u-boot/drivers/i2c/mxc_i2c.c
Troy Kisky c4330d283c mxc_i2c: call i2c_imx_stop on error in i2c_read/i2c_write
Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
2012-07-31 07:43:25 +02:00

409 lines
8.8 KiB
C

/*
* i2c driver for Freescale i.MX series
*
* (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
* (c) 2011 Marek Vasut <marek.vasut@gmail.com>
*
* Based on i2c-imx.c from linux kernel:
* Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de>
* Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de>
* Copyright (C) 2007 RightHand Technologies, Inc.
* Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
*
*
* 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
*/
#include <common.h>
#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <i2c.h>
struct mxc_i2c_regs {
uint32_t iadr;
uint32_t ifdr;
uint32_t i2cr;
uint32_t i2sr;
uint32_t i2dr;
};
#define I2CR_IEN (1 << 7)
#define I2CR_IIEN (1 << 6)
#define I2CR_MSTA (1 << 5)
#define I2CR_MTX (1 << 4)
#define I2CR_TX_NO_AK (1 << 3)
#define I2CR_RSTA (1 << 2)
#define I2SR_ICF (1 << 7)
#define I2SR_IBB (1 << 5)
#define I2SR_IIF (1 << 1)
#define I2SR_RX_NO_AK (1 << 0)
#ifdef CONFIG_SYS_I2C_BASE
#define I2C_BASE CONFIG_SYS_I2C_BASE
#else
#error "define CONFIG_SYS_I2C_BASE to use the mxc_i2c driver"
#endif
#define I2C_MAX_TIMEOUT 10000
static u16 i2c_clk_div[50][2] = {
{ 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 },
{ 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 },
{ 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 },
{ 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B },
{ 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A },
{ 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 },
{ 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 },
{ 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 },
{ 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 },
{ 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B },
{ 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
{ 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
{ 3072, 0x1E }, { 3840, 0x1F }
};
/*
* Calculate and set proper clock divider
*/
static uint8_t i2c_imx_get_clk(unsigned int rate)
{
unsigned int i2c_clk_rate;
unsigned int div;
u8 clk_div;
#if defined(CONFIG_MX31)
struct clock_control_regs *sc_regs =
(struct clock_control_regs *)CCM_BASE;
/* start the required I2C clock */
writel(readl(&sc_regs->cgr0) | (3 << CONFIG_SYS_I2C_CLK_OFFSET),
&sc_regs->cgr0);
#endif
/* Divider value calculation */
i2c_clk_rate = mxc_get_clock(MXC_IPG_PERCLK);
div = (i2c_clk_rate + rate - 1) / rate;
if (div < i2c_clk_div[0][0])
clk_div = 0;
else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0])
clk_div = ARRAY_SIZE(i2c_clk_div) - 1;
else
for (clk_div = 0; i2c_clk_div[clk_div][0] < div; clk_div++)
;
/* Store divider value */
return clk_div;
}
/*
* Reset I2C Controller
*/
void i2c_reset(void)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
writeb(0, &i2c_regs->i2cr); /* Reset module */
writeb(0, &i2c_regs->i2sr);
}
/*
* Init I2C Bus
*/
void i2c_init(int speed, int unused)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
u8 clk_idx = i2c_imx_get_clk(speed);
u8 idx = i2c_clk_div[clk_idx][1];
/* Store divider value */
writeb(idx, &i2c_regs->ifdr);
i2c_reset();
}
/*
* Set I2C Speed
*/
int i2c_set_bus_speed(unsigned int speed)
{
i2c_init(speed, 0);
return 0;
}
/*
* Get I2C Speed
*/
unsigned int i2c_get_bus_speed(void)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
u8 clk_idx = readb(&i2c_regs->ifdr);
u8 clk_div;
for (clk_div = 0; i2c_clk_div[clk_div][1] != clk_idx; clk_div++)
;
return mxc_get_clock(MXC_IPG_PERCLK) / i2c_clk_div[clk_div][0];
}
/*
* Wait for bus to be busy (or free if for_busy = 0)
*
* for_busy = 1: Wait for IBB to be asserted
* for_busy = 0: Wait for IBB to be de-asserted
*/
int i2c_imx_bus_busy(int for_busy)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
