| /* |
| * Copyright (C) 2012 Boundary Devices Inc. |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| */ |
| #include <common.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, |
| (void *)I2C3_BASE_ADDR, |
| (void *)I2C4_BASE_ADDR, |
| }; |
| |
| /* i2c_index can be from 0 - 3 */ |
| void setup_i2c(unsigned i2c_index, int speed, int slave_addr, |
| struct i2c_pads_info *p) |
| { |
| if (i2c_index >= ARRAY_SIZE(i2c_bases)) |
| return; |
| /* Enable i2c clock */ |
| enable_i2c_clk(1, i2c_index); |
| /* Make sure bus is idle */ |
| force_idle_bus(p); |
| bus_i2c_init(i2c_bases[i2c_index], speed, slave_addr, |
| force_idle_bus, p); |
| } |