- 根目录:
- drivers
- i2c
- busses
- i2c-s3c2410.c
/* linux/drivers/i2c/busses/i2c-s3c2410.c
*
* Copyright (C) 2004,2005,2009 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* S3C2410 I2C Controller
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/consumer.h>
#include <asm/irq.h>
#include <linux/platform_data/i2c-s3c2410.h>
/* see s3c2410x user guide, v1.1, section 9 (p447) for more info */
#define S3C2410_IICCON 0x00
#define S3C2410_IICSTAT 0x04
#define S3C2410_IICADD 0x08
#define S3C2410_IICDS 0x0C
#define S3C2440_IICLC 0x10
#define S3C2410_IICCON_ACKEN (1 << 7)
#define S3C2410_IICCON_TXDIV_16 (0 << 6)
#define S3C2410_IICCON_TXDIV_512 (1 << 6)
#define S3C2410_IICCON_IRQEN (1 << 5)
#define S3C2410_IICCON_IRQPEND (1 << 4)
#define S3C2410_IICCON_SCALE(x) ((x) & 0xf)
#define S3C2410_IICCON_SCALEMASK (0xf)
#define S3C2410_IICSTAT_MASTER_RX (2 << 6)
#define S3C2410_IICSTAT_MASTER_TX (3 << 6)
#define S3C2410_IICSTAT_SLAVE_RX (0 << 6)
#define S3C2410_IICSTAT_SLAVE_TX (1 << 6)
#define S3C2410_IICSTAT_MODEMASK (3 << 6)
#define S3C2410_IICSTAT_START (1 << 5)
#define S3C2410_IICSTAT_BUSBUSY (1 << 5)
#define S3C2410_IICSTAT_TXRXEN (1 << 4)
#define S3C2410_IICSTAT_ARBITR (1 << 3)
#define S3C2410_IICSTAT_ASSLAVE (1 << 2)
#define S3C2410_IICSTAT_ADDR0 (1 << 1)
#define S3C2410_IICSTAT_LASTBIT (1 << 0)
#define S3C2410_IICLC_SDA_DELAY0 (0 << 0)
#define S3C2410_IICLC_SDA_DELAY5 (1 << 0)
#define S3C2410_IICLC_SDA_DELAY10 (2 << 0)
#define S3C2410_IICLC_SDA_DELAY15 (3 << 0)
#define S3C2410_IICLC_SDA_DELAY_MASK (3 << 0)
#define S3C2410_IICLC_FILTER_ON (1 << 2)
/* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
#define QUIRK_S3C2440 (1 << 0)
#define QUIRK_HDMIPHY (1 << 1)
#define QUIRK_NO_GPIO (1 << 2)
#define QUIRK_POLL (1 << 3)
/* Max time to wait for bus to become idle after a xfer (in us) */
#define S3C2410_IDLE_TIMEOUT 5000
/* i2c controller state */
enum s3c24xx_i2c_state {
STATE_IDLE,
STATE_START,
STATE_READ,
STATE_WRITE,
STATE_STOP
};
struct s3c24xx_i2c {
wait_queue_head_t wait;
kernel_ulong_t quirks;
unsigned int suspended:1;
struct i2c_msg *msg;
unsigned int msg_num;
unsigned int msg_idx;
unsigned int msg_ptr;
unsigned int tx_setup;
unsigned int irq;
enum s3c24xx_i2c_state state;
unsigned long clkrate;
void __iomem *regs;
struct clk *clk;
struct device *dev;
struct i2c_adapter adap;
struct s3c2410_platform_i2c *pdata;
int gpios[2];
struct pinctrl *pctrl;
#if defined(CONFIG_ARM_S3C24XX_CPUFREQ)
struct notifier_block freq_transition;
#endif
};
static struct platform_device_id s3c24xx_driver_ids[] = {
{
.name = "s3c2410-i2c",
.driver_data = 0,
}, {
.name = "s3c2440-i2c",
.driver_data = QUIRK_S3C2440,
}, {
.name = "s3c2440-hdmiphy-i2c",
.driver_data = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
}, { },
};
MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat);
#ifdef CONFIG_OF
static const struct of_device_id s3c24xx_i2c_match[] = {
{ .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
{ .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
{ .compatible = "samsung,s3c2440-hdmiphy-i2c",
.data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
{ .compatible = "samsung,exynos5440-i2c",
.data = (void *)(QUIRK_S3C2440 | QUIRK_NO_GPIO) },
{ .compatible = "samsung,exynos5-sata-phy-i2c",
.data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) },
{},
};
MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
#endif
/* s3c24xx_get_device_quirks
*
* Get controller type either from device tree or platform device variant.
