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linux/drivers/spi/spi-rspi.c

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/*
* SH RSPI driver
*
* Copyright (C) 2012 Renesas Solutions Corp.
*
* Based on spi-sh.c:
* Copyright (C) 2011 Renesas Solutions Corp.
*
* 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; version 2 of the License.
*
* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/spi/spi.h>
#define RSPI_SPCR 0x00
#define RSPI_SSLP 0x01
#define RSPI_SPPCR 0x02
#define RSPI_SPSR 0x03
#define RSPI_SPDR 0x04
#define RSPI_SPSCR 0x08
#define RSPI_SPSSR 0x09
#define RSPI_SPBR 0x0a
#define RSPI_SPDCR 0x0b
#define RSPI_SPCKD 0x0c
#define RSPI_SSLND 0x0d
#define RSPI_SPND 0x0e
#define RSPI_SPCR2 0x0f
#define RSPI_SPCMD0 0x10
#define RSPI_SPCMD1 0x12
#define RSPI_SPCMD2 0x14
#define RSPI_SPCMD3 0x16
#define RSPI_SPCMD4 0x18
#define RSPI_SPCMD5 0x1a
#define RSPI_SPCMD6 0x1c
#define RSPI_SPCMD7 0x1e
/* SPCR */
#define SPCR_SPRIE 0x80
#define SPCR_SPE 0x40
#define SPCR_SPTIE 0x20
#define SPCR_SPEIE 0x10
#define SPCR_MSTR 0x08
#define SPCR_MODFEN 0x04
#define SPCR_TXMD 0x02
#define SPCR_SPMS 0x01
/* SSLP */
#define SSLP_SSL1P 0x02
#define SSLP_SSL0P 0x01
/* SPPCR */
#define SPPCR_MOIFE 0x20
#define SPPCR_MOIFV 0x10
#define SPPCR_SPOM 0x04
#define SPPCR_SPLP2 0x02
#define SPPCR_SPLP 0x01
/* SPSR */
#define SPSR_SPRF 0x80
#define SPSR_SPTEF 0x20
#define SPSR_PERF 0x08
#define SPSR_MODF 0x04
#define SPSR_IDLNF 0x02
#define SPSR_OVRF 0x01
/* SPSCR */
#define SPSCR_SPSLN_MASK 0x07
/* SPSSR */
#define SPSSR_SPECM_MASK 0x70
#define SPSSR_SPCP_MASK 0x07
/* SPDCR */
#define SPDCR_SPLW 0x20
#define SPDCR_SPRDTD 0x10
#define SPDCR_SLSEL1 0x08
#define SPDCR_SLSEL0 0x04
#define SPDCR_SLSEL_MASK 0x0c
#define SPDCR_SPFC1 0x02
#define SPDCR_SPFC0 0x01
/* SPCKD */
#define SPCKD_SCKDL_MASK 0x07
/* SSLND */
#define SSLND_SLNDL_MASK 0x07
/* SPND */
#define SPND_SPNDL_MASK 0x07
/* SPCR2 */
#define SPCR2_PTE 0x08
#define SPCR2_SPIE 0x04
#define SPCR2_SPOE 0x02
#define SPCR2_SPPE 0x01
/* SPCMDn */
#define SPCMD_SCKDEN 0x8000
#define SPCMD_SLNDEN 0x4000
#define SPCMD_SPNDEN 0x2000
#define SPCMD_LSBF 0x1000
#define SPCMD_SPB_MASK 0x0f00
#define SPCMD_SPB_8_TO_16(bit) (((bit - 1) << 8) & SPCMD_SPB_MASK)
#define SPCMD_SPB_20BIT 0x0000
#define SPCMD_SPB_24BIT 0x0100
#define SPCMD_SPB_32BIT 0x0200
#define SPCMD_SSLKP 0x0080
#define SPCMD_SSLA_MASK 0x0030
#define SPCMD_BRDV_MASK 0x000c
#define SPCMD_CPOL 0x0002
#define SPCMD_CPHA 0x0001
struct rspi_data {
void __iomem *addr;
u32 max_speed_hz;
struct spi_master *master;
struct list_head queue;
struct work_struct ws;
wait_queue_head_t wait;
spinlock_t lock;
struct clk *clk;
unsigned char spsr;
};
static void rspi_write8(struct rspi_data *rspi, u8 data, u16 offset)
{
iowrite8(data, rspi->addr + offset);
}
static void rspi_write16(struct rspi_data *rspi, u16 data, u16 offset)
{
iowrite16(data, rspi->addr + offset);
}
static u8 rspi_read8(struct rspi_data *rspi, u16 offset)
{
return ioread8(rspi->addr + offset);
}
static u16 rspi_read16(struct rspi_data *rspi, u16 offset)
{
return ioread16(rspi->addr + offset);
}
static unsigned char rspi_calc_spbr(struct rspi_data *rspi)
{
int tmp;
unsigned char spbr;
tmp = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz) - 1;
spbr = clamp(tmp, 0, 255);
return spbr;
}
static void rspi_enable_irq(struct rspi_data *rspi, u8 enable)
{
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | enable, RSPI_SPCR);
}
static void rspi_disable_irq(struct rspi_data *rspi, u8 disable)
{
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~disable, RSPI_SPCR);
}
