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u-boot/drivers/i2c/s3c24x0_i2c.c
Rajeshwari Shinde cb466c056a I2C: S3C24X0: Bug fixes in i2c_transfer 
This patch corrects the following issues

1) Write the correct M/T Stop value to I2CSTAT after i2c write.
   According to the spec, after finish the data transmission, we should
   write a M/T Stop (I2C_MODE_MT | I2C_TXRX_ENA) to I2CSTAT instead of
   a M/R Stop (I2C_MODE_MR | I2C_TXRX_ENA).
2) Not split the write to I2CSTAT into 2 steps in i2c read.
   According to the spec, we should write the combined M/R Start value to
   I2CSTAT after setting the slave address to I2CDS
3) Fix the mistake of making an equality check to an assignment.
   In the case of I2C write with the zero-length address, while tranfering the
   data, it should be an equality check (==) instead of an assignment (=).

Signed-off-by: Tom Wai-Hong Tam <waihong@chromium.org>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
2013-03-12 19:33:11 +01:00

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/*
* (C) Copyright 2002
* David Mueller, ELSOFT AG, d.mueller@elsoft.ch
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* 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
*/
/* This code should work for both the S3C2400 and the S3C2410
* as they seem to have the same I2C controller inside.
* The different address mapping is handled by the s3c24xx.h files below.
*/
#include <common.h>
#include <fdtdec.h>
#if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
#include <asm/arch/clk.h>
#include <asm/arch/cpu.h>
#include <asm/arch/pinmux.h>
#else
#include <asm/arch/s3c24x0_cpu.h>
#endif
#include <asm/io.h>
#include <i2c.h>
#include "s3c24x0_i2c.h"
#ifdef CONFIG_HARD_I2C
#define I2C_WRITE 0
#define I2C_READ 1
#define I2C_OK 0
#define I2C_NOK 1
#define I2C_NACK 2
#define I2C_NOK_LA 3 /* Lost arbitration */
#define I2C_NOK_TOUT 4 /* time out */
#define I2CSTAT_BSY 0x20 /* Busy bit */
#define I2CSTAT_NACK 0x01 /* Nack bit */
#define I2CCON_ACKGEN 0x80 /* Acknowledge generation */
#define I2CCON_IRPND 0x10 /* Interrupt pending bit */
#define I2C_MODE_MT 0xC0 /* Master Transmit Mode */
#define I2C_MODE_MR 0x80 /* Master Receive Mode */
#define I2C_START_STOP 0x20 /* START / STOP */
#define I2C_TXRX_ENA 0x10 /* I2C Tx/Rx enable */
#define I2C_TIMEOUT 1 /* 1 second */
/*
* For SPL boot some boards need i2c before SDRAM is initialised so force
* variables to live in SRAM
*/
static unsigned int g_current_bus __attribute__((section(".data")));
#ifdef CONFIG_OF_CONTROL
static int i2c_busses __attribute__((section(".data")));
static struct s3c24x0_i2c_bus i2c_bus[CONFIG_MAX_I2C_NUM]
__attribute__((section(".data")));
#endif
#if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
static int GetI2CSDA(void)
{
struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
#ifdef CONFIG_S3C2410
return (readl(&gpio->gpedat) & 0x8000) >> 15;
#endif
#ifdef CONFIG_S3C2400
return (readl(&gpio->pgdat) & 0x0020) >> 5;
#endif
}
static void SetI2CSCL(int x)
{
struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
#ifdef CONFIG_S3C2410
writel((readl(&gpio->gpedat) & ~0x4000) |
(x & 1) << 14, &gpio->gpedat);
#endif
#ifdef CONFIG_S3C2400
writel((readl(&gpio->pgdat) & ~0x0040) | (x & 1) << 6, &gpio->pgdat);
#endif
}
#endif
static int WaitForXfer(struct s3c24x0_i2c *i2c)
{
int i;
i = I2C_TIMEOUT * 10000;
while (!(readl(&i2c->iiccon) & I2CCON_IRPND) && (i > 0)) {
