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u-boot/drivers/i2c/fsl_i2c.c
Chunhe Lan 9c3f77eb3b fsl_i2c: add workaround for the erratum I2C A004447 
This workaround is for the erratum I2C A004447. Device reference
manual provides a scheme that allows the I2C master controller
to generate nine SCL pulses, which enable an I2C slave device
that held SDA low to release SDA. However, due to this erratum,
this scheme no longer works. In addition, when I2C is used as
a source of the PBL, the state machine is not able to recover.

At the same time, delete the reduplicative definition of SVR_VER
and SVR_REV. The SVR_REV is the low 8 bits rather than the low 16
bits of svr. And we use the CONFIG_SYS_FSL_A004447_SVR_REV macro
instead of hard-code value 0x10, 0x11 and 0x20.

The CONFIG_SYS_FSL_A004447_SVR_REV = 0x00 represents that one
version of platform has this I2C errata. So enable this errata
by IS_SVR_REV(svr, maj, min) function.

Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Chunhe Lan <Chunhe.Lan@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Heiko Schocher <hs@denx.de>
2013-08-20 11:15:31 +02:00

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/*
* Copyright 2006,2009 Freescale Semiconductor, Inc.
*
* 2012, Heiko Schocher, DENX Software Engineering, hs@denx.de.
* Changes for multibus/multiadapter I2C support.
*
* 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.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <command.h>
#include <i2c.h> /* Functional interface */
#include <asm/io.h>
#include <asm/fsl_i2c.h> /* HW definitions */
/* The maximum number of microseconds we will wait until another master has
* released the bus. If not defined in the board header file, then use a
* generic value.
*/
#ifndef CONFIG_I2C_MBB_TIMEOUT
#define CONFIG_I2C_MBB_TIMEOUT 100000
#endif
/* The maximum number of microseconds we will wait for a read or write
* operation to complete. If not defined in the board header file, then use a
* generic value.
*/
#ifndef CONFIG_I2C_TIMEOUT
#define CONFIG_I2C_TIMEOUT 10000
#endif
#define I2C_READ_BIT 1
#define I2C_WRITE_BIT 0
DECLARE_GLOBAL_DATA_PTR;
static const struct fsl_i2c *i2c_dev[2] = {
(struct fsl_i2c *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C_OFFSET),
#ifdef CONFIG_SYS_FSL_I2C2_OFFSET
(struct fsl_i2c *)(CONFIG_SYS_IMMR + CONFIG_SYS_FSL_I2C2_OFFSET)
#endif
};
/* I2C speed map for a DFSR value of 1 */
/*
* Map I2C frequency dividers to FDR and DFSR values
*
* This structure is used to define the elements of a table that maps I2C
* frequency divider (I2C clock rate divided by I2C bus speed) to a value to be
* programmed into the Frequency Divider Ratio (FDR) and Digital Filter
* Sampling Rate (DFSR) registers.
*
* The actual table should be defined in the board file, and it must be called
* fsl_i2c_speed_map[].
*
* The last entry of the table must have a value of {-1, X}, where X is same
* FDR/DFSR values as the second-to-last entry. This guarantees that any
* search through the array will always find a match.
*
* The values of the divider must be in increasing numerical order, i.e.
* fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider.
*
* For this table, the values are based on a value of 1 for the DFSR
* register. See the application note AN2919 "Determining the I2C Frequency
* Divider Ratio for SCL"
*
* ColdFire I2C frequency dividers for FDR values are different from
* PowerPC. The protocol to use the I2C module is still the same.
* A different table is defined and are based on MCF5xxx user manual.
