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ARM: OMAP: I2C: New read, write and probe functions

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New i2c_read, i2c_write and i2c_probe functions, tested on OMAP4
(4430/60/70), OMAP5 (5430) and AM335X (3359); should work on older
OMAPs and derivatives as well. The only anticipated exception would
be the OMAP2420, which shall require driver modification.
- Rewritten i2c_read to operate correctly with all types of chips
  (old function could not read consistent data from some I2C slaves).
- Optimised i2c_write.
- New i2c_probe, performs write access vs read. The old probe could
  hang the system under certain conditions (e.g. unconfigured pads).
- The read/write/probe functions try to identify unconfigured bus.
- Status functions now read irqstatus_raw as per TRM guidelines
  (except for OMAP243X and OMAP34XX).
- Driver now supports up to I2C5 (OMAP5).

Signed-off-by: Lubomir Popov <lpopov@mm-sol.com>
Tested-by: Heiko Schocher <hs@denx.de>
master
Lubomir Popov 12 years ago committed by Tom Rini
parent 7f5eef93af
commit 960187ffa1
1 changed files with 299 additions and 191 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 490
      drivers/i2c/omap24xx_i2c.c

490
drivers/i2c/omap24xx_i2c.c
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@ -18,6 +18,20 @@
*
* Adapted for OMAP2420 I2C, r-woodruff2@ti.com
*
* Copyright (c) 2013 Lubomir Popov <lpopov@mm-sol.com>, MM Solutions
* New i2c_read, i2c_write and i2c_probe functions, tested on OMAP4
* (4430/60/70), OMAP5 (5430) and AM335X (3359); should work on older
* OMAPs and derivatives as well. The only anticipated exception would
* be the OMAP2420, which shall require driver modification.
* - Rewritten i2c_read to operate correctly with all types of chips
* (old function could not read consistent data from some I2C slaves).
* - Optimized i2c_write.
* - New i2c_probe, performs write access vs read. The old probe could
* hang the system under certain conditions (e.g. unconfigured pads).
* - The read/write/probe functions try to identify unconfigured bus.
* - Status functions now read irqstatus_raw as per TRM guidelines
* (except for OMAP243X and OMAP34XX).
* - Driver now supports up to I2C5 (OMAP5).
*/
#include <common.h>
@ -31,8 +45,11 @@ DECLARE_GLOBAL_DATA_PTR;
#define I2C_TIMEOUT 1000
/* Absolutely safe for status update at 100 kHz I2C: */
#define I2C_WAIT 200
static int wait_for_bb(void);
static u16 wait_for_pin(void);
static u16 wait_for_event(void);
static void flush_fifo(void);
/*
@ -137,10 +154,14 @@ void i2c_init(int speed, int slaveadd)
/* own address */
writew(slaveadd, &i2c_base->oa);
writew(I2C_CON_EN, &i2c_base->con);
/* have to enable intrrupts or OMAP i2c module doesn't work */
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
/*
* Have to enable interrupts for OMAP2/3, these IPs don't have
* an 'irqstatus_raw' register and we shall have to poll 'stat'
*/
writew(I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
I2C_IE_NACK_IE | I2C_IE_AL_IE, &i2c_base->ie);
#endif
udelay(1000);
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
@ -150,88 +171,6 @@ void i2c_init(int speed, int slaveadd)
bus_initialized[current_bus] = 1;
}
static int i2c_read_byte(u8 devaddr, u16 regoffset, u8 alen, u8 *value)
{
int i2c_error = 0;
u16 status;
int i = 2 - alen;
u8 tmpbuf[2] = {(regoffset) >> 8, regoffset & 0xff};
u16 w;
/* wait until bus not busy */
if (wait_for_bb())
return 1;
/* one byte only */
writew(alen, &i2c_base->cnt);
/* set slave address */
writew(devaddr, &i2c_base->sa);
/* no stop bit needed here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
I2C_CON_TRX, &i2c_base->con);
/* send register offset */
while (1) {
status = wait_for_pin();
if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
goto read_exit;
}
if (status & I2C_STAT_XRDY) {
w = tmpbuf[i++];
#if !(defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
defined(CONFIG_OMAP54XX))
w |= tmpbuf[i++] << 8;
#endif
writew(w, &i2c_base->data);
writew(I2C_STAT_XRDY, &i2c_base->stat);
}
if (status & I2C_STAT_ARDY) {
writew(I2C_STAT_ARDY, &i2c_base->stat);
break;
}
}
/* set slave address */
