net: mdio-gpio: Add support for active low gpio pins

Some systems using mdio-gpio may use active-low gpio pins
(eg with inverters or FETs connected to all or some of the
gpio pins).

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 16 insertions, 6 deletions

diff --git a/drivers/net/phy/mdio-gpio.c b/drivers/net/phy/mdio-gpio.c
index e853066c805a..fac211a5001e 100644
--- a/drivers/net/phy/mdio-gpio.c
+++ b/drivers/net/phy/mdio-gpio.c
@@ -33,28 +33,32 @@
 struct mdio_gpio_info {
         struct mdiobb_ctrl ctrl;
         int mdc, mdio;
+        int mdc_active_low, mdio_active_low;
 };
 
 static void *mdio_gpio_of_get_data(struct platform_device *pdev)
 {
         struct device_node *np = pdev->dev.of_node;
         struct mdio_gpio_platform_data *pdata;
+        enum of_gpio_flags flags;
         int ret;
 
         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
         if (!pdata)
                 return NULL;
 
-        ret = of_get_gpio(np, 0);
+        ret = of_get_gpio_flags(np, 0, &flags);
         if (ret < 0)
                 return NULL;
 
         pdata->mdc = ret;
+        pdata->mdc_active_low = flags & OF_GPIO_ACTIVE_LOW;
 
-        ret = of_get_gpio(np, 1);
+        ret = of_get_gpio_flags(np, 1, &flags);
         if (ret < 0)
                 return NULL;
         pdata->mdio = ret;
+        pdata->mdio_active_low = flags & OF_GPIO_ACTIVE_LOW;
 
         return pdata;
 }
@@ -65,7 +69,8 @@ static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
                 container_of(ctrl, struct mdio_gpio_info, ctrl);
 
         if (dir)
-                gpio_direction_output(bitbang->mdio, 1);
+                gpio_direction_output(bitbang->mdio,
+                                      1 ^ bitbang->mdio_active_low);
         else
                 gpio_direction_input(bitbang->mdio);
 }
@@ -75,7 +80,7 @@ static int mdio_get(struct mdiobb_ctrl *ctrl)
         struct mdio_gpio_info *bitbang =
                 container_of(ctrl, struct mdio_gpio_info, ctrl);
 
-        return gpio_get_value(bitbang->mdio);
+        return gpio_get_value(bitbang->mdio) ^ bitbang->mdio_active_low;
 }
 
 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
@@ -83,7 +88,7 @@ static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
         struct mdio_gpio_info *bitbang =
                 container_of(ctrl, struct mdio_gpio_info, ctrl);
 
-        gpio_set_value(bitbang->mdio, what);
+        gpio_set_value(bitbang->mdio, what ^ bitbang->mdio_active_low);
 }
 
 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
@@ -91,7 +96,7 @@ static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
         struct mdio_gpio_info *bitbang =
                 container_of(ctrl, struct mdio_gpio_info, ctrl);
 
-        gpio_set_value(bitbang->mdc, what);
+        gpio_set_value(bitbang->mdc, what ^ bitbang->mdc_active_low);
 }
 
 static struct mdiobb_ops mdio_gpio_ops = {
@@ -117,7 +122,9 @@ static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
         bitbang->ctrl.ops = &mdio_gpio_ops;
         bitbang->ctrl.reset = pdata->reset;
         bitbang->mdc = pdata->mdc;
+        bitbang->mdc_active_low = pdata->mdc_active_low;
         bitbang->mdio = pdata->mdio;
+        bitbang->mdio_active_low = pdata->mdio_active_low;
 
         new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
         if (!new_bus)
diff --git a/include/linux/mdio-gpio.h b/include/linux/mdio-gpio.h
index 7c9fe3c2be73..57e57fe6055c 100644
--- a/include/linux/mdio-gpio.h
+++ b/include/linux/mdio-gpio.h
@@ -18,6 +18,9 @@ struct mdio_gpio_platform_data {
         unsigned int mdc;
         unsigned int mdio;
 
+        bool mdc_active_low;
+        bool mdio_active_low;
+
         unsigned int phy_mask;
         int irqs[PHY_MAX_ADDR];
         /* reset callback */