1 files changed, 58 insertions, 0 deletions

diff --git a/drivers/net/ethernet/smsc/smc91x.c b/drivers/net/ethernet/smsc/smc91x.c
index 5e94d00b96b3..2c62208077fe 100644
--- a/drivers/net/ethernet/smsc/smc91x.c
+++ b/drivers/net/ethernet/smsc/smc91x.c
@@ -81,6 +81,7 @@ static const char version[] =
 #include <linux/workqueue.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
@@ -2188,6 +2189,41 @@ static const struct of_device_id smc91x_match[] = {
         {},
 };
 MODULE_DEVICE_TABLE(of, smc91x_match);
+
+/**
+ * of_try_set_control_gpio - configure a gpio if it exists
+ */
+static int try_toggle_control_gpio(struct device *dev,
+                                   struct gpio_desc **desc,
+                                   const char *name, int index,
+                                   int value, unsigned int nsdelay)
+{
+        struct gpio_desc *gpio = *desc;
+        int res;
+
+        gpio = devm_gpiod_get_index(dev, name, index);
+        if (IS_ERR(gpio)) {
+                if (PTR_ERR(gpio) == -ENOENT) {
+                        *desc = NULL;
+                        return 0;
+                }
+
+                return PTR_ERR(gpio);
+        }
+        res = gpiod_direction_output(gpio, !value);
+        if (res) {
+                dev_err(dev, "unable to toggle gpio %s: %i\n", name, res);
+                devm_gpiod_put(dev, gpio);
+                gpio = NULL;
+                return res;
+        }
+        if (nsdelay)
+                usleep_range(nsdelay, 2 * nsdelay);
+        gpiod_set_value_cansleep(gpio, value);
+        *desc = gpio;
+
+        return 0;
+}
 #endif
 
 /*
@@ -2237,6 +2273,28 @@ static int smc_drv_probe(struct platform_device *pdev)
                 struct device_node *np = pdev->dev.of_node;
                 u32 val;
 
+                /* Optional pwrdwn GPIO configured? */
+                ret = try_toggle_control_gpio(&pdev->dev, &lp->power_gpio,
+                                              "power", 0, 0, 100);
+                if (ret)
+                        return ret;
+
+                /*
+                 * Optional reset GPIO configured? Minimum 100 ns reset needed
+                 * according to LAN91C96 datasheet page 14.
+                 */
+                ret = try_toggle_control_gpio(&pdev->dev, &lp->reset_gpio,
+                                              "reset", 0, 0, 100);
+                if (ret)
+                        return ret;
+
+                /*
+                 * Need to wait for optional EEPROM to load, max 750 us according
+                 * to LAN91C96 datasheet page 55.
+                 */
+                if (lp->reset_gpio)
+                        usleep_range(750, 1000);
+
                 /* Combination of IO widths supported, default to 16-bit */
                 if (!of_property_read_u32(np, "reg-io-width", &val)) {
                         if (val & 1)