/*
* SuperH MSIOF SPI Master Interface
*
* Copyright (c) 2009 Magnus Damm
*
* 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/delay.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/completion.h>
#include <linux/pm_runtime.h>
#include <linux/gpio.h>
#include <linux/bitmap.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/sh_msiof.h>
#include <asm/spi.h>
#include <asm/unaligned.h>
struct sh_msiof_spi_priv {
struct spi_bitbang bitbang; /* must be first for spi_bitbang.c */
void __iomem *mapbase;
struct clk *clk;
struct platform_device *pdev;
struct sh_msiof_spi_info *info;
struct completion done;
unsigned long flags;
int tx_fifo_size;
int rx_fifo_size;
};
#define TMDR1 0x00
#define TMDR2 0x04
#define TMDR3 0x08
#define RMDR1 0x10
#define RMDR2 0x14
#define RMDR3 0x18
#define TSCR 0x20
#define RSCR 0x22
#define CTR 0x28
#define FCTR 0x30
#define STR 0x40
#define IER 0x44
#define TDR1 0x48
#define TDR2 0x4c
#define TFDR 0x50
#define RDR1 0x58
#define RDR2 0x5c
#define RFDR 0x60
#define CTR_TSCKE (1 << 15)
#define CTR_TFSE (1 << 14)
#define CTR_TXE (1 << 9)
#define CTR_RXE (1 << 8)
#define STR_TEOF (1 << 23)
#define STR_REOF (1 << 7)
static unsigned long sh_msiof_read(struct sh_msiof_spi_priv *p, int reg_offs)
{
switch (reg_offs) {
case TSCR:
case RSCR:
return ioread16(p->mapbase + reg_offs);
default:
return ioread32(p->mapbase + reg_offs);
}
}
static void sh_msiof_write(struct sh_msiof_spi_priv *p, int reg_offs,
unsigned long value)
{
switch (reg_offs) {
case TSCR:
case RSCR:
iowrite16(value, p->mapbase + reg_offs);
break;
default:
iowrite32(value, p->mapbase + reg_offs);
break;
}
}
static int sh_msiof_modify_ctr_wait(struct sh_msiof_spi_priv *p,
unsigned long clr, unsigned long set)
{
unsigned long mask = clr | set;
unsigned long data;
int k;
data = sh_msiof_read(p, CTR);
data &= ~clr;
data |= set;
sh_msiof_write(p, CTR, data);
for (k = 100; k > 0; k--) {
if ((sh_msiof_read(p, CTR) & mask) == set)
break;
udelay(10);
}
return k > 0 ? 0 : -ETIMEDOUT;
}
static irqreturn_t sh_msiof_spi_irq(int irq, void *data)
{
struct sh_msiof_spi_priv *p = data;
/* just disable the interrupt and wake up */
sh_msiof_write(p, IER, 0);
complete(&p->done);
return IRQ_HANDLED;
}
static struct {
unsigned short div;
unsigned short scr;
} const sh_msiof_spi_clk_table[] = {
{ 1, 0x0007 },
{ 2, 0x0000 },
{ 4, 0x0001 },
{ 8, 0x0002 },
{ 16, 0x0003 },
{ 32, 0x0004 },
{ 64, 0x1f00 },
{ 128, 0x1f01 },
{ 256, 0x1f02 },
{ 512, 0x1f03 },
{ 1024, 0x1f04 },
};
static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p,
unsigned long parent_rate,
unsigned long spi_hz)
{
unsigned long div = 1024;
size_t k;
if (!WARN_ON(!spi_hz || !parent_rate))
div = parent_rate / spi_hz;
/* TODO: make more fine grained */
for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_clk_table); k++) {
if (sh_msiof_spi_clk_table[k].div >= div)
break;
}
k = min_t(int, k, ARRAY_SIZE(sh_msiof_spi_clk_table) - 1);
sh_msiof_write(p, TSCR, sh_msiof_spi_clk_table[k].scr);
sh_msiof_write(p, RSCR, sh_msiof_spi_clk_table[k].scr);
}
