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android_kernel_xiaomi_sm8350/drivers/i2c/busses/i2c-pxa.c
Roel Kluin a746b578d8 i2c: Timeouts reach -1 
With a postfix decrement these timeouts reach -1 rather than 0, but
after the loop it is tested whether they have become 0.

As pointed out by Jean Delvare, the condition we are waiting for should
also be tested before the timeout. With the current order, you could
exit with a timeout error while the job is actually done.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-02-24 19:19:48 +01:00

1169 lines
26 KiB
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Raw Blame History

/*
* i2c_adap_pxa.c
*
* I2C adapter for the PXA I2C bus access.
*
* Copyright (C) 2002 Intrinsyc Software Inc.
* Copyright (C) 2004-2005 Deep Blue Solutions Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* History:
* Apr 2002: Initial version [CS]
* Jun 2002: Properly seperated algo/adap [FB]
* Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem]
* Jan 2003: added limited signal handling [Kai-Uwe Bloem]
* Sep 2004: Major rework to ensure efficient bus handling [RMK]
* Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood]
* Feb 2005: Rework slave mode handling [RMK]
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/i2c-pxa.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <mach/i2c.h>
/*
* I2C registers and bit definitions
*/
#define IBMR (0x00)
#define IDBR (0x08)
#define ICR (0x10)
#define ISR (0x18)
#define ISAR (0x20)
#define ICR_START (1 << 0) /* start bit */
#define ICR_STOP (1 << 1) /* stop bit */
#define ICR_ACKNAK (1 << 2) /* send ACK(0) or NAK(1) */
#define ICR_TB (1 << 3) /* transfer byte bit */
#define ICR_MA (1 << 4) /* master abort */
#define ICR_SCLE (1 << 5) /* master clock enable */
#define ICR_IUE (1 << 6) /* unit enable */
#define ICR_GCD (1 << 7) /* general call disable */
#define ICR_ITEIE (1 << 8) /* enable tx interrupts */
#define ICR_IRFIE (1 << 9) /* enable rx interrupts */
#define ICR_BEIE (1 << 10) /* enable bus error ints */
#define ICR_SSDIE (1 << 11) /* slave STOP detected int enable */
#define ICR_ALDIE (1 << 12) /* enable arbitration interrupt */
#define ICR_SADIE (1 << 13) /* slave address detected int enable */
#define ICR_UR (1 << 14) /* unit reset */
#define ICR_FM (1 << 15) /* fast mode */
#define ISR_RWM (1 << 0) /* read/write mode */
#define ISR_ACKNAK (1 << 1) /* ack/nak status */
#define ISR_UB (1 << 2) /* unit busy */
#define ISR_IBB (1 << 3) /* bus busy */
#define ISR_SSD (1 << 4) /* slave stop detected */
#define ISR_ALD (1 << 5) /* arbitration loss detected */
#define ISR_ITE (1 << 6) /* tx buffer empty */
#define ISR_IRF (1 << 7) /* rx buffer full */
#define ISR_GCAD (1 << 8) /* general call address detected */
#define ISR_SAD (1 << 9) /* slave address detected */
#define ISR_BED (1 << 10) /* bus error no ACK/NAK */
struct pxa_i2c {
spinlock_t lock;
wait_queue_head_t wait;
struct i2c_msg *msg;
unsigned int msg_num;
unsigned int msg_idx;
unsigned int msg_ptr;
unsigned int slave_addr;
struct i2c_adapter adap;
struct clk *clk;
#ifdef CONFIG_I2C_PXA_SLAVE
struct i2c_slave_client *slave;
#endif
unsigned int irqlogidx;
u32 isrlog[32];
u32 icrlog[32];
void __iomem *reg_base;
unsigned int reg_shift;
unsigned long iobase;
unsigned long iosize;
int irq;
unsigned int use_pio :1;
unsigned int fast_mode :1;
};
#define _IBMR(i2c) ((i2c)->reg_base + (0x0 << (i2c)->reg_shift))
#define _IDBR(i2c) ((i2c)->reg_base + (0x4 << (i2c)->reg_shift))
#define _ICR(i2c) ((i2c)->reg_base + (0x8 << (i2c)->reg_shift))
#define _ISR(i2c) ((i2c)->reg_base + (0xc << (i2c)->reg_shift))
#define _ISAR(i2c) ((i2c)->reg_base + (0x10 << (i2c)->reg_shift))
/*
* I2C Slave mode address
*/
#define I2C_PXA_SLAVE_ADDR 0x1
#ifdef DEBUG
struct bits {
