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linux/drivers/i2c/busses/i2c-sh_mobile.c

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/*
* SuperH Mobile I2C Controller
*
* Copyright (C) 2008 Magnus Damm
*
* Portions of the code based on out-of-tree driver i2c-sh7343.c
* Copyright (c) 2006 Carlos Munoz <carlos@kenati.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
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/slab.h>
/* Transmit operation: */
/* */
/* 0 byte transmit */
/* BUS: S A8 ACK P */
/* IRQ: DTE WAIT */
/* ICIC: */
/* ICCR: 0x94 0x90 */
/* ICDR: A8 */
/* */
/* 1 byte transmit */
/* BUS: S A8 ACK D8(1) ACK P */
/* IRQ: DTE WAIT WAIT */
/* ICIC: -DTE */
/* ICCR: 0x94 0x90 */
/* ICDR: A8 D8(1) */
/* */
/* 2 byte transmit */
/* BUS: S A8 ACK D8(1) ACK D8(2) ACK P */
/* IRQ: DTE WAIT WAIT WAIT */
/* ICIC: -DTE */
/* ICCR: 0x94 0x90 */
/* ICDR: A8 D8(1) D8(2) */
/* */
/* 3 bytes or more, +---------+ gets repeated */
/* */
/* */
/* Receive operation: */
/* */
/* 0 byte receive - not supported since slave may hold SDA low */
/* */
/* 1 byte receive [TX] | [RX] */
/* BUS: S A8 ACK | D8(1) ACK P */
/* IRQ: DTE WAIT | WAIT DTE */
/* ICIC: -DTE | +DTE */
/* ICCR: 0x94 0x81 | 0xc0 */
/* ICDR: A8 | D8(1) */
/* */
/* 2 byte receive [TX]| [RX] */
/* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P */
/* IRQ: DTE WAIT | WAIT WAIT DTE */
/* ICIC: -DTE | +DTE */
/* ICCR: 0x94 0x81 | 0xc0 */
/* ICDR: A8 | D8(1) D8(2) */
/* */
/* 3 byte receive [TX] | [RX] */
/* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
/* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
/* ICIC: -DTE | +DTE */
/* ICCR: 0x94 0x81 | 0xc0 */
/* ICDR: A8 | D8(1) D8(2) D8(3) */
/* */
/* 4 bytes or more, this part is repeated +---------+ */
/* */
/* */
/* Interrupt order and BUSY flag */
/* ___ _ */
/* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
/* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
/* */
/* S D7 D6 D5 D4 D3 D2 D1 D0 P */
/* ___ */
/* WAIT IRQ ________________________________/ \___________ */
/* TACK IRQ ____________________________________/ \_______ */
/* DTE IRQ __________________________________________/ \_ */
/* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
/* _______________________________________________ */
/* BUSY __/ \_ */
/* */
enum sh_mobile_i2c_op {
OP_START = 0,
OP_TX_FIRST,
OP_TX,
OP_TX_STOP,
OP_TX_TO_RX,
OP_RX,
OP_RX_STOP,
OP_RX_STOP_DATA,
};
struct sh_mobile_i2c_data {
struct device *dev;
void __iomem *reg;
struct i2c_adapter adap;
struct clk *clk;
u_int8_t icic;
u_int8_t iccl;
u_int8_t icch;
u_int8_t flags;
spinlock_t lock;
wait_queue_head_t wait;
struct i2c_msg *msg;
int pos;
int sr;
};
#define IIC_FLAG_HAS_ICIC67 (1 << 0)
#define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */
/* Register offsets */
#define ICDR 0x00
#define ICCR 0x04
#define ICSR 0x08
#define ICIC 0x0c
#define ICCL 0x10
#define ICCH 0x14
/* Register bits */
#define ICCR_ICE 0x80
#define ICCR_RACK 0x40
#define ICCR_TRS 0x10
#define ICCR_BBSY 0x04
#define ICCR_SCP 0x01
#define ICSR_SCLM 0x80
#define ICSR_SDAM 0x40
#define SW_DONE 0x20
#define ICSR_BUSY 0x10
#define ICSR_AL 0x08
#define ICSR_TACK 0x04
#define ICSR_WAIT 0x02
#define ICSR_DTE 0x01
#define ICIC_ICCLB8 0x80
#define ICIC_ICCHB8 0x40
#define ICIC_ALE 0x08
#define ICIC_TACKE 0x04
#define ICIC_WAITE 0x02
#define ICIC_DTEE 0x01
static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
{
if (offs == ICIC)
data |= pd->icic;
iowrite8(data, pd->reg + offs);
}
static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
{
return ioread8(pd->reg + offs);
}
static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
unsigned char set, unsigned char clr)
{
iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
}
static void activate_ch(struct sh_mobile_i2c_data *pd)
{
unsigned long i2c_clk;
u_int32_t num;
u_int32_t denom;
u_int32_t tmp;
/* Wake up device and enable clock */
pm_runtime_get_sync(pd->dev);
clk_enable(pd->clk);
/* Get clock rate after clock is enabled */
i2c_clk = clk_get_rate(pd->clk);
/* Calculate the value for iccl. From the data sheet:
* iccl = (p clock / transfer rate) * (L / (L + H))
* where L and H are the SCL low/high ratio (5/4 in this case).
