board/keymile/km83xx/km83xx_i2c.c

   1 /*
   2  * (C) Copyright 2011
   3  * Holger Brunck, Keymile GmbH Hannover, holger.brunck@keymile.com
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <i2c.h>
  10 #include <asm/io.h>
  11 #include <linux/ctype.h>
  12 #include "../common/common.h"
  13
  14 static void i2c_write_start_seq(void)
  15 {
  16         struct fsl_i2c_base *base;
  17         base = (struct fsl_i2c_base *)(CONFIG_SYS_IMMR +
  18                         CONFIG_SYS_I2C_OFFSET);
  19         udelay(DELAY_ABORT_SEQ);
  20         out_8(&base->cr, (I2C_CR_MEN | I2C_CR_MSTA));
  21         udelay(DELAY_ABORT_SEQ);
  22         out_8(&base->cr, (I2C_CR_MEN));
  23 }
  24
  25 int i2c_make_abort(void)
  26 {
  27         struct fsl_i2c_base *base;
  28         base = (struct fsl_i2c_base *)(CONFIG_SYS_IMMR +
  29                         CONFIG_SYS_I2C_OFFSET);
  30         uchar   last;
  31         int     nbr_read = 0;
  32         int     i = 0;
  33         int         ret = 0;
  34
  35         /* wait after each operation to finsh with a delay */
  36         out_8(&base->cr, (I2C_CR_MSTA));
  37         udelay(DELAY_ABORT_SEQ);
  38         out_8(&base->cr, (I2C_CR_MEN | I2C_CR_MSTA));
  39         udelay(DELAY_ABORT_SEQ);
  40         in_8(&base->dr);
  41         udelay(DELAY_ABORT_SEQ);
  42         last = in_8(&base->dr);
  43         nbr_read++;
  44
  45         /*
  46          * do read until the last bit is 1, but stop if the full eeprom is
  47          * read.
  48          */
  49         while (((last & 0x01) != 0x01) &&
  50                 (nbr_read < CONFIG_SYS_IVM_EEPROM_MAX_LEN)) {
  51                 udelay(DELAY_ABORT_SEQ);
  52                 last = in_8(&base->dr);
  53                 nbr_read++;
  54         }
  55         if ((last & 0x01) != 0x01)
  56                 ret = -2;
  57         if ((last != 0xff) || (nbr_read > 1))
  58                 printf("[INFO] i2c abort after %d bytes (0x%02x)\n",
  59                         nbr_read, last);
  60         udelay(DELAY_ABORT_SEQ);
  61         out_8(&base->cr, (I2C_CR_MEN));
  62         udelay(DELAY_ABORT_SEQ);
  63         /* clear status reg */
  64         out_8(&base->sr, 0);
  65
  66         for (i = 0; i < 5; i++)
  67                 i2c_write_start_seq();
  68         if (ret != 0)
  69                 printf("[ERROR] i2c abort failed after %d bytes (0x%02x)\n",
  70                         nbr_read, last);
  71
  72         return ret;
  73 }