static int rspi_wait_for_interrupt(struct rspi_data *rspi, u8 wait_mask,
u8 enable_bit)
{
int ret;
rspi->spsr = rspi_read8(rspi, RSPI_SPSR);
rspi_enable_irq(rspi, enable_bit);
ret = wait_event_timeout(rspi->wait, rspi->spsr & wait_mask, HZ);
if (ret == 0 && !(rspi->spsr & wait_mask))
return -ETIMEDOUT;
return 0;
}
static void rspi_assert_ssl(struct rspi_data *rspi)
{
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_SPE, RSPI_SPCR);
}
static void rspi_negate_ssl(struct rspi_data *rspi)
{
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_SPE, RSPI_SPCR);
}
static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
{
/* Sets output mode(CMOS) and MOSI signal(from previous transfer) */
rspi_write8(rspi, 0x00, RSPI_SPPCR);
/* Sets transfer bit rate */
rspi_write8(rspi, rspi_calc_spbr(rspi), RSPI_SPBR);
/* Sets number of frames to be used: 1 frame */
rspi_write8(rspi, 0x00, RSPI_SPDCR);
/* Sets RSPCK, SSL, next-access delay value */
rspi_write8(rspi, 0x00, RSPI_SPCKD);
rspi_write8(rspi, 0x00, RSPI_SSLND);
rspi_write8(rspi, 0x00, RSPI_SPND);
/* Sets parity, interrupt mask */
rspi_write8(rspi, 0x00, RSPI_SPCR2);
/* Sets SPCMD */
rspi_write16(rspi, SPCMD_SPB_8_TO_16(access_size) | SPCMD_SSLKP,
RSPI_SPCMD0);
/* Sets RSPI mode */
rspi_write8(rspi, SPCR_MSTR, RSPI_SPCR);
return 0;
}
static int rspi_send_pio(struct rspi_data *rspi, struct spi_message *mesg,
struct spi_transfer *t)
{
int remain = t->len;
u8 *data;
data = (u8 *)t->tx_buf;
while (remain > 0) {
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD,
RSPI_SPCR);
if (rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE) < 0) {
dev_err(&rspi->master->dev,
"%s: tx empty timeout\n", __func__);
return -ETIMEDOUT;
}
rspi_write16(rspi, *data, RSPI_SPDR);
data++;
remain--;
}
/* Waiting for the last transmition */
rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
return 0;
}
static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
struct spi_transfer *t)
{
int remain = t->len;
u8 *data;
unsigned char spsr;
spsr = rspi_read8(rspi, RSPI_SPSR);
if (spsr & SPSR_SPRF)
rspi_read16(rspi, RSPI_SPDR); /* dummy read */
if (spsr & SPSR_OVRF)
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,
RSPI_SPCR);
data = (u8 *)t->rx_buf;
while (remain > 0) {
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD,
RSPI_SPCR);
if (rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE) < 0) {
dev_err(&rspi->master->dev,
"%s: tx empty timeout\n", __func__);
return -ETIMEDOUT;
}
/* dummy write for generate clock */
rspi_write16(rspi, 0x00, RSPI_SPDR);
if (rspi_wait_for_interrupt(rspi, SPSR_SPRF, SPCR_SPRIE) < 0) {
dev_err(&rspi->master->dev,
"%s: receive timeout\n", __func__);
return -ETIMEDOUT;
}
/* SPDR allows 16 or 32-bit access only */
*data = (u8)rspi_read16(rspi, RSPI_SPDR);
data++;
remain--;
}
return 0;
}
static void rspi_work(struct work_struct *work)
{
struct rspi_data *rspi = container_of(work, struct rspi_data, ws);
struct spi_message *mesg;
struct spi_transfer *t;
unsigned long flags;
int ret;
spin_lock_irqsave(&rspi->lock, flags);
while (!list_empty(&rspi->queue)) {
mesg = list_entry(rspi->queue.next, struct spi_message, queue);
list_del_init(&mesg->queue);
spin_unlock_irqrestore(&rspi->lock, flags);
rspi_assert_ssl(rspi);
list_for_each_entry(t, &mesg->transfers, transfer_list) {
if (t->tx_buf) {
ret = rspi_send_pio(rspi, mesg, t);
if (ret < 0)
goto error;
}
if (t->rx_buf) {
ret = rspi_receive_pio(rspi, mesg, t);
if (ret < 0)
goto error;
}
mesg->actual_length += t->len;
}
rspi_negate_ssl(rspi);
mesg->status = 0;
mesg->complete(mesg->context);
spin_lock_irqsave(&rspi->lock, flags);
}
return;
error:
mesg->status = ret;