*/
static inline kernel_ulong_t s3c24xx_get_device_quirks(struct platform_device *pdev)
{
if (pdev->dev.of_node) {
const struct of_device_id *match;
match = of_match_node(s3c24xx_i2c_match, pdev->dev.of_node);
return (kernel_ulong_t)match->data;
}
return platform_get_device_id(pdev)->driver_data;
}
/* s3c24xx_i2c_master_complete
*
* complete the message and wake up the caller, using the given return code,
* or zero to mean ok.
*/
static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
{
dev_dbg(i2c->dev, "master_complete %d\n", ret);
i2c->msg_ptr = 0;
i2c->msg = NULL;
i2c->msg_idx++;
i2c->msg_num = 0;
if (ret)
i2c->msg_idx = ret;
if (!(i2c->quirks & QUIRK_POLL))
wake_up(&i2c->wait);
}
static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
{
unsigned long tmp;
tmp = readl(i2c->regs + S3C2410_IICCON);
writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
}
static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
{
unsigned long tmp;
tmp = readl(i2c->regs + S3C2410_IICCON);
writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
}
/* irq enable/disable functions */
static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
{
unsigned long tmp;
tmp = readl(i2c->regs + S3C2410_IICCON);
writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
}
static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
{
unsigned long tmp;
tmp = readl(i2c->regs + S3C2410_IICCON);
writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
}
static bool is_ack(struct s3c24xx_i2c *i2c)
{
int tries;
for (tries = 50; tries; --tries) {
if (readl(i2c->regs + S3C2410_IICCON)
& S3C2410_IICCON_IRQPEND) {
if (!(readl(i2c->regs + S3C2410_IICSTAT)
& S3C2410_IICSTAT_LASTBIT))
return true;
}
usleep_range(1000, 2000);
}
dev_err(i2c->dev, "ack was not recieved\n");
return false;
}
/* s3c24xx_i2c_message_start
*
* put the start of a message onto the bus
*/
static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
struct i2c_msg *msg)
{
unsigned int addr = (msg->addr & 0x7f) << 1;
unsigned long stat;
unsigned long iiccon;
stat = 0;
stat |= S3C2410_IICSTAT_TXRXEN;
if (msg->flags & I2C_M_RD) {
stat |= S3C2410_IICSTAT_MASTER_RX;
addr |= 1;
} else
stat |= S3C2410_IICSTAT_MASTER_TX;
if (msg->flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
/* todo - check for whether ack wanted or not */
s3c24xx_i2c_enable_ack(i2c);
iiccon = readl(i2c->regs + S3C2410_IICCON);
writel(stat, i2c->regs + S3C2410_IICSTAT);
dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
writeb(addr, i2c->regs + S3C2410_IICDS);
/* delay here to ensure the data byte has gotten onto the bus
* before the transaction is started */
ndelay(i2c->tx_setup);
dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
writel(iiccon, i2c->regs + S3C2410_IICCON);
stat |= S3C2410_IICSTAT_START;
writel(stat, i2c->regs + S3C2410_IICSTAT);
if (i2c->quirks & QUIRK_POLL) {
while ((i2c->msg_num != 0) && is_ack(i2c)) {
i2c_s3c_irq_nextbyte(i2c, stat);
stat = readl(i2c->regs + S3C2410_IICSTAT);
if (stat & S3C2410_IICSTAT_ARBITR)
dev_err(i2c->dev, "deal with arbitration loss\n");
}
}
}
static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
{
unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
dev_dbg(i2c->dev, "STOP\n");
/*
* The datasheet says that the STOP sequence should be:
* 1) I2CSTAT.5 = 0 - Clear BUSY (or 'generate STOP')
* 2) I2CCON.4 = 0 - Clear IRQPEND
* 3) Wait until the stop condition takes effect.