u32 mask;
const char *set;
const char *unset;
};
#define PXA_BIT(m, s, u) { .mask = m, .set = s, .unset = u }
static inline void
decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
{
printk("%s %08x: ", prefix, val);
while (num--) {
const char *str = val & bits->mask ? bits->set : bits->unset;
if (str)
printk("%s ", str);
bits++;
}
}
static const struct bits isr_bits[] = {
PXA_BIT(ISR_RWM, "RX", "TX"),
PXA_BIT(ISR_ACKNAK, "NAK", "ACK"),
PXA_BIT(ISR_UB, "Bsy", "Rdy"),
PXA_BIT(ISR_IBB, "BusBsy", "BusRdy"),
PXA_BIT(ISR_SSD, "SlaveStop", NULL),
PXA_BIT(ISR_ALD, "ALD", NULL),
PXA_BIT(ISR_ITE, "TxEmpty", NULL),
PXA_BIT(ISR_IRF, "RxFull", NULL),
PXA_BIT(ISR_GCAD, "GenCall", NULL),
PXA_BIT(ISR_SAD, "SlaveAddr", NULL),
PXA_BIT(ISR_BED, "BusErr", NULL),
};
static void decode_ISR(unsigned int val)
{
decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
printk("\n");
}
static const struct bits icr_bits[] = {
PXA_BIT(ICR_START, "START", NULL),
PXA_BIT(ICR_STOP, "STOP", NULL),
PXA_BIT(ICR_ACKNAK, "ACKNAK", NULL),
PXA_BIT(ICR_TB, "TB", NULL),
PXA_BIT(ICR_MA, "MA", NULL),
PXA_BIT(ICR_SCLE, "SCLE", "scle"),
PXA_BIT(ICR_IUE, "IUE", "iue"),
PXA_BIT(ICR_GCD, "GCD", NULL),
PXA_BIT(ICR_ITEIE, "ITEIE", NULL),
PXA_BIT(ICR_IRFIE, "IRFIE", NULL),
PXA_BIT(ICR_BEIE, "BEIE", NULL),
PXA_BIT(ICR_SSDIE, "SSDIE", NULL),
PXA_BIT(ICR_ALDIE, "ALDIE", NULL),
PXA_BIT(ICR_SADIE, "SADIE", NULL),
PXA_BIT(ICR_UR, "UR", "ur"),
};
#ifdef CONFIG_I2C_PXA_SLAVE
static void decode_ICR(unsigned int val)
{
decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
printk("\n");
}
#endif
static unsigned int i2c_debug = DEBUG;
static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
{
dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno,
readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
}
#define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __func__)
#else
#define i2c_debug 0
#define show_state(i2c) do { } while (0)
#define decode_ISR(val) do { } while (0)
#define decode_ICR(val) do { } while (0)
#endif
#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
{
unsigned int i;
printk("i2c: error: %s\n", why);
printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
printk("i2c: ICR: %08x ISR: %08x\n"
"i2c: log: ", readl(_ICR(i2c)), readl(_ISR(i2c)));
for (i = 0; i < i2c->irqlogidx; i++)
printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
printk("\n");
}
static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
{
return !(readl(_ICR(i2c)) & ICR_SCLE);
}
static void i2c_pxa_abort(struct pxa_i2c *i2c)
{
int i = 250;
if (i2c_pxa_is_slavemode(i2c)) {
dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
return;
}
while ((i > 0) && (readl(_IBMR(i2c)) & 0x1) == 0) {
unsigned long icr = readl(_ICR(i2c));
icr &= ~ICR_START;
icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;
writel(icr, _ICR(i2c));
show_state(i2c);
mdelay(1);
i --;
}
writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP),
_ICR(i2c));
}
static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
{
int timeout = DEF_TIMEOUT;
while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
if ((readl(_ISR(i2c)) & ISR_SAD) != 0)
timeout += 4;
msleep(2);
show_state(i2c);
}
if (timeout <= 0)
show_state(i2c);
return timeout <= 0 ? I2C_RETRY : 0;
}
static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
{
unsigned long timeout = jiffies + HZ*4;
while (time_before(jiffies, timeout)) {
if (i2c_debug > 1)
dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
__func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
if (readl(_ISR(i2c)) & ISR_SAD) {
if (i2c_debug > 0)
dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
goto out;
}
/* wait for unit and bus being not busy, and we also do a
* quick check of the i2c lines themselves to ensure they've
* gone high...