*
*/
static const struct {
unsigned short divider;
u8 fdr;
} fsl_i2c_speed_map[] = {
#ifdef __M68K__
{20, 32}, {22, 33}, {24, 34}, {26, 35},
{28, 0}, {28, 36}, {30, 1}, {32, 37},
{34, 2}, {36, 38}, {40, 3}, {40, 39},
{44, 4}, {48, 5}, {48, 40}, {56, 6},
{56, 41}, {64, 42}, {68, 7}, {72, 43},
{80, 8}, {80, 44}, {88, 9}, {96, 41},
{104, 10}, {112, 42}, {128, 11}, {128, 43},
{144, 12}, {160, 13}, {160, 48}, {192, 14},
{192, 49}, {224, 50}, {240, 15}, {256, 51},
{288, 16}, {320, 17}, {320, 52}, {384, 18},
{384, 53}, {448, 54}, {480, 19}, {512, 55},
{576, 20}, {640, 21}, {640, 56}, {768, 22},
{768, 57}, {960, 23}, {896, 58}, {1024, 59},
{1152, 24}, {1280, 25}, {1280, 60}, {1536, 26},
{1536, 61}, {1792, 62}, {1920, 27}, {2048, 63},
{2304, 28}, {2560, 29}, {3072, 30}, {3840, 31},
{-1, 31}
#endif
};
/**
* Set the I2C bus speed for a given I2C device
*
* @param dev: the I2C device
* @i2c_clk: I2C bus clock frequency
* @speed: the desired speed of the bus
*
* The I2C device must be stopped before calling this function.
*
* The return value is the actual bus speed that is set.
*/
static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev,
unsigned int i2c_clk, unsigned int speed)
{
unsigned short divider = min(i2c_clk / speed, (unsigned short) -1);
/*
* We want to choose an FDR/DFSR that generates an I2C bus speed that
* is equal to or lower than the requested speed. That means that we
* want the first divider that is equal to or greater than the
* calculated divider.
*/
#ifdef __PPC__
u8 dfsr, fdr = 0x31; /* Default if no FDR found */
/* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */
unsigned short a, b, ga, gb;
unsigned long c_div, est_div;
#ifdef CONFIG_FSL_I2C_CUSTOM_DFSR
dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR;
#else
/* Condition 1: dfsr <= 50/T */
dfsr = (5 * (i2c_clk / 1000)) / 100000;
#endif
#ifdef CONFIG_FSL_I2C_CUSTOM_FDR
fdr = CONFIG_FSL_I2C_CUSTOM_FDR;
speed = i2c_clk / divider; /* Fake something */
#else
debug("Requested speed:%d, i2c_clk:%d\n", speed, i2c_clk);
if (!dfsr)
dfsr = 1;
est_div = ~0;
for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) {
for (gb = 0; gb < 8; gb++) {
b = 16 << gb;
c_div = b * (a + ((3*dfsr)/b)*2);
if ((c_div > divider) && (c_div < est_div)) {
unsigned short bin_gb, bin_ga;
est_div = c_div;
bin_gb = gb << 2;
bin_ga = (ga & 0x3) | ((ga & 0x4) << 3);
fdr = bin_gb | bin_ga;
speed = i2c_clk / est_div;
debug("FDR:0x%.2x, div:%ld, ga:0x%x, gb:0x%x, "
"a:%d, b:%d, speed:%d\n",
fdr, est_div, ga, gb, a, b, speed);
/* Condition 2 not accounted for */
debug("Tr <= %d ns\n",
(b - 3 * dfsr) * 1000000 /
(i2c_clk / 1000));
}
}
if (a == 20)
a += 2;
if (a == 24)
a += 4;
}
debug("divider:%d, est_div:%ld, DFSR:%d\n", divider, est_div, dfsr);
debug("FDR:0x%.2x, speed:%d\n", fdr, speed);
#endif
writeb(dfsr, &dev->dfsrr); /* set default filter */
writeb(fdr, &dev->fdr); /* set bus speed */
#else
unsigned int i;
for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++)
if (fsl_i2c_speed_map[i].divider >= divider) {
u8 fdr;
fdr = fsl_i2c_speed_map[i].fdr;
speed = i2c_clk / fsl_i2c_speed_map[i].divider;
writeb(fdr, &dev->fdr); /* set bus speed */
break;
}
#endif
return speed;
}
static unsigned int get_i2c_clock(int bus)
{
if (bus)
return gd->arch.i2c2_clk; /* I2C2 clock */
else
return gd->arch.i2c1_clk; /* I2C1 clock */
}
static int fsl_i2c_fixup(const struct fsl_i2c *dev)
{
