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kernel-ark/drivers/i2c/busses/i2c-ocores.c
Wolfram Sang 687b81d083 i2c: move OF helpers into the core 
I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
that it is much cleaner to have this in the core. This also removes a
circular dependency between the helpers and the core, and so we can
finally register child nodes in the core instead of doing this manually
in each driver. So, fix the drivers and documentation, too.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-08-23 10:22:20 +02:00

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/*
* i2c-ocores.c: I2C bus driver for OpenCores I2C controller
* (http://www.opencores.org/projects.cgi/web/i2c/overview).
*
* Peter Korsgaard <jacmet@sunsite.dk>
*
* Support for the GRLIB port of the controller by
* Andreas Larsson <andreas@gaisler.com>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/i2c-ocores.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/log2.h>
struct ocores_i2c {
void __iomem *base;
u32 reg_shift;
u32 reg_io_width;
wait_queue_head_t wait;
struct i2c_adapter adap;
struct i2c_msg *msg;
int pos;
int nmsgs;
int state; /* see STATE_ */
int clock_khz;
void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);
u8 (*getreg)(struct ocores_i2c *i2c, int reg);
};
/* registers */
#define OCI2C_PRELOW 0
#define OCI2C_PREHIGH 1
#define OCI2C_CONTROL 2
#define OCI2C_DATA 3
#define OCI2C_CMD 4 /* write only */
#define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */
#define OCI2C_CTRL_IEN 0x40
#define OCI2C_CTRL_EN 0x80
#define OCI2C_CMD_START 0x91
#define OCI2C_CMD_STOP 0x41
#define OCI2C_CMD_READ 0x21
#define OCI2C_CMD_WRITE 0x11
#define OCI2C_CMD_READ_ACK 0x21
#define OCI2C_CMD_READ_NACK 0x29
#define OCI2C_CMD_IACK 0x01
#define OCI2C_STAT_IF 0x01
#define OCI2C_STAT_TIP 0x02
#define OCI2C_STAT_ARBLOST 0x20
#define OCI2C_STAT_BUSY 0x40
#define OCI2C_STAT_NACK 0x80
#define STATE_DONE 0
#define STATE_START 1
#define STATE_WRITE 2
#define STATE_READ 3
#define STATE_ERROR 4
#define TYPE_OCORES 0
#define TYPE_GRLIB 1
static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
{
iowrite8(value, i2c->base + (reg << i2c->reg_shift));
}
static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value)
{
iowrite16(value, i2c->base + (reg << i2c->reg_shift));
}
static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value)
{
iowrite32(value, i2c->base + (reg << i2c->reg_shift));
}
static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg)
{
return ioread8(i2c->base + (reg << i2c->reg_shift));
}
static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg)
{
return ioread16(i2c->base + (reg << i2c->reg_shift));
}
static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg)
{
return ioread32(i2c->base + (reg << i2c->reg_shift));
}
static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
{
i2c->setreg(i2c, reg, value);
}
static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
{
return i2c->getreg(i2c, reg);
}
static void ocores_process(struct ocores_i2c *i2c)
{
struct i2c_msg *msg = i2c->msg;
u8 stat = oc_getreg(i2c, OCI2C_STATUS);
if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
/* stop has been sent */
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
wake_up(&i2c->wait);
return;
}
/* error? */
if (stat & OCI2C_STAT_ARBLOST) {
i2c->state = STATE_ERROR;
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
return;
}
if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
i2c->state =
(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
if (stat & OCI2C_STAT_NACK) {
i2c->state = STATE_ERROR;
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
return;
}
} else
msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
/* end of msg? */
if (i2c->pos == msg->len) {
i2c->nmsgs--;
i2c->msg++;
i2c->pos = 0;
msg = i2c->msg;
if (i2c->nmsgs) { /* end? */
/* send start? */
if (!(msg->flags & I2C_M_NOSTART)) {
u8 addr = (msg->addr << 1);
if (msg->flags & I2C_M_RD)
addr |= 1;
i2c->state = STATE_START;
oc_setreg(i2c, OCI2C_DATA, addr);
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
return;
} else
i2c->state = (msg->flags & I2C_M_RD)
? STATE_READ : STATE_WRITE;
} else {
i2c->state = STATE_DONE;
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
return;
}
}
if (i2c->state == STATE_READ) {
oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
} else {
oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
}
}
static irqreturn_t ocores_isr(int irq, void *dev_id)
{
struct ocores_i2c *i2c = dev_id;
ocores_process(i2c);
return IRQ_HANDLED;
}
static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct ocores_i2c *i2c = i2c_get_adapdata(adap);
i2c->msg = msgs;
i2c->pos = 0;
i2c->nmsgs = num;
i2c->state = STATE_START;
oc_setreg(i2c, OCI2C_DATA,
(i2c->msg->addr << 1) |
((i2c->msg->flags & I2C_M_RD) ? 1:0));
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
(i2c->state == STATE_DONE), HZ))
return (i2c->state == STATE_DONE) ? num : -EIO;
else
return -ETIMEDOUT;
}
static void ocores_init(struct ocores_i2c *i2c)
{
int prescale;
u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
/* make sure the device is disabled */
oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
prescale = (i2c->clock_khz / (5*100)) - 1;
oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
/* Init the device */
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
}
static u32 ocores_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm ocores_algorithm = {
.master_xfer = ocores_xfer,