static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
int cpol, int cpha,
int tx_hi_z, int lsb_first)
{
unsigned long tmp;
int edge;
/*
* CPOL CPHA TSCKIZ RSCKIZ TEDG REDG
* 0 0 10 10 1 1
* 0 1 10 10 0 0
* 1 0 11 11 0 0
* 1 1 11 11 1 1
*/
sh_msiof_write(p, FCTR, 0);
sh_msiof_write(p, TMDR1, 0xe2000005 | (lsb_first << 24));
sh_msiof_write(p, RMDR1, 0x22000005 | (lsb_first << 24));
tmp = 0xa0000000;
tmp |= cpol << 30; /* TSCKIZ */
tmp |= cpol << 28; /* RSCKIZ */
edge = cpol ? cpha : !cpha;
tmp |= edge << 27; /* TEDG */
tmp |= edge << 26; /* REDG */
tmp |= (tx_hi_z ? 2 : 0) << 22; /* TXDIZ */
sh_msiof_write(p, CTR, tmp);
}
static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
const void *tx_buf, void *rx_buf,
int bits, int words)
{
unsigned long dr2;
dr2 = ((bits - 1) << 24) | ((words - 1) << 16);
if (tx_buf)
sh_msiof_write(p, TMDR2, dr2);
else
sh_msiof_write(p, TMDR2, dr2 | 1);
if (rx_buf)
sh_msiof_write(p, RMDR2, dr2);
sh_msiof_write(p, IER, STR_TEOF | STR_REOF);
}
static void sh_msiof_reset_str(struct sh_msiof_spi_priv *p)
{
sh_msiof_write(p, STR, sh_msiof_read(p, STR));
}
static void sh_msiof_spi_write_fifo_8(struct sh_msiof_spi_priv *p,
const void *tx_buf, int words, int fs)
{
const unsigned char *buf_8 = tx_buf;
int k;
for (k = 0; k < words; k++)
sh_msiof_write(p, TFDR, buf_8[k] << fs);
}
static void sh_msiof_spi_write_fifo_16(struct sh_msiof_spi_priv *p,
const void *tx_buf, int words, int fs)
{
const unsigned short *buf_16 = tx_buf;
int k;
for (k = 0; k < words; k++)
sh_msiof_write(p, TFDR, buf_16[k] << fs);
}
static void sh_msiof_spi_write_fifo_16u(struct sh_msiof_spi_priv *p,
const void *tx_buf, int words, int fs)
{
const unsigned short *buf_16 = tx_buf;
int k;
for (k = 0; k < words; k++)
sh_msiof_write(p, TFDR, get_unaligned(&buf_16[k]) << fs);
}
static void sh_msiof_spi_write_fifo_32(struct sh_msiof_spi_priv *p,
const void *tx_buf, int words, int fs)
{
const unsigned int *buf_32 = tx_buf;
int k;
for (k = 0; k < words; k++)
sh_msiof_write(p, TFDR, buf_32[k] << fs);
}
static void sh_msiof_spi_write_fifo_32u(struct sh_msiof_spi_priv *p,
const void *tx_buf, int words, int fs)
{
const unsigned int *buf_32 = tx_buf;
int k;
for (k = 0; k < words; k++)
sh_msiof_write(p, TFDR, get_unaligned(&buf_32[k]) << fs);
}
static void sh_msiof_spi_read_fifo_8(struct sh_msiof_spi_priv *p,
void *rx_buf, int words, int fs)
{
unsigned char *buf_8 = rx_buf;
int k;
for (k = 0; k < words; k++)
buf_8[k] = sh_msiof_read(p, RFDR) >> fs;
}
static void sh_msiof_spi_read_fifo_16(struct sh_msiof_spi_priv *p,
void *rx_buf, int words, int fs)
{
unsigned short *buf_16 = rx_buf;
int k;
for (k = 0; k < words; k++)
buf_16[k] = sh_msiof_read(p, RFDR) >> fs;
}
static void sh_msiof_spi_read_fifo_16u(struct sh_msiof_spi_priv *p,
void *rx_buf, int words, int fs)
{
unsigned short *buf_16 = rx_buf;
int k;
for (k = 0; k < words; k++)
put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_16[k]);
}
static void sh_msiof_spi_read_fifo_32(struct sh_msiof_spi_priv *p,
void *rx_buf, int words, int fs)
{
unsigned int *buf_32 = rx_buf;