const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
unsigned long long timeval = 0;
int ret = -1;
unsigned int flags = 0;
#ifdef CONFIG_SYS_FSL_ERRATUM_I2C_A004447
unsigned int svr = get_svr();
if ((SVR_SOC_VER(svr) == SVR_8548 && IS_SVR_REV(svr, 3, 1)) ||
(SVR_REV(svr) <= CONFIG_SYS_FSL_A004447_SVR_REV))
flags = I2C_CR_BIT6;
#endif
writeb(I2C_CR_MEN | I2C_CR_MSTA, &dev->cr);
timeval = get_ticks();
while (!(readb(&dev->sr) & I2C_SR_MBB)) {
if ((get_ticks() - timeval) > timeout)
goto err;
}
if (readb(&dev->sr) & I2C_SR_MAL) {
/* SDA is stuck low */
writeb(0, &dev->cr);
udelay(100);
writeb(I2C_CR_MSTA | flags, &dev->cr);
writeb(I2C_CR_MEN | I2C_CR_MSTA | flags, &dev->cr);
}
readb(&dev->dr);
timeval = get_ticks();
while (!(readb(&dev->sr) & I2C_SR_MIF)) {
if ((get_ticks() - timeval) > timeout)
goto err;
}
ret = 0;
err:
writeb(I2C_CR_MEN | flags, &dev->cr);
writeb(0, &dev->sr);
udelay(100);
return ret;
}
static void fsl_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
{
const struct fsl_i2c *dev;
const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
unsigned long long timeval;
#ifdef CONFIG_SYS_I2C_INIT_BOARD
/* Call board specific i2c bus reset routine before accessing the
* environment, which might be in a chip on that bus. For details
* about this problem see doc/I2C_Edge_Conditions.
*/
i2c_init_board();
#endif
dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
writeb(0, &dev->cr); /* stop I2C controller */
udelay(5); /* let it shutdown in peace */
set_i2c_bus_speed(dev, get_i2c_clock(adap->hwadapnr), speed);
writeb(slaveadd << 1, &dev->adr);/* write slave address */
writeb(0x0, &dev->sr); /* clear status register */
writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */
timeval = get_ticks();
while (readb(&dev->sr) & I2C_SR_MBB) {
if ((get_ticks() - timeval) < timeout)
continue;
if (fsl_i2c_fixup(dev))
debug("i2c_init: BUS#%d failed to init\n",
adap->hwadapnr);
break;
}
#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
/* Call board specific i2c bus reset routine AFTER the bus has been
* initialized. Use either this callpoint or i2c_init_board;
* which is called before i2c_init operations.
* For details about this problem see doc/I2C_Edge_Conditions.
*/
i2c_board_late_init();
#endif
}
static int
i2c_wait4bus(struct i2c_adapter *adap)
{
struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
unsigned long long timeval = get_ticks();
const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
while (readb(&dev->sr) & I2C_SR_MBB) {
if ((get_ticks() - timeval) > timeout)
return -1;
}
return 0;
}
static __inline__ int
i2c_wait(struct i2c_adapter *adap, int write)
{
u32 csr;
unsigned long long timeval = get_ticks();
const unsigned long long timeout = usec2ticks(CONFIG_I2C_TIMEOUT);
struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
do {
csr = readb(&dev->sr);
if (!(csr & I2C_SR_MIF))
continue;
/* Read again to allow register to stabilise */
csr = readb(&dev->sr);
writeb(0x0, &dev->sr);
if (csr & I2C_SR_MAL) {
debug("i2c_wait: MAL\n");
return -1;
}
if (!(csr & I2C_SR_MCF)) {
debug("i2c_wait: unfinished\n");
return -1;
}
if (write == I2C_WRITE_BIT && (csr & I2C_SR_RXAK)) {
debug("i2c_wait: No RXACK\n");
return -1;
}
return 0;
} while ((get_ticks() - timeval) < timeout);
debug("i2c_wait: timed out\n");
return -1;
}
static __inline__ int
i2c_write_addr(struct i2c_adapter *adap, u8 dev, u8 dir, int rsta)
{