* 4*) I2CSTAT.4 = 0 - Clear TXRXEN
*
* Where, step "4*" is only for buses with the "HDMIPHY" quirk.
*
* However, after much experimentation, it appears that:
* a) normal buses automatically clear BUSY and transition from
* Master->Slave when they complete generating a STOP condition.
* Therefore, step (3) can be done in doxfer() by polling I2CCON.4
* after starting the STOP generation here.
* b) HDMIPHY bus does neither, so there is no way to do step 3.
* There is no indication when this bus has finished generating
* STOP.
*
* In fact, we have found that as soon as the IRQPEND bit is cleared in
* step 2, the HDMIPHY bus generates the STOP condition, and then
* immediately starts transferring another data byte, even though the
* bus is supposedly stopped. This is presumably because the bus is
* still in "Master" mode, and its BUSY bit is still set.
*
* To avoid these extra post-STOP transactions on HDMI phy devices, we
* just disable Serial Output on the bus (I2CSTAT.4 = 0) directly,
* instead of first generating a proper STOP condition. This should
* float SDA & SCK terminating the transfer. Subsequent transfers
* start with a proper START condition, and proceed normally.
*
* The HDMIPHY bus is an internal bus that always has exactly two
* devices, the host as Master and the HDMIPHY device as the slave.
* Skipping the STOP condition has been tested on this bus and works.
*/
if (i2c->quirks & QUIRK_HDMIPHY) {
/* Stop driving the I2C pins */
iicstat &= ~S3C2410_IICSTAT_TXRXEN;
} else {
/* stop the transfer */
iicstat &= ~S3C2410_IICSTAT_START;
}
writel(iicstat, i2c->regs + S3C2410_IICSTAT);
i2c->state = STATE_STOP;
s3c24xx_i2c_master_complete(i2c, ret);
s3c24xx_i2c_disable_irq(i2c);
}
/* helper functions to determine the current state in the set of
* messages we are sending */
/* is_lastmsg()
*
* returns TRUE if the current message is the last in the set
*/
static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
{
return i2c->msg_idx >= (i2c->msg_num - 1);
}
/* is_msglast
*
* returns TRUE if we this is the last byte in the current message
*/
static inline int is_msglast(struct s3c24xx_i2c *i2c)
{
/* msg->len is always 1 for the first byte of smbus block read.
