i2c: uniphier: avoid WARN_ON() of clk_disable() in failure path

If clk_prepare_enable() fails, clk_disable_unprepare() is called in
the failure path, where the enable_count is still zero, so it hits
WARN_ON(core->enable_count == 0) in the clk_core_disable().

To fix this, make the clock setting more linear in the probe function
so that it can exploit "goto err" in case of error.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-uniphier.c b/drivers/i2c/busses/i2c-uniphier.c
index d6e612a..56e92af 100644 (file)
--- a/drivers/i2c/busses/i2c-uniphier.c
+++ b/drivers/i2c/busses/i2c-uniphier.c
@@ -316,50 +316,15 @@ static struct i2c_bus_recovery_info uniphier_i2c_bus_recovery_info = {
        .unprepare_recovery = uniphier_i2c_unprepare_recovery,
 };
 
-static int uniphier_i2c_clk_init(struct device *dev,
-                                struct uniphier_i2c_priv *priv)
+static void uniphier_i2c_hw_init(struct uniphier_i2c_priv *priv,
+                                u32 bus_speed, unsigned long clk_rate)
 {
-       struct device_node *np = dev->of_node;
-       unsigned long clk_rate;
-       u32 bus_speed;
-       int ret;
-
-       if (of_property_read_u32(np, "clock-frequency", &bus_speed))
-               bus_speed = UNIPHIER_I2C_DEFAULT_SPEED;
-
-       if (!bus_speed) {
-               dev_err(dev, "clock-frequency should not be zero\n");
-               return -EINVAL;
-       }
-
-       if (bus_speed > UNIPHIER_I2C_MAX_SPEED)
-               bus_speed = UNIPHIER_I2C_MAX_SPEED;
-
-       /* Get input clk rate through clk driver */
-       priv->clk = devm_clk_get(dev, NULL);
-       if (IS_ERR(priv->clk)) {
-               dev_err(dev, "failed to get clock\n");
-               return PTR_ERR(priv->clk);
-       }
-
-       ret = clk_prepare_enable(priv->clk);
-       if (ret)
-               return ret;
-
-       clk_rate = clk_get_rate(priv->clk);
-       if (!clk_rate) {
-               dev_err(dev, "input clock rate should not be zero\n");
-               return -EINVAL;
-       }
-
        uniphier_i2c_reset(priv, true);
 
        writel((clk_rate / bus_speed / 2 << 16) | (clk_rate / bus_speed),
               priv->membase + UNIPHIER_I2C_CLK);
 
        uniphier_i2c_reset(priv, false);
-
-       return 0;
 }
 
 static int uniphier_i2c_probe(struct platform_device *pdev)
@@ -367,8 +332,9 @@ static int uniphier_i2c_probe(struct platform_device *pdev)
        struct device *dev = &pdev->dev;
        struct uniphier_i2c_priv *priv;
        struct resource *regs;
-       int irq;
-       int ret;
+       u32 bus_speed;
+       unsigned long clk_rate;
+       int irq, ret;
 
        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
@@ -385,6 +351,31 @@ static int uniphier_i2c_probe(struct platform_device *pdev)
                return irq;
        }
 
+       if (of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed))
+               bus_speed = UNIPHIER_I2C_DEFAULT_SPEED;
+
+       if (!bus_speed || bus_speed > UNIPHIER_I2C_MAX_SPEED) {
+               dev_err(dev, "invalid clock-frequency %d\n", bus_speed);
+               return -EINVAL;
+       }
+
+       priv->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(priv->clk)) {
+               dev_err(dev, "failed to get clock\n");
+               return PTR_ERR(priv->clk);
+       }
+
+       ret = clk_prepare_enable(priv->clk);
+       if (ret)
+               return ret;
+
+       clk_rate = clk_get_rate(priv->clk);
+       if (!clk_rate) {
+               dev_err(dev, "input clock rate should not be zero\n");
+               ret = -EINVAL;
+               goto err;
+       }
+
        init_completion(&priv->comp);
        priv->adap.owner = THIS_MODULE;
        priv->adap.algo = &uniphier_i2c_algo;
@@ -395,9 +386,7 @@ static int uniphier_i2c_probe(struct platform_device *pdev)
        i2c_set_adapdata(&priv->adap, priv);
        platform_set_drvdata(pdev, priv);
 
-       ret = uniphier_i2c_clk_init(dev, priv);
-       if (ret)
-               goto err;
+       uniphier_i2c_hw_init(priv, bus_speed, clk_rate);
 
        ret = devm_request_irq(dev, irq, uniphier_i2c_interrupt, 0, pdev->name,
                               priv);