/*
* I2C bus driver for the SH7760 I2C Interfaces.
*
* (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
*
* licensed under the terms outlined in the file COPYING.
*
*/
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <asm/clock.h>
#include <asm/i2c-sh7760.h>
#include <asm/io.h>
/* register offsets */
#define I2CSCR 0x0 /* slave ctrl */
#define I2CMCR 0x4 /* master ctrl */
#define I2CSSR 0x8 /* slave status */
#define I2CMSR 0xC /* master status */
#define I2CSIER 0x10 /* slave irq enable */
#define I2CMIER 0x14 /* master irq enable */
#define I2CCCR 0x18 /* clock dividers */
#define I2CSAR 0x1c /* slave address */
#define I2CMAR 0x20 /* master address */
#define I2CRXTX 0x24 /* data port */
#define I2CFCR 0x28 /* fifo control */
#define I2CFSR 0x2C /* fifo status */
#define I2CFIER 0x30 /* fifo irq enable */
#define I2CRFDR 0x34 /* rx fifo count */
#define I2CTFDR 0x38 /* tx fifo count */
#define REGSIZE 0x3C
#define MCR_MDBS 0x80 /* non-fifo mode switch */
#define MCR_FSCL 0x40 /* override SCL pin */
#define MCR_FSDA 0x20 /* override SDA pin */
#define MCR_OBPC 0x10 /* override pins */
#define MCR_MIE 0x08 /* master if enable */
#define MCR_TSBE 0x04
#define MCR_FSB 0x02 /* force stop bit */
#define MCR_ESG 0x01 /* en startbit gen. */
#define MSR_MNR 0x40 /* nack received */
#define MSR_MAL 0x20 /* arbitration lost */
#define MSR_MST 0x10 /* sent a stop */
#define MSR_MDE 0x08
#define MSR_MDT 0x04
#define MSR_MDR 0x02
#define MSR_MAT 0x01 /* slave addr xfer done */
#define MIE_MNRE 0x40 /* nack irq en */
#define MIE_MALE 0x20 /* arblos irq en */
#define MIE_MSTE 0x10 /* stop irq en */
#define MIE_MDEE 0x08
#define MIE_MDTE 0x04
#define MIE_MDRE 0x02
#define MIE_MATE 0x01 /* address sent irq en */
#define FCR_RFRST 0x02 /* reset rx fifo */
#define FCR_TFRST 0x01 /* reset tx fifo */
#define FSR_TEND 0x04 /* last byte sent */
#define FSR_RDF 0x02 /* rx fifo trigger */
#define FSR_TDFE 0x01 /* tx fifo empty */
#define FIER_TEIE 0x04 /* tx fifo empty irq en */
#define FIER_RXIE 0x02 /* rx fifo trig irq en */
#define FIER_TXIE 0x01 /* tx fifo trig irq en */
#define FIFO_SIZE 16
struct cami2c {
void __iomem *iobase;
struct i2c_adapter adap;
/* message processing */
struct i2c_msg *msg;
#define IDF_SEND 1
#define IDF_RECV 2
#define IDF_STOP 4
int flags;
#define IDS_DONE 1
#define IDS_ARBLOST 2
#define IDS_NACK 4
int status;
struct completion xfer_done;
int irq;
struct resource *ioarea;
};
static inline void OUT32(struct cami2c *cam, int reg, unsigned long val)
{
ctrl_outl(val, (unsigned long)cam->iobase + reg);
}
static inline unsigned long IN32(struct cami2c *cam, int reg)
{
return ctrl_inl((unsigned long)cam->iobase + reg);
}
static irqreturn_t sh7760_i2c_irq(int irq, void *ptr)
{
struct cami2c *id = ptr;
struct i2c_msg *msg = id->msg;
char *data = msg->buf;
unsigned long msr, fsr, fier, len;
msr = IN32(id, I2CMSR);