* We also round off the result.
*/
num = i2c_clk * 5;
denom = NORMAL_SPEED * 9;
tmp = num * 10 / denom;
if (tmp % 10 >= 5)
pd->iccl = (u_int8_t)((num/denom) + 1);
else
pd->iccl = (u_int8_t)(num/denom);
/* one more bit of ICCL in ICIC */
if (pd->flags & IIC_FLAG_HAS_ICIC67) {
if ((num/denom) > 0xff)
pd->icic |= ICIC_ICCLB8;
else
pd->icic &= ~ICIC_ICCLB8;
}
/* Calculate the value for icch. From the data sheet:
icch = (p clock / transfer rate) * (H / (L + H)) */
num = i2c_clk * 4;
tmp = num * 10 / denom;
if (tmp % 10 >= 5)
pd->icch = (u_int8_t)((num/denom) + 1);
else
pd->icch = (u_int8_t)(num/denom);
/* one more bit of ICCH in ICIC */
if (pd->flags & IIC_FLAG_HAS_ICIC67) {
if ((num/denom) > 0xff)
pd->icic |= ICIC_ICCHB8;
else
pd->icic &= ~ICIC_ICCHB8;
}
/* Enable channel and configure rx ack */
iic_set_clr(pd, ICCR, ICCR_ICE, 0);
/* Mask all interrupts */
iic_wr(pd, ICIC, 0);
/* Set the clock */
iic_wr(pd, ICCL, pd->iccl);
iic_wr(pd, ICCH, pd->icch);
}
static void deactivate_ch(struct sh_mobile_i2c_data *pd)
{
/* Clear/disable interrupts */
iic_wr(pd, ICSR, 0);
iic_wr(pd, ICIC, 0);
/* Disable channel */
iic_set_clr(pd, ICCR, 0, ICCR_ICE);
/* Disable clock and mark device as idle */
clk_disable(pd->clk);
pm_runtime_put_sync(pd->dev);
}
static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
enum sh_mobile_i2c_op op, unsigned char data)
{
unsigned char ret = 0;
unsigned long flags;
dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
spin_lock_irqsave(&pd->lock, flags);
switch (op) {
case OP_START: /* issue start and trigger DTE interrupt */
iic_wr(pd, ICCR, 0x94);
break;
case OP_TX_FIRST: /* disable DTE interrupt and write data */
iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
iic_wr(pd, ICDR, data);
break;
case OP_TX: /* write data */
iic_wr(pd, ICDR, data);
break;
case OP_TX_STOP: /* write data and issue a stop afterwards */
iic_wr(pd, ICDR, data);
iic_wr(pd, ICCR, 0x90);
break;
case OP_TX_TO_RX: /* select read mode */
iic_wr(pd, ICCR, 0x81);
break;
case OP_RX: /* just read data */
ret = iic_rd(pd, ICDR);
break;
case OP_RX_STOP: /* enable DTE interrupt, issue stop */
iic_wr(pd, ICIC,
ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
iic_wr(pd, ICCR, 0xc0);
break;
case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
iic_wr(pd, ICIC,
ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
ret = iic_rd(pd, ICDR);
iic_wr(pd, ICCR, 0xc0);
break;
}
spin_unlock_irqrestore(&pd->lock, flags);
dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
return ret;
}
static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
{
if (pd->pos == -1)
return 1;
return 0;
}
static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
{
if (pd->pos == (pd->msg->len - 1))
return 1;
return 0;
}
static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
unsigned char *buf)
{
switch (pd->pos) {
case -1:
*buf = (pd->msg->addr & 0x7f) << 1;
*buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
break;
default:
*buf = pd->msg->buf[pd->pos];
}
}
static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