.functionality = ocores_func,
};
static struct i2c_adapter ocores_adapter = {
.owner = THIS_MODULE,
.name = "i2c-ocores",
.class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
.algo = &ocores_algorithm,
};
static struct of_device_id ocores_i2c_match[] = {
{
.compatible = "opencores,i2c-ocores",
.data = (void *)TYPE_OCORES,
},
{
.compatible = "aeroflexgaisler,i2cmst",
.data = (void *)TYPE_GRLIB,
},
{},
};
MODULE_DEVICE_TABLE(of, ocores_i2c_match);
#ifdef CONFIG_OF
/* Read and write functions for the GRLIB port of the controller. Registers are
* 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
* register. The subsequent registers has their offset decreased accordingly. */
static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
{
u32 rd;
int rreg = reg;
if (reg != OCI2C_PRELOW)
rreg--;
rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
if (reg == OCI2C_PREHIGH)
return (u8)(rd >> 8);
else
return (u8)rd;
}
static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value)
{
u32 curr, wr;
int rreg = reg;
if (reg != OCI2C_PRELOW)
rreg--;
if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {
curr = ioread32be(i2c->base + (rreg << i2c->reg_shift));
if (reg == OCI2C_PRELOW)
wr = (curr & 0xff00) | value;
else
wr = (((u32)value) << 8) | (curr & 0xff);
} else {
wr = value;
}
iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift));
}
static int ocores_i2c_of_probe(struct platform_device *pdev,
struct ocores_i2c *i2c)
{
struct device_node *np = pdev->dev.of_node;
const struct of_device_id *match;
u32 val;
if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
/* no 'reg-shift', check for deprecated 'regstep' */
if (!of_property_read_u32(np, "regstep", &val)) {
if (!is_power_of_2(val)) {
dev_err(&pdev->dev, "invalid regstep %d\n",
val);
return -EINVAL;
}
i2c->reg_shift = ilog2(val);
dev_warn(&pdev->dev,
"regstep property deprecated, use reg-shift\n");
}
}
if (of_property_read_u32(np, "clock-frequency", &val)) {
dev_err(&pdev->dev,
"Missing required parameter 'clock-frequency'\n");
return -ENODEV;
}
i2c->clock_khz = val / 1000;
of_property_read_u32(pdev->dev.of_node, "reg-io-width",
&i2c->reg_io_width);
match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
if (match && (long)match->data == TYPE_GRLIB) {
dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n");
i2c->setreg = oc_setreg_grlib;
i2c->getreg = oc_getreg_grlib;
}
return 0;
}
#else
#define ocores_i2c_of_probe(pdev,i2c) -ENODEV
#endif
static int ocores_i2c_probe(struct platform_device *pdev)
{
struct ocores_i2c *i2c;
struct ocores_i2c_platform_data *pdata;
struct resource *res;
int irq;
int ret;
int i;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
i2c->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(i2c->base))
return PTR_ERR(i2c->base);
pdata = dev_get_platdata(&pdev->dev);
if (pdata) {
i2c->reg_shift = pdata->reg_shift;
i2c->reg_io_width = pdata->reg_io_width;
i2c->clock_khz = pdata->clock_khz;
} else {
ret = ocores_i2c_of_probe(pdev, i2c);
if (ret)
return ret;
}
if (i2c->reg_io_width == 0)
i2c->reg_io_width = 1; /* Set to default value */
if (!i2c->setreg || !i2c->getreg) {
switch (i2c->reg_io_width) {
case 1:
i2c->setreg = oc_setreg_8;
i2c->getreg = oc_getreg_8;
break;
case 2:
i2c->setreg = oc_setreg_16;
i2c->getreg = oc_getreg_16;
break;
case 4:
i2c->setreg = oc_setreg_32;
i2c->getreg = oc_getreg_32;
break;
default:
dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
i2c->reg_io_width);
return -EINVAL;
}
}
ocores_init(i2c);
init_waitqueue_head(&i2c->wait);
ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
pdev->name, i2c);
if (ret) {
dev_err(&pdev->dev, "Cannot claim IRQ\n");
return ret;
}
/* hook up driver to tree */
platform_set_drvdata(pdev, i2c);
i2c->adap = ocores_adapter;
i2c_set_adapdata(&i2c->adap, i2c);
i2c->adap.dev.parent = &pdev->dev;
i2c->adap.dev.of_node = pdev->dev.of_node;
/* add i2c adapter to i2c tree */
ret = i2c_add_adapter(&i2c->adap);
if (ret) {
dev_err(&pdev->dev, "Failed to add adapter\n");
return ret;
}
/* add in known devices to the bus */
if (pdata) {
for (i = 0; i < pdata->num_devices; i++)
i2c_new_device(&i2c->adap, pdata->devices + i);
}
return 0;
}
static int ocores_i2c_remove(struct platform_device *pdev)
{
struct ocores_i2c *i2c = platform_get_drvdata(pdev);
/* disable i2c logic */
oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
& ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
/* remove adapter & data */
i2c_del_adapter(&i2c->adap);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ocores_i2c_suspend(struct device *dev)
{
struct ocores_i2c *i2c = dev_get_drvdata(dev);
u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
/* make sure the device is disabled */
oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
return 0;
}
static int ocores_i2c_resume(struct device *dev)
{
struct ocores_i2c *i2c = dev_get_drvdata(dev);
ocores_init(i2c);
return 0;
}
static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);
#define OCORES_I2C_PM (&ocores_i2c_pm)
#else
#define OCORES_I2C_PM NULL
#endif
static struct platform_driver ocores_i2c_driver = {
.probe = ocores_i2c_probe,
.remove = ocores_i2c_remove,
.driver = {
.owner = THIS_MODULE,
.name = "ocores-i2c",
.of_match_table = ocores_i2c_match,
.pm = OCORES_I2C_PM,
},
};
module_platform_driver(ocores_i2c_driver);
MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
MODULE_DESCRIPTION("OpenCores I2C bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ocores-i2c");
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