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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
Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/net/phy/mdio_bus.c
View File

@@ -38,6 +38,7 @@
#include <linux/phy.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/gpio/consumer.h>
#include <asm/irq.h>
@@ -48,9 +49,26 @@
int mdiobus_register_device(struct mdio_device *mdiodev)
{
struct gpio_desc *gpiod = NULL;
if (mdiodev->bus->mdio_map[mdiodev->addr])
return -EBUSY;
/* Deassert the optional reset signal */
if (mdiodev->dev.of_node)
gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
"reset-gpios", 0, GPIOD_OUT_LOW,
"PHY reset");
if (PTR_ERR(gpiod) == -ENOENT)
gpiod = NULL;
else if (IS_ERR(gpiod))
return PTR_ERR(gpiod);
mdiodev->reset = gpiod;
/* Assert the reset signal again */
mdio_device_reset(mdiodev, 1);
mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
return 0;
@@ -420,6 +438,9 @@ void mdiobus_unregister(struct mii_bus *bus)
if (!mdiodev)
continue;
if (mdiodev->reset)
gpiod_put(mdiodev->reset);
mdiodev->device_remove(mdiodev);
mdiodev->device_free(mdiodev);
}