i2c: imx: fix divide by zero warning

Add "i2c_clk_rate / 2" check to avoid "divide by zero warning".
i2c_clk_rate may be zero if i2c clock is disabled.

Signed-off-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 5c9a8dfbc4a008ac2803e2887c44a0b79174a11b..da77ba5ee579307ede16e65f2be810b48990bb59 100644 (file)
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -621,8 +621,8 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
        return 0;
 }
 
-static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
-                           unsigned int i2c_clk_rate)
+static int i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
+                          unsigned int i2c_clk_rate)
 {
        struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div;
        unsigned int div;
@@ -637,7 +637,11 @@ static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
 
        /* Divider value calculation */
        if (i2c_imx->cur_clk == i2c_clk_rate)
-               return;
+               return 0;
+
+       /* Keep the denominator of the following program always NOT equal to 0. */
+       if (!(i2c_clk_rate / 2))
+               return -EINVAL;
 
        i2c_imx->cur_clk = i2c_clk_rate;
 
@@ -668,6 +672,8 @@ static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
        dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n",
                i2c_clk_div[i].val, i2c_clk_div[i].div);
 #endif
+
+       return 0;
 }
 
 static int i2c_imx_clk_notifier_call(struct notifier_block *nb,
@@ -677,11 +683,12 @@ static int i2c_imx_clk_notifier_call(struct notifier_block *nb,
        struct imx_i2c_struct *i2c_imx = container_of(nb,
                                                      struct imx_i2c_struct,
                                                      clk_change_nb);
+       int ret = 0;
 
        if (action & POST_RATE_CHANGE)
-               i2c_imx_set_clk(i2c_imx, ndata->new_rate);
+               ret = i2c_imx_set_clk(i2c_imx, ndata->new_rate);
 
-       return NOTIFY_OK;
+       return notifier_from_errno(ret);
 }
 
 static int i2c_imx_start(struct imx_i2c_struct *i2c_imx, bool atomic)
@@ -1780,7 +1787,11 @@ static int i2c_imx_probe(struct platform_device *pdev)
                i2c_imx->bitrate = pdata->bitrate;
        i2c_imx->clk_change_nb.notifier_call = i2c_imx_clk_notifier_call;
        clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
-       i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
+       ret = i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
+       if (ret < 0) {
+               dev_err(&pdev->dev, "can't get I2C clock\n");
+               goto clk_notifier_unregister;
+       }
 
        i2c_imx_reset_regs(i2c_imx);