420 строки
10 KiB
C
420 строки
10 KiB
C
/*
|
|
* Freescale MXS I2C bus driver
|
|
*
|
|
* Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
|
|
*
|
|
* based on a (non-working) driver which was:
|
|
*
|
|
* Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
|
|
*
|
|
* TODO: add dma-support if platform-support for it is available
|
|
*
|
|
* 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, or
|
|
* (at your option) any later version.
|
|
*
|
|
*/
|
|
|
|
#include <linux/slab.h>
|
|
#include <linux/device.h>
|
|
#include <linux/module.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/err.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/io.h>
|
|
|
|
#include <mach/common.h>
|
|
|
|
#define DRIVER_NAME "mxs-i2c"
|
|
|
|
#define MXS_I2C_CTRL0 (0x00)
|
|
#define MXS_I2C_CTRL0_SET (0x04)
|
|
|
|
#define MXS_I2C_CTRL0_SFTRST 0x80000000
|
|
#define MXS_I2C_CTRL0_SEND_NAK_ON_LAST 0x02000000
|
|
#define MXS_I2C_CTRL0_RETAIN_CLOCK 0x00200000
|
|
#define MXS_I2C_CTRL0_POST_SEND_STOP 0x00100000
|
|
#define MXS_I2C_CTRL0_PRE_SEND_START 0x00080000
|
|
#define MXS_I2C_CTRL0_MASTER_MODE 0x00020000
|
|
#define MXS_I2C_CTRL0_DIRECTION 0x00010000
|
|
#define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF)
|
|
|
|
#define MXS_I2C_CTRL1 (0x40)
|
|
#define MXS_I2C_CTRL1_SET (0x44)
|
|
#define MXS_I2C_CTRL1_CLR (0x48)
|
|
|
|
#define MXS_I2C_CTRL1_BUS_FREE_IRQ 0x80
|
|
#define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ 0x40
|
|
#define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ 0x20
|
|
#define MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ 0x10
|
|
#define MXS_I2C_CTRL1_EARLY_TERM_IRQ 0x08
|
|
#define MXS_I2C_CTRL1_MASTER_LOSS_IRQ 0x04
|
|
#define MXS_I2C_CTRL1_SLAVE_STOP_IRQ 0x02
|
|
#define MXS_I2C_CTRL1_SLAVE_IRQ 0x01
|
|
|
|
#define MXS_I2C_IRQ_MASK (MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | \
|
|
MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ | \
|
|
MXS_I2C_CTRL1_EARLY_TERM_IRQ | \
|
|
MXS_I2C_CTRL1_MASTER_LOSS_IRQ | \
|
|
MXS_I2C_CTRL1_SLAVE_STOP_IRQ | \
|
|
MXS_I2C_CTRL1_SLAVE_IRQ)
|
|
|
|
#define MXS_I2C_QUEUECTRL (0x60)
|
|
#define MXS_I2C_QUEUECTRL_SET (0x64)
|
|
#define MXS_I2C_QUEUECTRL_CLR (0x68)
|
|
|
|
#define MXS_I2C_QUEUECTRL_QUEUE_RUN 0x20
|
|
#define MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE 0x04
|
|
|
|
#define MXS_I2C_QUEUESTAT (0x70)
|
|
#define MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY 0x00002000
|
|
#define MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK 0x0000001F
|
|
|
|
#define MXS_I2C_QUEUECMD (0x80)
|
|
|
|
#define MXS_I2C_QUEUEDATA (0x90)
|
|
|
|
#define MXS_I2C_DATA (0xa0)
|
|
|
|
|
|
#define MXS_CMD_I2C_SELECT (MXS_I2C_CTRL0_RETAIN_CLOCK | \
|
|
MXS_I2C_CTRL0_PRE_SEND_START | \
|
|
MXS_I2C_CTRL0_MASTER_MODE | \
|
|
MXS_I2C_CTRL0_DIRECTION | \
|
|
MXS_I2C_CTRL0_XFER_COUNT(1))
|
|
|
|
#define MXS_CMD_I2C_WRITE (MXS_I2C_CTRL0_PRE_SEND_START | \
|
|
MXS_I2C_CTRL0_MASTER_MODE | \
|
|
MXS_I2C_CTRL0_DIRECTION)
|
|
|
|
#define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
|
|
MXS_I2C_CTRL0_MASTER_MODE)
|
|
|
|
/**
|
|
* struct mxs_i2c_dev - per device, private MXS-I2C data
|
|
*
|
|
* @dev: driver model device node
|
|
* @regs: IO registers pointer
