u-boot/drivers/i2c/designware_i2c.c

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/*
* (C) Copyright 2009
* Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
*
* 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/io.h>
#include <asm/arch/hardware.h>
#include "designware_i2c.h"
static struct i2c_regs *const i2c_regs_p =
(struct i2c_regs *)CONFIG_SYS_I2C_BASE;
/*
* set_speed - Set the i2c speed mode (standard, high, fast)
* @i2c_spd: required i2c speed mode
*
* Set the i2c speed mode (standard, high, fast)
*/
static void set_speed(int i2c_spd)
{
unsigned int cntl;
unsigned int hcnt, lcnt;
unsigned int high, low;
unsigned int enbl;
/* to set speed cltr must be disabled */
enbl = readl(&i2c_regs_p->ic_enable);
enbl &= ~IC_ENABLE_0B;
writel(enbl, &i2c_regs_p->ic_enable);
cntl = (readl(&i2c_regs_p->ic_con) & (~IC_CON_SPD_MSK));
switch (i2c_spd) {
case IC_SPEED_MODE_MAX:
cntl |= IC_CON_SPD_HS;
high = MIN_HS_SCL_HIGHTIME;
low = MIN_HS_SCL_LOWTIME;
break;
case IC_SPEED_MODE_STANDARD:
cntl |= IC_CON_SPD_SS;
high = MIN_SS_SCL_HIGHTIME;
low = MIN_SS_SCL_LOWTIME;
break;
case IC_SPEED_MODE_FAST:
default:
cntl |= IC_CON_SPD_FS;
high = MIN_FS_SCL_HIGHTIME;
low = MIN_FS_SCL_LOWTIME;
break;
}
writel(cntl, &i2c_regs_p->ic_con);
hcnt = (IC_CLK * high) / NANO_TO_MICRO;
writel(hcnt, &i2c_regs_p->ic_fs_scl_hcnt);
lcnt = (IC_CLK * low) / NANO_TO_MICRO;
writel(lcnt, &i2c_regs_p->ic_fs_scl_lcnt);
/* re-enable i2c ctrl back now that speed is set */
enbl |= IC_ENABLE_0B;
writel(enbl, &i2c_regs_p->ic_enable);
}
/*
* i2c_set_bus_speed - Set the i2c speed
* @speed: required i2c speed
*
* Set the i2c speed.
*/
void i2c_set_bus_speed(int speed)
{
if (speed >= I2C_MAX_SPEED)
set_speed(IC_SPEED_MODE_MAX);
else if (speed >= I2C_FAST_SPEED)
set_speed(IC_SPEED_MODE_FAST);
else
set_speed(IC_SPEED_MODE_STANDARD);
}
/*
* i2c_get_bus_speed - Gets the i2c speed
*
* Gets the i2c speed.
*/
int i2c_get_bus_speed(void)
{
u32 cntl;
cntl = (readl(&i2c_regs_p->ic_con) & IC_CON_SPD_MSK);
if (cntl == IC_CON_SPD_HS)
return I2C_MAX_SPEED;
else if (cntl == IC_CON_SPD_FS)
return I2C_FAST_SPEED;
else if (cntl == IC_CON_SPD_SS)
return I2C_STANDARD_SPEED;
return 0;
}
/*
* i2c_init - Init function
* @speed: required i2c speed
* @slaveadd: slave address for the device
*
* Initialization function.
*/
void i2c_init(int speed, int slaveadd)
{
unsigned int enbl;
/* Disable i2c */
enbl = readl(&i2c_regs_p->ic_enable);
enbl &= ~IC_ENABLE_0B;
writel(enbl, &i2c_regs_p->ic_enable);
writel((IC_CON_SD | IC_CON_SPD_FS | IC_CON_MM), &i2c_regs_p->ic_con);
writel(IC_RX_TL, &i2c_regs_p->ic_rx_tl);
writel(IC_TX_TL, &i2c_regs_p->ic_tx_tl);
i2c_set_bus_speed(speed);
writel(IC_STOP_DET, &i2c_regs_p->ic_intr_mask);
writel(slaveadd, &i2c_regs_p->ic_sar);
/* Enable i2c */
enbl = readl(&i2c_regs_p->ic_enable);
enbl |= IC_ENABLE_0B;
writel(enbl, &i2c_regs_p->ic_enable);
}
/*
* i2c_setaddress - Sets the target slave address
* @i2c_addr: target i2c address
*
* Sets the target slave address.