struct fsl_i2c *device = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX
| (rsta ? I2C_CR_RSTA : 0),
&device->cr);
writeb((dev << 1) | dir, &device->dr);
if (i2c_wait(adap, I2C_WRITE_BIT) < 0)
return 0;
return 1;
}
static __inline__ int
__i2c_write(struct i2c_adapter *adap, u8 *data, int length)
{
struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
int i;
for (i = 0; i < length; i++) {
writeb(data[i], &dev->dr);
if (i2c_wait(adap, I2C_WRITE_BIT) < 0)
break;
}
return i;
}
static __inline__ int
__i2c_read(struct i2c_adapter *adap, u8 *data, int length)
{
struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
int i;
writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
&dev->cr);
/* dummy read */
readb(&dev->dr);
for (i = 0; i < length; i++) {
if (i2c_wait(adap, I2C_READ_BIT) < 0)
break;
/* Generate ack on last next to last byte */
if (i == length - 2)
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
&dev->cr);
/* Do not generate stop on last byte */
if (i == length - 1)
writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
&dev->cr);
data[i] = readb(&dev->dr);
}
return i;
}
static int
fsl_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr, int alen, u8 *data,
int length)
{
struct fsl_i2c *device = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus(adap) < 0)
return -1;
if ((!length || alen > 0)
&& i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0
&& __i2c_write(adap, &a[4 - alen], alen) == alen)
i = 0; /* No error so far */
if (length &&
i2c_write_addr(adap, dev, I2C_READ_BIT, alen ? 1 : 0) != 0)
i = __i2c_read(adap, data, length);
writeb(I2C_CR_MEN, &device->cr);
if (i2c_wait4bus(adap)) /* Wait until STOP */
debug("i2c_read: wait4bus timed out\n");
if (i == length)
return 0;
return -1;
}
static int
fsl_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr, int alen,
u8 *data, int length)
{
struct fsl_i2c *device = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus(adap) < 0)
return -1;
if (i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0 &&
__i2c_write(adap, &a[4 - alen], alen) == alen) {
i = __i2c_write(adap, data, length);
}
writeb(I2C_CR_MEN, &device->cr);
if (i2c_wait4bus(adap)) /* Wait until STOP */
debug("i2c_write: wait4bus timed out\n");
if (i == length)
return 0;
return -1;
}
static int
fsl_i2c_probe(struct i2c_adapter *adap, uchar chip)
{
struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
/* For unknow reason the controller will ACK when
* probing for a slave with the same address, so skip
* it.
*/
if (chip == (readb(&dev->adr) >> 1))
return -1;
return fsl_i2c_read(adap, chip, 0, 0, NULL, 0);
}
static unsigned int fsl_i2c_set_bus_speed(struct i2c_adapter *adap,
unsigned int speed)
{
struct fsl_i2c *dev = (struct fsl_i2c *)i2c_dev[adap->hwadapnr];
writeb(0, &dev->cr); /* stop controller */
set_i2c_bus_speed(dev, get_i2c_clock(adap->hwadapnr), speed);
writeb(I2C_CR_MEN, &dev->cr); /* start controller */
return 0;
}
/*
* Register fsl i2c adapters
*/
U_BOOT_I2C_ADAP_COMPLETE(fsl_0, fsl_i2c_init, fsl_i2c_probe, fsl_i2c_read,
fsl_i2c_write, fsl_i2c_set_bus_speed,
CONFIG_SYS_FSL_I2C_SPEED, CONFIG_SYS_FSL_I2C_SLAVE,
0)
#ifdef CONFIG_SYS_FSL_I2C2_OFFSET
U_BOOT_I2C_ADAP_COMPLETE(fsl_1, fsl_i2c_init, fsl_i2c_probe, fsl_i2c_read,
fsl_i2c_write, fsl_i2c_set_bus_speed,
CONFIG_SYS_FSL_I2C2_SPEED, CONFIG_SYS_FSL_I2C2_SLAVE,
1)
#endif
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