|
|
* @cmd_complete: completion object for transaction wait
|
|
* @cmd_err: error code for last transaction
|
|
* @adapter: i2c subsystem adapter node
|
|
*/
|
|
struct mxs_i2c_dev {
|
|
struct device *dev;
|
|
void __iomem *regs;
|
|
struct completion cmd_complete;
|
|
u32 cmd_err;
|
|
struct i2c_adapter adapter;
|
|
};
|
|
|
|
/*
|
|
* TODO: check if calls to here are really needed. If not, we could get rid of
|
|
* mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
|
|
*/
|
|
static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
|
|
{
|
|
mxs_reset_block(i2c->regs);
|
|
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
|
|
writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
|
|
i2c->regs + MXS_I2C_QUEUECTRL_SET);
|
|
}
|
|
|
|
static void mxs_i2c_pioq_setup_read(struct mxs_i2c_dev *i2c, u8 addr, int len,
|
|
int flags)
|
|
{
|
|
u32 data;
|
|
|
|
writel(MXS_CMD_I2C_SELECT, i2c->regs + MXS_I2C_QUEUECMD);
|
|
|
|
data = (addr << 1) | I2C_SMBUS_READ;
|
|
writel(data, i2c->regs + MXS_I2C_DATA);
|
|
|
|
data = MXS_CMD_I2C_READ | MXS_I2C_CTRL0_XFER_COUNT(len) | flags;
|
|
writel(data, i2c->regs + MXS_I2C_QUEUECMD);
|
|
}
|
|
|
|
static void mxs_i2c_pioq_setup_write(struct mxs_i2c_dev *i2c,
|
|
u8 addr, u8 *buf, int len, int flags)
|
|
{
|
|
u32 data;
|
|
int i, shifts_left;
|
|
|
|
data = MXS_CMD_I2C_WRITE | MXS_I2C_CTRL0_XFER_COUNT(len + 1) | flags;
|
|
writel(data, i2c->regs + MXS_I2C_QUEUECMD);
|
|
|
|
/*
|
|
* We have to copy the slave address (u8) and buffer (arbitrary number
|
|
* of u8) into the data register (u32). To achieve that, the u8 are put
|
|
* into the MSBs of 'data' which is then shifted for the next u8. When
|
|
* appropriate, 'data' is written to MXS_I2C_DATA. So, the first u32
|
|
* looks like this:
|
|
*
|
|
* 3 2 1 0
|
|
* 10987654|32109876|54321098|76543210
|
|
* --------+--------+--------+--------
|
|
* buffer+2|buffer+1|buffer+0|slave_addr
|
|
*/
|
|
|
|
data = ((addr << 1) | I2C_SMBUS_WRITE) << 24;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
data >>= 8;
|
|
data |= buf[i] << 24;
|
|
if ((i & 3) == 2)
|
|
writel(data, i2c->regs + MXS_I2C_DATA);
|
|
}
|
|
|
|
/* Write out the remaining bytes if any */
|
|
shifts_left = 24 - (i & 3) * 8;
|
|
if (shifts_left)
|
|
writel(data >> shifts_left, i2c->regs + MXS_I2C_DATA);
|
|
}
|
|
|
|
/*
|
|
* TODO: should be replaceable with a waitqueue and RD_QUEUE_IRQ (setting the
|
|
* rd_threshold to 1). Couldn't get this to work, though.
|
|
*/
|
|
static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
|
|
{
|
|
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
|
|
|
|
while (readl(i2c->regs + MXS_I2C_QUEUESTAT)
|
|
& MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY) {
|
|
if (time_after(jiffies, timeout))
|
|
return -ETIMEDOUT;
|
|
cond_resched();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
|
|
{
|
|
u32 data;
|
|
int i;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
if ((i & 3) == 0) {
|
|
if (mxs_i2c_wait_for_data(i2c))
|
|
return -ETIMEDOUT;
|
|
data = readl(i2c->regs + MXS_I2C_QUEUEDATA);
|
|
}
|
|
buf[i] = data & 0xff;
|
|
data >>= 8;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Low level master read/write transaction.
