/*
* TI DAVINCI I2C adapter driver.
*
* Copyright (C) 2006 Texas Instruments.
* Copyright (C) 2007 MontaVista Software Inc.
*
* Updated by Vinod & Sudhakar Feb 2005
*
* ----------------------------------------------------------------------------
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <mach/hardware.h>
#include <mach/i2c.h>
/* ----- global defines ----------------------------------------------- */
#define DAVINCI_I2C_TIMEOUT (1*HZ)
#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \
DAVINCI_I2C_IMR_SCD | \
DAVINCI_I2C_IMR_ARDY | \
DAVINCI_I2C_IMR_NACK | \
DAVINCI_I2C_IMR_AL)
#define DAVINCI_I2C_OAR_REG 0x00
#define DAVINCI_I2C_IMR_REG 0x04
#define DAVINCI_I2C_STR_REG 0x08
#define DAVINCI_I2C_CLKL_REG 0x0c
#define DAVINCI_I2C_CLKH_REG 0x10
#define DAVINCI_I2C_CNT_REG 0x14
#define DAVINCI_I2C_DRR_REG 0x18
#define DAVINCI_I2C_SAR_REG 0x1c
#define DAVINCI_I2C_DXR_REG 0x20
#define DAVINCI_I2C_MDR_REG 0x24
#define DAVINCI_I2C_IVR_REG 0x28
#define DAVINCI_I2C_EMDR_REG 0x2c
#define DAVINCI_I2C_PSC_REG 0x30
#define DAVINCI_I2C_IVR_AAS 0x07
#define DAVINCI_I2C_IVR_SCD 0x06
#define DAVINCI_I2C_IVR_XRDY 0x05
#define DAVINCI_I2C_IVR_RDR 0x04
#define DAVINCI_I2C_IVR_ARDY 0x03
#define DAVINCI_I2C_IVR_NACK 0x02
#define DAVINCI_I2C_IVR_AL 0x01
#define DAVINCI_I2C_STR_BB (1 << 12)
#define DAVINCI_I2C_STR_RSFULL (1 << 11)
#define DAVINCI_I2C_STR_SCD (1 << 5)
#define DAVINCI_I2C_STR_ARDY (1 << 2)
#define DAVINCI_I2C_STR_NACK (1 << 1)
#define DAVINCI_I2C_STR_AL (1 << 0)
#define DAVINCI_I2C_MDR_NACK (1 << 15)
#define DAVINCI_I2C_MDR_STT (1 << 13)
#define DAVINCI_I2C_MDR_STP (1 << 11)
#define DAVINCI_I2C_MDR_MST (1 << 10)
#define DAVINCI_I2C_MDR_TRX (1 << 9)
#define DAVINCI_I2C_MDR_XA (1 << 8)
#define DAVINCI_I2C_MDR_RM (1 << 7)
#define DAVINCI_I2C_MDR_IRS (1 << 5)
#define DAVINCI_I2C_IMR_AAS (1 << 6)
#define DAVINCI_I2C_IMR_SCD (1 << 5)
#define DAVINCI_I2C_IMR_XRDY (1 << 4)
#define DAVINCI_I2C_IMR_RRDY (1 << 3)
#define DAVINCI_I2C_IMR_ARDY (1 << 2)
#define DAVINCI_I2C_IMR_NACK (1 << 1)
#define DAVINCI_I2C_IMR_AL (1 << 0)
#define MOD_REG_BIT(val, mask, set) do { \
if (set) { \
val |= mask; \
} else { \
val &= ~mask; \
} \
} while (0)
struct davinci_i2c_dev {
struct device *dev;
void __iomem *base;
struct completion cmd_complete;
struct clk *clk;
int cmd_err;
u8 *buf;
size_t buf_len;
int irq;
u8 terminate;
struct i2c_adapter adapter;
};
/* default platform data to use if not supplied in the platform_device */
static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
.bus_freq = 100,
.bus_delay = 0,
};
static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
int reg, u16 val)
{
__raw_writew(val, i2c_dev->base + reg);
}
static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
{
return __raw_readw(i2c_dev->base + reg);
}
/*
* This functions configures I2C and brings I2C out of reset.
* This function is called during I2C init function. This function
* also gets called if I2C encounters any errors.
