_spi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
u8 clk_cfg, reg;
int i;
/* Find the closest clock configuration */
for (i = 0; i < SPI_CLK_MASK; i++) {
if (t->speed_hz >= bcm63xx_spi_freq_table[i][0]) {
clk_cfg = bcm63xx_spi_freq_table[i][1];
break;
}
}
/* No matching configuration found, default to lowest */
if (i == SPI_CLK_MASK)
clk_cfg = SPI_CLK_0_391MHZ;
/* clear existing clock configuration bits of the register */
reg = bcm_spi_readb(bs, SPI_CLK_CFG);
reg &= ~SPI_CLK_MASK;
reg |= clk_cfg;
bcm_spi_writeb(bs, reg, SPI_CLK_CFG);
dev_dbg(&spi->dev, "Setting clock register to %02x (hz %d)\n",
clk_cfg, t->speed_hz);
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA)
static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *first,
unsigned int num_transfers)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
u16 msg_ctl;
u16 cmd;
u8 rx_tail;
unsigned int i, timeout = 0, prepend_len = 0, len = 0;
struct spi_transfer *t = first;
bool do_rx = false;
bool do_tx = false;
/* Disable the CMD_DONE interrupt */
bcm_spi_writeb(bs, 0, SPI_INT_MASK);
dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
t->tx_buf, t->rx_buf, t->len);
if (num_transfers > 1 && t->tx_buf && t->len <= BCM63XX_SPI_MAX_PREPEND)
prepend_len = t->len;
/* prepare the buffer */
for (i = 0; i < num_transfers; i++) {
if (t->tx_buf) {
do_tx = true;
memcpy_toio(bs->tx_io + len, t->tx_buf, t->len);
/* don't prepend more than one tx */
if (t != first)
prepend_len = 0;
}
if (t->rx_buf) {
do_rx = true;
/* prepend is half-duplex write only */
if (t == first)
prepend_len = 0;
}
len += t->len;
t = list_entry(t->transfer_list.next, struct spi_transfer,
transfer_list);
}
reinit_completion(&bs->done);
/* Fill in the Message control register */
msg_ctl = (len << SPI_BYTE_CNT_SHIFT);
if (do_rx && do_tx && prepend_len == 0)
msg_ctl |= (SPI_FD_RW << bs->msg_type_shift);
else if (do_rx)
msg_ctl |= (SPI_HD_R << bs->msg_type_shift);
else if (do_tx)
msg_ctl |= (SPI_HD_W << bs->msg_type_shift);
switch (bs->msg_ctl_width) {
case 8:
bcm_spi_writeb(bs, msg_ctl, SPI_MSG_CTL);
break;
case 16:
bcm_spi_writew(bs, msg_ctl, SPI_MSG_CTL);
break;
}
/* Issue the transfer */
cmd = SPI_CMD_START_IMMEDIATE;
cmd |= (prepend_len << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
bcm_spi_writew(bs, cmd, SPI_CMD);
/* Enable the CMD_DONE interrupt */
bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
timeout = wait_for_completion_timeout(&bs->done, HZ);
if (!timeout)
return -ETIMEDOUT;
if (!do_rx)
return 0;
len = 0;
t = first;
/* Read out all the data */
for (i = 0; i < num_transfers; i++) {
if (t->rx_buf)
memcpy_fromio(t->rx_buf, bs->rx_io + len, t->len);
if (t != first || prepend_len == 0)
len += t->len;
t = list_entry(t->transfer_list.next, struct spi_transfer,
transfer_list);
}
return 0;
}
static int bcm63xx_spi_transfer_one(struct spi_master *master,
struct spi_message *m)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
struct spi_transfer *t, *first = NULL;
struct spi_device *spi = m->spi;
int status = 0;
unsigned int n_transfers = 0, total_len = 0;
bool can_use_prepend = false;
/*
* This SPI controller does not support keeping CS active after a
* transfer.
* Work around this by merging as many transfers we can into one big
* full-duplex transfers.