{
unsigned char data;
if (pd->pos == pd->msg->len)
return 1;
sh_mobile_i2c_get_data(pd, &data);
if (sh_mobile_i2c_is_last_byte(pd))
i2c_op(pd, OP_TX_STOP, data);
else if (sh_mobile_i2c_is_first_byte(pd))
i2c_op(pd, OP_TX_FIRST, data);
else
i2c_op(pd, OP_TX, data);
pd->pos++;
return 0;
}
static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
{
unsigned char data;
int real_pos;
do {
if (pd->pos <= -1) {
sh_mobile_i2c_get_data(pd, &data);
if (sh_mobile_i2c_is_first_byte(pd))
i2c_op(pd, OP_TX_FIRST, data);
else
i2c_op(pd, OP_TX, data);
break;
}
if (pd->pos == 0) {
i2c_op(pd, OP_TX_TO_RX, 0);
break;
}
real_pos = pd->pos - 2;
if (pd->pos == pd->msg->len) {
if (real_pos < 0) {
i2c_op(pd, OP_RX_STOP, 0);
break;
}
data = i2c_op(pd, OP_RX_STOP_DATA, 0);
} else
data = i2c_op(pd, OP_RX, 0);
if (real_pos >= 0)
pd->msg->buf[real_pos] = data;
} while (0);
pd->pos++;
return pd->pos == (pd->msg->len + 2);
}
static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
{
struct platform_device *dev = dev_id;
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
unsigned char sr;
int wakeup;
sr = iic_rd(pd, ICSR);
pd->sr |= sr; /* remember state */
dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
(pd->msg->flags & I2C_M_RD) ? "read" : "write",
pd->pos, pd->msg->len);
if (sr & (ICSR_AL | ICSR_TACK)) {
/* don't interrupt transaction - continue to issue stop */
iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
wakeup = 0;
} else if (pd->msg->flags & I2C_M_RD)
wakeup = sh_mobile_i2c_isr_rx(pd);
else
wakeup = sh_mobile_i2c_isr_tx(pd);
if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
if (wakeup) {
pd->sr |= SW_DONE;
wake_up(&pd->wait);
}
return IRQ_HANDLED;
}
static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
{
if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
dev_err(pd->dev, "Unsupported zero length i2c read\n");
return -EIO;
}
/* Initialize channel registers */
iic_set_clr(pd, ICCR, 0, ICCR_ICE);
/* Enable channel and configure rx ack */
iic_set_clr(pd, ICCR, ICCR_ICE, 0);
/* Set the clock */
iic_wr(pd, ICCL, pd->iccl);
iic_wr(pd, ICCH, pd->icch);
pd->msg = usr_msg;
pd->pos = -1;
pd->sr = 0;
/* Enable all interrupts to begin with */
iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
return 0;
}
static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs,
int num)
{
struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
struct i2c_msg *msg;
int err = 0;
u_int8_t val;
int i, k, retry_count;
activate_ch(pd);
/* Process all messages */
for (i = 0; i < num; i++) {
msg = &msgs[i];
err = start_ch(pd, msg);
if (err)
break;
i2c_op(pd, OP_START, 0);
/* The interrupt handler takes care of the rest... */
k = wait_event_timeout(pd->wait,
pd->sr & (ICSR_TACK | SW_DONE),
5 * HZ);
if (!k)
dev_err(pd->dev, "Transfer request timed out\n");
retry_count = 1000;
again:
val = iic_rd(pd, ICSR);
dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
/* the interrupt handler may wake us up before the
* transfer is finished, so poll the hardware
* until we're done.