fsr = IN32(id, I2CFSR);
/* arbitration lost */
if (msr & MSR_MAL) {
OUT32(id, I2CMCR, 0);
OUT32(id, I2CSCR, 0);
OUT32(id, I2CSAR, 0);
id->status |= IDS_DONE | IDS_ARBLOST;
goto out;
}
if (msr & MSR_MNR) {
/* NACK handling is very screwed up. After receiving a
* NAK IRQ one has to wait a bit before writing to any
* registers, or the ctl will lock up. After that delay
* do a normal i2c stop. Then wait at least 1 ms before
* attempting another transfer or ctl will stop working
*/
udelay(100); /* wait or risk ctl hang */
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
OUT32(id, I2CFIER, 0);
OUT32(id, I2CMIER, MIE_MSTE);
OUT32(id, I2CSCR, 0);
OUT32(id, I2CSAR, 0);
id->status |= IDS_NACK;
msr &= ~MSR_MAT;
fsr = 0;
/* In some cases the MST bit is also set. */
}
/* i2c-stop was sent */
if (msr & MSR_MST) {
id->status |= IDS_DONE;
goto out;
}
/* i2c slave addr was sent; set to "normal" operation */
if (msr & MSR_MAT)
OUT32(id, I2CMCR, MCR_MIE);
fier = IN32(id, I2CFIER);
if (fsr & FSR_RDF) {
len = IN32(id, I2CRFDR);
if (msg->len <= len) {
if (id->flags & IDF_STOP) {
OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
OUT32(id, I2CFIER, 0);
/* manual says: wait >= 0.5 SCL times */
udelay(5);
/* next int should be MST */
} else {
id->status |= IDS_DONE;
/* keep the RDF bit: ctrl holds SCL low
* until the setup for the next i2c_msg
* clears this bit.
*/
fsr &= ~FSR_RDF;
}
}
while (msg->len && len) {
*data++ = IN32(id, I2CRXTX);
msg->len--;
len--;
}
if (msg->len) {
len = (msg->len >= FIFO_SIZE) ? FIFO_SIZE - 1
: msg->len - 1;
OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xf) << 4));
}
} else if (id->flags & IDF_SEND) {
if ((fsr & FSR_TEND) && (msg->len < 1)) {
if (id->flags & IDF_STOP) {
OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
} else {
id->status |= IDS_DONE;
/* keep the TEND bit: ctl holds SCL low
* until the setup for the next i2c_msg
* clears this bit.
*/
fsr &= ~FSR_TEND;
}
}
if (fsr & FSR_TDFE) {
while (msg->len && (IN32(id, I2CTFDR) < FIFO_SIZE)) {
OUT32(id, I2CRXTX, *data++);
msg->len--;
}
if (msg->len < 1) {
fier &= ~FIER_TXIE;
OUT32(id, I2CFIER, fier);
} else {
len = (msg->len >= FIFO_SIZE) ? 2 : 0;
OUT32(id, I2CFCR,
FCR_RFRST | ((len & 3) << 2));
}
}
}
out:
if (id->status & IDS_DONE) {
OUT32(id, I2CMIER, 0);
OUT32(id, I2CFIER, 0);
id->msg = NULL;
complete(&id->xfer_done);
}
/* clear status flags and ctrl resumes work */
OUT32(id, I2CMSR, ~msr);
OUT32(id, I2CFSR, ~fsr);
OUT32(id, I2CSSR, 0);
return IRQ_HANDLED;
}
/* prepare and start a master receive operation */
static void sh7760_i2c_mrecv(struct cami2c *id)
{
int len;
id->flags |= IDF_RECV;
/* set the slave addr reg; otherwise rcv wont work! */
OUT32(id, I2CSAR, 0xfe);
OUT32(id, I2CMAR, (id->msg->addr << 1) | 1);
/* adjust rx fifo trigger */
if (id->msg->len >= FIFO_SIZE)
len = FIFO_SIZE - 1; /* trigger at fifo full */
else