udelay(100);
i--;
}
return (readl(&i2c->iiccon) & I2CCON_IRPND) ? I2C_OK : I2C_NOK_TOUT;
}
static int IsACK(struct s3c24x0_i2c *i2c)
{
return !(readl(&i2c->iicstat) & I2CSTAT_NACK);
}
static void ReadWriteByte(struct s3c24x0_i2c *i2c)
{
writel(readl(&i2c->iiccon) & ~I2CCON_IRPND, &i2c->iiccon);
}
static struct s3c24x0_i2c *get_base_i2c(void)
{
#ifdef CONFIG_EXYNOS4
struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c *)(samsung_get_base_i2c()
+ (EXYNOS4_I2C_SPACING
* g_current_bus));
return i2c;
#elif defined CONFIG_EXYNOS5
struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c *)(samsung_get_base_i2c()
+ (EXYNOS5_I2C_SPACING
* g_current_bus));
return i2c;
#else
return s3c24x0_get_base_i2c();
#endif
}
static void i2c_ch_init(struct s3c24x0_i2c *i2c, int speed, int slaveadd)
{
ulong freq, pres = 16, div;
#if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
freq = get_i2c_clk();
#else
freq = get_PCLK();
#endif
/* calculate prescaler and divisor values */
if ((freq / pres / (16 + 1)) > speed)
/* set prescaler to 512 */
pres = 512;
div = 0;
while ((freq / pres / (div + 1)) > speed)
div++;
/* set prescaler, divisor according to freq, also set ACKGEN, IRQ */
writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->iiccon);
/* init to SLAVE REVEIVE and set slaveaddr */
writel(0, &i2c->iicstat);
writel(slaveadd, &i2c->iicadd);
/* program Master Transmit (and implicit STOP) */
writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
}
/*
* MULTI BUS I2C support
*/
#ifdef CONFIG_I2C_MULTI_BUS
int i2c_set_bus_num(unsigned int bus)
{
struct s3c24x0_i2c *i2c;
if ((bus < 0) || (bus >= CONFIG_MAX_I2C_NUM)) {
debug("Bad bus: %d\n", bus);
return -1;
}
g_current_bus = bus;
i2c = get_base_i2c();
i2c_ch_init(i2c, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
unsigned int i2c_get_bus_num(void)
{
return g_current_bus;
}
#endif
void i2c_init(int speed, int slaveadd)
{
struct s3c24x0_i2c *i2c;
#if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
#endif
int i;
/* By default i2c channel 0 is the current bus */
g_current_bus = 0;
i2c = get_base_i2c();
/* wait for some time to give previous transfer a chance to finish */
i = I2C_TIMEOUT * 1000;
while ((readl(&i2c->iicstat) & I2CSTAT_BSY) && (i > 0)) {
udelay(1000);
i--;
}
#if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
if ((readl(&i2c->iicstat) & I2CSTAT_BSY) || GetI2CSDA() == 0) {
#ifdef CONFIG_S3C2410
ulong old_gpecon = readl(&gpio->gpecon);
#endif
#ifdef CONFIG_S3C2400
ulong old_gpecon = readl(&gpio->pgcon);
#endif
/* bus still busy probably by (most) previously interrupted
transfer */
#ifdef CONFIG_S3C2410
/* set I2CSDA and I2CSCL (GPE15, GPE14) to GPIO */
writel((readl(&gpio->gpecon) & ~0xF0000000) | 0x10000000,
&gpio->gpecon);
#endif
#ifdef CONFIG_S3C2400
/* set I2CSDA and I2CSCL (PG5, PG6) to GPIO */
writel((readl(&gpio->pgcon) & ~0x00003c00) | 0x00001000,
&gpio->pgcon);
#endif
/* toggle I2CSCL until bus idle */
SetI2CSCL(0);
udelay(1000);
i = 10;
while ((i > 0) && (GetI2CSDA() != 1)) {
SetI2CSCL(1);
udelay(1000);
SetI2CSCL(0);
udelay(1000);
i--;
}
SetI2CSCL(1);
udelay(1000);
/* restore pin functions */
#ifdef CONFIG_S3C2410
writel(old_gpecon, &gpio->gpecon);
#endif
#ifdef CONFIG_S3C2400
writel(old_gpecon, &gpio->pgcon);
#endif
}
#endif /* #if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5) */
i2c_ch_init(i2c, speed, slaveadd);
}
/*
* cmd_type is 0 for write, 1 for read.
