/*
* TI OMAP I2C master mode driver
*
* Copyright (C) 2003 MontaVista Software, Inc.
* Copyright (C) 2004 Texas Instruments.
*
* Updated to work with multiple I2C interfaces on 24xx by
* Tony Lindgren <tony@atomide.com> and Imre Deak <imre.deak@nokia.com>
* Copyright (C) 2005 Nokia Corporation
*
* Cleaned up by Juha Yrjölä <juha.yrjola@nokia.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, or
* (at your option) any later version.
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <asm/io.h>
/* timeout waiting for the controller to respond */
#define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))
#define OMAP_I2C_REV_REG 0x00
#define OMAP_I2C_IE_REG 0x04
#define OMAP_I2C_STAT_REG 0x08
#define OMAP_I2C_IV_REG 0x0c
#define OMAP_I2C_SYSS_REG 0x10
#define OMAP_I2C_BUF_REG 0x14
#define OMAP_I2C_CNT_REG 0x18
#define OMAP_I2C_DATA_REG 0x1c
#define OMAP_I2C_SYSC_REG 0x20
#define OMAP_I2C_CON_REG 0x24
#define OMAP_I2C_OA_REG 0x28
#define OMAP_I2C_SA_REG 0x2c
#define OMAP_I2C_PSC_REG 0x30
#define OMAP_I2C_SCLL_REG 0x34
#define OMAP_I2C_SCLH_REG 0x38
#define OMAP_I2C_SYSTEST_REG 0x3c
/* I2C Interrupt Enable Register (OMAP_I2C_IE): */
#define OMAP_I2C_IE_XRDY (1 << 4) /* TX data ready int enable */
#define OMAP_I2C_IE_RRDY (1 << 3) /* RX data ready int enable */
#define OMAP_I2C_IE_ARDY (1 << 2) /* Access ready int enable */
#define OMAP_I2C_IE_NACK (1 << 1) /* No ack interrupt enable */
#define OMAP_I2C_IE_AL (1 << 0) /* Arbitration lost int ena */
/* I2C Status Register (OMAP_I2C_STAT): */
#define OMAP_I2C_STAT_SBD (1 << 15) /* Single byte data */
#define OMAP_I2C_STAT_BB (1 << 12) /* Bus busy */
#define OMAP_I2C_STAT_ROVR (1 << 11) /* Receive overrun */
#define OMAP_I2C_STAT_XUDF (1 << 10) /* Transmit underflow */
#define OMAP_I2C_STAT_AAS (1 << 9) /* Address as slave */
#define OMAP_I2C_STAT_AD0 (1 << 8) /* Address zero */
#define OMAP_I2C_STAT_XRDY (1 << 4) /* Transmit data ready */
#define OMAP_I2C_STAT_RRDY (1 << 3) /* Receive data ready */
#define OMAP_I2C_STAT_ARDY (1 << 2) /* Register access ready */
#define OMAP_I2C_STAT_NACK (1 << 1) /* No ack interrupt enable */
#define OMAP_I2C_STAT_AL (1 << 0) /* Arbitration lost int ena */
/* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
#define OMAP_I2C_BUF_RDMA_EN (1 << 15) /* RX DMA channel enable */
#define OMAP_I2C_BUF_XDMA_EN (1 << 7) /* TX DMA channel enable */
/* I2C Configuration Register (OMAP_I2C_CON): */
#define OMAP_I2C_CON_EN (1 << 15) /* I2C module enable */
#define OMAP_I2C_CON_BE (1 << 14) /* Big endian mode */
#define OMAP_I2C_CON_STB (1 << 11) /* Start byte mode (master) */
#define OMAP_I2C_CON_MST (1 << 10) /* Master/slave mode */
#define OMAP_I2C_CON_TRX (1 << 9) /* TX/RX mode (master only) */
#define OMAP_I2C_CON_XA (1 << 8) /* Expand address */
#define OMAP_I2C_CON_RM (1 << 2) /* Repeat mode (master only) */
#define OMAP_I2C_CON_STP (1 << 1) /* Stop cond (master only) */
#define OMAP_I2C_CON_STT (1 << 0) /* Start condition (master) */
/* I2C System Test Register (OMAP_I2C_SYSTEST): */
#ifdef DEBUG
#define OMAP_I2C_SYSTEST_ST_EN (1 << 15) /* System test enable */
#define OMAP_I2C_SYSTEST_FREE (1 << 14) /* Free running mode */
#define OMAP_I2C_SYSTEST_TMODE_MASK (3 << 12) /* Test mode select */
#define OMAP_I2C_SYSTEST_TMODE_SHIFT (12) /* Test mode select */
#define OMAP_I2C_SYSTEST_SCL_I (1 << 3) /* SCL line sense in */
#define OMAP_I2C_SYSTEST_SCL_O (1 << 2) /* SCL line drive out */
#define OMAP_I2C_SYSTEST_SDA_I (1 << 1) /* SDA line sense in */
#define OMAP_I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive out */
#endif
/* I2C System Status register (OMAP_I2C_SYSS): */
#define OMAP_I2C_SYSS_RDONE (1 << 0) /* Reset Done */
/* I2C System Configuration Register (OMAP_I2C_SYSC): */
#define OMAP_I2C_SYSC_SRST (1 << 1) /* Soft Reset */
