Messages in this thread Patch in this message | | | From | Alexander Stein <> | Subject | Re: [PATCH v2] net: mdiobus: Add a function to deassert reset | Date | Wed, 10 May 2023 13:55:15 +0200 |
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Am Mittwoch, 10. Mai 2023, 10:02:52 CEST schrieb Yan Wang: > It is possible to mount multiple sub-devices on the mido bus.
mdio bus
> The hardware power-on does not necessarily reset these devices. > The device may be in an uncertain state, causing the device's ID > to be scanned. > > So, before adding a reset to the scan, make sure the device is in > normal working mode. > > I found that the subsequent drive registers the reset pin into the > structure of the sub-device to prevent conflicts, so release the > reset pin. > > Signed-off-by: Yan Wang <rk.code@outlook.com>
We had similar cases where the (single) PHY was in reset during Linux boot. Should you be able to make this work by using a "ethernet-phy-id%4x.%4x" compatible? See also [1]
[1] https://lkml.org/lkml/2020/10/28/1139
> --- > v2: > - fixed commit message > - Using gpiod_ replace gpio_ > v1: > https://lore.kernel.org/all/KL1PR01MB5448631F2D6F71021602117FE6769@KL1PR01M > B5448.apcprd01.prod.exchangelabs.com/ - Incorrect description of commit > message. > - The gpio-api too old > --- > drivers/net/mdio/fwnode_mdio.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/net/mdio/fwnode_mdio.c b/drivers/net/mdio/fwnode_mdio.c > index 1183ef5e203e..6695848b8ef2 100644 > --- a/drivers/net/mdio/fwnode_mdio.c > +++ b/drivers/net/mdio/fwnode_mdio.c > @@ -57,6 +57,20 @@ fwnode_find_mii_timestamper(struct fwnode_handle *fwnode) > return register_mii_timestamper(arg.np, arg.args[0]); > } > > +static void fwnode_mdiobus_pre_enable_phy(struct fwnode_handle *fwnode) > +{ > + struct gpio_desc *reset; > + > + reset = fwnode_gpiod_get_index(fwnode, "reset", 0, GPIOD_OUT_HIGH, NULL); > + if (IS_ERR(reset) && PTR_ERR(reset) != -EPROBE_DEFER)
How are you dealing with EPROBE_DEFER if the reset line is e.g. attached to an i2c expander, which is to be probed later on?
> + return; > + > + usleep_range(100, 200);
How do you know a PHY's reset pulse width?
> + gpiod_set_value_cansleep(reset, 0);
What about post-reset stabilization times before MDIO access is allowed?
> + /*Release the reset pin,it needs to be registered with the PHY.*/ /* Release [...] PHY. */ Best regards, Alexander
> + gpiod_put(reset); > +} > + > int fwnode_mdiobus_phy_device_register(struct mii_bus *mdio, > struct phy_device *phy, > struct fwnode_handle *child, u32 addr) > @@ -119,6 +133,8 @@ int fwnode_mdiobus_register_phy(struct mii_bus *bus, > u32 phy_id; > int rc; > > + fwnode_mdiobus_pre_enable_phy(child); > + > psec = fwnode_find_pse_control(child); > if (IS_ERR(psec)) > return PTR_ERR(psec);
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