UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/drivers/i2c/busses/i2c-pxa.c

1185 lines
27 KiB
C
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 <asm/irq.h>
#include <asm/io.h>
#include <plat/i2c.h>
/*
* I2C register offsets will be shifted 0 or 1 bit left, depending on
* different SoCs
*/
#define REG_SHIFT_0 (0 << 0)
#define REG_SHIFT_1 (1 << 0)
#define REG_SHIFT(d) ((d) & 0x1)
static const struct platform_device_id i2c_pxa_id_table[] = {
{ "pxa2xx-i2c", REG_SHIFT_1 },
{ "pxa3xx-pwri2c", REG_SHIFT_0 },
{ },
};
MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
/*
* 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(KERN_ERR "i2c: error: %s\n", why);
printk(KERN_ERR "i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
printk(KERN_ERR "i2c: ICR: %08x ISR: %08x\n",
readl(_ICR(i2c)), readl(_ISR(i2c)));
printk(KERN_DEBUG "i2c: log: ");
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,
};
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;
struct platform_device_id *id = platform_get_device_id(dev);
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, resource_size(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, resource_size(res));
if (!i2c->reg_base) {
ret = -EIO;
goto eremap;
}
i2c->reg_shift = REG_SHIFT(id->driver_data);
i2c->iobase = res->start;
i2c->iosize = resource_size(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, resource_size(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,
},
.id_table = i2c_pxa_id_table,
};
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);
Reference in New Issue View Git Blame Copy Permalink