dt:net:stmmac: Add dt specific phy reset callback support.

This patch adds phy reset callback support for stmmac driver via device
trees. It adds three new properties to gmac device tree bindings to
define the reset signal via gpio.

With this patch users can conveniently pass reset gpio number with pre,
pulse and post delay in micro secs via DTs.

 active low:
		_________		 ____________
	<pre-delay>	|<pulse-delay>	|<post-delay>
		 	|		|
		 	|_______________|

 active high:
 			 ________________
	<pre-delay>	|<pulse-delay>	|<post-delay>
			|		|
		________|		|___________

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 2 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index cc15039eaa47..fe7bc9903867 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -27,6 +27,9 @@
 #include <linux/mii.h>
 #include <linux/phy.h>
 #include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+
 #include <asm/io.h>
 
 #include "stmmac.h"
@@ -131,10 +134,46 @@ static int stmmac_mdio_reset(struct mii_bus *bus)
         struct net_device *ndev = bus->priv;
         struct stmmac_priv *priv = netdev_priv(ndev);
         unsigned int mii_address = priv->hw->mii.addr;
+        struct stmmac_mdio_bus_data *data = priv->plat->mdio_bus_data;
+
+#ifdef CONFIG_OF
+        if (priv->device->of_node) {
+                int reset_gpio, active_low;
+
+                if (data->reset_gpio < 0) {
+                        struct device_node *np = priv->device->of_node;
+                        if (!np)
+                                return 0;
+
+                        data->reset_gpio = of_get_named_gpio(np,
+                                                "snps,reset-gpio", 0);
+                        if (data->reset_gpio < 0)
+                                return 0;
+
+                        data->active_low = of_property_read_bool(np,
+                                                "snps,reset-active-low");
+                        of_property_read_u32_array(np,
+                                "snps,reset-delays-us", data->delays, 3);
+                }
+
+                reset_gpio = data->reset_gpio;
+                active_low = data->active_low;
+
+                if (!gpio_request(reset_gpio, "mdio-reset")) {
+                        gpio_direction_output(reset_gpio, active_low ? 1 : 0);
+                        udelay(data->delays[0]);
+                        gpio_set_value(reset_gpio, active_low ? 0 : 1);
+                        udelay(data->delays[1]);
+                        gpio_set_value(reset_gpio, active_low ? 1 : 0);
+                        udelay(data->delays[2]);
+                        gpio_free(reset_gpio);
+                }
+        }
+#endif
 
-        if (priv->plat->mdio_bus_data->phy_reset) {
+        if (data->phy_reset) {
                 pr_debug("stmmac_mdio_reset: calling phy_reset\n");
-                priv->plat->mdio_bus_data->phy_reset(priv->plat->bsp_priv);
+                data->phy_reset(priv->plat->bsp_priv);
         }
 
         /* This is a workaround for problems with the STE101P PHY.
@@ -172,6 +211,11 @@ int stmmac_mdio_register(struct net_device *ndev)
         else
                 irqlist = priv->mii_irq;
 
+#ifdef CONFIG_OF
+        if (priv->device->of_node)
+                mdio_bus_data->reset_gpio = -1;
+#endif
+
         new_bus->name = "stmmac";
         new_bus->read = &stmmac_mdio_read;
         new_bus->write = &stmmac_mdio_write;