len = id->msg->len - 1; /* trigger before all received */
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xF) << 4));
OUT32(id, I2CMSR, 0);
OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
OUT32(id, I2CFIER, FIER_RXIE);
}
/* prepare and start a master send operation */
static void sh7760_i2c_msend(struct cami2c *id)
{
int len;
id->flags |= IDF_SEND;
/* set the slave addr reg; otherwise xmit wont work! */
OUT32(id, I2CSAR, 0xfe);
OUT32(id, I2CMAR, (id->msg->addr << 1) | 0);
/* adjust tx fifo trigger */
if (id->msg->len >= FIFO_SIZE)
len = 2; /* trig: 2 bytes left in TX fifo */
else
len = 0; /* trig: 8 bytes left in TX fifo */
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CFCR, FCR_RFRST | ((len & 3) << 2));
while (id->msg->len && IN32(id, I2CTFDR) < FIFO_SIZE) {
OUT32(id, I2CRXTX, *(id->msg->buf));
(id->msg->len)--;
(id->msg->buf)++;
}
OUT32(id, I2CMSR, 0);
OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
OUT32(id, I2CFSR, 0);
OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
OUT32(id, I2CFIER, FIER_TEIE | (id->msg->len ? FIER_TXIE : 0));
}
static inline int sh7760_i2c_busy_check(struct cami2c *id)
{
return (IN32(id, I2CMCR) & MCR_FSDA);
}
static int sh7760_i2c_master_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs,
int num)
{
struct cami2c *id = adap->algo_data;
int i, retr;
if (sh7760_i2c_busy_check(id)) {
dev_err(&adap->dev, "sh7760-i2c%d: bus busy!\n", adap->nr);
return -EBUSY;
}
i = 0;
while (i < num) {
retr = adap->retries;
retry:
id->flags = ((i == (num-1)) ? IDF_STOP : 0);
id->status = 0;
id->msg = msgs;
init_completion(&id->xfer_done);
if (msgs->flags & I2C_M_RD)
sh7760_i2c_mrecv(id);
else
sh7760_i2c_msend(id);
wait_for_completion(&id->xfer_done);
if (id->status == 0) {
num = -EIO;
break;
}
if (id->status & IDS_NACK) {
/* wait a bit or i2c module stops working */
mdelay(1);
num = -EREMOTEIO;
break;
}
if (id->status & IDS_ARBLOST) {
if (retr--) {
mdelay(2);
goto retry;
}
num = -EREMOTEIO;
break;
}
msgs++;
i++;
}
id->msg = NULL;
id->flags = 0;
id->status = 0;
OUT32(id, I2CMCR, 0);
OUT32(id, I2CMSR, 0);
OUT32(id, I2CMIER, 0);
OUT32(id, I2CFIER, 0);
/* reset slave module registers too: master mode enables slave
* module for receive ops (ack, data). Without this reset,
* eternal bus activity might be reported after NACK / ARBLOST.
*/
OUT32(id, I2CSCR, 0);
OUT32(id, I2CSAR, 0);
OUT32(id, I2CSSR, 0);
return num;
}
static u32 sh7760_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
static const struct i2c_algorithm sh7760_i2c_algo = {
.master_xfer = sh7760_i2c_master_xfer,
.functionality = sh7760_i2c_func,
};
/* calculate CCR register setting for a desired scl clock. SCL clock is
* derived from I2C module clock (iclk) which in turn is derived from
* peripheral module clock (mclk, usually around 33MHz):
* iclk = mclk/(CDF + 1). iclk must be < 20MHz.
* scl = iclk/(SCGD*8 + 20).
