mirror of
https://github.com/AsahiLinux/u-boot
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100 lines
2.7 KiB
C
100 lines
2.7 KiB
C
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/*
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* Copyright (C) 2012 Boundary Devices Inc.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#include <asm/arch/clock.h>
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#include <asm/arch/imx-regs.h>
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#include <asm/errno.h>
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#include <asm/gpio.h>
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#include <asm/imx-common/mxc_i2c.h>
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#include <watchdog.h>
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static int force_idle_bus(void *priv)
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{
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int i;
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int sda, scl;
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ulong elapsed, start_time;
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struct i2c_pads_info *p = (struct i2c_pads_info *)priv;
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int ret = 0;
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gpio_direction_input(p->sda.gp);
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gpio_direction_input(p->scl.gp);
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imx_iomux_v3_setup_pad(p->sda.gpio_mode);
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imx_iomux_v3_setup_pad(p->scl.gpio_mode);
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sda = gpio_get_value(p->sda.gp);
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scl = gpio_get_value(p->scl.gp);
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if ((sda & scl) == 1)
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goto exit; /* Bus is idle already */
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printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__,
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sda, scl, p->sda.gp, p->scl.gp);
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/* Send high and low on the SCL line */
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for (i = 0; i < 9; i++) {
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gpio_direction_output(p->scl.gp, 0);
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udelay(50);
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gpio_direction_input(p->scl.gp);
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udelay(50);
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}
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start_time = get_timer(0);
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for (;;) {
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sda = gpio_get_value(p->sda.gp);
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scl = gpio_get_value(p->scl.gp);
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if ((sda & scl) == 1)
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break;
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WATCHDOG_RESET();
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elapsed = get_timer(start_time);
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if (elapsed > (CONFIG_SYS_HZ / 5)) { /* .2 seconds */
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ret = -EBUSY;
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printf("%s: failed to clear bus, sda=%d scl=%d\n",
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__func__, sda, scl);
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break;
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}
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}
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exit:
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imx_iomux_v3_setup_pad(p->sda.i2c_mode);
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imx_iomux_v3_setup_pad(p->scl.i2c_mode);
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return ret;
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}
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static void * const i2c_bases[] = {
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(void *)I2C1_BASE_ADDR,
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(void *)I2C2_BASE_ADDR,
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#ifdef I2C3_BASE_ADDR
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(void *)I2C3_BASE_ADDR,
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#endif
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};
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/* i2c_index can be from 0 - 2 */
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void setup_i2c(unsigned i2c_index, int speed, int slave_addr,
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struct i2c_pads_info *p)
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{
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if (i2c_index >= ARRAY_SIZE(i2c_bases))
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return;
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/* Enable i2c clock */
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enable_i2c_clk(1, i2c_index);
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/* Make sure bus is idle */
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force_idle_bus(p);
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bus_i2c_init(i2c_bases[i2c_index], speed, slave_addr,
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force_idle_bus, p);
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}
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