* Actual length will be read from slave. More bytes will be
* read according to the length then. */
if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
return 0;
return i2c->msg_ptr == i2c->msg->len-1;
}
/* is_msgend
*
* returns TRUE if we reached the end of the current message
*/
static inline int is_msgend(struct s3c24xx_i2c *i2c)
{
return i2c->msg_ptr >= i2c->msg->len;
}
/* i2c_s3c_irq_nextbyte
*
* process an interrupt and work out what to do
*/
static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
{
unsigned long tmp;
unsigned char byte;
int ret = 0;
switch (i2c->state) {
case STATE_IDLE:
dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
goto out;
case STATE_STOP:
dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
s3c24xx_i2c_disable_irq(i2c);
goto out_ack;
case STATE_START:
/* last thing we did was send a start condition on the
* bus, or started a new i2c message
*/
if (iicstat & S3C2410_IICSTAT_LASTBIT &&
!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
/* ack was not received... */
dev_dbg(i2c->dev, "ack was not received\n");
s3c24xx_i2c_stop(i2c, -ENXIO);
goto out_ack;
}
if (i2c->msg->flags & I2C_M_RD)
i2c->state = STATE_READ;
else
i2c->state = STATE_WRITE;
/* terminate the transfer if there is nothing to do
* as this is used by the i2c probe to find devices. */
if (is_lastmsg(i2c) && i2c->msg->len == 0) {
s3c24xx_i2c_stop(i2c, 0);
goto out_ack;
}
if (i2c->state == STATE_READ)
goto prepare_read;
/* fall through to the write state, as we will need to
* send a byte as well */
case STATE_WRITE:
/* we are writing data to the device... check for the
* end of the message, and if so, work out what to do
*/
if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
if (iicstat & S3C2410_IICSTAT_LASTBIT) {
dev_dbg(i2c->dev, "WRITE: No Ack\n");
s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
goto out_ack;
}
}
retry_write:
if (!is_msgend(i2c)) {
byte = i2c->msg->buf[i2c->msg_ptr++];
writeb(byte, i2c->regs + S3C2410_IICDS);
/* delay after writing the byte to allow the
* data setup time on the bus, as writing the
* data to the register causes the first bit
* to appear on SDA, and SCL will change as
* soon as the interrupt is acknowledged */
ndelay(i2c->tx_setup);
} else if (!is_lastmsg(i2c)) {
/* we need to go to the next i2c message */
dev_dbg(i2c->dev, "WRITE: Next Message\n");
i2c->msg_ptr = 0;
i2c->msg_idx++;
i2c->msg++;
/* check to see if we need to do another message */
if (i2c->msg->flags & I2C_M_NOSTART) {
if (i2c->msg->flags & I2C_M_RD) {
/* cannot do this, the controller
* forces us to send a new START
* when we change direction */
s3c24xx_i2c_stop(i2c, -EINVAL);
}
goto retry_write;
} else {
/* send the new start */
s3c24xx_i2c_message_start(i2c, i2c->msg);
i2c->state = STATE_START;
}
} else {
/* send stop */
s3c24xx_i2c_stop(i2c, 0);
}
break;
case STATE_READ:
/* we have a byte of data in the data register, do
* something with it, and then work out whether we are
* going to do any more read/write
*/
byte = readb(i2c->regs + S3C2410_IICDS);
i2c->msg->buf[i2c->msg_ptr++] = byte;
/* Add actual length to read for smbus block read */
if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
i2c->msg->len += byte;
prepare_read:
if (is_msglast(i2c)) {
/* last byte of buffer */
if (is_lastmsg(i2c))
s3c24xx_i2c_disable_ack(i2c);
} else if (is_msgend(i2c)) {
/* ok, we've read the entire buffer, see if there
* is anything else we need to do */
if (is_lastmsg(i2c)) {
/* last message, send stop and complete */
dev_dbg(i2c->dev, "READ: Send Stop\n");
s3c24xx_i2c_stop(i2c, 0);
} else {
/* go to the next transfer */
dev_dbg(i2c->dev, "READ: Next Transfer\n");
i2c->msg_ptr = 0;
i2c->msg_idx++;
i2c->msg++;
}
}
break;
}
/* acknowlegde the IRQ and get back on with the work */
out_ack:
tmp = readl(i2c->regs + S3C2410_IICCON);
tmp &= ~S3C2410_IICCON_IRQPEND;
writel(tmp, i2c->regs + S3C2410_IICCON);
out:
return ret;
}
/* s3c24xx_i2c_irq
*
* top level IRQ servicing routine
*/
static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
{
struct s3c24xx_i2c *i2c = dev_id;
unsigned long status;
unsigned long tmp;
status = readl(i2c->regs + S3C2410_IICSTAT);
if (status & S3C2410_IICSTAT_ARBITR) {
/* deal with arbitration loss */
dev_err(i2c->dev, "deal with arbitration loss\n");
}
if (i2c->state == STATE_IDLE) {
dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
tmp = readl(i2c->regs + S3C2410_IICCON);
tmp &= ~S3C2410_IICCON_IRQPEND;
writel(tmp, i2c->regs + S3C2410_IICCON);
goto out;
}
/* pretty much this leaves us with the fact that we've
* transmitted or received whatever byte we last sent */
i2c_s3c_irq_nextbyte(i2c, status);
out:
return IRQ_HANDLED;
}
/* s3c24xx_i2c_set_master
*
* get the i2c bus for a master transaction
*/
static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
{
unsigned long iicstat;
int timeout = 400;
while (timeout-- > 0) {
iicstat = readl(i2c->regs + S3C2410_IICSTAT);
if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
return 0;
msleep(1);
}
return -ETIMEDOUT;
}
/* s3c24xx_i2c_wait_idle
*
* wait for the i2c bus to become idle.