/* REVISIT: Use platform_data instead of module parameters */
/* Fast Mode = 400 kHz, Standard = 100 kHz */
static int clock = 100; /* Default: 100 kHz */
module_param(clock, int, 0);
MODULE_PARM_DESC(clock, "Set I2C clock in kHz: 400=fast mode (default == 100)");
struct omap_i2c_dev {
struct device *dev;
void __iomem *base; /* virtual */
int irq;
struct clk *iclk; /* Interface clock */
struct clk *fclk; /* Functional clock */
struct completion cmd_complete;
struct resource *ioarea;
u16 cmd_err;
u8 *buf;
size_t buf_len;
struct i2c_adapter adapter;
unsigned rev1:1;
};
static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
int reg, u16 val)
{
__raw_writew(val, i2c_dev->base + reg);
}
static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
{
return __raw_readw(i2c_dev->base + reg);
}
static int omap_i2c_get_clocks(struct omap_i2c_dev *dev)
{
if (cpu_is_omap16xx() || cpu_is_omap24xx()) {
dev->iclk = clk_get(dev->dev, "i2c_ick");
if (IS_ERR(dev->iclk)) {
dev->iclk = NULL;
return -ENODEV;
}
}
dev->fclk = clk_get(dev->dev, "i2c_fck");
if (IS_ERR(dev->fclk)) {
if (dev->iclk != NULL) {
clk_put(dev->iclk);
dev->iclk = NULL;
}
dev->fclk = NULL;
return -ENODEV;
}
return 0;
}
static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
{
clk_put(dev->fclk);
dev->fclk = NULL;
if (dev->iclk != NULL) {
clk_put(dev->iclk);
dev->iclk = NULL;
}
}
static void omap_i2c_enable_clocks(struct omap_i2c_dev *dev)
{
if (dev->iclk != NULL)
clk_enable(dev->iclk);
clk_enable(dev->fclk);
}
static void omap_i2c_disable_clocks(struct omap_i2c_dev *dev)
{
if (dev->iclk != NULL)
clk_disable(dev->iclk);
clk_disable(dev->fclk);
}
static int omap_i2c_init(struct omap_i2c_dev *dev)
{
u16 psc = 0;
unsigned long fclk_rate = 12000000;
unsigned long timeout;
if (!dev->rev1) {
omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, OMAP_I2C_SYSC_SRST);
/* For some reason we need to set the EN bit before the
* reset done bit gets set. */
timeout = jiffies + OMAP_I2C_TIMEOUT;
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
OMAP_I2C_SYSS_RDONE)) {
if (time_after(jiffies, timeout)) {
dev_warn(dev->dev, "timeout waiting"
"for controller reset\n");
return -ETIMEDOUT;
}
msleep(1);
}
}
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
if (cpu_class_is_omap1()) {
struct clk *armxor_ck;
armxor_ck = clk_get(NULL, "armxor_ck");
if (IS_ERR(armxor_ck))
dev_warn(dev->dev, "Could not get armxor_ck\n");
else {
fclk_rate = clk_get_rate(armxor_ck);
clk_put(armxor_ck);
}
/* TRM for 5912 says the I2C clock must be prescaled to be
* between 7 - 12 MHz. The XOR input clock is typically
* 12, 13 or 19.2 MHz. So we should have code that produces:
*
* XOR MHz Divider Prescaler
* 12 1 0
* 13 2 1
* 19.2 2 1
*/
if (fclk_rate > 12000000)
psc = fclk_rate / 12000000;
}
/* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
/* Program desired operating rate */
fclk_rate /= (psc + 1) * 1000;
if (psc > 2)
psc = 2;
omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG,
fclk_rate / (clock * 2) - 7 + psc);
omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG,
fclk_rate / (clock * 2) - 7 + psc);
/* Take the I2C module out of reset: */
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
/* Enable interrupts */
omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,
(OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
OMAP_I2C_IE_AL));
return 0;
}
/*
* Waiting on Bus Busy
*/
static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
{
unsigned long timeout;
timeout = jiffies + OMAP_I2C_TIMEOUT;
while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
if (time_after(jiffies, timeout)) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return -ETIMEDOUT;
}
msleep(1);
}
return 0;
}
/*
* Low level master read/write transaction.