*/
if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) == 0 && readl(_IBMR(i2c)) == 3) {
if (i2c_debug > 0)
dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
return 1;
}
msleep(1);
}
if (i2c_debug > 0)
dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
out:
return 0;
}
static int i2c_pxa_set_master(struct pxa_i2c *i2c)
{
if (i2c_debug)
dev_dbg(&i2c->adap.dev, "setting to bus master\n");
if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) != 0) {
dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
if (!i2c_pxa_wait_master(i2c)) {
dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
return I2C_RETRY;
}
}
writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
return 0;
}
#ifdef CONFIG_I2C_PXA_SLAVE
static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
{
unsigned long timeout = jiffies + HZ*1;
/* wait for stop */
show_state(i2c);
while (time_before(jiffies, timeout)) {
if (i2c_debug > 1)
dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
__func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c)));
if ((readl(_ISR(i2c)) & (ISR_UB|ISR_IBB)) == 0 ||
(readl(_ISR(i2c)) & ISR_SAD) != 0 ||
(readl(_ICR(i2c)) & ICR_SCLE) == 0) {
if (i2c_debug > 1)
dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
return 1;
}
msleep(1);
}
if (i2c_debug > 0)
dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
return 0;
}
/*
* clear the hold on the bus, and take of anything else
* that has been configured
*/
static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
{
show_state(i2c);
if (errcode < 0) {
udelay(100); /* simple delay */
} else {
/* we need to wait for the stop condition to end */
/* if we where in stop, then clear... */
if (readl(_ICR(i2c)) & ICR_STOP) {
udelay(100);
writel(readl(_ICR(i2c)) & ~ICR_STOP, _ICR(i2c));
}
if (!i2c_pxa_wait_slave(i2c)) {
dev_err(&i2c->adap.dev, "%s: wait timedout\n",
__func__);
return;
}
}
writel(readl(_ICR(i2c)) & ~(ICR_STOP|ICR_ACKNAK|ICR_MA), _ICR(i2c));
writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
if (i2c_debug) {
dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", readl(_ICR(i2c)), readl(_ISR(i2c)));
decode_ICR(readl(_ICR(i2c)));
}
}
#else
#define i2c_pxa_set_slave(i2c, err) do { } while (0)
#endif
static void i2c_pxa_reset(struct pxa_i2c *i2c)
{
pr_debug("Resetting I2C Controller Unit\n");
/* abort any transfer currently under way */
i2c_pxa_abort(i2c);
/* reset according to 9.8 */
writel(ICR_UR, _ICR(i2c));
writel(I2C_ISR_INIT, _ISR(i2c));
writel(readl(_ICR(i2c)) & ~ICR_UR, _ICR(i2c));
writel(i2c->slave_addr, _ISAR(i2c));
/* set control register values */
writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
#ifdef CONFIG_I2C_PXA_SLAVE
dev_info(&i2c->adap.dev, "Enabling slave mode\n");
writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c));
#endif
i2c_pxa_set_slave(i2c, 0);
/* enable unit */
writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
udelay(100);
}
#ifdef CONFIG_I2C_PXA_SLAVE
/*
* PXA I2C Slave mode
*/
static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
{
if (isr & ISR_BED) {
/* what should we do here? */
} else {
int ret = 0;
if (i2c->slave != NULL)
ret = i2c->slave->read(i2c->slave->data);
writel(ret, _IDBR(i2c));
writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); /* allow next byte */
}
}
static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
{
unsigned int byte = readl(_IDBR(i2c));
if (i2c->slave != NULL)
i2c->slave->write(i2c->slave->data, byte);
writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
}
static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
{
int timeout;
if (i2c_debug > 0)
dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
(isr & ISR_RWM) ? 'r' : 't');
if (i2c->slave != NULL)
i2c->slave->event(i2c->slave->data,
(isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
/*
* slave could interrupt in the middle of us generating a
* start condition... if this happens, we'd better back off
* and stop holding the poor thing up
*/
writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
timeout = 0x10000;
while (1) {
if ((readl(_IBMR(i2c)) & 2) == 2)
break;
timeout--;
if (timeout <= 0) {
dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
break;
}
}
writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
}
static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
{
if (i2c_debug > 2)
dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
if (i2c->slave != NULL)
i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
if (i2c_debug > 2)
dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
/*
* If we have a master-mode message waiting,
* kick it off now that the slave has completed.
