gpio: msm: return correct value return for special output pins

When a special pin is output only, the current code would return 0,
but if the pin is output only we can get the output value.

Try to return the output value and in all the other cases return
an error instead of 0.

Fixes: f9bb539460d ("gpio: msm: add support for special pins")
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250401-topic-sm8x50-msm-gpio-special-fixes-v1-2-a1148a02bb16@linaro.org
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>

diff --git a/drivers/gpio/msm_gpio.c b/drivers/gpio/msm_gpio.c
index f208eec..54afd44 100644 (file)
--- a/drivers/gpio/msm_gpio.c
+++ b/drivers/gpio/msm_gpio.c
@@ -172,12 +172,19 @@ static int msm_gpio_get_value_special(struct msm_gpio_bank *priv, unsigned int g
        const struct msm_special_pin_data *data;
 
        if (!priv->pin_data->special_pins_data)
-               return 0;
+               return -EINVAL;
 
        data = &priv->pin_data->special_pins_data[offset];
 
-       if (!data->io_reg || data->in_bit >= 31)
-               return 0;
+       if (!data->io_reg)
+               return -EINVAL;
+
+       if (data->in_bit >= 31) {
+               if (data->out_bit >= 31)
+                       return -EINVAL;
+
+               return !!(readl(priv->base + data->io_reg) >> data->out_bit);
+       }
 
        return !!(readl(priv->base + data->io_reg) >> data->in_bit);
 }