*/
static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
struct i2c_msg *msg, int stop)
{
struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
int r;
u16 w;
dev_dbg(dev->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;
omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
/* REVISIT: Could the STB bit of I2C_CON be used with probing? */
dev->buf = msg->buf;
dev->buf_len = msg->len;
omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
init_completion(&dev->cmd_complete);
dev->cmd_err = 0;
w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
if (msg->flags & I2C_M_TEN)
w |= OMAP_I2C_CON_XA;
if (!(msg->flags & I2C_M_RD))
w |= OMAP_I2C_CON_TRX;
if (stop)
w |= OMAP_I2C_CON_STP;
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
OMAP_I2C_TIMEOUT);
dev->buf_len = 0;
if (r < 0)
return r;
if (r == 0) {
dev_err(dev->dev, "controller timed out\n");
omap_i2c_init(dev);
return -ETIMEDOUT;
}
if (likely(!dev->cmd_err))
return 0;
/* We have an error */
if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
OMAP_I2C_STAT_XUDF)) {
omap_i2c_init(dev);
return -EIO;
}
if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
if (msg->flags & I2C_M_IGNORE_NAK)
return 0;
if (stop) {
w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
w |= OMAP_I2C_CON_STP;
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
}
return -EREMOTEIO;
}
return -EIO;
}
/*
* Prepare controller for a transaction and call omap_i2c_xfer_msg
* to do the work during IRQ processing.
*/
static int
omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
int i;
int r;
omap_i2c_enable_clocks(dev);
/* REVISIT: initialize and use adap->retries. This is an optional
* feature */
if ((r = omap_i2c_wait_for_bb(dev)) < 0)
goto out;
for (i = 0; i < num; i++) {
r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
if (r != 0)
break;
}
if (r == 0)
r = num;
out:
omap_i2c_disable_clocks(dev);
return r;
}
static u32
omap_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
static inline void
omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
{
dev->cmd_err |= err;
complete(&dev->cmd_complete);
}
static inline void
omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
{
omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
}
static irqreturn_t
omap_i2c_rev1_isr(int this_irq, void *dev_id)
{
struct omap_i2c_dev *dev = dev_id;
u16 iv, w;
iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
switch (iv) {
case 0x00: /* None */
break;
case 0x01: /* Arbitration lost */
dev_err(dev->dev, "Arbitration lost\n");
omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
break;
case 0x02: /* No acknowledgement */
omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
break;
case 0x03: /* Register access ready */
omap_i2c_complete_cmd(dev, 0);
break;
case 0x04: /* Receive data ready */
if (dev->buf_len) {
w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
*dev->buf++ = w;
dev->buf_len--;
if (dev->buf_len) {
*dev->buf++ = w >> 8;
dev->buf_len--;
}
} else
dev_err(dev->dev, "RRDY IRQ while no data requested\n");
break;
case 0x05: /* Transmit data ready */
if (dev->buf_len) {
w = *dev->buf++;
dev->buf_len--;
if (dev->buf_len) {
w |= *dev->buf++ << 8;
dev->buf_len--;
}
omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
} else
dev_err(dev->dev, "XRDY IRQ while no data to send\n");
break;
default:
return IRQ_NONE;
}
return IRQ_HANDLED;
}
static irqreturn_t
omap_i2c_isr(int this_irq, void *dev_id)
{
struct omap_i2c_dev *dev = dev_id;
u16 bits;
u16 stat, w;
int count = 0;
bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
if (count++ == 100) {
dev_warn(dev->dev, "Too much work in one IRQ\n");
break;
}
omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
if (stat & OMAP_I2C_STAT_ARDY) {
omap_i2c_complete_cmd(dev, 0);
continue;
}
if (stat & OMAP_I2C_STAT_RRDY) {
w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
if (dev->buf_len) {
*dev->buf++ = w;
dev->buf_len--;
if (dev->buf_len) {
*dev->buf++ = w >> 8;
dev->buf_len--;
}
} else
dev_err(dev->dev, "RRDY IRQ while no data"
"requested\n");
omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY);
