arch/arm/mach-imx/i2c-mxv7.c

   1 /*
   2  * Copyright (C) 2012 Boundary Devices Inc.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6 #include <common.h>
   7 #include <malloc.h>
   8 #include <asm/arch/clock.h>
   9 #include <asm/arch/imx-regs.h>
  10 #include <linux/errno.h>
  11 #include <asm/gpio.h>
  12 #include <asm/mach-imx/mxc_i2c.h>
  13 #include <watchdog.h>
  14
  15 int force_idle_bus(void *priv)
  16 {
  17         int i;
  18         int sda, scl;
  19         ulong elapsed, start_time;
  20         struct i2c_pads_info *p = (struct i2c_pads_info *)priv;
  21         int ret = 0;
  22
  23         gpio_direction_input(p->sda.gp);
  24         gpio_direction_input(p->scl.gp);
  25
  26         imx_iomux_v3_setup_pad(p->sda.gpio_mode);
  27         imx_iomux_v3_setup_pad(p->scl.gpio_mode);
  28
  29         sda = gpio_get_value(p->sda.gp);
  30         scl = gpio_get_value(p->scl.gp);
  31         if ((sda & scl) == 1)
  32                 goto exit;              /* Bus is idle already */
  33
  34         printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__,
  35                 sda, scl, p->sda.gp, p->scl.gp);
  36         /* Send high and low on the SCL line */
  37         for (i = 0; i < 9; i++) {
  38                 gpio_direction_output(p->scl.gp, 0);
  39                 udelay(50);
  40                 gpio_direction_input(p->scl.gp);
  41                 udelay(50);
  42         }
  43         start_time = get_timer(0);
  44         for (;;) {
  45                 sda = gpio_get_value(p->sda.gp);
  46                 scl = gpio_get_value(p->scl.gp);
  47                 if ((sda & scl) == 1)
  48                         break;
  49                 WATCHDOG_RESET();
  50                 elapsed = get_timer(start_time);
  51                 if (elapsed > (CONFIG_SYS_HZ / 5)) {    /* .2 seconds */
  52                         ret = -EBUSY;
  53                         printf("%s: failed to clear bus, sda=%d scl=%d\n",
  54                                         __func__, sda, scl);
  55                         break;
  56                 }
  57         }
  58 exit:
  59         imx_iomux_v3_setup_pad(p->sda.i2c_mode);
  60         imx_iomux_v3_setup_pad(p->scl.i2c_mode);
  61         return ret;
  62 }
  63
  64 static void * const i2c_bases[] = {
  65         (void *)I2C1_BASE_ADDR,
  66         (void *)I2C2_BASE_ADDR,
  67 #ifdef I2C3_BASE_ADDR
  68         (void *)I2C3_BASE_ADDR,
  69 #endif
  70 #ifdef I2C4_BASE_ADDR
  71         (void *)I2C4_BASE_ADDR,
  72 #endif
  73 };
  74
  75 /* i2c_index can be from 0 - 3 */
  76 int setup_i2c(unsigned i2c_index, int speed, int slave_addr,
  77               struct i2c_pads_info *p)
  78 {
  79         char name[9];
  80         int ret;
  81
  82         if (i2c_index >= ARRAY_SIZE(i2c_bases))
  83                 return -EINVAL;
  84
  85         snprintf(name, sizeof(name), "i2c_sda%01d", i2c_index);
  86         ret = gpio_request(p->sda.gp, name);
  87         if (ret)
  88                 return ret;
  89
  90         snprintf(name, sizeof(name), "i2c_scl%01d", i2c_index);
  91         ret = gpio_request(p->scl.gp, name);
  92         if (ret)
  93                 goto err_req;
  94
  95         /* Enable i2c clock */
  96         ret = enable_i2c_clk(1, i2c_index);
  97         if (ret)
  98                 goto err_clk;
  99
 100         /* Make sure bus is idle */
 101         ret = force_idle_bus(p);
 102         if (ret)
 103                 goto err_idle;
 104
 105 #ifndef CONFIG_DM_I2C
 106         bus_i2c_init(i2c_index, speed, slave_addr, force_idle_bus, p);
 107 #endif
 108
 109         return 0;
 110
 111 err_idle:
 112 err_clk:
 113         gpio_free(p->scl.gp);
 114 err_req:
 115         gpio_free(p->sda.gp);
 116
 117         return ret;
 118 }