*/
static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
{
unsigned long iicstat;
ktime_t start, now;
unsigned long delay;
int spins;
/* ensure the stop has been through the bus */
dev_dbg(i2c->dev, "waiting for bus idle\n");
start = now = ktime_get();
/*
* Most of the time, the bus is already idle within a few usec of the
* end of a transaction. However, really slow i2c devices can stretch
* the clock, delaying STOP generation.
*
* On slower SoCs this typically happens within a very small number of
* instructions so busy wait briefly to avoid scheduling overhead.
*/
spins = 3;
iicstat = readl(i2c->regs + S3C2410_IICSTAT);
while ((iicstat & S3C2410_IICSTAT_START) && --spins) {
cpu_relax();
iicstat = readl(i2c->regs + S3C2410_IICSTAT);
}
/*
* If we do get an appreciable delay as a compromise between idle
* detection latency for the normal, fast case, and system load in the
* slow device case, use an exponential back off in the polling loop,
* up to 1/10th of the total timeout, then continue to poll at a
* constant rate up to the timeout.
*/
delay = 1;
while ((iicstat & S3C2410_IICSTAT_START) &&
ktime_us_delta(now, start) < S3C2410_IDLE_TIMEOUT) {
usleep_range(delay, 2 * delay);
if (delay < S3C2410_IDLE_TIMEOUT / 10)
delay <<= 1;
now = ktime_get();
iicstat = readl(i2c->regs + S3C2410_IICSTAT);
}
if (iicstat & S3C2410_IICSTAT_START)
dev_warn(i2c->dev, "timeout waiting for bus idle\n");
}
/* s3c24xx_i2c_doxfer
*
* this starts an i2c transfer
*/
static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
struct i2c_msg *msgs, int num)
{
unsigned long timeout;
int ret;
if (i2c->suspended)
return -EIO;
ret = s3c24xx_i2c_set_master(i2c);
if (ret != 0) {
dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
ret = -EAGAIN;
goto out;
}
i2c->msg = msgs;
i2c->msg_num = num;
i2c->msg_ptr = 0;
i2c->msg_idx = 0;
i2c->state = STATE_START;
s3c24xx_i2c_enable_irq(i2c);
s3c24xx_i2c_message_start(i2c, msgs);
if (i2c->quirks & QUIRK_POLL) {
ret = i2c->msg_idx;
if (ret != num)
dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
goto out;
}
timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
ret = i2c->msg_idx;
/* having these next two as dev_err() makes life very
* noisy when doing an i2cdetect */
if (timeout == 0)
dev_dbg(i2c->dev, "timeout\n");
else if (ret != num)
dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
/* For QUIRK_HDMIPHY, bus is already disabled */
if (i2c->quirks & QUIRK_HDMIPHY)
goto out;
s3c24xx_i2c_wait_idle(i2c);
out:
return ret;
}
/* s3c24xx_i2c_xfer
*
* first port of call from the i2c bus code when an message needs
* transferring across the i2c bus.