mesg->complete(mesg->context);
}
static int rspi_setup(struct spi_device *spi)
{
struct rspi_data *rspi = spi_master_get_devdata(spi->master);
if (!spi->bits_per_word)
spi->bits_per_word = 8;
rspi->max_speed_hz = spi->max_speed_hz;
rspi_set_config_register(rspi, 8);
return 0;
}
static int rspi_transfer(struct spi_device *spi, struct spi_message *mesg)
{
struct rspi_data *rspi = spi_master_get_devdata(spi->master);
unsigned long flags;
mesg->actual_length = 0;
mesg->status = -EINPROGRESS;
spin_lock_irqsave(&rspi->lock, flags);
list_add_tail(&mesg->queue, &rspi->queue);
schedule_work(&rspi->ws);
spin_unlock_irqrestore(&rspi->lock, flags);
return 0;
}
static void rspi_cleanup(struct spi_device *spi)
{
}
static irqreturn_t rspi_irq(int irq, void *_sr)
{
struct rspi_data *rspi = (struct rspi_data *)_sr;
unsigned long spsr;
irqreturn_t ret = IRQ_NONE;
unsigned char disable_irq = 0;
rspi->spsr = spsr = rspi_read8(rspi, RSPI_SPSR);
if (spsr & SPSR_SPRF)
disable_irq |= SPCR_SPRIE;
if (spsr & SPSR_SPTEF)
disable_irq |= SPCR_SPTIE;
if (disable_irq) {
ret = IRQ_HANDLED;
rspi_disable_irq(rspi, disable_irq);
wake_up(&rspi->wait);
}
return ret;
}
static int __devexit rspi_remove(struct platform_device *pdev)
{
struct rspi_data *rspi = dev_get_drvdata(&pdev->dev);
spi_unregister_master(rspi->master);
free_irq(platform_get_irq(pdev, 0), rspi);
clk_put(rspi->clk);
iounmap(rspi->addr);
spi_master_put(rspi->master);
return 0;
}
static int __devinit rspi_probe(struct platform_device *pdev)
{
struct resource *res;
struct spi_master *master;
struct rspi_data *rspi;
int ret, irq;
char clk_name[16];
/* get base addr */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (unlikely(res == NULL)) {
dev_err(&pdev->dev, "invalid resource\n");
return -EINVAL;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "platform_get_irq error\n");
return -ENODEV;
}
master = spi_alloc_master(&pdev->dev, sizeof(struct rspi_data));
if (master == NULL) {
dev_err(&pdev->dev, "spi_alloc_master error.\n");
return -ENOMEM;
}
rspi = spi_master_get_devdata(master);
dev_set_drvdata(&pdev->dev, rspi);
rspi->master = master;
rspi->addr = ioremap(res->start, resource_size(res));
if (rspi->addr == NULL) {
dev_err(&pdev->dev, "ioremap error.\n");
ret = -ENOMEM;
goto error1;
}
snprintf(clk_name, sizeof(clk_name), "rspi%d", pdev->id);
rspi->clk = clk_get(&pdev->dev, clk_name);
if (IS_ERR(rspi->clk)) {
dev_err(&pdev->dev, "cannot get clock\n");
ret = PTR_ERR(rspi->clk);
goto error2;
}
clk_enable(rspi->clk);
INIT_LIST_HEAD(&rspi->queue);
spin_lock_init(&rspi->lock);
INIT_WORK(&rspi->ws, rspi_work);
init_waitqueue_head(&rspi->wait);
master->num_chipselect = 2;
master->bus_num = pdev->id;
master->setup = rspi_setup;
master->transfer = rspi_transfer;
master->cleanup = rspi_cleanup;
ret = request_irq(irq, rspi_irq, 0, dev_name(&pdev->dev), rspi);
if (ret < 0) {
dev_err(&pdev->dev, "request_irq error\n");
goto error3;
}
ret = spi_register_master(master);
if (ret < 0) {
dev_err(&pdev->dev, "spi_register_master error.\n");
goto error4;
}
dev_info(&pdev->dev, "probed\n");
return 0;
error4:
free_irq(irq, rspi);
error3:
clk_put(rspi->clk);
error2:
iounmap(rspi->addr);
error1:
spi_master_put(master);
return ret;
}
static struct platform_driver rspi_driver = {
.probe = rspi_probe,
.remove = __devexit_p(rspi_remove),
.driver = {
.name = "rspi",
.owner = THIS_MODULE,
},
};
module_platform_driver(rspi_driver);
MODULE_DESCRIPTION("Renesas RSPI bus driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Yoshihiro Shimoda");
MODULE_ALIAS("platform:rspi");
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