- 根目录:
- drivers
- i2c
- busses
- i2c-puv3.c
/*
* I2C driver for PKUnity-v3 SoC
* Code specific to PKUnity SoC and UniCore ISA
*
* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
* Copyright (C) 2001-2010 Guan Xuetao
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <mach/hardware.h>
/*
* Poll the i2c status register until the specified bit is set.
* Returns 0 if timed out (100 msec).
*/
static short poll_status(unsigned long bit)
{
int loop_cntr = 1000;
if (bit & I2C_STATUS_TFNF) {
do {
udelay(10);
} while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
} else {
/* RXRDY handler */
do {
if (readl(I2C_TAR) == I2C_TAR_EEPROM)
msleep(20);
else
udelay(10);
} while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
}
return (loop_cntr > 0);
}
static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
{
int i2c_reg = *buf;
/* Read data */
while (length--) {
if (!poll_status(I2C_STATUS_TFNF)) {
dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
return -ETIMEDOUT;
}
/* send addr */
writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
/* get ready to next write */
i2c_reg++;
/* send read CMD */
writel(I2C_DATACMD_READ, I2C_DATACMD);
/* wait until the Rx FIFO have available */
if (!poll_status(I2C_STATUS_RFNE)) {
dev_dbg(&adap->dev, "RXRDY timeout\n");
return -ETIMEDOUT;
}
/* read the data to buf */
*buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
buf++;
}
return 0;
}
static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
{
int i2c_reg = *buf;
/* Do nothing but storing the reg_num to a static variable */
if (i2c_reg == -1) {
printk(KERN_WARNING "Error i2c reg\n");
return -ETIMEDOUT;
}
if (length == 1)
return 0;
buf++;
length--;
while (length--) {
/* send addr */
writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
/* send write CMD */
writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
/* wait until the Rx FIFO have available */
msleep(20);
/* read the data to buf */
i2c_reg++;
buf++;
}
return 0;
}
/*
* Generic i2c master transfer entrypoint.
*
*/
static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
int num)
{
int i, ret;
unsigned char swap;
/* Disable i2c */
writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
/* Set the work mode and speed*/
writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
writel(pmsg->addr, I2C_TAR);
/* Enable i2c */
writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
for (i = 0; i < num; i++) {
dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
pmsg->flags & I2C_M_RD ? "read" : "writ",
pmsg->len, pmsg->len > 1 ? "s" : "",
pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
if (pmsg->len && pmsg->buf) { /* sanity check */
if (pmsg->flags & I2C_M_RD)
ret = xfer_read(adap, pmsg->buf, pmsg->len);
else
ret = xfer_write(adap, pmsg->buf, pmsg->len);
if (ret)
return ret;
}
dev_dbg(&adap->dev, "transfer complete\n");
pmsg++; /* next message */
}
/* XXX: fixup be16_to_cpu in bq27x00_battery.c */
if (pmsg->addr == I2C_TAR_PWIC) {
swap = pmsg->buf[0];
pmsg->buf[0] = pmsg->buf[1];
pmsg->buf[1] = swap;
}
return i;
}
/*
* Return list of supported functionality.
*/
static u32 puv3_i2c_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm puv3_i2c_algorithm = {
.master_xfer = puv3_i2c_xfer,
.functionality = puv3_i2c_func,
};
/*
* Main initialization routine.
*/
static int puv3_i2c_probe(struct platform_device *pdev)
{
struct i2c_adapter *adapter;
struct resource *mem;
int rc;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem)
return -ENODEV;
if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
return -EBUSY;
adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
if (adapter == NULL) {
dev_err(&pdev->dev, "can't allocate interface!\n");
rc = -ENOMEM;
goto fail_nomem;
}
snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
mem->start);
adapter->algo = &puv3_i2c_algorithm;
adapter->class = I2C_CLASS_HWMON;
adapter->dev.parent = &pdev->dev;
platform_set_drvdata(pdev, adapter);
adapter->nr = pdev->id;
rc = i2c_add_numbered_adapter(adapter);
if (rc) {
dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
adapter->name);
goto fail_add_adapter;
}
dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
return 0;
fail_add_adapter:
kfree(adapter);
fail_nomem:
release_mem_region(mem->start, resource_size(mem));
return rc;
}
static int puv3_i2c_remove(struct platform_device *pdev)
{
struct i2c_adapter *adapter = platform_get_drvdata(pdev);
struct resource *mem;
i2c_del_adapter(adapter);
put_device(&pdev->dev);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(mem->start, resource_size(mem));
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int puv3_i2c_suspend(struct device *dev)
{
int poll_count;
/* Disable the IIC */
writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
for (poll_count = 0; poll_count < 50; poll_count++) {
if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
udelay(25);
}
return 0;
}
static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
#define PUV3_I2C_PM (&puv3_i2c_pm)
#else
#define PUV3_I2C_PM NULL
#endif
static struct platform_driver puv3_i2c_driver = {
.probe = puv3_i2c_probe,
.remove = puv3_i2c_remove,
.driver = {
.name = "PKUnity-v3-I2C",
.owner = THIS_MODULE,
.pm = PUV3_I2C_PM,
}
};
module_platform_driver(puv3_i2c_driver);
MODULE_DESCRIPTION("PKUnity v3 I2C driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:puv3_i2c");