*/
if (i2c->msg)
i2c_pxa_master_complete(i2c, I2C_RETRY);
}
#else
static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
{
if (isr & ISR_BED) {
/* what should we do here? */
} else {
writel(0, _IDBR(i2c));
writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
}
}
static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
{
writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
}
static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
{
int timeout;
/*
* slave could interrupt in the middle of us generating a
* start condition... if this happens, we'd better back off
* and stop holding the poor thing up
*/
writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c));
writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c));
timeout = 0x10000;
while (1) {
if ((readl(_IBMR(i2c)) & 2) == 2)
break;
timeout--;
if (timeout <= 0) {
dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
break;
}
}
writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c));
}
static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
{
if (i2c->msg)
i2c_pxa_master_complete(i2c, I2C_RETRY);
}
#endif
/*
* PXA I2C Master mode
*/
static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
{
unsigned int addr = (msg->addr & 0x7f) << 1;
if (msg->flags & I2C_M_RD)
addr |= 1;
return addr;
}
static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
{
u32 icr;
/*
* Step 1: target slave address into IDBR
*/
writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
/*
* Step 2: initiate the write.
*/
icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
writel(icr | ICR_START | ICR_TB, _ICR(i2c));
}
static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
{
u32 icr;
/*
* Clear the STOP and ACK flags
*/
icr = readl(_ICR(i2c));
icr &= ~(ICR_STOP | ICR_ACKNAK);
writel(icr, _ICR(i2c));
}
static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
{
/* make timeout the same as for interrupt based functions */
long timeout = 2 * DEF_TIMEOUT;
/*
* Wait for the bus to become free.
*/
while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
udelay(1000);
show_state(i2c);
}
if (timeout <= 0) {
show_state(i2c);
dev_err(&i2c->adap.dev,
"i2c_pxa: timeout waiting for bus free\n");
return I2C_RETRY;
}
/*
* Set master mode.
*/
writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
return 0;
}
static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
struct i2c_msg *msg, int num)
{
unsigned long timeout = 500000; /* 5 seconds */
int ret = 0;
ret = i2c_pxa_pio_set_master(i2c);
if (ret)
goto out;
i2c->msg = msg;
i2c->msg_num = num;
i2c->msg_idx = 0;
i2c->msg_ptr = 0;
i2c->irqlogidx = 0;
i2c_pxa_start_message(i2c);
while (i2c->msg_num > 0 && --timeout) {
i2c_pxa_handler(0, i2c);
udelay(10);
}
i2c_pxa_stop_message(i2c);
/*
* We place the return code in i2c->msg_idx.
*/
ret = i2c->msg_idx;
out:
if (timeout == 0)
i2c_pxa_scream_blue_murder(i2c, "timeout");
return ret;
}
/*
* We are protected by the adapter bus mutex.
*/
static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
{
long timeout;
int ret;
/*
* Wait for the bus to become free.