int k;
for (k = 0; k < words; k++)
buf_32[k] = sh_msiof_read(p, RFDR) >> fs;
}
static void sh_msiof_spi_read_fifo_32u(struct sh_msiof_spi_priv *p,
void *rx_buf, int words, int fs)
{
unsigned int *buf_32 = rx_buf;
int k;
for (k = 0; k < words; k++)
put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_32[k]);
}
static int sh_msiof_spi_bits(struct spi_device *spi, struct spi_transfer *t)
{
int bits;
bits = t ? t->bits_per_word : 0;
bits = bits ? bits : spi->bits_per_word;
return bits;
}
static unsigned long sh_msiof_spi_hz(struct spi_device *spi,
struct spi_transfer *t)
{
unsigned long hz;
hz = t ? t->speed_hz : 0;
hz = hz ? hz : spi->max_speed_hz;
return hz;
}
static int sh_msiof_spi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
int bits;
/* noting to check hz values against since parent clock is disabled */
bits = sh_msiof_spi_bits(spi, t);
if (bits < 8)
return -EINVAL;
if (bits > 32)
return -EINVAL;
return spi_bitbang_setup_transfer(spi, t);
}
static void sh_msiof_spi_chipselect(struct spi_device *spi, int is_on)
{
struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
int value;
/* chip select is active low unless SPI_CS_HIGH is set */
if (spi->mode & SPI_CS_HIGH)
value = (is_on == BITBANG_CS_ACTIVE) ? 1 : 0;
else
value = (is_on == BITBANG_CS_ACTIVE) ? 0 : 1;
if (is_on == BITBANG_CS_ACTIVE) {
if (!test_and_set_bit(0, &p->flags)) {
pm_runtime_get_sync(&p->pdev->dev);
clk_enable(p->clk);
}
/* Configure pins before asserting CS */
sh_msiof_spi_set_pin_regs(p, !!(spi->mode & SPI_CPOL),
!!(spi->mode & SPI_CPHA),
!!(spi->mode & SPI_3WIRE),
!!(spi->mode & SPI_LSB_FIRST));
}
/* use spi->controller data for CS (same strategy as spi_gpio) */
gpio_set_value((unsigned)spi->controller_data, value);
if (is_on == BITBANG_CS_INACTIVE) {
if (test_and_clear_bit(0, &p->flags)) {
clk_disable(p->clk);
pm_runtime_put(&p->pdev->dev);
}
}
}
static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
void (*tx_fifo)(struct sh_msiof_spi_priv *,
const void *, int, int),
void (*rx_fifo)(struct sh_msiof_spi_priv *,
void *, int, int),
const void *tx_buf, void *rx_buf,
int words, int bits)
{
int fifo_shift;
int ret;
/* limit maximum word transfer to rx/tx fifo size */
if (tx_buf)
words = min_t(int, words, p->tx_fifo_size);
if (rx_buf)
words = min_t(int, words, p->rx_fifo_size);
/* the fifo contents need shifting */
fifo_shift = 32 - bits;
/* setup msiof transfer mode registers */
sh_msiof_spi_set_mode_regs(p, tx_buf, rx_buf, bits, words);
/* write tx fifo */
if (tx_buf)
tx_fifo(p, tx_buf, words, fifo_shift);
/* setup clock and rx/tx signals */
ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
if (rx_buf)
ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_RXE);
ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TXE);
/* start by setting frame bit */
INIT_COMPLETION(p->done);
ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TFSE);
if (ret) {
dev_err(&p->pdev->dev, "failed to start hardware\n");
goto err;
}
/* wait for tx fifo to be emptied / rx fifo to be filled */