*/
if (val & ICSR_BUSY) {
udelay(10);
if (retry_count--)
goto again;
err = -EIO;
dev_err(pd->dev, "Polling timed out\n");
break;
}
/* handle missing acknowledge and arbitration lost */
if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
err = -EIO;
break;
}
}
deactivate_ch(pd);
if (!err)
err = num;
return err;
}
static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm sh_mobile_i2c_algorithm = {
.functionality = sh_mobile_i2c_func,
.master_xfer = sh_mobile_i2c_xfer,
};
static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
{
struct resource *res;
int ret = -ENXIO;
int n, k = 0;
while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
for (n = res->start; hook && n <= res->end; n++) {
if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
dev_name(&dev->dev), dev)) {
for (n--; n >= res->start; n--)
free_irq(n, dev);
goto rollback;
}
}
k++;
}
if (hook)
return k > 0 ? 0 : -ENOENT;
ret = 0;
rollback:
k--;
while (k >= 0) {
res = platform_get_resource(dev, IORESOURCE_IRQ, k);
for (n = res->start; n <= res->end; n++)
free_irq(n, dev);
k--;
}
return ret;
}
static int sh_mobile_i2c_probe(struct platform_device *dev)
{
struct sh_mobile_i2c_data *pd;
struct i2c_adapter *adap;
struct resource *res;
char clk_name[8];
int size;
int ret;
pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
if (pd == NULL) {
dev_err(&dev->dev, "cannot allocate private data\n");
return -ENOMEM;
}
snprintf(clk_name, sizeof(clk_name), "i2c%d", dev->id);
pd->clk = clk_get(&dev->dev, clk_name);
if (IS_ERR(pd->clk)) {
dev_err(&dev->dev, "cannot get clock \"%s\"\n", clk_name);
ret = PTR_ERR(pd->clk);
goto err;
}
ret = sh_mobile_i2c_hook_irqs(dev, 1);
if (ret) {
dev_err(&dev->dev, "cannot request IRQ\n");
goto err_clk;
}
pd->dev = &dev->dev;
platform_set_drvdata(dev, pd);
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&dev->dev, "cannot find IO resource\n");
ret = -ENOENT;
goto err_irq;
}
size = resource_size(res);
pd->reg = ioremap(res->start, size);
if (pd->reg == NULL) {
dev_err(&dev->dev, "cannot map IO\n");
ret = -ENXIO;
goto err_irq;
}
/* The IIC blocks on SH-Mobile ARM processors
* come with two new bits in ICIC.
*/
if (size > 0x17)
pd->flags |= IIC_FLAG_HAS_ICIC67;
/* Enable Runtime PM for this device.
*
* Also tell the Runtime PM core to ignore children
* for this device since it is valid for us to suspend
* this I2C master driver even though the slave devices
* on the I2C bus may not be suspended.
*
* The state of the I2C hardware bus is unaffected by
* the Runtime PM state.
*/
pm_suspend_ignore_children(&dev->dev, true);
pm_runtime_enable(&dev->dev);
/* setup the private data */
adap = &pd->adap;
i2c_set_adapdata(adap, pd);
adap->owner = THIS_MODULE;
adap->algo = &sh_mobile_i2c_algorithm;
adap->dev.parent = &dev->dev;
adap->retries = 5;
adap->nr = dev->id;
strlcpy(adap->name, dev->name, sizeof(adap->name));
spin_lock_init(&pd->lock);
init_waitqueue_head(&pd->wait);
ret = i2c_add_numbered_adapter(adap);
if (ret < 0) {
dev_err(&dev->dev, "cannot add numbered adapter\n");
goto err_all;
}
return 0;
err_all:
iounmap(pd->reg);
err_irq:
sh_mobile_i2c_hook_irqs(dev, 0);
err_clk:
clk_put(pd->clk);
err:
kfree(pd);
return ret;
}
static int sh_mobile_i2c_remove(struct platform_device *dev)
{
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
i2c_del_adapter(&pd->adap);
iounmap(pd->reg);
sh_mobile_i2c_hook_irqs(dev, 0);
clk_put(pd->clk);
pm_runtime_disable(&dev->dev);
kfree(pd);
return 0;
}
static int sh_mobile_i2c_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 const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
.runtime_suspend = sh_mobile_i2c_runtime_nop,
.runtime_resume = sh_mobile_i2c_runtime_nop,
};
static struct platform_driver sh_mobile_i2c_driver = {
.driver = {
.name = "i2c-sh_mobile",
.owner = THIS_MODULE,
.pm = &sh_mobile_i2c_dev_pm_ops,
},
.probe = sh_mobile_i2c_probe,
.remove = sh_mobile_i2c_remove,
};
static int __init sh_mobile_i2c_adap_init(void)
{
return platform_driver_register(&sh_mobile_i2c_driver);
}
static void __exit sh_mobile_i2c_adap_exit(void)
{
platform_driver_unregister(&sh_mobile_i2c_driver);
}
subsys_initcall(sh_mobile_i2c_adap_init);
module_exit(sh_mobile_i2c_adap_exit);
MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
MODULE_AUTHOR("Magnus Damm");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-sh_mobile");
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