2 files changed, 61 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)
diff --git a/drivers/net/ethernet/smsc/smc91x.h b/drivers/net/ethernet/smsc/smc91x.h
index 47dce918eb0f..2a38dacbbd27 100644
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -298,6 +298,9 @@ struct smc_local {
 	struct sk_buff *pending_tx_skb;
 	struct tasklet_struct tx_task;
 
+	struct gpio_desc *power_gpio;
+	struct gpio_desc *reset_gpio;
+
 	/* version/revision of the SMC91x chip */
 	int	version;