*/
static void i2c_setaddress(unsigned int i2c_addr)
{
writel(i2c_addr, &i2c_regs_p->ic_tar);
}
/*
* i2c_flush_rxfifo - Flushes the i2c RX FIFO
*
* Flushes the i2c RX FIFO
*/
static void i2c_flush_rxfifo(void)
{
while (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE)
readl(&i2c_regs_p->ic_cmd_data);
}
/*
* i2c_wait_for_bb - Waits for bus busy
*
* Waits for bus busy
*/
static int i2c_wait_for_bb(void)
{
unsigned long start_time_bb = get_timer(0);
while ((readl(&i2c_regs_p->ic_status) & IC_STATUS_MA) ||
!(readl(&i2c_regs_p->ic_status) & IC_STATUS_TFE)) {
/* Evaluate timeout */
if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
return 1;
}
return 0;
}
/* check parameters for i2c_read and i2c_write */
static int check_params(uint addr, int alen, uchar *buffer, int len)
{
if (buffer == NULL) {
printf("Buffer is invalid\n");
return 1;
}
if (alen > 1) {
printf("addr len %d not supported\n", alen);
return 1;
}
if (addr + len > 256) {
printf("address out of range\n");
return 1;
}
return 0;
}
static int i2c_xfer_init(uchar chip, uint addr)
{
if (i2c_wait_for_bb()) {
printf("Timed out waiting for bus\n");
return 1;
}
i2c_setaddress(chip);
writel(addr, &i2c_regs_p->ic_cmd_data);
return 0;
}
static int i2c_xfer_finish(void)
{
ulong start_stop_det = get_timer(0);
while (1) {
if ((readl(&i2c_regs_p->ic_raw_intr_stat) & IC_STOP_DET)) {
readl(&i2c_regs_p->ic_clr_stop_det);
break;
} else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
break;
}
}
if (i2c_wait_for_bb()) {
printf("Timed out waiting for bus\n");
return 1;
}
i2c_flush_rxfifo();
/* Wait for read/write operation to complete on actual memory */
udelay(10000);
return 0;
}
/*
* i2c_read - Read from i2c memory
* @chip: target i2c address
* @addr: address to read from
* @alen:
* @buffer: buffer for read data
* @len: no of bytes to be read
*
* Read from i2c memory.
*/
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
unsigned long start_time_rx;
if (check_params(addr, alen, buffer, len))
return 1;
if (i2c_xfer_init(chip, addr))
return 1;
start_time_rx = get_timer(0);
while (len) {
writel(IC_CMD, &i2c_regs_p->ic_cmd_data);
if (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE) {
*buffer++ = (uchar)readl(&i2c_regs_p->ic_cmd_data);
len--;
start_time_rx = get_timer(0);
} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
printf("Timed out. i2c read Failed\n");
return 1;
}
}
return i2c_xfer_finish();
}
/*
* i2c_write - Write to i2c memory
* @chip: target i2c address
* @addr: address to read from
* @alen:
* @buffer: buffer for read data
* @len: no of bytes to be read
*
* Write to i2c memory.
*/
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
int nb = len;
unsigned long start_time_tx;
if (check_params(addr, alen, buffer, len))
return 1;
if (i2c_xfer_init(chip, addr))
return 1;
start_time_tx = get_timer(0);
while (len) {
if (readl(&i2c_regs_p->ic_status) & IC_STATUS_TFNF) {
writel(*buffer, &i2c_regs_p->ic_cmd_data);
buffer++;
len--;
start_time_tx = get_timer(0);
} else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
printf("Timed out. i2c write Failed\n");
return 1;
}
}
return i2c_xfer_finish();
}
/*
* i2c_probe - Probe the i2c chip
*/
int i2c_probe(uchar chip)
{
u32 tmp;
/*
* Try to read the first location of the chip.
*/
return i2c_read(chip, 0, 1, (uchar *)&tmp, 1);
}