target/linux/layerscape/patches-5.4/808-i2c-0006-MLK-20368-i2c-imx-Coverity-fix-divide-by-zero-warnin.patch

   1 From 2c2c7e16ad0401f85dd8ff9bc0789fa10e715c0e Mon Sep 17 00:00:00 2001
   2 From: Clark Wang <xiaoning.wang@nxp.com>
   3 Date: Tue, 15 Jan 2019 10:04:30 +0800
   4 Subject: [PATCH] MLK-20368 i2c-imx: Coverity: fix divide by zero warning
   5
   6 "i2c_clk_rate / 2" might be zero when the i2c_clk_rate gets the clock is
   7 0 or 1, so add a judgment to avoid the denominator is equal to 0.
   8
   9 Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
  10 [Arul: Add support to check return value everywhere in the driver]
  11 Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>
  12
  13 Signed-off-by: Shrikant Bobade <Shrikant_Bobade@mentor.com>
  14 (cherry picked from commit d382de595bffc0975ab7c0582e08dd4f7afc0c1a)
  15 (cherry picked from commit 456caa9ba270ca8f4f962918a0625d1a8348f316)
  16 ---
  17  drivers/i2c/busses/i2c-imx.c | 31 +++++++++++++++++++++++++------
  18  1 file changed, 25 insertions(+), 6 deletions(-)
  19
  20 --- a/drivers/i2c/busses/i2c-imx.c
  21 +++ b/drivers/i2c/busses/i2c-imx.c
  22 @@ -492,16 +492,24 @@ static int i2c_imx_acked(struct imx_i2c_
  23         return 0;
  24  }
  25
  26 -static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
  27 +static int i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
  28                             unsigned int i2c_clk_rate)
  29  {
  30         struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div;
  31         unsigned int div;
  32         int i;
  33
  34 -       /* Divider value calculation */
  35         if (i2c_imx->cur_clk == i2c_clk_rate)
  36 -               return;
  37 +               return 0;
  38 +
  39 +       /*
  40 +        * Keep the denominator of the following program
  41 +        * always NOT equal to 0.
  42 +        */
  43 +
  44 +       /* Divider value calculation */
  45 +       if (!(i2c_clk_rate / 2))
  46 +               return -EINVAL;
  47
  48         i2c_imx->cur_clk = i2c_clk_rate;
  49
  50 @@ -532,20 +540,23 @@ static void i2c_imx_set_clk(struct imx_i
  51         dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n",
  52                 i2c_clk_div[i].val, i2c_clk_div[i].div);
  53  #endif
  54 +
  55 +       return 0;
  56  }
  57
  58  static int i2c_imx_clk_notifier_call(struct notifier_block *nb,
  59                                      unsigned long action, void *data)
  60  {
  61 +       int ret = 0;
  62         struct clk_notifier_data *ndata = data;
  63         struct imx_i2c_struct *i2c_imx = container_of(nb,
  64                                                       struct imx_i2c_struct,
  65                                                       clk_change_nb);
  66
  67         if (action & POST_RATE_CHANGE)
  68 -               i2c_imx_set_clk(i2c_imx, ndata->new_rate);
  69 +               ret = i2c_imx_set_clk(i2c_imx, ndata->new_rate);
  70
  71 -       return NOTIFY_OK;
  72 +       return notifier_from_errno(ret);
  73  }
  74
  75  static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
  76 @@ -555,6 +566,10 @@ static int i2c_imx_start(struct imx_i2c_
  77
  78         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
  79
  80 +       result = i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
  81 +       if (result)
  82 +               return result;
  83 +
  84         imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
  85         /* Enable I2C controller */
  86         imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
  87 @@ -1175,7 +1190,11 @@ static int i2c_imx_probe(struct platform
  88                 i2c_imx->bitrate = pdata->bitrate;
  89         i2c_imx->clk_change_nb.notifier_call = i2c_imx_clk_notifier_call;
  90         clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
  91 -       i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
  92 +       ret = i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
  93 +       if (ret < 0) {
  94 +               dev_err(&pdev->dev, "can't get I2C clock\n");
  95 +               goto clk_notifier_unregister;
  96 +       }
  97
  98         /*
  99          * This limit caused by an i.MX7D hardware issue(e7805 in Errata).