wait_for_completion(&p->done);
/* read rx fifo */
if (rx_buf)
rx_fifo(p, rx_buf, words, fifo_shift);
/* clear status bits */
sh_msiof_reset_str(p);
/* shut down frame, tx/tx and clock signals */
ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TXE, 0);
if (rx_buf)
ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_RXE, 0);
ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TSCKE, 0);
if (ret) {
dev_err(&p->pdev->dev, "failed to shut down hardware\n");
goto err;
}
return words;
err:
sh_msiof_write(p, IER, 0);
return ret;
}
static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
{
struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
void (*tx_fifo)(struct sh_msiof_spi_priv *, const void *, int, int);
void (*rx_fifo)(struct sh_msiof_spi_priv *, void *, int, int);
int bits;
int bytes_per_word;
int bytes_done;
int words;
int n;
bits = sh_msiof_spi_bits(spi, t);
/* setup bytes per word and fifo read/write functions */
if (bits <= 8) {
bytes_per_word = 1;
tx_fifo = sh_msiof_spi_write_fifo_8;
rx_fifo = sh_msiof_spi_read_fifo_8;
} else if (bits <= 16) {
bytes_per_word = 2;
if ((unsigned long)t->tx_buf & 0x01)
tx_fifo = sh_msiof_spi_write_fifo_16u;
else
tx_fifo = sh_msiof_spi_write_fifo_16;
if ((unsigned long)t->rx_buf & 0x01)
rx_fifo = sh_msiof_spi_read_fifo_16u;
else
rx_fifo = sh_msiof_spi_read_fifo_16;
} else {
bytes_per_word = 4;
if ((unsigned long)t->tx_buf & 0x03)
tx_fifo = sh_msiof_spi_write_fifo_32u;
else
tx_fifo = sh_msiof_spi_write_fifo_32;
if ((unsigned long)t->rx_buf & 0x03)
rx_fifo = sh_msiof_spi_read_fifo_32u;
else
rx_fifo = sh_msiof_spi_read_fifo_32;
}
/* setup clocks (clock already enabled in chipselect()) */
sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk),
sh_msiof_spi_hz(spi, t));
/* transfer in fifo sized chunks */
words = t->len / bytes_per_word;
bytes_done = 0;
while (bytes_done < t->len) {
n = sh_msiof_spi_txrx_once(p, tx_fifo, rx_fifo,
t->tx_buf + bytes_done,
t->rx_buf + bytes_done,
words, bits);
if (n < 0)
break;
bytes_done += n * bytes_per_word;
words -= n;
}
return bytes_done;
}
static u32 sh_msiof_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
u32 word, u8 bits)
{
BUG(); /* unused but needed by bitbang code */
return 0;
}
static int sh_msiof_spi_probe(struct platform_device *pdev)
{
struct resource *r;
struct spi_master *master;
struct sh_msiof_spi_priv *p;
char clk_name[16];
int i;
int ret;
master = spi_alloc_master(&pdev->dev, sizeof(struct sh_msiof_spi_priv));
if (master == NULL) {
dev_err(&pdev->dev, "failed to allocate spi master\n");
ret = -ENOMEM;
goto err0;
}
p = spi_master_get_devdata(master);
platform_set_drvdata(pdev, p);
p->info = pdev->dev.platform_data;
init_completion(&p->done);
snprintf(clk_name, sizeof(clk_name), "msiof%d", pdev->id);
p->clk = clk_get(&pdev->dev, clk_name);
if (IS_ERR(p->clk)) {
dev_err(&pdev->dev, "cannot get clock \"%s\"\n", clk_name);
ret = PTR_ERR(p->clk);
goto err1;
}
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
i = platform_get_irq(pdev, 0);
if (!r || i < 0) {
dev_err(&pdev->dev, "cannot get platform resources\n");
