| Troy Kisky | d4fdc99 | 2012-07-19 08:18:25 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 Boundary Devices Inc. |
| 3 | * |
| 4 | * See file CREDITS for list of people who contributed to this |
| 5 | * project. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License as |
| 9 | * published by the Free Software Foundation; either version 2 of |
| 10 | * the License, or (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
| 20 | * MA 02111-1307 USA |
| 21 | */ |
| 22 | #include <common.h> |
| 23 | #include <asm/arch/clock.h> |
| 24 | #include <asm/arch/imx-regs.h> |
| 25 | #include <asm/errno.h> |
| 26 | #include <asm/gpio.h> |
| 27 | #include <asm/imx-common/mxc_i2c.h> |
| 28 | #include <watchdog.h> |
| 29 | |
| 30 | static int force_idle_bus(void *priv) |
| 31 | { |
| 32 | int i; |
| 33 | int sda, scl; |
| 34 | ulong elapsed, start_time; |
| 35 | struct i2c_pads_info *p = (struct i2c_pads_info *)priv; |
| 36 | int ret = 0; |
| 37 | |
| 38 | gpio_direction_input(p->sda.gp); |
| 39 | gpio_direction_input(p->scl.gp); |
| 40 | |
| 41 | imx_iomux_v3_setup_pad(p->sda.gpio_mode); |
| 42 | imx_iomux_v3_setup_pad(p->scl.gpio_mode); |
| 43 | |
| 44 | sda = gpio_get_value(p->sda.gp); |
| 45 | scl = gpio_get_value(p->scl.gp); |
| 46 | if ((sda & scl) == 1) |
| 47 | goto exit; /* Bus is idle already */ |
| 48 | |
| 49 | printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__, |
| 50 | sda, scl, p->sda.gp, p->scl.gp); |
| 51 | /* Send high and low on the SCL line */ |
| 52 | for (i = 0; i < 9; i++) { |
| 53 | gpio_direction_output(p->scl.gp, 0); |
| 54 | udelay(50); |
| 55 | gpio_direction_input(p->scl.gp); |
| 56 | udelay(50); |
| 57 | } |
| 58 | start_time = get_timer(0); |
| 59 | for (;;) { |
| 60 | sda = gpio_get_value(p->sda.gp); |
| 61 | scl = gpio_get_value(p->scl.gp); |
| 62 | if ((sda & scl) == 1) |
| 63 | break; |
| 64 | WATCHDOG_RESET(); |
| 65 | elapsed = get_timer(start_time); |
| 66 | if (elapsed > (CONFIG_SYS_HZ / 5)) { /* .2 seconds */ |
| 67 | ret = -EBUSY; |
| 68 | printf("%s: failed to clear bus, sda=%d scl=%d\n", |
| 69 | __func__, sda, scl); |
| 70 | break; |
| 71 | } |
| 72 | } |
| 73 | exit: |
| 74 | imx_iomux_v3_setup_pad(p->sda.i2c_mode); |
| 75 | imx_iomux_v3_setup_pad(p->scl.i2c_mode); |
| 76 | return ret; |
| 77 | } |
| 78 | |
| 79 | static void * const i2c_bases[] = { |
| 80 | (void *)I2C1_BASE_ADDR, |
| 81 | (void *)I2C2_BASE_ADDR, |
| 82 | #ifdef I2C3_BASE_ADDR |
| 83 | (void *)I2C3_BASE_ADDR, |
| 84 | #endif |
| 85 | }; |
| 86 | |
| 87 | /* i2c_index can be from 0 - 2 */ |
| 88 | void setup_i2c(unsigned i2c_index, int speed, int slave_addr, |
| 89 | struct i2c_pads_info *p) |
| 90 | { |
| 91 | if (i2c_index >= ARRAY_SIZE(i2c_bases)) |
| 92 | return; |
| 93 | /* Enable i2c clock */ |
| 94 | enable_i2c_clk(1, i2c_index); |
| 95 | /* Make sure bus is idle */ |
| 96 | force_idle_bus(p); |
| 97 | bus_i2c_init(i2c_bases[i2c_index], speed, slave_addr, |
| 98 | force_idle_bus, p); |
| 99 | } |