unsigned int temp;
int timeout = I2C_MAX_TIMEOUT;
while (timeout--) {
temp = readb(&i2c_regs->i2sr);
if (for_busy && (temp & I2SR_IBB))
return 0;
if (!for_busy && !(temp & I2SR_IBB))
return 0;
udelay(1);
}
return 1;
}
/*
* Wait for transaction to complete
*/
int i2c_imx_trx_complete(void)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
int timeout = I2C_MAX_TIMEOUT;
while (timeout--) {
if (readb(&i2c_regs->i2sr) & I2SR_IIF)
return 0;
udelay(1);
}
return -ETIMEDOUT;
}
static int tx_byte(struct mxc_i2c_regs *i2c_regs, u8 byte)
{
int ret;
writeb(0, &i2c_regs->i2sr);
writeb(byte, &i2c_regs->i2dr);
ret = i2c_imx_trx_complete();
if (ret < 0)
return ret;
ret = readb(&i2c_regs->i2sr);
if (ret & I2SR_RX_NO_AK)
return -ENODEV;
return 0;
}
/*
* Start the controller
*/
int i2c_imx_start(void)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
unsigned int temp = 0;
int result;
/* Enable I2C controller */
writeb(0, &i2c_regs->i2sr);
writeb(I2CR_IEN, &i2c_regs->i2cr);
/* Wait controller to be stable */
udelay(50);
/* Start I2C transaction */
temp = readb(&i2c_regs->i2cr);
temp |= I2CR_MSTA;
writeb(temp, &i2c_regs->i2cr);
result = i2c_imx_bus_busy(1);
if (result)
return result;
temp |= I2CR_MTX | I2CR_TX_NO_AK;
writeb(temp, &i2c_regs->i2cr);
return 0;
}
/*
* Stop the controller
*/
void i2c_imx_stop(void)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
unsigned int temp = 0;
/* Stop I2C transaction */
temp = readb(&i2c_regs->i2cr);
temp &= ~(I2CR_MSTA | I2CR_MTX);
writeb(temp, &i2c_regs->i2cr);
i2c_imx_bus_busy(0);
/* Disable I2C controller */
writeb(0, &i2c_regs->i2cr);
}
/*
* Send start signal, chip address and
* write register address
*/
static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
uchar chip, uint addr, int alen)
{
int ret = i2c_imx_start();
if (ret)
goto exit;
/* write slave address */
ret = tx_byte(i2c_regs, chip << 1);
if (ret < 0)
goto exit;
while (alen--) {
ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff);
if (ret < 0)
goto exit;
}
return 0;
exit:
i2c_imx_stop();
return ret;
}
/*
* Try if a chip add given address responds (probe the chip)
*/
int i2c_probe(uchar chip)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
int ret;
ret = i2c_imx_start();
if (ret)
return ret;
ret = tx_byte(i2c_regs, chip << 1);
i2c_imx_stop();
return ret;
}
/*
* Read data from I2C device
*/
int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
int ret;
unsigned int temp;
int i;
ret = i2c_init_transfer(i2c_regs, chip, addr, alen);
if (ret < 0)
return ret;
temp = readb(&i2c_regs->i2cr);
temp |= I2CR_RSTA;
writeb(temp, &i2c_regs->i2cr);
ret = tx_byte(i2c_regs, (chip << 1) | 1);
if (ret < 0) {
i2c_imx_stop();
return ret;
}
/* setup bus to read data */
temp = readb(&i2c_regs->i2cr);
temp &= ~(I2CR_MTX | I2CR_TX_NO_AK);
if (len == 1)
temp |= I2CR_TX_NO_AK;
writeb(temp, &i2c_regs->i2cr);
writeb(0, &i2c_regs->i2sr);
readb(&i2c_regs->i2dr); /* dummy read to clear ICF */
/* read data */
for (i = 0; i < len; i++) {
ret = i2c_imx_trx_complete();
if (ret) {
i2c_imx_stop();
return ret;
}
/*
* It must generate STOP before read I2DR to prevent
* controller from generating another clock cycle
*/
if (i == (len - 1)) {
temp = readb(&i2c_regs->i2cr);
temp &= ~(I2CR_MSTA | I2CR_MTX);
writeb(temp, &i2c_regs->i2cr);
i2c_imx_bus_busy(0);
} else if (i == (len - 2)) {
temp = readb(&i2c_regs->i2cr);
temp |= I2CR_TX_NO_AK;
writeb(temp, &i2c_regs->i2cr);
}
writeb(0, &i2c_regs->i2sr);
buf[i] = readb(&i2c_regs->i2dr);
}
i2c_imx_stop();
return ret;
}
/*
* Write data to I2C device
*/
int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
{
struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
int ret;
int i;
ret = i2c_init_transfer(i2c_regs, chip, addr, alen);
if (ret < 0)
return ret;
for (i = 0; i < len; i++) {
ret = tx_byte(i2c_regs, buf[i]);
if (ret < 0)
break;
}
i2c_imx_stop();
return ret;
}