[PATCH] net: mdiobus: Prevent spike on MDIO bus reset signal
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STALE2080d
From: Mike Looijmans <hidden>
Date: 2021-01-26 17:32:14
Also in:
lkml
Subsystem:
ethernet phy library, networking drivers, the rest · Maintainers:
Andrew Lunn, Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The mdio_bus reset code first de-asserted the reset by allocating with GPIOD_OUT_LOW, then asserted and de-asserted again. In other words, if the reset signal defaulted to asserted, there'd be a short "spike" before the reset. Instead, directly assert the reset signal using GPIOD_OUT_HIGH, this removes the spike and also removes a line of code since the signal is already high. Signed-off-by: Mike Looijmans <redacted> --- drivers/net/phy/mdio_bus.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2b42e46066b4..34e98ae75110 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c@@ -543,8 +543,8 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) mutex_init(&bus->mdio_lock); mutex_init(&bus->shared_lock); - /* de-assert bus level PHY GPIO reset */ - gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_LOW); + /* assert bus level PHY GPIO reset */ + gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(gpiod)) { err = dev_err_probe(&bus->dev, PTR_ERR(gpiod), "mii_bus %s couldn't get reset GPIO\n",
@@ -553,8 +553,6 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) return err; } else if (gpiod) { bus->reset_gpiod = gpiod; - - gpiod_set_value_cansleep(gpiod, 1); fsleep(bus->reset_delay_us); gpiod_set_value_cansleep(gpiod, 0); if (bus->reset_post_delay_us > 0)
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2.17.1