*/
ret = i2c_pxa_wait_bus_not_busy(i2c);
if (ret) {
dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
goto out;
}
/*
* Set master mode.
*/
ret = i2c_pxa_set_master(i2c);
if (ret) {
dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
goto out;
}
spin_lock_irq(&i2c->lock);
i2c->msg = msg;
i2c->msg_num = num;
i2c->msg_idx = 0;
i2c->msg_ptr = 0;
i2c->irqlogidx = 0;
i2c_pxa_start_message(i2c);
spin_unlock_irq(&i2c->lock);
/*
* The rest of the processing occurs in the interrupt handler.
*/
timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
i2c_pxa_stop_message(i2c);
/*
* We place the return code in i2c->msg_idx.
*/
ret = i2c->msg_idx;
if (timeout == 0)
i2c_pxa_scream_blue_murder(i2c, "timeout");
out:
return ret;
}
static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
struct i2c_msg msgs[], int num)
{
struct pxa_i2c *i2c = adap->algo_data;
int ret, i;
/* If the I2C controller is disabled we need to reset it
(probably due to a suspend/resume destroying state). We do
this here as we can then avoid worrying about resuming the
controller before its users. */
if (!(readl(_ICR(i2c)) & ICR_IUE))
i2c_pxa_reset(i2c);
for (i = adap->retries; i >= 0; i--) {
ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
if (ret != I2C_RETRY)
goto out;
if (i2c_debug)
dev_dbg(&adap->dev, "Retrying transmission\n");
udelay(100);
}
i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
ret = -EREMOTEIO;
out:
i2c_pxa_set_slave(i2c, ret);
return ret;
}
/*
* i2c_pxa_master_complete - complete the message and wake up.
*/
static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
{
i2c->msg_ptr = 0;
i2c->msg = NULL;
i2c->msg_idx ++;
i2c->msg_num = 0;
if (ret)
i2c->msg_idx = ret;
if (!i2c->use_pio)
wake_up(&i2c->wait);
}
static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
{
u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
again:
/*
* If ISR_ALD is set, we lost arbitration.
*/
if (isr & ISR_ALD) {
/*
* Do we need to do anything here? The PXA docs
* are vague about what happens.
*/
i2c_pxa_scream_blue_murder(i2c, "ALD set");
/*
* We ignore this error. We seem to see spurious ALDs
* for seemingly no reason. If we handle them as I think
* they should, we end up causing an I2C error, which
* is painful for some systems.
*/
return; /* ignore */
}
if (isr & ISR_BED) {
int ret = BUS_ERROR;
/*
* I2C bus error - either the device NAK'd us, or
* something more serious happened. If we were NAK'd
* on the initial address phase, we can retry.
*/
if (isr & ISR_ACKNAK) {
if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
ret = I2C_RETRY;
else
ret = XFER_NAKED;
}
i2c_pxa_master_complete(i2c, ret);
} else if (isr & ISR_RWM) {
/*
* Read mode. We have just sent the address byte, and
* now we must initiate the transfer.
*/
if (i2c->msg_ptr == i2c->msg->len - 1 &&
i2c->msg_idx == i2c->msg_num - 1)
icr |= ICR_STOP | ICR_ACKNAK;
icr |= ICR_ALDIE | ICR_TB;
} else if (i2c->msg_ptr < i2c->msg->len) {
/*
* Write mode. Write the next data byte.
*/
writel(i2c->msg->buf[i2c->msg_ptr++], _IDBR(i2c));
icr |= ICR_ALDIE | ICR_TB;
/*
* If this is the last byte of the last message, send
* a STOP.
*/
if (i2c->msg_ptr == i2c->msg->len &&
i2c->msg_idx == i2c->msg_num - 1)
icr |= ICR_STOP;
} else if (i2c->msg_idx < i2c->msg_num - 1) {
/*
* Next segment of the message.
*/
i2c->msg_ptr = 0;
i2c->msg_idx ++;
i2c->msg++;
/*
* If we aren't doing a repeated start and address,
* go back and try to send the next byte. Note that
* we do not support switching the R/W direction here.
