[PATCH] button: gpio: handle broken controller

[Caleb Connolly]

Avoid crashing U-Boot when the GPIO controller for a button is disabled
or failed to probe. We also need to check the priv data for each button
since even if a button fails to probe it will still be polled by the
core code.

Signed-off-by: Caleb Connolly <caleb.conno...@linaro.org>
---
 drivers/button/button-gpio.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/button/button-gpio.c b/drivers/button/button-gpio.c
index 43b82d98aeb7..31b85c8150e8 100644
--- a/drivers/button/button-gpio.c
+++ b/drivers/button/button-gpio.c
@@ -19,8 +19,11 @@ static enum button_state_t button_gpio_get_state(struct 
udevice *dev)
 {
        struct button_gpio_priv *priv = dev_get_priv(dev);
        int ret;
 
+       if (!priv)
+               return -ENODATA;
+
        if (!dm_gpio_is_valid(&priv->gpio))
                return -EREMOTEIO;
        ret = dm_gpio_get_value(&priv->gpio);
        if (ret < 0)
@@ -31,8 +34,10 @@ static enum button_state_t button_gpio_get_state(struct 
udevice *dev)
 
 static int button_gpio_get_code(struct udevice *dev)
 {
        struct button_gpio_priv *priv = dev_get_priv(dev);
+       if (!priv)
+               return -ENODATA;
        int code = priv->linux_code;
 
        if (!code)
                return -ENODATA;
@@ -50,9 +55,9 @@ static int button_gpio_probe(struct udevice *dev)
        if (!uc_plat->label)
                return 0;
 
        ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, GPIOD_IS_IN);
-       if (ret)
+       if (ret || !dm_gpio_is_valid(&priv->gpio))
                return ret;
 
        ret = dev_read_u32(dev, "linux,code", &priv->linux_code);
 
@@ -97,8 +102,10 @@ static int button_gpio_bind(struct udevice *parent)
                if (ret)
                        return ret;
                uc_plat = dev_get_uclass_plat(dev);
                uc_plat->label = label;
+               debug("Button '%s' bound to driver '%s'\n", label,
+                     dev->driver->name);
        }
 
        return 0;
 }
-- 
2.47.0