*/
static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
int retry;
int ret;
pm_runtime_get_sync(&adap->dev);
clk_prepare_enable(i2c->clk);
for (retry = 0; retry < adap->retries; retry++) {
ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
if (ret != -EAGAIN) {
clk_disable_unprepare(i2c->clk);
pm_runtime_put(&adap->dev);
return ret;
}
dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
udelay(100);
}
clk_disable_unprepare(i2c->clk);
pm_runtime_put(&adap->dev);
return -EREMOTEIO;
}
/* declare our i2c functionality */
static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
I2C_FUNC_PROTOCOL_MANGLING;
}
/* i2c bus registration info */
static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
.master_xfer = s3c24xx_i2c_xfer,
.functionality = s3c24xx_i2c_func,
};
/* s3c24xx_i2c_calcdivisor
*
* return the divisor settings for a given frequency
*/
static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
unsigned int *div1, unsigned int *divs)
{
unsigned int calc_divs = clkin / wanted;
unsigned int calc_div1;
if (calc_divs > (16*16))
calc_div1 = 512;
else
calc_div1 = 16;
calc_divs += calc_div1-1;
calc_divs /= calc_div1;
if (calc_divs == 0)
calc_divs = 1;
if (calc_divs > 17)
calc_divs = 17;
*divs = calc_divs;
*div1 = calc_div1;
return clkin / (calc_divs * calc_div1);
}
/* s3c24xx_i2c_clockrate
*
* work out a divisor for the user requested frequency setting,
* either by the requested frequency, or scanning the acceptable
* range of frequencies until something is found
*/
static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
{
struct s3c2410_platform_i2c *pdata = i2c->pdata;
unsigned long clkin = clk_get_rate(i2c->clk);
unsigned int divs, div1;
unsigned long target_frequency;
u32 iiccon;
int freq;
i2c->clkrate = clkin;
clkin /= 1000; /* clkin now in KHz */
dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
target_frequency = pdata->frequency ? pdata->frequency : 100000;
target_frequency /= 1000; /* Target frequency now in KHz */
freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
if (freq > target_frequency) {
dev_err(i2c->dev,
"Unable to achieve desired frequency %luKHz." \
" Lowest achievable %dKHz\n", target_frequency, freq);
return -EINVAL;
}
*got = freq;
iiccon = readl(i2c->regs + S3C2410_IICCON);
iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
iiccon |= (divs-1);
if (div1 == 512)
iiccon |= S3C2410_IICCON_TXDIV_512;
if (i2c->quirks & QUIRK_POLL)
iiccon |= S3C2410_IICCON_SCALE(2);
writel(iiccon, i2c->regs + S3C2410_IICCON);
if (i2c->quirks & QUIRK_S3C2440) {
unsigned long sda_delay;
if (pdata->sda_delay) {
sda_delay = clkin * pdata->sda_delay;
sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
sda_delay = DIV_ROUND_UP(sda_delay, 5);
if (sda_delay > 3)
sda_delay = 3;
sda_delay |= S3C2410_IICLC_FILTER_ON;
} else
sda_delay = 0;
dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
writel(sda_delay, i2c->regs + S3C2440_IICLC);
}
return 0;
}
#if defined(CONFIG_ARM_S3C24XX_CPUFREQ)
#define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
unsigned long val, void *data)
{
struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
unsigned int got;
int delta_f;
int ret;
delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
/* if we're post-change and the input clock has slowed down
* or at pre-change and the clock is about to speed up, then
* adjust our clock rate. <0 is slow, >0 speedup.