*/
if (i2c->msg->flags & I2C_M_NOSTART)
goto again;
/*
* Write the next address.
*/
writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c));
/*
* And trigger a repeated start, and send the byte.
*/
icr &= ~ICR_ALDIE;
icr |= ICR_START | ICR_TB;
} else {
if (i2c->msg->len == 0) {
/*
* Device probes have a message length of zero
* and need the bus to be reset before it can
* be used again.
*/
i2c_pxa_reset(i2c);
}
i2c_pxa_master_complete(i2c, 0);
}
i2c->icrlog[i2c->irqlogidx-1] = icr;
writel(icr, _ICR(i2c));
show_state(i2c);
}
static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
{
u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);
/*
* Read the byte.
*/
i2c->msg->buf[i2c->msg_ptr++] = readl(_IDBR(i2c));
if (i2c->msg_ptr < i2c->msg->len) {
/*
* If this is the last byte of the last
* message, send a STOP.
*/
if (i2c->msg_ptr == i2c->msg->len - 1)
icr |= ICR_STOP | ICR_ACKNAK;
icr |= ICR_ALDIE | ICR_TB;
} else {
i2c_pxa_master_complete(i2c, 0);
}
i2c->icrlog[i2c->irqlogidx-1] = icr;
writel(icr, _ICR(i2c));
}
static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
{
struct pxa_i2c *i2c = dev_id;
u32 isr = readl(_ISR(i2c));
if (i2c_debug > 2 && 0) {
dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
__func__, isr, readl(_ICR(i2c)), readl(_IBMR(i2c)));
decode_ISR(isr);
}
if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
i2c->isrlog[i2c->irqlogidx++] = isr;
show_state(i2c);
/*
* Always clear all pending IRQs.
*/
writel(isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED), _ISR(i2c));
if (isr & ISR_SAD)
i2c_pxa_slave_start(i2c, isr);
if (isr & ISR_SSD)
i2c_pxa_slave_stop(i2c);
if (i2c_pxa_is_slavemode(i2c)) {
if (isr & ISR_ITE)
i2c_pxa_slave_txempty(i2c, isr);
if (isr & ISR_IRF)
i2c_pxa_slave_rxfull(i2c, isr);
} else if (i2c->msg) {
if (isr & ISR_ITE)
i2c_pxa_irq_txempty(i2c, isr);
if (isr & ISR_IRF)
i2c_pxa_irq_rxfull(i2c, isr);
} else {
i2c_pxa_scream_blue_murder(i2c, "spurious irq");
}
return IRQ_HANDLED;
}
static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct pxa_i2c *i2c = adap->algo_data;
int ret, i;
for (i = adap->retries; i >= 0; i--) {
ret = i2c_pxa_do_xfer(i2c, msgs, num);
if (ret != I2C_RETRY)
goto out;
if (i2c_debug)
dev_dbg(&adap->dev, "Retrying transmission\n");
udelay(100);
}
i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
ret = -EREMOTEIO;
out:
i2c_pxa_set_slave(i2c, ret);
return ret;
}
static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm i2c_pxa_algorithm = {
.master_xfer = i2c_pxa_xfer,
.functionality = i2c_pxa_functionality,
};
static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
.master_xfer = i2c_pxa_pio_xfer,
.functionality = i2c_pxa_functionality,
};
#define res_len(r) ((r)->end - (r)->start + 1)
static int i2c_pxa_probe(struct platform_device *dev)
{
struct pxa_i2c *i2c;
struct resource *res;
struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
int ret;
int irq;
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
irq = platform_get_irq(dev, 0);
if (res == NULL || irq < 0)
return -ENODEV;
if (!request_mem_region(res->start, res_len(res), res->name))
return -ENOMEM;
i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
if (!i2c) {
ret = -ENOMEM;
goto emalloc;
}
i2c->adap.owner = THIS_MODULE;
i2c->adap.retries = 5;
spin_lock_init(&i2c->lock);
init_waitqueue_head(&i2c->wait);
/*
* If "dev->id" is negative we consider it as zero.
