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openwrt-xburst/target/linux/brcm63xx/files/drivers/spi/bcm63xx_spi.c

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/*
* Broadcom BCM63xx SPI controller support
*
* Copyright (C) 2009 Florian Fainelli <florian@openwrt.org>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
*/
#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/interrupt.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/gpio.h>
#include <linux/completion.h>
#include <linux/err.h>
#include <bcm63xx_io.h>
#include <bcm63xx_regs.h>
#include <bcm63xx_dev_spi.h>
#define PFX KBUILD_MODNAME
#define DRV_VER "0.1.2"
struct bcm63xx_spi {
/* bitbang has to be first */
struct spi_bitbang bitbang;
struct completion done;
void __iomem *regs;
int irq;
/* Platform data */
u32 speed_hz;
unsigned fifo_size;
/* Data buffers */
const unsigned char *tx_ptr;
unsigned char *rx_ptr;
int remaining_bytes;
struct clk *clk;
struct resource *ioarea;
struct platform_device *pdev;
};
static void bcm63xx_spi_chipselect(struct spi_device *spi, int is_on)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
u16 val;
val = bcm_spi_readw(bs->regs, SPI_CMD);
if (is_on == BITBANG_CS_INACTIVE)
val |= SPI_CMD_NOOP;
else if (is_on == BITBANG_CS_ACTIVE)
val |= (1 << spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
bcm_spi_writew(val, bs->regs, SPI_CMD);
}
static int bcm63xx_spi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
u8 bits_per_word;
u8 clk_cfg;
u32 hz;
unsigned int div;
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
hz = (t) ? t->speed_hz : spi->max_speed_hz;
if (bits_per_word != 8) {
dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
__func__, bits_per_word);
return -EINVAL;
}
if (spi->chip_select > spi->master->num_chipselect) {
dev_err(&spi->dev, "%s, unsupported slave %d\n",
__func__, spi->chip_select);
return -EINVAL;
}
/* Check clock setting */
div = (bs->speed_hz / hz);
switch (div) {
case 2:
clk_cfg = SPI_CLK_25MHZ;
break;
case 4:
clk_cfg = SPI_CLK_12_50MHZ;
break;
case 8:
clk_cfg = SPI_CLK_6_250MHZ;
break;
case 16:
clk_cfg = SPI_CLK_3_125MHZ;
break;
case 32:
clk_cfg = SPI_CLK_1_563MHZ;
break;
case 128:
clk_cfg = SPI_CLK_0_781MHZ;
break;
case 64:
default:
/* Set to slowest mode for compatibility */
clk_cfg = SPI_CLK_0_781MHZ;
break;
}
bcm_spi_writeb(clk_cfg, bs->regs, SPI_CLK_CFG);
dev_dbg(&spi->dev, "Setting clock register to %d (hz %d, cmd %02x)\n",
div, hz, clk_cfg);
return 0;
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA)
static int bcm63xx_spi_setup(struct spi_device *spi)
{
struct spi_bitbang *bitbang;
struct bcm63xx_spi *bs;
int retval;
bs = spi_master_get_devdata(spi->master);
bitbang = &bs->bitbang;
if (!spi->bits_per_word)
spi->bits_per_word = 8;
if (spi->mode & ~MODEBITS) {
dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
__func__, spi->mode & ~MODEBITS);
return -EINVAL;
}
retval = bcm63xx_spi_setup_transfer(spi, NULL);
if (retval < 0) {
dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
spi->mode & ~MODEBITS);
return retval;
}
dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
__func__, spi->mode & MODEBITS, spi->bits_per_word, 0);
return 0;
}
/* Fill the TX FIFO with as many bytes as possible */
static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
{
u8 tail;
/* Fill the Tx FIFO with as many bytes as possible */
tail = bcm_spi_readb(bs->regs, SPI_MSG_TAIL);
while ((tail < bs->fifo_size) && (bs->remaining_bytes > 0)) {
if (bs->tx_ptr)
bcm_spi_writeb(*bs->tx_ptr++, bs->regs, SPI_MSG_DATA);
else
bcm_spi_writeb(0, bs->regs, SPI_MSG_DATA);
bs->remaining_bytes--;
tail = bcm_spi_readb(bs->regs, SPI_MSG_TAIL);
}
}
static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
u8 msg_ctl;
u16 cmd;
dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
t->tx_buf, t->rx_buf, t->len);
/* Transmitter is inhibited */
bs->tx_ptr = t->tx_buf;
bs->rx_ptr = t->rx_buf;
bs->remaining_bytes = t->len;
init_completion(&bs->done);
bcm63xx_spi_fill_tx_fifo(bs);
/* Enable the command done interrupt which
* we use to determine completion of a command */
bcm_spi_writeb(SPI_INTR_CMD_DONE, bs->regs, SPI_INT_MASK);
/* Fill in the Message control register */
msg_ctl = bcm_spi_readb(bs->regs, SPI_MSG_CTL);
msg_ctl |= (t->len << SPI_BYTE_CNT_SHIFT);
msg_ctl |= (SPI_FD_RW << SPI_MSG_TYPE_SHIFT);
bcm_spi_writeb(msg_ctl, bs->regs, SPI_MSG_CTL);
/* Issue the transfer */
cmd = bcm_spi_readb(bs->regs, SPI_CMD);
cmd |= SPI_CMD_START_IMMEDIATE;
cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
