net: dsa: Add support for a switch reset gpio

Some boards have a gpio line tied to the switch reset pin. Allow this
gpio to be retrieved from the device tree, and take the switch out of
reset before performing the probe.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 0 deletions

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 1eba07feb34a..0b5565f923cc 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -21,6 +21,7 @@
 #include <linux/of_mdio.h>
 #include <linux/of_platform.h>
 #include <linux/of_net.h>
+#include <linux/of_gpio.h>
 #include <linux/sysfs.h>
 #include <linux/phy_fixed.h>
 #include "dsa_priv.h"
@@ -688,6 +689,9 @@ static int dsa_of_probe(struct device *dev)
         const char *port_name;
         int chip_index, port_index;
         const unsigned int *sw_addr, *port_reg;
+        int gpio;
+        enum of_gpio_flags of_flags;
+        unsigned long flags;
         u32 eeprom_len;
         int ret;
 
@@ -766,6 +770,19 @@ static int dsa_of_probe(struct device *dev)
                         put_device(cd->host_dev);
                         cd->host_dev = &mdio_bus_switch->dev;
                 }
+                gpio = of_get_named_gpio_flags(child, "reset-gpios", 0,
+                                               &of_flags);
+                if (gpio_is_valid(gpio)) {
+                        flags = (of_flags == OF_GPIO_ACTIVE_LOW ?
+                                 GPIOF_ACTIVE_LOW : 0);
+                        ret = devm_gpio_request_one(dev, gpio, flags,
+                                                    "switch_reset");
+                        if (ret)
+                                goto out_free_chip;
+
+                        cd->reset = gpio_to_desc(gpio);
+                        gpiod_direction_output(cd->reset, 0);
+                }
 
                 for_each_available_child_of_node(child, port) {
                         port_reg = of_get_property(port, "reg", NULL);