|
|
*/
|
|
static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
|
|
int stop)
|
|
{
|
|
struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
|
|
int ret;
|
|
int flags;
|
|
|
|
dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
|
|
msg->addr, msg->len, msg->flags, stop);
|
|
|
|
if (msg->len == 0)
|
|
return -EINVAL;
|
|
|
|
init_completion(&i2c->cmd_complete);
|
|
i2c->cmd_err = 0;
|
|
|
|
flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
|
|
|
|
if (msg->flags & I2C_M_RD)
|
|
mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags);
|
|
else
|
|
mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len,
|
|
flags);
|
|
|
|
writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
|
|
i2c->regs + MXS_I2C_QUEUECTRL_SET);
|
|
|
|
ret = wait_for_completion_timeout(&i2c->cmd_complete,
|
|
msecs_to_jiffies(1000));
|
|
if (ret == 0)
|
|
goto timeout;
|
|
|
|
if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
|
|
ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len);
|
|
if (ret)
|
|
goto timeout;
|
|
}
|
|
|
|
if (i2c->cmd_err == -ENXIO)
|
|
mxs_i2c_reset(i2c);
|
|
else
|
|
writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
|
|
i2c->regs + MXS_I2C_QUEUECTRL_CLR);
|
|
|
|
dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err);
|
|
|
|
return i2c->cmd_err;
|
|
|
|
timeout:
|
|
dev_dbg(i2c->dev, "Timeout!\n");
|
|
mxs_i2c_reset(i2c);
|
|
return -ETIMEDOUT;
|
|
}
|
|
|
|
static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
|
|
int num)
|
|
{
|
|
int i;
|
|
int err;
|
|
|
|
for (i = 0; i < num; i++) {
|
|
err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1));
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
return num;
|
|
}
|
|
|
|
static u32 mxs_i2c_func(struct i2c_adapter *adap)
|
|
{
|
|
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
|
|
}
|
|
|
|
static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
|
|
{
|
|
struct mxs_i2c_dev *i2c = dev_id;
|
|
u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;
|
|
bool is_last_cmd;
|
|
|
|
if (!stat)
|
|
return IRQ_NONE;
|
|
|
|
if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
|
|
i2c->cmd_err = -ENXIO;
|
|
else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
|
|
MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
|
|
MXS_I2C_CTRL1_SLAVE_STOP_IRQ | MXS_I2C_CTRL1_SLAVE_IRQ))
|
|
/* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
|
|
i2c->cmd_err = -EIO;
|
|
|
|
is_last_cmd = (readl(i2c->regs + MXS_I2C_QUEUESTAT) &
|
|
MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK) == 0;
|
|
|
|
if (is_last_cmd || i2c->cmd_err)
|
|
complete(&i2c->cmd_complete);
|
|
|
|
writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static const struct i2c_algorithm mxs_i2c_algo = {
|
|
.master_xfer = mxs_i2c_xfer,
|
|
.functionality = mxs_i2c_func,
|
|
};
|
|
|
|
static int __devinit mxs_i2c_probe(struct platform_device *pdev)
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
struct mxs_i2c_dev *i2c;
|
|
struct i2c_adapter *adap;
|
|
struct resource *res;
|
|
resource_size_t res_size;
|
|
int err, irq;
|
|
|
|
i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
|
|
if (!i2c)
|
|
return -ENOMEM;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!res)
|
|
return -ENOENT;
|
|
|
|
res_size = resource_size(res);
|
|
if (!devm_request_mem_region(dev, res->start, res_size, res->name))
|
|
return -EBUSY;
|
|
|
|
i2c->regs = devm_ioremap_nocache(dev, res->start, res_size);
|
|
if (!i2c->regs)
|
|
return -EBUSY;
|
|
|
|
irq = platform_get_irq(pdev, 0);
|
|
if (irq < 0)
|
|
return irq;
|
|
|
|
err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
|
|
if (err)
|
|
return err;
|
|
|
|
i2c->dev = dev;
|
|
platform_set_drvdata(pdev, i2c);
|
|
|
|
/* Do reset to enforce correct startup after pinmuxing */
|
|
mxs_i2c_reset(i2c);
|
|
|
|
adap = &i2c->adapter;
|
|
strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name));
|
|
adap->owner = THIS_MODULE;
|
|
adap->algo = &mxs_i2c_algo;
|
|
adap->dev.parent = dev;
|
|
adap->nr = pdev->id;
|
|
i2c_set_adapdata(adap, i2c);
|
|
err = i2c_add_numbered_adapter(adap);
|
|
if (err) {
|
|
dev_err(dev, "Failed to add adapter (%d)\n", err);
|
|
writel(MXS_I2C_CTRL0_SFTRST,
|
|
i2c->regs + MXS_I2C_CTRL0_SET);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __devexit mxs_i2c_remove(struct platform_device *pdev)
|
|
{
|
|
struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
|
|
int ret;
|
|
|
|
ret = i2c_del_adapter(&i2c->adapter);
|
|
if (ret)
|
|
return -EBUSY;
|
|
|
|
writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
|
|
|
|
platform_set_drvdata(pdev, NULL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver mxs_i2c_driver = {
|
|
.driver = {
|
|
.name = DRIVER_NAME,
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.remove = __devexit_p(mxs_i2c_remove),
|
|
};
|
|
|
|
static int __init mxs_i2c_init(void)
|
|
{
|
|
return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe);
|
|
}
|
|
subsys_initcall(mxs_i2c_init);
|
|
|
|
static void __exit mxs_i2c_exit(void)
|
|
{
|
|
platform_driver_unregister(&mxs_i2c_driver);
|
|
}
|
|
module_exit(mxs_i2c_exit);
|
|
|
|
MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
|
|
MODULE_DESCRIPTION("MXS I2C Bus Driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:" DRIVER_NAME);
|