bcm_spi_writeb(cmd, bs->regs, SPI_CMD);
wait_for_completion(&bs->done);
/* Disable the CMD_DONE interrupt */
bcm_spi_writeb(~(SPI_INTR_CMD_DONE), bs->regs, SPI_INT_MASK);
return t->len - bs->remaining_bytes;
}
/* 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;
u16 cmd;
/* Read interupts and clear them immediately */
intr = bcm_spi_readb(bs->regs, SPI_INT_STATUS);
bcm_spi_writeb(SPI_INTR_CLEAR_ALL, bs->regs, SPI_INT_STATUS);
/* A tansfer completed */
if (intr & SPI_INTR_CMD_DONE) {
u8 rx_empty;
rx_empty = bcm_spi_readb(bs->regs, SPI_ST);
/* Read out all the data */
while ((rx_empty & SPI_RX_EMPTY) == 0) {
u8 data;
data = bcm_spi_readb(bs->regs, SPI_RX_DATA);
if (bs->rx_ptr)
*bs->rx_ptr++ = data;
rx_empty = bcm_spi_readb(bs->regs, SPI_RX_EMPTY);
}
/* See if there is more data to send */
if (bs->remaining_bytes > 0) {
bcm63xx_spi_fill_tx_fifo(bs);
/* Start the transfer */
cmd = bcm_spi_readb(bs->regs, SPI_CMD);
cmd |= SPI_CMD_START_IMMEDIATE;
cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
bcm_spi_writeb(cmd, bs->regs, SPI_CMD);
} else
complete(&bs->done);
}
return IRQ_HANDLED;
}
static int __init bcm63xx_spi_probe(struct platform_device *pdev)
{
struct resource *r;
struct bcm63xx_spi_pdata *pdata = pdev->dev.platform_data;
int irq;
struct spi_master *master;
struct clk *clk;
struct bcm63xx_spi *bs;
int ret;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
ret = -ENXIO;
goto out;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
ret = -ENXIO;
goto out;
}
clk = clk_get(&pdev->dev, "spi");
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "No clock for device\n");
ret = -ENODEV;
goto out;
}
master = spi_alloc_master(&pdev->dev, sizeof(struct bcm63xx_spi));
if (!master) {
ret = -ENOMEM;
goto out_free;
}
bs = spi_master_get_devdata(master);
bs->bitbang.master = spi_master_get(master);
bs->bitbang.chipselect = bcm63xx_spi_chipselect;
bs->bitbang.setup_transfer = bcm63xx_spi_setup_transfer;
bs->bitbang.txrx_bufs = bcm63xx_txrx_bufs;
bs->bitbang.master->setup = bcm63xx_spi_setup;
init_completion(&bs->done);
platform_set_drvdata(pdev, master);
bs->pdev = pdev;
if (!request_mem_region(r->start,
r->end - r->start, PFX)) {
ret = -ENXIO;
goto out_free;
}
bs->regs = ioremap_nocache(r->start, r->end - r->start);
if (!bs->regs) {
printk(KERN_ERR PFX " unable to ioremap regs\n");
ret = -ENOMEM;
goto out_free;
}
bs->irq = irq;
bs->clk = clk;
bs->fifo_size = pdata->fifo_size;
ret = request_irq(irq, bcm63xx_spi_interrupt, 0,
pdev->dev.bus_id, master);
if (ret) {
printk(KERN_ERR PFX " unable to request irq\n");
goto out_unmap;
}
master->bus_num = pdata->bus_num;
master->num_chipselect = pdata->num_chipselect;
bs->speed_hz = pdata->speed_hz;
/* Initialize hardware */
clk_enable(bs->clk);
bcm_spi_writew(SPI_CMD_HARD_RESET, bs->regs, SPI_CMD);
bcm_spi_writeb(SPI_INTR_CLEAR_ALL, bs->regs, SPI_INT_MASK);
dev_info(&pdev->dev, " at 0x%08x (irq %d, FIFOs size %d) v%s\n",
r->start, irq, bs->fifo_size, DRV_VER);
ret = spi_bitbang_start(&bs->bitbang);
if (ret) {
dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
goto out_reset_hw;
}
return ret;
out_reset_hw:
clk_disable(clk);
free_irq(irq, master);
out_unmap:
iounmap(bs->regs);
out_free:
clk_put(clk);
spi_master_put(master);
out:
return ret;
}
static int __exit bcm63xx_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
spi_bitbang_stop(&bs->bitbang);
clk_disable(bs->clk);
clk_put(bs->clk);
free_irq(bs->irq, master);
iounmap(bs->regs);
platform_set_drvdata(pdev, 0);
spi_master_put(bs->bitbang.master);
return 0;
}
#ifdef CONFIG_PM
static int bcm63xx_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
clk_disable(bs->clk);
return 0;
}
static int bcm63xx_spi_resume(struct platform_device *pdev)
{
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
struct bcm63xx_spi *bs = spi_master_get_devdata(master);
clk_enable(bs->clk);
return 0;
}
#else
#define bcm63xx_spi_suspend NULL
#define bcm63xx_spi_resume NULL
#endif
static struct platform_driver bcm63xx_spi_driver = {
.driver = {
.name = "bcm63xx-spi",
.owner = THIS_MODULE,
},
.probe = bcm63xx_spi_probe,
.remove = bcm63xx_spi_remove,
.suspend = bcm63xx_spi_suspend,
.resume = bcm63xx_spi_resume,
};
static int __init bcm63xx_spi_init(void)
{
return platform_driver_register(&bcm63xx_spi_driver);
}
static void __exit bcm63xx_spi_exit(void)
{
platform_driver_unregister(&bcm63xx_spi_driver);
}
module_init(bcm63xx_spi_init);
module_exit(bcm63xx_spi_exit);
MODULE_ALIAS("platform:bcm63xx_spi");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VER);