*/
if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
(val == CPUFREQ_PRECHANGE && delta_f > 0)) {
i2c_lock_adapter(&i2c->adap);
ret = s3c24xx_i2c_clockrate(i2c, &got);
i2c_unlock_adapter(&i2c->adap);
if (ret < 0)
dev_err(i2c->dev, "cannot find frequency\n");
else
dev_info(i2c->dev, "setting freq %d\n", got);
}
return 0;
}
static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
{
i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
return cpufreq_register_notifier(&i2c->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
{
cpufreq_unregister_notifier(&i2c->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
#else
static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
{
return 0;
}
static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
{
}
#endif
#ifdef CONFIG_OF
static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
{
int idx, gpio, ret;
if (i2c->quirks & QUIRK_NO_GPIO)
return 0;
for (idx = 0; idx < 2; idx++) {
gpio = of_get_gpio(i2c->dev->of_node, idx);
if (!gpio_is_valid(gpio)) {
dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
goto free_gpio;
}
i2c->gpios[idx] = gpio;
ret = gpio_request(gpio, "i2c-bus");
if (ret) {
dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
goto free_gpio;
}
}
return 0;
free_gpio:
while (--idx >= 0)
gpio_free(i2c->gpios[idx]);
return -EINVAL;
}
static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
{
unsigned int idx;
if (i2c->quirks & QUIRK_NO_GPIO)
return;
for (idx = 0; idx < 2; idx++)
gpio_free(i2c->gpios[idx]);
}
#else
static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
{
return 0;
}
static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
{
}
#endif
/* s3c24xx_i2c_init
*
* initialise the controller, set the IO lines and frequency
*/
static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
{
unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
struct s3c2410_platform_i2c *pdata;
unsigned int freq;
/* get the plafrom data */
pdata = i2c->pdata;
/* write slave address */
writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
writel(iicon, i2c->regs + S3C2410_IICCON);
/* we need to work out the divisors for the clock... */
if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
writel(0, i2c->regs + S3C2410_IICCON);
dev_err(i2c->dev, "cannot meet bus frequency required\n");
return -EINVAL;
}
/* todo - check that the i2c lines aren't being dragged anywhere */
dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
return 0;
}
#ifdef CONFIG_OF
/* s3c24xx_i2c_parse_dt
*
* Parse the device tree node and retreive the platform data.
*/
static void
s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
{
struct s3c2410_platform_i2c *pdata = i2c->pdata;
if (!np)
return;
pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
of_property_read_u32(np, "samsung,i2c-max-bus-freq",
(u32 *)&pdata->frequency);
}
#else
static void
s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
{
return;
}
#endif
/* s3c24xx_i2c_probe
*
* called by the bus driver when a suitable device is found
*/
static int s3c24xx_i2c_probe(struct platform_device *pdev)
{
struct s3c24xx_i2c *i2c;
struct s3c2410_platform_i2c *pdata = NULL;
struct resource *res;
int ret;
if (!pdev->dev.of_node) {
pdata = dev_get_platdata(&pdev->dev);
if (!pdata) {
dev_err(&pdev->dev, "no platform data\n");
return -EINVAL;
}
}
i2c = devm_kzalloc(&pdev->dev, sizeof(struct s3c24xx_i2c), GFP_KERNEL);
if (!i2c) {
dev_err(&pdev->dev, "no memory for state\n");
return -ENOMEM;
}
i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!i2c->pdata) {
dev_err(&pdev->dev, "no memory for platform data\n");
return -ENOMEM;
}
i2c->quirks = s3c24xx_get_device_quirks(pdev);
if (pdata)
memcpy(i2c->pdata, pdata, sizeof(*pdata));
else
s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
i2c->adap.owner = THIS_MODULE;
i2c->adap.algo = &s3c24xx_i2c_algorithm;
i2c->adap.retries = 2;
i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
i2c->tx_setup = 50;