*/
static int __devinit calc_CCR(unsigned long scl_hz)
{
struct clk *mclk;
unsigned long mck, m1, dff, odff, iclk;
signed char cdf, cdfm;
int scgd, scgdm, scgds;
mclk = clk_get(NULL, "module_clk");
if (IS_ERR(mclk)) {
return PTR_ERR(mclk);
} else {
mck = mclk->rate;
clk_put(mclk);
}
odff = scl_hz;
scgdm = cdfm = m1 = 0;
for (cdf = 3; cdf >= 0; cdf--) {
iclk = mck / (1 + cdf);
if (iclk >= 20000000)
continue;
scgds = ((iclk / scl_hz) - 20) >> 3;
for (scgd = scgds; (scgd < 63) && scgd <= scgds + 1; scgd++) {
m1 = iclk / (20 + (scgd << 3));
dff = abs(scl_hz - m1);
if (dff < odff) {
odff = dff;
cdfm = cdf;
scgdm = scgd;
}
}
}
/* fail if more than 25% off of requested SCL */
if (odff > (scl_hz >> 2))
return -EINVAL;
/* create a CCR register value */
return ((scgdm << 2) | cdfm);
}
static int __devinit sh7760_i2c_probe(struct platform_device *pdev)
{
struct sh7760_i2c_platdata *pd;
struct resource *res;
struct cami2c *id;
int ret;
pd = pdev->dev.platform_data;
if (!pd) {
dev_err(&pdev->dev, "no platform_data!\n");
ret = -ENODEV;
goto out0;
}
id = kzalloc(sizeof(struct cami2c), GFP_KERNEL);
if (!id) {
dev_err(&pdev->dev, "no mem for private data\n");
ret = -ENOMEM;
goto out0;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "no mmio resources\n");
ret = -ENODEV;
goto out1;
}
id->ioarea = request_mem_region(res->start, REGSIZE, pdev->name);
if (!id->ioarea) {
dev_err(&pdev->dev, "mmio already reserved\n");
ret = -EBUSY;
goto out1;
}
id->iobase = ioremap(res->start, REGSIZE);
if (!id->iobase) {
dev_err(&pdev->dev, "cannot ioremap\n");
ret = -ENODEV;
goto out2;
}
id->irq = platform_get_irq(pdev, 0);
id->adap.nr = pdev->id;
id->adap.algo = &sh7760_i2c_algo;
id->adap.class = I2C_CLASS_ALL;
id->adap.retries = 3;
id->adap.algo_data = id;
id->adap.dev.parent = &pdev->dev;
snprintf(id->adap.name, sizeof(id->adap.name),
"SH7760 I2C at %08lx", (unsigned long)res->start);
OUT32(id, I2CMCR, 0);
OUT32(id, I2CMSR, 0);
OUT32(id, I2CMIER, 0);
OUT32(id, I2CMAR, 0);
OUT32(id, I2CSIER, 0);
OUT32(id, I2CSAR, 0);
OUT32(id, I2CSCR, 0);
OUT32(id, I2CSSR, 0);
OUT32(id, I2CFIER, 0);
OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
OUT32(id, I2CFSR, 0);
ret = calc_CCR(pd->speed_khz * 1000);
if (ret < 0) {
dev_err(&pdev->dev, "invalid SCL clock: %dkHz\n",
pd->speed_khz);
goto out3;
}
OUT32(id, I2CCCR, ret);
if (request_irq(id->irq, sh7760_i2c_irq, IRQF_DISABLED,
SH7760_I2C_DEVNAME, id)) {
dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
ret = -EBUSY;
goto out3;
}
ret = i2c_add_numbered_adapter(&id->adap);
if (ret < 0) {
dev_err(&pdev->dev, "reg adap failed: %d\n", ret);
goto out4;
}
platform_set_drvdata(pdev, id);
dev_info(&pdev->dev, "%d kHz mmio %08x irq %d\n",
pd->speed_khz, res->start, id->irq);
return 0;
out4:
free_irq(id->irq, id);
out3:
iounmap(id->iobase);
out2:
release_resource(id->ioarea);
kfree(id->ioarea);
out1:
kfree(id);
out0:
return ret;
}
static int __devexit sh7760_i2c_remove(struct platform_device *pdev)
{
struct cami2c *id = platform_get_drvdata(pdev);
i2c_del_adapter(&id->adap);
free_irq(id->irq, id);
iounmap(id->iobase);
release_resource(id->ioarea);
kfree(id->ioarea);
kfree(id);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver sh7760_i2c_drv = {
.driver = {
.name = SH7760_I2C_DEVNAME,
.owner = THIS_MODULE,
},
.probe = sh7760_i2c_probe,
.remove = __devexit_p(sh7760_i2c_remove),
};
static int __init sh7760_i2c_init(void)
{
return platform_driver_register(&sh7760_i2c_drv);
}
static void __exit sh7760_i2c_exit(void)
{
platform_driver_unregister(&sh7760_i2c_drv);
}
module_init(sh7760_i2c_init);
module_exit(sh7760_i2c_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SH7760 I2C bus driver");
MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");