*
* addr_len can take any value from 0-255, it is only limited
* by the char, we could make it larger if needed. If it is
* 0 we skip the address write cycle.
*/
static int i2c_transfer(struct s3c24x0_i2c *i2c,
unsigned char cmd_type,
unsigned char chip,
unsigned char addr[],
unsigned char addr_len,
unsigned char data[],
unsigned short data_len)
{
int i, result;
if (data == 0 || data_len == 0) {
/*Don't support data transfer of no length or to address 0 */
debug("i2c_transfer: bad call\n");
return I2C_NOK;
}
/* Check I2C bus idle */
i = I2C_TIMEOUT * 1000;
while ((readl(&i2c->iicstat) & I2CSTAT_BSY) && (i > 0)) {
udelay(1000);
i--;
}
if (readl(&i2c->iicstat) & I2CSTAT_BSY)
return I2C_NOK_TOUT;
writel(readl(&i2c->iiccon) | I2CCON_ACKGEN, &i2c->iiccon);
result = I2C_OK;
switch (cmd_type) {
case I2C_WRITE:
if (addr && addr_len) {
writel(chip, &i2c->iicds);
/* send START */
writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP,
&i2c->iicstat);
i = 0;
while ((i < addr_len) && (result == I2C_OK)) {
result = WaitForXfer(i2c);
writel(addr[i], &i2c->iicds);
ReadWriteByte(i2c);
i++;
}
i = 0;
while ((i < data_len) && (result == I2C_OK)) {
result = WaitForXfer(i2c);
writel(data[i], &i2c->iicds);
ReadWriteByte(i2c);
i++;
}
} else {
writel(chip, &i2c->iicds);
/* send START */
writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP,
&i2c->iicstat);
i = 0;
while ((i < data_len) && (result == I2C_OK)) {
result = WaitForXfer(i2c);
writel(data[i], &i2c->iicds);
ReadWriteByte(i2c);
i++;
}
}
if (result == I2C_OK)
result = WaitForXfer(i2c);
/* send STOP */
writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
ReadWriteByte(i2c);
break;
case I2C_READ:
if (addr && addr_len) {
writel(chip, &i2c->iicds);
/* send START */
writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP,
&i2c->iicstat);
result = WaitForXfer(i2c);
if (IsACK(i2c)) {
i = 0;
while ((i < addr_len) && (result == I2C_OK)) {
writel(addr[i], &i2c->iicds);
ReadWriteByte(i2c);
result = WaitForXfer(i2c);
i++;
}
writel(chip, &i2c->iicds);
/* resend START */
writel(I2C_MODE_MR | I2C_TXRX_ENA |
I2C_START_STOP, &i2c->iicstat);
ReadWriteByte(i2c);
result = WaitForXfer(i2c);
i = 0;
while ((i < data_len) && (result == I2C_OK)) {
/* disable ACK for final READ */
if (i == data_len - 1)
writel(readl(&i2c->iiccon)
& ~I2CCON_ACKGEN,
&i2c->iiccon);
ReadWriteByte(i2c);
result = WaitForXfer(i2c);
data[i] = readl(&i2c->iicds);
i++;
}
} else {
result = I2C_NACK;
}
} else {
writel(chip, &i2c->iicds);
/* send START */
writel(I2C_MODE_MR | I2C_TXRX_ENA | I2C_START_STOP,
&i2c->iicstat);
result = WaitForXfer(i2c);
if (IsACK(i2c)) {
i = 0;
while ((i < data_len) && (result == I2C_OK)) {
/* disable ACK for final READ */
if (i == data_len - 1)
writel(readl(&i2c->iiccon) &
~I2CCON_ACKGEN,
&i2c->iiccon);
ReadWriteByte(i2c);
result = WaitForXfer(i2c);
data[i] = readl(&i2c->iicds);
i++;
}
} else {
result = I2C_NACK;
}
}
/* send STOP */
writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
ReadWriteByte(i2c);
break;
default:
debug("i2c_transfer: bad call\n");
result = I2C_NOK;
break;
}
return result;
}
int i2c_probe(uchar chip)
{
struct s3c24x0_i2c *i2c;
uchar buf[1];
i2c = get_base_i2c();
buf[0] = 0;
/*
* What is needed is to send the chip address and verify that the
* address was <ACK>ed (i.e. there was a chip at that address which
* drove the data line low).