writew(devaddr, &i2c_base->sa);
/* read one byte from slave */
writew(1, &i2c_base->cnt);
/* need stop bit here */
writew(I2C_CON_EN | I2C_CON_MST |
I2C_CON_STT | I2C_CON_STP,
&i2c_base->con);
/* receive data */
while (1) {
status = wait_for_pin();
if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
goto read_exit;
}
if (status & I2C_STAT_RRDY) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
defined(CONFIG_OMAP54XX)
*value = readb(&i2c_base->data);
#else
*value = readw(&i2c_base->data);
#endif
writew(I2C_STAT_RRDY, &i2c_base->stat);
}
if (status & I2C_STAT_ARDY) {
writew(I2C_STAT_ARDY, &i2c_base->stat);
break;
}
}
read_exit:
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
return i2c_error;
}
static void flush_fifo(void)
{ u16 stat;
@ -241,13 +180,7 @@ static void flush_fifo(void)
while (1) {
stat = readw(&i2c_base->stat);
if (stat == I2C_STAT_RRDY) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
defined(CONFIG_OMAP54XX)
readb(&i2c_base->data);
#else
readw(&i2c_base->data);
#endif
writew(I2C_STAT_RRDY, &i2c_base->stat);
udelay(1000);
} else
@ -255,6 +188,10 @@ static void flush_fifo(void)
}
}
/*
* i2c_probe: Use write access. Allows to identify addresses that are
* write-only (like the config register of dual-port EEPROMs)
*/
int i2c_probe(uchar chip)
{
u16 status;
@ -263,61 +200,81 @@ int i2c_probe(uchar chip)
if (chip == readw(&i2c_base->oa))
return res;
/* wait until bus not busy */
/* Wait until bus is free */
if (wait_for_bb())
return res;
/* try to read one byte */
writew(1, &i2c_base->cnt);
/* set slave address */
/* No data transfer, slave addr only */
writew(0, &i2c_base->cnt);
/* Set slave address */
writew(chip, &i2c_base->sa);
/* stop bit needed here */
writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, &i2c_base->con);
while (1) {
status = wait_for_pin();
if (status == 0 || status & I2C_STAT_AL) {
res = 1;
goto probe_exit;
}
if (status & I2C_STAT_NACK) {
res = 1;
writew(0xff, &i2c_base->stat);
writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con);
if (wait_for_bb())
res = 1;
break;
}
if (status & I2C_STAT_ARDY) {
writew(I2C_STAT_ARDY, &i2c_base->stat);
break;
}
if (status & I2C_STAT_RRDY) {
res = 0;
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
defined(CONFIG_OMAP54XX)
readb(&i2c_base->data);
#else
readw(&i2c_base->data);
#endif
writew(I2C_STAT_RRDY, &i2c_base->stat);
}
/* Stop bit needed here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
I2C_CON_STP, &i2c_base->con);
status = wait_for_event();
if ((status & ~I2C_STAT_XRDY) == 0 || (status & I2C_STAT_AL)) {
/*
* With current high-level command implementation, notifying
* the user shall flood the console with 127 messages. If
* silent exit is desired upon unconfigured bus, remove the
* following 'if' section:
*/
if (status == I2C_STAT_XRDY)
printf("i2c_probe: pads on bus %d probably not configured (status=0x%x)\n",
current_bus, status);
goto pr_exit;
}
probe_exit:
/* Check for ACK (!NAK) */
if (!(status & I2C_STAT_NACK)) {
res = 0; /* Device found */
udelay(I2C_WAIT); /* Required by AM335X in SPL */
/* Abort transfer (force idle state) */
writew(I2C_CON_MST | I2C_CON_TRX, &i2c_base->con); /* Reset */
udelay(1000);
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_TRX |
I2C_CON_STP, &i2c_base->con); /* STP */
}
pr_exit:
flush_fifo();
/* don't allow any more data in... we don't want it. */
writew(0, &i2c_base->cnt);
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
return res;
}
/*
* i2c_read: Function now uses a single I2C read transaction with bulk transfer
* of the requested number of bytes (note that the 'i2c md' command
* limits this to 16 bytes anyway). If CONFIG_I2C_REPEATED_START is
* defined in the board config header, this transaction shall be with
* Repeated Start (Sr) between the address and data phases; otherwise
* Stop-Start (P-S) shall be used (some I2C chips do require a P-S).
* The address (reg offset) may be 0, 1 or 2 bytes long.
* Function now reads correctly from chips that return more than one
* byte of data per addressed register (like TI temperature sensors),
* or that do not need a register address at all (such as some clock
* distributors).