*/
static int i2c_davinci_init(struct davinci_i2c_dev *dev)
{
struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
u16 psc;
u32 clk;
u32 d;
u32 clkh;
u32 clkl;
u32 input_clock = clk_get_rate(dev->clk);
u16 w;
if (!pdata)
pdata = &davinci_i2c_platform_data_default;
/* put I2C into reset */
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
/* NOTE: I2C Clock divider programming info
* As per I2C specs the following formulas provide prescaler
* and low/high divider values
* input clk --> PSC Div -----------> ICCL/H Div --> output clock
* module clk
*
* output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
*
* Thus,
* (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
*
* where if PSC == 0, d = 7,
* if PSC == 1, d = 6
* if PSC > 1 , d = 5
*/
/* get minimum of 7 MHz clock, but max of 12 MHz */
psc = (input_clock / 7000000) - 1;
if ((input_clock / (psc + 1)) > 12000000)
psc++; /* better to run under spec than over */
d = (psc >= 2) ? 5 : 7 - psc;
clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
clkh = clk >> 1;
clkl = clk - clkh;
davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
/* Respond at reserved "SMBus Host" slave address" (and zero);
* we seem to have no option to not respond...
*/
davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
dev_dbg(dev->dev, "PSC = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
dev_dbg(dev->dev, "CLKL = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
dev_dbg(dev->dev, "CLKH = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
pdata->bus_freq, pdata->bus_delay);
/* Take the I2C module out of reset: */
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
/* Enable interrupts */
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
return 0;
}
/*
* Waiting for bus not busy
*/
static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
char allow_sleep)
{
unsigned long timeout;
timeout = jiffies + dev->adapter.timeout;
while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
& DAVINCI_I2C_STR_BB) {
if (time_after(jiffies, timeout)) {
dev_warn(dev->dev,
"timeout waiting for bus ready\n");
return -ETIMEDOUT;
}
if (allow_sleep)
schedule_timeout(1);
}
return 0;
}
/*
* Low level master read/write transaction. This function is called
* from i2c_davinci_xfer.
*/
static int
i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
u32 flag;
u16 w;
int r;
if (msg->len == 0)
return -EINVAL;
if (!pdata)
pdata = &davinci_i2c_platform_data_default;
/* Introduce a delay, required for some boards (e.g Davinci EVM) */
if (pdata->bus_delay)
udelay(pdata->bus_delay);
/* set the slave address */
davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
dev->buf = msg->buf;
dev->buf_len = msg->len;
davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
INIT_COMPLETION(dev->cmd_complete);
dev->cmd_err = 0;
/* Take I2C out of reset, configure it as master and set the
* start bit */
flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
/* if the slave address is ten bit address, enable XA bit */
if (msg->flags & I2C_M_TEN)
flag |= DAVINCI_I2C_MDR_XA;
if (!(msg->flags & I2C_M_RD))
flag |= DAVINCI_I2C_MDR_TRX;
if (stop)
flag |= DAVINCI_I2C_MDR_STP;
/* Enable receive or transmit interrupts */
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
if (msg->flags & I2C_M_RD)
MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
else
MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
dev->terminate = 0;
/* write the data into mode register */
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
dev->adapter.timeout);
if (r == 0) {
dev_err(dev->dev, "controller timed out\n");
i2c_davinci_init(dev);
dev->buf_len = 0;
return -ETIMEDOUT;
}
if (dev->buf_len) {
/* This should be 0 if all bytes were transferred
* or dev->cmd_err denotes an error.
* A signal may have aborted the transfer.
*/
if (r >= 0) {
dev_err(dev->dev, "abnormal termination buf_len=%i\n",
dev->buf_len);
r = -EREMOTEIO;
}
dev->terminate = 1;
wmb();
dev->buf_len = 0;
}
if (r < 0)
return r;
/* no error */
if (likely(!dev->cmd_err))
return msg->len;
/* We have an error */
if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
i2c_davinci_init(dev);
return -EIO;
}
if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
if (msg->flags & I2C_M_IGNORE_NAK)
return msg->len;
if (stop) {
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
}
return -EREMOTEIO;
}
return -EIO;
}
/*
* Prepare controller for a transaction and call i2c_davinci_xfer_msg
*/
static int
i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
int i;
int ret;
dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
ret = i2c_davinci_wait_bus_not_busy(dev, 1);
if (ret < 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return ret;
}
for (i = 0; i < num; i++) {
ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
ret);
if (ret < 0)
return ret;
}
return num;
}
static u32 i2c_davinci_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
static void terminate_read(struct davinci_i2c_dev *dev)
{
u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
w |= DAVINCI_I2C_MDR_NACK;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
/* Throw away data */
davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
if (!dev->terminate)
dev_err(dev->dev, "RDR IRQ while no data requested\n");
}
static void terminate_write(struct davinci_i2c_dev *dev)
{
u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
if (!dev->terminate)
dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
}
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
* occurs.