ret = -ENOENT;
goto err2;
}
p->mapbase = ioremap_nocache(r->start, resource_size(r));
if (!p->mapbase) {
dev_err(&pdev->dev, "unable to ioremap\n");
ret = -ENXIO;
goto err2;
}
ret = request_irq(i, sh_msiof_spi_irq, IRQF_DISABLED,
dev_name(&pdev->dev), p);
if (ret) {
dev_err(&pdev->dev, "unable to request irq\n");
goto err3;
}
p->pdev = pdev;
pm_runtime_enable(&pdev->dev);
/* The standard version of MSIOF use 64 word FIFOs */
p->tx_fifo_size = 64;
p->rx_fifo_size = 64;
/* Platform data may override FIFO sizes */
if (p->info->tx_fifo_override)
p->tx_fifo_size = p->info->tx_fifo_override;
if (p->info->rx_fifo_override)
p->rx_fifo_size = p->info->rx_fifo_override;
/* init master and bitbang code */
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->mode_bits |= SPI_LSB_FIRST | SPI_3WIRE;
master->flags = 0;
master->bus_num = pdev->id;
master->num_chipselect = p->info->num_chipselect;
master->setup = spi_bitbang_setup;
master->cleanup = spi_bitbang_cleanup;
p->bitbang.master = master;
p->bitbang.chipselect = sh_msiof_spi_chipselect;
p->bitbang.setup_transfer = sh_msiof_spi_setup_transfer;
p->bitbang.txrx_bufs = sh_msiof_spi_txrx;
p->bitbang.txrx_word[SPI_MODE_0] = sh_msiof_spi_txrx_word;
p->bitbang.txrx_word[SPI_MODE_1] = sh_msiof_spi_txrx_word;
p->bitbang.txrx_word[SPI_MODE_2] = sh_msiof_spi_txrx_word;
p->bitbang.txrx_word[SPI_MODE_3] = sh_msiof_spi_txrx_word;
ret = spi_bitbang_start(&p->bitbang);
if (ret == 0)
return 0;
pm_runtime_disable(&pdev->dev);
err3:
iounmap(p->mapbase);
err2:
clk_put(p->clk);
err1:
spi_master_put(master);
err0:
return ret;
}
static int sh_msiof_spi_remove(struct platform_device *pdev)
{
struct sh_msiof_spi_priv *p = platform_get_drvdata(pdev);
int ret;
ret = spi_bitbang_stop(&p->bitbang);
if (!ret) {
pm_runtime_disable(&pdev->dev);
free_irq(platform_get_irq(pdev, 0), sh_msiof_spi_irq);
iounmap(p->mapbase);
clk_put(p->clk);
spi_master_put(p->bitbang.master);
}
return ret;
}
static int sh_msiof_spi_runtime_nop(struct device *dev)
{
/* Runtime PM callback shared between ->runtime_suspend()
* and ->runtime_resume(). Simply returns success.
*
* This driver re-initializes all registers after
* pm_runtime_get_sync() anyway so there is no need
* to save and restore registers here.
*/
return 0;
}
static struct dev_pm_ops sh_msiof_spi_dev_pm_ops = {
.runtime_suspend = sh_msiof_spi_runtime_nop,
.runtime_resume = sh_msiof_spi_runtime_nop,
};
static struct platform_driver sh_msiof_spi_drv = {
.probe = sh_msiof_spi_probe,
.remove = sh_msiof_spi_remove,
.driver = {
.name = "spi_sh_msiof",
.owner = THIS_MODULE,
.pm = &sh_msiof_spi_dev_pm_ops,
},
};
static int __init sh_msiof_spi_init(void)
{
return platform_driver_register(&sh_msiof_spi_drv);
}
module_init(sh_msiof_spi_init);
static void __exit sh_msiof_spi_exit(void)
{
platform_driver_unregister(&sh_msiof_spi_drv);
}
module_exit(sh_msiof_spi_exit);
MODULE_DESCRIPTION("SuperH MSIOF SPI Master Interface Driver");
MODULE_AUTHOR("Magnus Damm");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:spi_sh_msiof");