*/
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int i;
int i2c_error = 0;
u16 status;
if (alen < 0) {
puts("I2C read: addr len < 0\n");
return 1;
}
if (len < 0) {
puts("I2C read: data len < 0\n");
return 1;
}
if (buffer == NULL) {
puts("I2C read: NULL pointer passed\n");
return 1;
}
if (alen > 2) {
printf("I2C read: addr len %d not supported\n", alen);
@ -329,24 +286,122 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
return 1;
}
for (i = 0; i < len; i++) {
if (i2c_read_byte(chip, addr + i, alen, &buffer[i])) {
puts("I2C read: I/O error\n");
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 1;
/* Wait until bus not busy */
if (wait_for_bb())
return 1;
/* Zero, one or two bytes reg address (offset) */
writew(alen, &i2c_base->cnt);
/* Set slave address */
writew(chip, &i2c_base->sa);
if (alen) {
/* Must write reg offset first */
#ifdef CONFIG_I2C_REPEATED_START
/* No stop bit, use Repeated Start (Sr) */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
I2C_CON_TRX, &i2c_base->con);
#else
/* Stop - Start (P-S) */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP |
I2C_CON_TRX, &i2c_base->con);
#endif
/* Send register offset */
while (1) {
status = wait_for_event();
/* Try to identify bus that is not padconf'd for I2C */
if (status == I2C_STAT_XRDY) {
i2c_error = 2;
printf("i2c_read (addr phase): pads on bus %d probably not configured (status=0x%x)\n",
current_bus, status);
goto rd_exit;
}
if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
printf("i2c_read: error waiting for addr ACK (status=0x%x)\n",
status);
goto rd_exit;
}
if (alen) {
if (status & I2C_STAT_XRDY) {
alen--;
/* Do we have to use byte access? */
writeb((addr >> (8 * alen)) & 0xff,
&i2c_base->data);
writew(I2C_STAT_XRDY, &i2c_base->stat);
}
}
if (status & I2C_STAT_ARDY) {
writew(I2C_STAT_ARDY, &i2c_base->stat);
break;
}
}
}
/* Set slave address */
writew(chip, &i2c_base->sa);
/* Read len bytes from slave */
writew(len, &i2c_base->cnt);
/* Need stop bit here */
writew(I2C_CON_EN | I2C_CON_MST |
I2C_CON_STT | I2C_CON_STP,
&i2c_base->con);
return 0;
/* Receive data */
while (1) {
status = wait_for_event();
/*
* Try to identify bus that is not padconf'd for I2C. This
* state could be left over from previous transactions if
* the address phase is skipped due to alen=0.
*/
if (status == I2C_STAT_XRDY) {
i2c_error = 2;
printf("i2c_read (data phase): pads on bus %d probably not configured (status=0x%x)\n",
current_bus, status);
goto rd_exit;
}
if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
goto rd_exit;
}
if (status & I2C_STAT_RRDY) {
*buffer++ = readb(&i2c_base->data);
writew(I2C_STAT_RRDY, &i2c_base->stat);
}
if (status & I2C_STAT_ARDY) {
writew(I2C_STAT_ARDY, &i2c_base->stat);
break;
}
}
rd_exit:
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
return i2c_error;
}
/* i2c_write: Address (reg offset) may be 0, 1 or 2 bytes long. */
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int i;
u16 status;
int i2c_error = 0;
u16 w;
u8 tmpbuf[2] = {addr >> 8, addr & 0xff};
if (alen < 0) {
puts("I2C write: addr len < 0\n");
return 1;
}
if (len < 0) {
puts("I2C write: data len < 0\n");
return 1;
}
if (buffer == NULL) {
puts("I2C write: NULL pointer passed\n");
return 1;
}
if (alen > 2) {
printf("I2C write: addr len %d not supported\n", alen);
@ -355,92 +410,137 @@ int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
if (addr + len > (1 << 16)) {
printf("I2C write: address 0x%x + 0x%x out of range\n",
addr, len);
addr, len);
return 1;
}
/* wait until bus not busy */
/* Wait until bus not busy */
if (wait_for_bb())
return 1;
/* start address phase - will write regoffset + len bytes data */
/* TODO consider case when !CONFIG_OMAP243X/34XX/44XX */
/* Start address phase - will write regoffset + len bytes data */
writew(alen + len, &i2c_base->cnt);
/* set slave address */
/* Set slave address */
writew(chip, &i2c_base->sa);
/* stop bit needed here */
/* Stop bit needed here */
writew(I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
I2C_CON_STP, &i2c_base->con);
/* Send address and data */
for (i = -alen; i < len; i++) {
status = wait_for_pin();
I2C_CON_STP, &i2c_base->con);
while (alen) {
/* Must write reg offset (one or two bytes) */