*/
list_for_each_entry(t, &m->transfers, transfer_list) {
if (!first)
first = t;
n_transfers++;
total_len += t->len;
if (n_transfers == 2 && !first->rx_buf && !t->tx_buf &&
first->len <= BCM63XX_SPI_MAX_PREPEND)
can_use_prepend = true;
else if (can_use_prepend && t->tx_buf)
can_use_prepend = false;
/* we can only transfer one fifo worth of data */
if ((can_use_prepend &&
total_len > (bs->fifo_size + BCM63XX_SPI_MAX_PREPEND)) ||
(!can_use_prepend && total_len > bs->fifo_size)) {
dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
total_len, bs->fifo_size);
status = -EINVAL;
goto exit;
}
/* all combined transfers have to have the same speed */
if (t->speed_hz != first->speed_hz) {
dev_err(&spi->dev, "unable to change speed between transfers\n");
status = -EINVAL;
goto exit;
}
/* CS will be deasserted directly after transfer */
if (t->delay_usecs) {
dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
status = -EINVAL;
goto exit;
}
if (t->cs_change ||
list_is_last(&t->transfer_list, &m->transfers)) {
/* configure adapter for a new transfer */
bcm63xx_spi_setup_transfer(spi, first);
/* send the data */
status = bcm63xx_txrx_bufs(spi, first, n_transfers);
if (status)
goto exit;
m->actual_length += total_len;
first = NULL;
n_transfers = 0;
total_len = 0;
can_use_prepend = false;
}
}
exit:
m->status = status;
spi_finalize_current_message(master);
return 0;
}
/* This driver supports single master mode only. Hence
* CMD_DONE is the only interrupt we care about
*/
static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
{
struct spi_master *master = (struct spi_master *)dev_id;
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
u8 intr;
/* Read interupts and clear them immediately */
intr = bcm_spi_readb(bs, SPI_INT_STATUS);
bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
bcm_spi_writeb(bs, 0, SPI_INT_MASK);
/* A transfer completed */
if (intr & SPI_INTR_CMD_DONE)
complete(&bs->done);
return IRQ_HANDLED;
}
static int bcm63xx_spi_probe(struct platform_device *pdev)
{
struct resource *r;
struct device *dev = &pdev->dev;
struct bcm63xx_spi_pdata *pdata = dev_get_platdata(&pdev->dev);
int irq;
struct spi_master *master;
struct clk *clk;
struct bcm63xx_spi *bs;
int ret;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(dev, "no irq\n");
return -ENXIO;
}
clk = devm_clk_get(dev, "spi");
if (IS_ERR(clk)) {
dev_err(dev, "no clock for device\n");
return PTR_ERR(clk);
}
master = spi_alloc_master(dev, sizeof(*bs));
if (!master) {
dev_err(dev, "out of memory\n");
return -ENOMEM;
}
bs = spi_master_get_devdata(master);
init_completion(&bs->done);
platform_set_drvdata(pdev, master);
bs->pdev = pdev;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
bs->regs = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(bs->regs)) {
ret = PTR_ERR(bs->regs);
goto out_err;
}
bs->irq = irq;
bs->clk = clk;
bs->fifo_size = pdata->fifo_size;
ret = devm_request_irq(&pdev->dev, irq, bcm63xx_spi_interrupt, 0,
pdev->name, master);
if (ret) {
dev_err(dev, "unable to request irq\n");
goto out_err;
}
master->bus_num = pdata->bus_num;
master->num_chipselect = pdata->num_chipselect;
master->transfer_one_message = bcm63xx_spi_transfer_one;
master->mode_bits = MODEBITS;
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->auto_runtime_pm = true;
bs->msg_type_shift = pdata->msg_type_shift;
bs->msg_ctl_width = pdata->msg_ctl_width;
bs->tx_io = (u8 *)(bs->regs + bcm63xx_spireg(SPI_MSG_DATA));
bs->rx_io = (const u8 *)(bs->regs + bcm63xx_spireg(SPI_RX_DATA));
switch (bs->msg_ctl_width) {
case 8:
case 16:
break;
default:
dev_err(dev, "unsupported MSG_CTL width: %d\n",
bs->msg_ctl_width);
goto out_err;
}
/* Initialize hardware */
ret = clk_prepare_enable(bs->clk);
if (ret)
goto out_err;
bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
/* register and we are done */
ret = devm_spi_register_master(dev, master);
if (ret) {
dev_err(dev, "spi register failed\n");
goto out_clk_disable;
}
dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d)\n",
r->start, irq, bs->fifo_size);
return 0;
out_clk_disable:
clk_disable_unprepare(clk);
out_err:
spi_master_put(master);
return ret;
}
static int bcm63xx_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
/* reset spi block */
bcm_spi_writeb(bs, 0, SPI_INT_MASK);
/* HW shutdown */
clk_disable_unprepare(bs->clk);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int bcm63xx_spi_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
spi_master_suspend(master);
clk_disable_unprepare(bs->clk);
return 0;
}
static int bcm63xx_spi_resume(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
int ret;
ret = clk_prepare_enable(bs->clk);
if (ret)
return ret;
spi_master_resume(master);
return 0;
}
#endif
static const struct dev_pm_ops bcm63xx_spi_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(bcm63xx_spi_suspend, bcm63xx_spi_resume)
};
static struct platform_driver bcm63xx_spi_driver = {
.driver = {
.name = "bcm63xx-spi",
.pm = &bcm63xx_spi_pm_ops,
},
.probe = bcm63xx_spi_probe,
.remove = bcm63xx_spi_remove,
};
module_platform_driver(bcm63xx_spi_driver);
MODULE_ALIAS("platform:bcm63xx_spi");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_AUTHOR("Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>");
MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
MODULE_LICENSE("GPL");