linux/drivers/i2c/busses/i2c-s3c2410.c
Wolfram Sang eadd709f5d i2c: s3c2410: enable RuntimePM before registering to the core
The core may register clients attached to this master which may use
funtionality from the master. So, RuntimePM must be enabled before, otherwise
this will fail. While here, move drvdata, too.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
2015-10-15 14:26:07 +02:00

1368 lines
33 KiB
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.
*/
#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 <linux/mfd/syscon.h>
#include <linux/regmap.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
/* Exynos5 Sysreg offset */
#define EXYNOS5_SYS_I2C_CFG 0x0234
/* 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
struct regmap *sysreg;
unsigned int sys_i2c_cfg;
};
static const 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 received\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;
}
/*
* Disable the bus so that we won't get any interrupts from now on, or try
* to drive any lines. This is the default state when we don't have
* anything to send/receive.
*
* If there is an event on the bus, or we have a pre-existing event at
* kernel boot time, we may not notice the event and the I2C controller
* will lock the bus with the I2C clock line low indefinitely.
*/
static inline void s3c24xx_i2c_disable_bus(struct s3c24xx_i2c *i2c)
{
unsigned long tmp;
/* Stop driving the I2C pins */
tmp = readl(i2c->regs + S3C2410_IICSTAT);
tmp &= ~S3C2410_IICSTAT_TXRXEN;
writel(tmp, i2c->regs + S3C2410_IICSTAT);
/* We don't expect any interrupts now, and don't want send acks */
tmp = readl(i2c->regs + S3C2410_IICCON);
tmp &= ~(S3C2410_IICCON_IRQEN | S3C2410_IICCON_IRQPEND |
S3C2410_IICCON_ACKEN);
writel(tmp, i2c->regs + S3C2410_IICCON);
}
/* 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);
s3c24xx_i2c_disable_bus(i2c);
out:
i2c->state = STATE_IDLE;
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);
ret = clk_enable(i2c->clk);
if (ret)
return ret;
for (retry = 0; retry < adap->retries; retry++) {
ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
if (ret != -EAGAIN) {
clk_disable(i2c->clk);
pm_runtime_put(&adap->dev);
return ret;
}
dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
udelay(100);
}
clk_disable(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)
{
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(0, i2c->regs + S3C2410_IICCON);
writel(0, i2c->regs + S3C2410_IICSTAT);
/* we need to work out the divisors for the clock... */
if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
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%02x\n",
readl(i2c->regs + S3C2410_IICCON));
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;
int id;
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);
/*
* Exynos5's legacy i2c controller and new high speed i2c
* controller have muxed interrupt sources. By default the
* interrupts for 4-channel HS-I2C controller are enabled.
* If nodes for first four channels of legacy i2c controller
* are available then re-configure the interrupts via the
* system register.
*/
id = of_alias_get_id(np, "i2c");
i2c->sysreg = syscon_regmap_lookup_by_phandle(np,
"samsung,sysreg-phandle");
if (IS_ERR(i2c->sysreg))
return;
regmap_update_bits(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), 0);
}
#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)
return -ENOMEM;
i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!i2c->pdata)
return -ENOMEM;
i2c->quirks = s3c24xx_get_device_quirks(pdev);
i2c->sysreg = ERR_PTR(-ENOENT);
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_DEPRECATED;
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(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");
clk_unprepare(i2c->clk);
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);
clk_unprepare(i2c->clk);
return ret;
}
}
ret = s3c24xx_i2c_register_cpufreq(i2c);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
clk_unprepare(i2c->clk);
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;
platform_set_drvdata(pdev, i2c);
pm_runtime_enable(&pdev->dev);
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add bus to i2c core\n");
pm_runtime_disable(&pdev->dev);
s3c24xx_i2c_deregister_cpufreq(i2c);
clk_unprepare(i2c->clk);
return ret;
}
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);
clk_unprepare(i2c->clk);
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;
if (!IS_ERR(i2c->sysreg))
regmap_read(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, &i2c->sys_i2c_cfg);
return 0;
}
static int s3c24xx_i2c_resume_noirq(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
int ret;
if (!IS_ERR(i2c->sysreg))
regmap_write(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, i2c->sys_i2c_cfg);
ret = clk_enable(i2c->clk);
if (ret)
return ret;
s3c24xx_i2c_init(i2c);
clk_disable(i2c->clk);
i2c->suspended = 0;
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_noirq = s3c24xx_i2c_resume_noirq,
.freeze_noirq = s3c24xx_i2c_suspend_noirq,
.thaw_noirq = s3c24xx_i2c_resume_noirq,
.poweroff_noirq = s3c24xx_i2c_suspend_noirq,
.restore_noirq = s3c24xx_i2c_resume_noirq,
#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 = {
.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");