- 根目录:
- drivers
- i2c
- busses
- i2c-ocores.c
/*
* 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/clk.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.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_ */
struct clk *clk;
int ip_clock_khz;
int bus_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 void oc_setreg_16be(struct ocores_i2c *i2c, int reg, u8 value)
{
iowrite16be(value, i2c->base + (reg << i2c->reg_shift));
}
static void oc_setreg_32be(struct ocores_i2c *i2c, int reg, u8 value)
{
iowrite32be(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 u8 oc_getreg_16be(struct ocores_i2c *i2c, int reg)
{
return ioread16be(i2c->base + (reg << i2c->reg_shift));
}
static inline u8 oc_getreg_32be(struct ocores_i2c *i2c, int reg)
{
return ioread32be(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 int ocores_init(struct device *dev, struct ocores_i2c *i2c)
{
int prescale;
int diff;
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->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
prescale = clamp(prescale, 0, 0xffff);
diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
if (abs(diff) > i2c->bus_clock_khz / 10) {
dev_err(dev,
"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
i2c->ip_clock_khz, i2c->bus_clock_khz);
return -EINVAL;
}
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);
return 0;
}
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_DEPRECATED,
.algo = &ocores_algorithm,
};
static const 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;
u32 clock_frequency;
bool clock_frequency_present;
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");
}
}
clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
&clock_frequency);
i2c->bus_clock_khz = 100;
i2c->clk = devm_clk_get(&pdev->dev, NULL);
if (!IS_ERR(i2c->clk)) {
int ret = clk_prepare_enable(i2c->clk);
if (ret) {
dev_err(&pdev->dev,
"clk_prepare_enable failed: %d\n", ret);
return ret;
}
i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000;
if (clock_frequency_present)
i2c->bus_clock_khz = clock_frequency / 1000;
}
if (i2c->ip_clock_khz == 0) {
if (of_property_read_u32(np, "opencores,ip-clock-frequency",
&val)) {
if (!clock_frequency_present) {
dev_err(&pdev->dev,
"Missing required parameter 'opencores,ip-clock-frequency'\n");
return -ENODEV;
}
i2c->ip_clock_khz = clock_frequency / 1000;
dev_warn(&pdev->dev,
"Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
} else {
i2c->ip_clock_khz = val / 1000;
if (clock_frequency_present)
i2c->bus_clock_khz = clock_frequency / 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->ip_clock_khz = pdata->clock_khz;
i2c->bus_clock_khz = 100;
} 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) {
bool be = pdata ? pdata->big_endian :
of_device_is_big_endian(pdev->dev.of_node);
switch (i2c->reg_io_width) {
case 1:
i2c->setreg = oc_setreg_8;
i2c->getreg = oc_getreg_8;
break;
case 2:
i2c->setreg = be ? oc_setreg_16be : oc_setreg_16;
i2c->getreg = be ? oc_getreg_16be : oc_getreg_16;
break;
case 4:
i2c->setreg = be ? oc_setreg_32be : oc_setreg_32;
i2c->getreg = be ? oc_getreg_32be : oc_getreg_32;
break;
default:
dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
i2c->reg_io_width);
return -EINVAL;
}
}
ret = ocores_init(&pdev->dev, i2c);
if (ret)
return ret;
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);
if (!IS_ERR(i2c->clk))
clk_disable_unprepare(i2c->clk);
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));
if (!IS_ERR(i2c->clk))
clk_disable_unprepare(i2c->clk);
return 0;
}
static int ocores_i2c_resume(struct device *dev)
{
struct ocores_i2c *i2c = dev_get_drvdata(dev);
if (!IS_ERR(i2c->clk)) {
unsigned long rate;
int ret = clk_prepare_enable(i2c->clk);
if (ret) {
dev_err(dev,
"clk_prepare_enable failed: %d\n", ret);
return ret;
}
rate = clk_get_rate(i2c->clk) / 1000;
if (rate)
i2c->ip_clock_khz = rate;
}
return ocores_init(dev, i2c);
}
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 = {
.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");