u-boot/drivers/i2c/omap24xx_i2c.c
Lubomir Popov 960187ffa1 ARM: OMAP: I2C: New read, write and probe functions
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>
2013-06-10 08:43:26 -04:00

595 lines
15 KiB
C

/*
* Basic I2C functions
*
* Copyright (c) 2004 Texas Instruments
*
* This package is free software; you can redistribute it and/or
* modify it under the terms of the license found in the file
* named COPYING that should have accompanied this file.
*
* THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Author: Jian Zhang jzhang@ti.com, Texas Instruments
*
* Copyright (c) 2003 Wolfgang Denk, wd@denx.de
* Rewritten to fit into the current U-Boot framework
*
* 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>
#include <asm/arch/i2c.h>
#include <asm/io.h>
#include "omap24xx_i2c.h"
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_event(void);
static void flush_fifo(void);
/*
* For SPL boot some boards need i2c before SDRAM is initialised so force
* variables to live in SRAM
*/
static struct i2c __attribute__((section (".data"))) *i2c_base =
(struct i2c *)I2C_DEFAULT_BASE;
static unsigned int __attribute__((section (".data"))) bus_initialized[I2C_BUS_MAX] =
{ [0 ... (I2C_BUS_MAX-1)] = 0 };
static unsigned int __attribute__((section (".data"))) current_bus = 0;
void i2c_init(int speed, int slaveadd)
{
int psc, fsscll, fssclh;
int hsscll = 0, hssclh = 0;
u32 scll, sclh;
int timeout = I2C_TIMEOUT;
/* Only handle standard, fast and high speeds */
if ((speed != OMAP_I2C_STANDARD) &&
(speed != OMAP_I2C_FAST_MODE) &&
(speed != OMAP_I2C_HIGH_SPEED)) {
printf("Error : I2C unsupported speed %d\n", speed);
return;
}
psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK;
psc -= 1;
if (psc < I2C_PSC_MIN) {
printf("Error : I2C unsupported prescalar %d\n", psc);
return;
}
if (speed == OMAP_I2C_HIGH_SPEED) {
/* High speed */
/* For first phase of HS mode */
fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK /
(2 * OMAP_I2C_FAST_MODE);
fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM;
fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM;
if (((fsscll < 0) || (fssclh < 0)) ||
((fsscll > 255) || (fssclh > 255))) {
puts("Error : I2C initializing first phase clock\n");
return;
}
/* For second phase of HS mode */
hsscll = hssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
hsscll -= I2C_HIGHSPEED_PHASE_TWO_SCLL_TRIM;
hssclh -= I2C_HIGHSPEED_PHASE_TWO_SCLH_TRIM;
if (((fsscll < 0) || (fssclh < 0)) ||
((fsscll > 255) || (fssclh > 255))) {
puts("Error : I2C initializing second phase clock\n");
return;
}
scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll;
sclh = (unsigned int)hssclh << 8 | (unsigned int)fssclh;
} else {
/* Standard and fast speed */
fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed);
fsscll -= I2C_FASTSPEED_SCLL_TRIM;
fssclh -= I2C_FASTSPEED_SCLH_TRIM;
if (((fsscll < 0) || (fssclh < 0)) ||
((fsscll > 255) || (fssclh > 255))) {
puts("Error : I2C initializing clock\n");
return;
}
scll = (unsigned int)fsscll;
sclh = (unsigned int)fssclh;
}
if (readw(&i2c_base->con) & I2C_CON_EN) {
writew(0, &i2c_base->con);
udelay(50000);
}
writew(0x2, &i2c_base->sysc); /* for ES2 after soft reset */
udelay(1000);
writew(I2C_CON_EN, &i2c_base->con);
while (!(readw(&i2c_base->syss) & I2C_SYSS_RDONE) && timeout--) {
if (timeout <= 0) {
puts("ERROR: Timeout in soft-reset\n");
return;
}
udelay(1000);
}
writew(0, &i2c_base->con);
writew(psc, &i2c_base->psc);
writew(scll, &i2c_base->scll);
writew(sclh, &i2c_base->sclh);
/* own address */
writew(slaveadd, &i2c_base->oa);
writew(I2C_CON_EN, &i2c_base->con);
#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);
#endif
udelay(1000);
flush_fifo();
writew(0xFFFF, &i2c_base->stat);
writew(0, &i2c_base->cnt);
if (gd->flags & GD_FLG_RELOC)
bus_initialized[current_bus] = 1;
}
static void flush_fifo(void)
{ u16 stat;
/* note: if you try and read data when its not there or ready
* you get a bus error
*/
while (1) {
stat = readw(&i2c_base->stat);
if (stat == I2C_STAT_RRDY) {
readb(&i2c_base->data);
writew(I2C_STAT_RRDY, &i2c_base->stat);
udelay(1000);
} else
break;
}
}
/*
* 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;
int res = 1; /* default = fail */
if (chip == readw(&i2c_base->oa))
return res;
/* Wait until bus is free */
if (wait_for_bb())
return res;
/* 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_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;
}
/* 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();
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 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);
return 1;
}
if (addr + len > (1 << 16)) {
puts("I2C read: address out of range\n");
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);
/* 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;
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);
return 1;
}
if (addr + len > (1 << 16)) {
printf("I2C write: address 0x%x + 0x%x out of range\n",
addr, len);
return 1;
}
/* Wait until bus not busy */
if (wait_for_bb())
return 1;
/* Start address phase - will write regoffset + len bytes data */
writew(alen + len, &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_TRX |
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_write: error waiting for addr ACK (status=0x%x)\n",
status);
goto wr_exit;
}
if (status & I2C_STAT_XRDY) {
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_write: bus not ready for data Tx (i=%d)\n",
i);
goto wr_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(I2C_WAIT);
}
if (timeout <= 0) {
printf("Timed out in wait_for_bb: status=%04x\n",
stat);
return 1;
}
writew(0xFFFF, &i2c_base->stat); /* clear delayed stuff*/
return 0;
}
/*
* 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(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_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;
}
return status;
}
int i2c_set_bus_num(unsigned int bus)
{
if (bus >= I2C_BUS_MAX) {
printf("Bad bus: %x\n", bus);
return -1;
}
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;
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
#endif
#endif
}
current_bus = bus;
if (!bus_initialized[current_bus])
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
int i2c_get_bus_num(void)
{
return (int) current_bus;
}