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 *dev;
  17         dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET);
  18         udelay(DELAY_ABORT_SEQ);
  19         out_8(&dev->cr, (I2C_CR_MEN | I2C_CR_MSTA));
  20         udelay(DELAY_ABORT_SEQ);
  21         out_8(&dev->cr, (I2C_CR_MEN));
  22 }
  23
  24 int i2c_make_abort(void)
  25 {
  26         struct fsl_i2c *dev;
  27         dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET);
  28         uchar   last;
  29         int     nbr_read = 0;
  30         int     i = 0;
  31         int         ret = 0;
  32
  33         /* wait after each operation to finsh with a delay */
  34         out_8(&dev->cr, (I2C_CR_MSTA));
  35         udelay(DELAY_ABORT_SEQ);
  36         out_8(&dev->cr, (I2C_CR_MEN | I2C_CR_MSTA));
  37         udelay(DELAY_ABORT_SEQ);
  38         in_8(&dev->dr);
  39         udelay(DELAY_ABORT_SEQ);
  40         last = in_8(&dev->dr);
  41         nbr_read++;
  42
  43         /*
  44          * do read until the last bit is 1, but stop if the full eeprom is
  45          * read.
  46          */
  47         while (((last & 0x01) != 0x01) &&
  48                 (nbr_read < CONFIG_SYS_IVM_EEPROM_MAX_LEN)) {
  49                 udelay(DELAY_ABORT_SEQ);
  50                 last = in_8(&dev->dr);
  51                 nbr_read++;
  52         }
  53         if ((last & 0x01) != 0x01)
  54                 ret = -2;
  55         if ((last != 0xff) || (nbr_read > 1))
  56                 printf("[INFO] i2c abort after %d bytes (0x%02x)\n",
  57                         nbr_read, last);
  58         udelay(DELAY_ABORT_SEQ);
  59         out_8(&dev->cr, (I2C_CR_MEN));
  60         udelay(DELAY_ABORT_SEQ);
  61         /* clear status reg */
  62         out_8(&dev->sr, 0);
  63
  64         for (i = 0; i < 5; i++)
  65                 i2c_write_start_seq();
  66         if (ret != 0)
  67                 printf("[ERROR] i2c abort failed after %d bytes (0x%02x)\n",
  68                         nbr_read, last);
  69
  70         return ret;
  71 }