target/linux/cns3xxx/patches-3.3/440-i2c_retry.patch

   1 --- a/drivers/i2c/busses/i2c-cns3xxx.c
   2 +++ b/drivers/i2c/busses/i2c-cns3xxx.c
   3 @@ -2,8 +2,9 @@
   4   * Cavium CNS3xxx I2C Host Controller
   5   *
   6   * Copyright 2010 Cavium Network
   7 - * Copyright 2011 Gateworks Corporation
   8 + * Copyright 2012 Gateworks Corporation
   9   *               Chris Lang <clang@gateworks.com>
  10 + *        Tim Harvey <tharvey@gateworks.com>
  11   *
  12   * This file is free software; you can redistribute it and/or modify
  13   * it under the terms of the GNU General Public License, Version 2, as
  14 @@ -63,13 +64,15 @@
  15  #define STATE_ERROR            2
  16
  17  struct cns3xxx_i2c {
  18 -       void __iomem *base;
  19 -       wait_queue_head_t wait;
  20 -       struct i2c_adapter adap;
  21 -       struct i2c_msg *msg;
  22 -       int state;              /* see STATE_ */
  23 -       int rd_wr_len;
  24 -       u8 *buf;
  25 +       struct device           *dev;
  26 +       void __iomem            *base;          /* virtual */
  27 +       wait_queue_head_t       wait;
  28 +       struct i2c_adapter      adap;
  29 +       struct i2c_msg          *msg;
  30 +       u8                      state;          /* see STATE_ */
  31 +       u8                      error;          /* see TWI_STATUS register */
  32 +       int                     rd_wr_len;
  33 +       u8                      *buf;
  34  };
  35
  36  static u32 cns3xxx_i2c_func(struct i2c_adapter *adap)
  37 @@ -150,14 +153,18 @@ cns3xxx_i2c_xfer_msg(struct i2c_adapter
  38
  39                 // Start the Transfer
  40                 i2c->state = 0;         // Clear out the State
  41 +               i2c->error = 0;
  42                 I2C_CONTROLLER_REG |= (1 << 6);
  43
  44                 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
  45                                 (i2c->state == STATE_DONE), TWI_TIMEOUT)) {
  46                         if (i2c->state == STATE_ERROR) {
  47 -                               return -EIO;
  48 +                               dev_dbg(i2c->dev, "controller error: 0x%2x", i2c->error);
  49 +                               return -EAGAIN; // try again
  50                         }
  51                 } else {
  52 +                       dev_err(i2c->dev, "controller timed out "
  53 +                               "waiting for start condition to finish\n");
  54                         return -ETIMEDOUT;
  55                 }
  56         }
  57 @@ -238,6 +245,7 @@ static irqreturn_t cns3xxx_i2c_isr(int i
  58
  59         if (stat & I2C_BUS_ERROR_FLAG) {
  60                 i2c->state = STATE_ERROR;
  61 +               i2c->error = (I2C_INTERRUPT_STATUS_REG & 0xff00)>>8;
  62         } else {
  63                 if (i2c->msg->flags & I2C_M_RD) {
  64                         for (i = 0; i <= i2c->rd_wr_len; i++)
  65 @@ -280,6 +288,7 @@ static int __devinit cns3xxx_i2c_probe(s
  66                 goto request_mem_failed;
  67         }
  68
  69 +       i2c->dev = &pdev->dev;
  70         i2c->base = ioremap(res->start, res->end - res->start + 1);
  71         if (!i2c->base) {
  72                 dev_err(&pdev->dev, "Unable to map registers\n");