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phylib: Add device reset GPIO support

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The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sergei Shtylyov
2017-12-04 13:35:05 +01:00
committed by David S. Miller
parent 62b32379fd
commit bafbdd527d
7 changed files with 87 additions and 19 deletions
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3
include/linux/mdio.h
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@@ -12,6 +12,7 @@
#include <uapi/linux/mdio.h>
#include <linux/mod_devicetable.h>
struct gpio_desc;
struct mii_bus;
/* Multiple levels of nesting are possible. However typically this is
@@ -39,6 +40,7 @@ struct mdio_device {
/* Bus address of the MDIO device (0-31) */
int addr;
int flags;
struct gpio_desc *reset;
};
#define to_mdio_device(d) container_of(d, struct mdio_device, dev)
@@ -71,6 +73,7 @@ void mdio_device_free(struct mdio_device *mdiodev);
struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr);
int mdio_device_register(struct mdio_device *mdiodev);
void mdio_device_remove(struct mdio_device *mdiodev);
void mdio_device_reset(struct mdio_device *mdiodev, int value);
int mdio_driver_register(struct mdio_driver *drv);
void mdio_driver_unregister(struct mdio_driver *drv);
int mdio_device_bus_match(struct device *dev, struct device_driver *drv);