[PATCH net-next v3 1/4] phylib: Add device reset delay support

Richard Leitner
2017-12-05T13:26:41Z

From: Richard Leitner <richard.leitner@skidata.com>

Some PHYs need a minimum time after the reset gpio was asserted and/or
deasserted. To ensure we meet these timing requirements add two new
optional devicetree parameters for the phy: reset-delay-us and
reset-post-delay-us.

This patch depends on the "phylib: Add device reset GPIO support" patch
submitted by Geert Uytterhoeven/Sergei Shtylyov, see:
https://patchwork.kernel.org/patch/10090149/

Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
---
Documentation/devicetree/bindings/net/phy.txt | 10 ++++++++++
drivers/net/phy/mdio_device.c | 13 +++++++++++--
drivers/of/of_mdio.c | 8 ++++++++
include/linux/mdio.h | 2 ++
4 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
index c05479f5ac7c..72860ce7f610 100644
--- a/Documentation/devicetree/bindings/net/phy.txt
+++ b/Documentation/devicetree/bindings/net/phy.txt
@@ -55,6 +55,12 @@ Optional Properties:

- reset-gpios: The GPIO phandle and specifier for the PHY reset signal.

+- reset-delay-us: Delay after the reset was asserted in microseconds.
+ If this property is missing the delay will be skipped.
+
+- reset-post-delay-us: Delay after the reset was deasserted in microseconds.
+ If this property is missing the delay will be skipped.
+
Example:

ethernet-phy@0 {
@@ -62,4 +68,8 @@ ethernet-phy@0 {
interrupt-parent = <&PIC>;
interrupts = <35 IRQ_TYPE_EDGE_RISING>;
reg = <0>;
+
+ reset-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>;
+ reset-delay-us = <1000>;
+ reset-post-delay-us = <2000>;
};
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index 75d97dd9fb28..ca3ff43f8ee8 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -24,6 +24,7 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/unistd.h>
+#include <linux/delay.h>

void mdio_device_free(struct mdio_device *mdiodev)
{
@@ -118,8 +119,16 @@ EXPORT_SYMBOL(mdio_device_remove);

void mdio_device_reset(struct mdio_device *mdiodev, int value)
{
- if (mdiodev->reset)
- gpiod_set_value(mdiodev->reset, value);
+ if (!mdiodev->reset)
+ return;
+
+ gpiod_set_value(mdiodev->reset, value);
+
+ if (value && mdiodev->reset_delay)
+ usleep_range(mdiodev->reset_delay, mdiodev->reset_delay + 100);
+ else if (!value && mdiodev->reset_post_delay)
+ usleep_range(mdiodev->reset_post_delay,
+ mdiodev->reset_post_delay + 100);
}
EXPORT_SYMBOL(mdio_device_reset);

diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 98258583abb0..fb56486dfaa0 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -77,6 +77,14 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
if (of_property_read_bool(child, "broken-turn-around"))
mdio->phy_ignore_ta_mask |= 1 << addr;

+ if (of_property_read_u32(child, "reset-delay-us",
+ &phy->mdio.reset_delay))
+ phy->mdio.reset_delay = 0;
+
+ if (of_property_read_u32(child, "reset-post-delay-us",
+ &phy->mdio.reset_post_delay))
+ phy->mdio.reset_post_delay = 0;
+
/* Associate the OF node with the device structure so it
* can be looked up later */
of_node_get(child);
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index 92d4e55ffe67..e37c21d8eb19 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -41,6 +41,8 @@ struct mdio_device {
int addr;
int flags;
struct gpio_desc *reset;
+ unsigned int reset_delay;
+ unsigned int reset_post_delay;
};
#define to_mdio_device(d) container_of(d, struct mdio_device, dev)

--
2.11.0