status = wait_for_event();
/* Try to identify bus that is not padconf'd for I2C */
if (status == I2C_STAT_XRDY) {
i2c_error = 2;
printf("i2c_write: pads on bus %d probably not configured (status=0x%x)\n",
current_bus, status);
goto wr_exit;
}
if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
printf("i2c error waiting for data ACK (status=0x%x)\n",
status);
goto write_exit;
printf("i2c_write: error waiting for addr ACK (status=0x%x)\n",
status);
goto wr_exit;
}
if (status & I2C_STAT_XRDY) {
w = (i < 0) ? tmpbuf[2+i] : buffer[i];
#if !(defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX) || defined(CONFIG_AM33XX) || \
defined(CONFIG_OMAP54XX))
w |= ((++i < 0) ? tmpbuf[2+i] : buffer[i]) << 8;
#endif
writew(w, &i2c_base->data);
alen--;
writeb((addr >> (8 * alen)) & 0xff, &i2c_base->data);
writew(I2C_STAT_XRDY, &i2c_base->stat);
} else {
i2c_error = 1;
printf("i2c_write: bus not ready for addr Tx (status=0x%x)\n",
status);
goto wr_exit;
}
}
/* Address phase is over, now write data */
for (i = 0; i < len; i++) {
status = wait_for_event();
if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
printf("i2c_write: error waiting for data ACK (status=0x%x)\n",
status);
goto wr_exit;
}
if (status & I2C_STAT_XRDY) {
writeb(buffer[i], &i2c_base->data);
writew(I2C_STAT_XRDY, &i2c_base->stat);
} else {
i2c_error = 1;
printf("i2c bus not ready for Tx (i=%d)\n", i);
goto write_exit;
printf("i2c_write: bus not ready for data Tx (i=%d)\n",
i);
goto wr_exit;
}
}
write_exit:
wr_exit:
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
return i2c_error;
}
/*
* Wait for the bus to be free by checking the Bus Busy (BB)
* bit to become clear
*/
static int wait_for_bb(void)
{
int timeout = I2C_TIMEOUT;
u16 stat;
writew(0xFFFF, &i2c_base->stat); /* clear current interrupts...*/
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
while ((stat = readw(&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
#else
/* Read RAW status */
while ((stat = readw(&i2c_base->irqstatus_raw) &
I2C_STAT_BB) && timeout--) {
#endif
writew(stat, &i2c_base->stat);
udelay(1000);
udelay(I2C_WAIT);
}
if (timeout <= 0) {
printf("timed out in wait_for_bb: I2C_STAT=%x\n",
readw(&i2c_base->stat));
printf("Timed out in wait_for_bb: status=%04x\n",
stat);
return 1;
}
writew(0xFFFF, &i2c_base->stat); /* clear delayed stuff*/
return 0;
}
static u16 wait_for_pin(void)
/*
* Wait for the I2C controller to complete current action
* and update status
*/
static u16 wait_for_event(void)
{
u16 status;
int timeout = I2C_TIMEOUT;
do {
udelay(1000);
udelay(I2C_WAIT);
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX)
status = readw(&i2c_base->stat);
#else
/* Read RAW status */
status = readw(&i2c_base->irqstatus_raw);
#endif
} while (!(status &
(I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
I2C_STAT_AL)) && timeout--);
if (timeout <= 0) {
printf("timed out in wait_for_pin: I2C_STAT=%x\n",
readw(&i2c_base->stat));
printf("Timed out in wait_for_event: status=%04x\n",
status);
/*
* If status is still 0 here, probably the bus pads have
* not been configured for I2C, and/or pull-ups are missing.
*/
printf("Check if pads/pull-ups of bus %d are properly configured\n",
current_bus);
writew(0xFFFF, &i2c_base->stat);
status = 0;
}
@ -450,28 +550,36 @@ static u16 wait_for_pin(void)
int i2c_set_bus_num(unsigned int bus)
{
if ((bus < 0) || (bus >= I2C_BUS_MAX)) {
printf("Bad bus: %d\n", bus);
if (bus >= I2C_BUS_MAX) {
printf("Bad bus: %x\n", bus);
return -1;
}
#if I2C_BUS_MAX == 4
if (bus == 3)
i2c_base = (struct i2c *)I2C_BASE4;
else
if (bus == 2)
switch (bus) {
default:
bus = 0; /* Fall through */
case 0:
i2c_base = (struct i2c *)I2C_BASE1;
break;
case 1:
i2c_base = (struct i2c *)I2C_BASE2;
break;
#if (I2C_BUS_MAX > 2)
case 2:
i2c_base = (struct i2c *)I2C_BASE3;
else
break;
#if (I2C_BUS_MAX > 3)
case 3:
i2c_base = (struct i2c *)I2C_BASE4;
break;
#if (I2C_BUS_MAX > 4)
case 4:
i2c_base = (struct i2c *)I2C_BASE5;
break;
#endif
#if I2C_BUS_MAX == 3
if (bus == 2)
i2c_base = (struct i2c *)I2C_BASE3;
else
#endif
if (bus == 1)
i2c_base = (struct i2c *)I2C_BASE2;
else
i2c_base = (struct i2c *)I2C_BASE1;
#endif
}
current_bus = bus;

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