init_waitqueue_head(&i2c->wait);
/* find the clock and enable it */
i2c->dev = &pdev->dev;
i2c->clk = devm_clk_get(&pdev->dev, "i2c");
if (IS_ERR(i2c->clk)) {
dev_err(&pdev->dev, "cannot get clock\n");
return -ENOENT;
}
dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
/* map the registers */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
i2c->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(i2c->regs))
return PTR_ERR(i2c->regs);
dev_dbg(&pdev->dev, "registers %p (%p)\n",
i2c->regs, res);
/* setup info block for the i2c core */
i2c->adap.algo_data = i2c;
i2c->adap.dev.parent = &pdev->dev;
i2c->pctrl = devm_pinctrl_get_select_default(i2c->dev);
/* inititalise the i2c gpio lines */
if (i2c->pdata->cfg_gpio) {
i2c->pdata->cfg_gpio(to_platform_device(i2c->dev));
} else if (IS_ERR(i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c)) {
return -EINVAL;
}
/* initialise the i2c controller */
clk_prepare_enable(i2c->clk);
ret = s3c24xx_i2c_init(i2c);
clk_disable_unprepare(i2c->clk);
if (ret != 0) {
dev_err(&pdev->dev, "I2C controller init failed\n");
return ret;
}
/* find the IRQ for this unit (note, this relies on the init call to
* ensure no current IRQs pending
*/
if (!(i2c->quirks & QUIRK_POLL)) {
i2c->irq = ret = platform_get_irq(pdev, 0);
if (ret <= 0) {
dev_err(&pdev->dev, "cannot find IRQ\n");
return ret;
}
ret = devm_request_irq(&pdev->dev, i2c->irq, s3c24xx_i2c_irq, 0,
dev_name(&pdev->dev), i2c);
if (ret != 0) {
dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
return ret;
}
}
ret = s3c24xx_i2c_register_cpufreq(i2c);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
return ret;
}
/* Note, previous versions of the driver used i2c_add_adapter()
* to add the bus at any number. We now pass the bus number via
* the platform data, so if unset it will now default to always
* being bus 0.
*/
i2c->adap.nr = i2c->pdata->bus_num;
i2c->adap.dev.of_node = pdev->dev.of_node;
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add bus to i2c core\n");
s3c24xx_i2c_deregister_cpufreq(i2c);
return ret;
}
platform_set_drvdata(pdev, i2c);
pm_runtime_enable(&pdev->dev);
pm_runtime_enable(&i2c->adap.dev);
dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
return 0;
}
/* s3c24xx_i2c_remove
*
* called when device is removed from the bus
*/
static int s3c24xx_i2c_remove(struct platform_device *pdev)
{
struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
pm_runtime_disable(&i2c->adap.dev);
pm_runtime_disable(&pdev->dev);
s3c24xx_i2c_deregister_cpufreq(i2c);
i2c_del_adapter(&i2c->adap);
if (pdev->dev.of_node && IS_ERR(i2c->pctrl))
s3c24xx_i2c_dt_gpio_free(i2c);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int s3c24xx_i2c_suspend_noirq(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
i2c->suspended = 1;
return 0;
}
static int s3c24xx_i2c_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
i2c->suspended = 0;
clk_prepare_enable(i2c->clk);
s3c24xx_i2c_init(i2c);
clk_disable_unprepare(i2c->clk);
return 0;
}
#endif
#ifdef CONFIG_PM
static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
#ifdef CONFIG_PM_SLEEP
.suspend_noirq = s3c24xx_i2c_suspend_noirq,
.resume = s3c24xx_i2c_resume,
#endif
};
#define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
#else
#define S3C24XX_DEV_PM_OPS NULL
#endif
/* device driver for platform bus bits */
static struct platform_driver s3c24xx_i2c_driver = {
.probe = s3c24xx_i2c_probe,
.remove = s3c24xx_i2c_remove,
.id_table = s3c24xx_driver_ids,
.driver = {
.owner = THIS_MODULE,
.name = "s3c-i2c",
.pm = S3C24XX_DEV_PM_OPS,
.of_match_table = of_match_ptr(s3c24xx_i2c_match),
},
};
static int __init i2c_adap_s3c_init(void)
{
return platform_driver_register(&s3c24xx_i2c_driver);
}
subsys_initcall(i2c_adap_s3c_init);
static void __exit i2c_adap_s3c_exit(void)
{
platform_driver_unregister(&s3c24xx_i2c_driver);
}
module_exit(i2c_adap_s3c_exit);
MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");