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/*
* Copyright (C) 2012 Boundary Devices Inc.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <malloc.h>
#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/errno.h>
#include <asm/gpio.h>
#include <asm/imx-common/mxc_i2c.h>
#include <watchdog.h>
static int force_idle_bus(void *priv)
{
int i;
int sda, scl;
ulong elapsed, start_time;
struct i2c_pads_info *p = (struct i2c_pads_info *)priv;
int ret = 0;
gpio_direction_input(p->sda.gp);
gpio_direction_input(p->scl.gp);
imx_iomux_v3_setup_pad(p->sda.gpio_mode);
imx_iomux_v3_setup_pad(p->scl.gpio_mode);
sda = gpio_get_value(p->sda.gp);
scl = gpio_get_value(p->scl.gp);
if ((sda & scl) == 1)
goto exit; /* Bus is idle already */
printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__,
sda, scl, p->sda.gp, p->scl.gp);
gpio_direction_output(p->scl.gp, 1);
udelay(1000);
/* Send high and low on the SCL line */
for (i = 0; i < 9; i++) {
gpio_direction_output(p->scl.gp, 1);
udelay(50);
gpio_direction_output(p->scl.gp, 0);
udelay(50);
}
/* Simulate the NACK */
gpio_direction_output(p->sda.gp, 1);
udelay(50);
gpio_direction_output(p->scl.gp, 1);
udelay(50);
gpio_direction_output(p->scl.gp, 0);
udelay(50);
/* Simulate the STOP signal */
gpio_direction_output(p->sda.gp, 0);
udelay(50);
gpio_direction_output(p->scl.gp, 1);
udelay(50);
gpio_direction_output(p->sda.gp, 1);
udelay(50);
/* Get the bus status */
gpio_direction_input(p->sda.gp);
gpio_direction_input(p->scl.gp);
start_time = get_timer(0);
for (;;) {
sda = gpio_get_value(p->sda.gp);
scl = gpio_get_value(p->scl.gp);
if ((sda & scl) == 1)
break;
WATCHDOG_RESET();
elapsed = get_timer(start_time);
if (elapsed > (CONFIG_SYS_HZ / 5)) { /* .2 seconds */
ret = -EBUSY;
printf("%s: failed to clear bus, sda=%d scl=%d\n",
__func__, sda, scl);
break;
}
}
exit:
imx_iomux_v3_setup_pad(p->sda.i2c_mode);
imx_iomux_v3_setup_pad(p->scl.i2c_mode);
return ret;
}
static void * const i2c_bases[] = {
(void *)I2C1_BASE_ADDR,
(void *)I2C2_BASE_ADDR,
#ifdef I2C3_BASE_ADDR
(void *)I2C3_BASE_ADDR,
#endif
#ifdef I2C4_BASE_ADDR
(void *)I2C4_BASE_ADDR,
#endif
};
/* i2c_index can be from 0 - 2 */
int setup_i2c(unsigned i2c_index, int speed, int slave_addr,
struct i2c_pads_info *p)
{
char name[9];
int ret;
if (i2c_index >= ARRAY_SIZE(i2c_bases))
return -EINVAL;
snprintf(name, sizeof(name), "i2c_sda%01d", i2c_index);
ret = gpio_request(p->sda.gp, name);
if (ret)
return ret;
snprintf(name, sizeof(name), "i2c_scl%01d", i2c_index);
ret = gpio_request(p->scl.gp, name);
if (ret)
goto err_req;
/* Enable i2c clock */
ret = enable_i2c_clk(1, i2c_index);
if (ret)
goto err_clk;
/* Make sure bus is idle */
ret = force_idle_bus(p);
if (ret)
goto err_idle;
bus_i2c_init(i2c_bases[i2c_index], speed, slave_addr,
force_idle_bus, p);
return 0;
err_idle:
err_clk:
gpio_free(p->scl.gp);
err_req:
gpio_free(p->sda.gp);
return ret;
}
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