continue;
}
if (stat & OMAP_I2C_STAT_XRDY) {
w = 0;
if (dev->buf_len) {
w = *dev->buf++;
dev->buf_len--;
if (dev->buf_len) {
w |= *dev->buf++ << 8;
dev->buf_len--;
}
} else
dev_err(dev->dev, "XRDY IRQ while no"
"data to send\n");
omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XRDY);
continue;
}
if (stat & OMAP_I2C_STAT_ROVR) {
dev_err(dev->dev, "Receive overrun\n");
dev->cmd_err |= OMAP_I2C_STAT_ROVR;
}
if (stat & OMAP_I2C_STAT_XUDF) {
dev_err(dev->dev, "Transmit overflow\n");
dev->cmd_err |= OMAP_I2C_STAT_XUDF;
}
if (stat & OMAP_I2C_STAT_NACK) {
omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
OMAP_I2C_CON_STP);
}
if (stat & OMAP_I2C_STAT_AL) {
dev_err(dev->dev, "Arbitration lost\n");
omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
}
}
return count ? IRQ_HANDLED : IRQ_NONE;
}
static const struct i2c_algorithm omap_i2c_algo = {
.master_xfer = omap_i2c_xfer,
.functionality = omap_i2c_func,
};
static int
omap_i2c_probe(struct platform_device *pdev)
{
struct omap_i2c_dev *dev;
struct i2c_adapter *adap;
struct resource *mem, *irq, *ioarea;
int r;
/* NOTE: driver uses the static register mapping */
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem) {
dev_err(&pdev->dev, "no mem resource?\n");
return -ENODEV;
}
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!irq) {
dev_err(&pdev->dev, "no irq resource?\n");
return -ENODEV;
}
ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
pdev->name);
if (!ioarea) {
dev_err(&pdev->dev, "I2C region already claimed\n");
return -EBUSY;
}
if (clock > 200)
clock = 400; /* Fast mode */
else
clock = 100; /* Standard mode */
dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
if (!dev) {
r = -ENOMEM;
goto err_release_region;
}
dev->dev = &pdev->dev;
dev->irq = irq->start;
dev->base = (void __iomem *) IO_ADDRESS(mem->start);
platform_set_drvdata(pdev, dev);
if ((r = omap_i2c_get_clocks(dev)) != 0)
goto err_free_mem;
omap_i2c_enable_clocks(dev);
if (cpu_is_omap15xx())
dev->rev1 = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) < 0x20;
/* reset ASAP, clearing any IRQs */
omap_i2c_init(dev);
r = request_irq(dev->irq, dev->rev1 ? omap_i2c_rev1_isr : omap_i2c_isr,
0, pdev->name, dev);
if (r) {
dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
goto err_unuse_clocks;
}
r = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
pdev->id, r >> 4, r & 0xf, clock);
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_HWMON;
strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
adap->algo = &omap_i2c_algo;
adap->dev.parent = &pdev->dev;
/* i2c device drivers may be active on return from add_adapter() */
adap->nr = pdev->id;
r = i2c_add_numbered_adapter(adap);
if (r) {
dev_err(dev->dev, "failure adding adapter\n");
goto err_free_irq;
}
omap_i2c_disable_clocks(dev);
return 0;
err_free_irq:
free_irq(dev->irq, dev);
err_unuse_clocks:
omap_i2c_disable_clocks(dev);
omap_i2c_put_clocks(dev);
err_free_mem:
platform_set_drvdata(pdev, NULL);
kfree(dev);
err_release_region:
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
release_mem_region(mem->start, (mem->end - mem->start) + 1);
return r;
}
static int
omap_i2c_remove(struct platform_device *pdev)
{
struct omap_i2c_dev *dev = platform_get_drvdata(pdev);
struct resource *mem;
platform_set_drvdata(pdev, NULL);
free_irq(dev->irq, dev);
i2c_del_adapter(&dev->adapter);
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
omap_i2c_put_clocks(dev);
kfree(dev);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(mem->start, (mem->end - mem->start) + 1);
return 0;
}
static struct platform_driver omap_i2c_driver = {
.probe = omap_i2c_probe,
.remove = omap_i2c_remove,
.driver = {
.name = "i2c_omap",
.owner = THIS_MODULE,
},
};
/* I2C may be needed to bring up other drivers */
static int __init
omap_i2c_init_driver(void)
{
return platform_driver_register(&omap_i2c_driver);
}
subsys_initcall(omap_i2c_init_driver);
static void __exit omap_i2c_exit_driver(void)
{
platform_driver_unregister(&omap_i2c_driver);
}
module_exit(omap_i2c_exit_driver);
MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
MODULE_LICENSE("GPL");