* The reason to do so is to avoid sysfs names that only make
* sense when there are multiple adapters.
*/
i2c->adap.nr = dev->id != -1 ? dev->id : 0;
snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u",
i2c->adap.nr);
i2c->clk = clk_get(&dev->dev, NULL);
if (IS_ERR(i2c->clk)) {
ret = PTR_ERR(i2c->clk);
goto eclk;
}
i2c->reg_base = ioremap(res->start, res_len(res));
if (!i2c->reg_base) {
ret = -EIO;
goto eremap;
}
i2c->reg_shift = (cpu_is_pxa3xx() && (dev->id == 1)) ? 0 : 1;
i2c->iobase = res->start;
i2c->iosize = res_len(res);
i2c->irq = irq;
i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
#ifdef CONFIG_I2C_PXA_SLAVE
if (plat) {
i2c->slave_addr = plat->slave_addr;
i2c->slave = plat->slave;
}
#endif
clk_enable(i2c->clk);
if (plat) {
i2c->adap.class = plat->class;
i2c->use_pio = plat->use_pio;
i2c->fast_mode = plat->fast_mode;
}
if (i2c->use_pio) {
i2c->adap.algo = &i2c_pxa_pio_algorithm;
} else {
i2c->adap.algo = &i2c_pxa_algorithm;
ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
i2c->adap.name, i2c);
if (ret)
goto ereqirq;
}
i2c_pxa_reset(i2c);
i2c->adap.algo_data = i2c;
i2c->adap.dev.parent = &dev->dev;
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret < 0) {
printk(KERN_INFO "I2C: Failed to add bus\n");
goto eadapt;
}
platform_set_drvdata(dev, i2c);
#ifdef CONFIG_I2C_PXA_SLAVE
printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
dev_name(&i2c->adap.dev), i2c->slave_addr);
#else
printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
dev_name(&i2c->adap.dev));
#endif
return 0;
eadapt:
if (!i2c->use_pio)
free_irq(irq, i2c);
ereqirq:
clk_disable(i2c->clk);
iounmap(i2c->reg_base);
eremap:
clk_put(i2c->clk);
eclk:
kfree(i2c);
emalloc:
release_mem_region(res->start, res_len(res));
return ret;
}
static int __exit i2c_pxa_remove(struct platform_device *dev)
{
struct pxa_i2c *i2c = platform_get_drvdata(dev);
platform_set_drvdata(dev, NULL);
i2c_del_adapter(&i2c->adap);
if (!i2c->use_pio)
free_irq(i2c->irq, i2c);
clk_disable(i2c->clk);
clk_put(i2c->clk);
iounmap(i2c->reg_base);
release_mem_region(i2c->iobase, i2c->iosize);
kfree(i2c);
return 0;
}
#ifdef CONFIG_PM
static int i2c_pxa_suspend_late(struct platform_device *dev, pm_message_t state)
{
struct pxa_i2c *i2c = platform_get_drvdata(dev);
clk_disable(i2c->clk);
return 0;
}
static int i2c_pxa_resume_early(struct platform_device *dev)
{
struct pxa_i2c *i2c = platform_get_drvdata(dev);
clk_enable(i2c->clk);
i2c_pxa_reset(i2c);
return 0;
}
#else
#define i2c_pxa_suspend_late NULL
#define i2c_pxa_resume_early NULL
#endif
static struct platform_driver i2c_pxa_driver = {
.probe = i2c_pxa_probe,
.remove = __exit_p(i2c_pxa_remove),
.suspend_late = i2c_pxa_suspend_late,
.resume_early = i2c_pxa_resume_early,
.driver = {
.name = "pxa2xx-i2c",
.owner = THIS_MODULE,
},
};
static int __init i2c_adap_pxa_init(void)
{
return platform_driver_register(&i2c_pxa_driver);
}
static void __exit i2c_adap_pxa_exit(void)
{
platform_driver_unregister(&i2c_pxa_driver);
}
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pxa2xx-i2c");
subsys_initcall(i2c_adap_pxa_init);
module_exit(i2c_adap_pxa_exit);
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