*/
static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
{
struct davinci_i2c_dev *dev = dev_id;
u32 stat;
int count = 0;
u16 w;
while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
if (count++ == 100) {
dev_warn(dev->dev, "Too much work in one IRQ\n");
break;
}
switch (stat) {
case DAVINCI_I2C_IVR_AL:
/* Arbitration lost, must retry */
dev->cmd_err |= DAVINCI_I2C_STR_AL;
dev->buf_len = 0;
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_NACK:
dev->cmd_err |= DAVINCI_I2C_STR_NACK;
dev->buf_len = 0;
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_ARDY:
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_RDR:
if (dev->buf_len) {
*dev->buf++ =
davinci_i2c_read_reg(dev,
DAVINCI_I2C_DRR_REG);
dev->buf_len--;
if (dev->buf_len)
continue;
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG,
DAVINCI_I2C_IMR_RRDY);
} else {
/* signal can terminate transfer */
terminate_read(dev);
}
break;
case DAVINCI_I2C_IVR_XRDY:
if (dev->buf_len) {
davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
*dev->buf++);
dev->buf_len--;
if (dev->buf_len)
continue;
w = davinci_i2c_read_reg(dev,
DAVINCI_I2C_IMR_REG);
MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
davinci_i2c_write_reg(dev,
DAVINCI_I2C_IMR_REG,
w);
} else {
/* signal can terminate transfer */
terminate_write(dev);
}
break;
case DAVINCI_I2C_IVR_SCD:
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
complete(&dev->cmd_complete);
break;
case DAVINCI_I2C_IVR_AAS:
dev_dbg(dev->dev, "Address as slave interrupt\n");
break;
default:
dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
break;
}
}
return count ? IRQ_HANDLED : IRQ_NONE;
}
static struct i2c_algorithm i2c_davinci_algo = {
.master_xfer = i2c_davinci_xfer,
.functionality = i2c_davinci_func,
};
static int davinci_i2c_probe(struct platform_device *pdev)
{
struct davinci_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, resource_size(mem),
pdev->name);
if (!ioarea) {
dev_err(&pdev->dev, "I2C region already claimed\n");
return -EBUSY;
}
dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
if (!dev) {
r = -ENOMEM;
goto err_release_region;
}
init_completion(&dev->cmd_complete);
dev->dev = get_device(&pdev->dev);
dev->irq = irq->start;
platform_set_drvdata(pdev, dev);
dev->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk)) {
r = -ENODEV;
goto err_free_mem;
}
clk_enable(dev->clk);
dev->base = (void __iomem *)IO_ADDRESS(mem->start);
i2c_davinci_init(dev);
r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
if (r) {
dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
goto err_unuse_clocks;
}
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_HWMON;
strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
adap->algo = &i2c_davinci_algo;
adap->dev.parent = &pdev->dev;
adap->timeout = DAVINCI_I2C_TIMEOUT;
adap->nr = pdev->id;
r = i2c_add_numbered_adapter(adap);
if (r) {
dev_err(&pdev->dev, "failure adding adapter\n");
goto err_free_irq;
}
return 0;
err_free_irq:
free_irq(dev->irq, dev);
err_unuse_clocks:
clk_disable(dev->clk);
clk_put(dev->clk);
dev->clk = NULL;
err_free_mem:
platform_set_drvdata(pdev, NULL);
put_device(&pdev->dev);
kfree(dev);
err_release_region:
release_mem_region(mem->start, resource_size(mem));
return r;
}
static int davinci_i2c_remove(struct platform_device *pdev)
{
struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
struct resource *mem;
platform_set_drvdata(pdev, NULL);
i2c_del_adapter(&dev->adapter);
put_device(&pdev->dev);
clk_disable(dev->clk);
clk_put(dev->clk);
dev->clk = NULL;
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
free_irq(IRQ_I2C, dev);
kfree(dev);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(mem->start, resource_size(mem));
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_davinci");
static struct platform_driver davinci_i2c_driver = {
.probe = davinci_i2c_probe,
.remove = davinci_i2c_remove,
.driver = {
.name = "i2c_davinci",
.owner = THIS_MODULE,
},
};
/* I2C may be needed to bring up other drivers */
static int __init davinci_i2c_init_driver(void)
{
return platform_driver_register(&davinci_i2c_driver);
}
subsys_initcall(davinci_i2c_init_driver);
static void __exit davinci_i2c_exit_driver(void)
{
platform_driver_unregister(&davinci_i2c_driver);
}
module_exit(davinci_i2c_exit_driver);
MODULE_AUTHOR("Texas Instruments India");
MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
MODULE_LICENSE("GPL");