*/
return i2c_transfer(i2c, I2C_READ, chip << 1, 0, 0, buf, 1) != I2C_OK;
}
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
struct s3c24x0_i2c *i2c;
uchar xaddr[4];
int ret;
if (alen > 4) {
debug("I2C read: addr len %d not supported\n", alen);
return 1;
}
if (alen > 0) {
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
}
#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
/*
* EEPROM chips that implement "address overflow" are ones
* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
* address and the extra bits end up in the "chip address"
* bit slots. This makes a 24WC08 (1Kbyte) chip look like
* four 256 byte chips.
*
* Note that we consider the length of the address field to
* still be one byte because the extra address bits are
* hidden in the chip address.
*/
if (alen > 0)
chip |= ((addr >> (alen * 8)) &
CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
#endif
i2c = get_base_i2c();
ret = i2c_transfer(i2c, I2C_READ, chip << 1, &xaddr[4 - alen], alen,
buffer, len);
if (ret != 0) {
debug("I2c read: failed %d\n", ret);
return 1;
}
return 0;
}
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
struct s3c24x0_i2c *i2c;
uchar xaddr[4];
if (alen > 4) {
debug("I2C write: addr len %d not supported\n", alen);
return 1;
}
if (alen > 0) {
xaddr[0] = (addr >> 24) & 0xFF;
xaddr[1] = (addr >> 16) & 0xFF;
xaddr[2] = (addr >> 8) & 0xFF;
xaddr[3] = addr & 0xFF;
}
#ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
/*
* EEPROM chips that implement "address overflow" are ones
* like Catalyst 24WC04/08/16 which has 9/10/11 bits of
* address and the extra bits end up in the "chip address"
* bit slots. This makes a 24WC08 (1Kbyte) chip look like
* four 256 byte chips.
*
* Note that we consider the length of the address field to
* still be one byte because the extra address bits are
* hidden in the chip address.
*/
if (alen > 0)
chip |= ((addr >> (alen * 8)) &
CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
#endif
i2c = get_base_i2c();
return (i2c_transfer
(i2c, I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer,
len) != 0);
}
#ifdef CONFIG_OF_CONTROL
void board_i2c_init(const void *blob)
{
int node_list[CONFIG_MAX_I2C_NUM];
int count, i;
count = fdtdec_find_aliases_for_id(blob, "i2c",
COMPAT_SAMSUNG_S3C2440_I2C, node_list,
CONFIG_MAX_I2C_NUM);
for (i = 0; i < count; i++) {
struct s3c24x0_i2c_bus *bus;
int node = node_list[i];
if (node <= 0)
continue;
bus = &i2c_bus[i];
bus->regs = (struct s3c24x0_i2c *)
fdtdec_get_addr(blob, node, "reg");
bus->id = pinmux_decode_periph_id(blob, node);
bus->node = node;
bus->bus_num = i2c_busses++;
exynos_pinmux_config(bus->id, 0);
}
}
static struct s3c24x0_i2c_bus *get_bus(unsigned int bus_idx)
{
if (bus_idx < i2c_busses)
return &i2c_bus[bus_idx];
debug("Undefined bus: %d\n", bus_idx);
return NULL;
}
int i2c_get_bus_num_fdt(int node)
{
int i;
for (i = 0; i < i2c_busses; i++) {
if (node == i2c_bus[i].node)
return i;
}
debug("%s: Can't find any matched I2C bus\n", __func__);
return -1;
}
int i2c_reset_port_fdt(const void *blob, int node)
{
struct s3c24x0_i2c_bus *i2c;
int bus;
bus = i2c_get_bus_num_fdt(node);
if (bus < 0) {
debug("could not get bus for node %d\n", node);
return -1;
}
i2c = get_bus(bus);
if (!i2c) {
debug("get_bus() failed for node node %d\n", node);
return -1;
}
i2c_ch_init(i2c->regs, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
}
#endif
#endif /* CONFIG_HARD_I2C */
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