net: mdio: ipq4019: add support for clock-frequency property

The IPQ4019 MDIO internally divide the clock feed by AHB based on the
MDIO_MODE reg. On reset or power up, the default value for the
divider is 0xff that reflect the divider set to /256.

This makes the MDC run at a very low rate, that is, considering AHB is
always fixed to 100Mhz, a value of 390KHz.

This hasn't have been a problem as MDIO wasn't used for time sensitive
operation, it is now that on IPQ807x is usually mounted with PHY that
requires MDIO to load their firmware (example Aquantia PHY).

To handle this problem and permit to set the correct designed MDC
frequency for the SoC add support for the standard "clock-frequency"
property for the MDIO node.

The divider supports value from /1 to /256 and the common value are to
set it to /16 to reflect 6.25Mhz or to /8 on newer platform to reflect
12.5Mhz.

To scan if the requested rate is supported by the divider, loop with
each supported divider and stop when the requested rate match the final
rate with the current divider. An error is returned if the rate doesn't
match any value.

On MDIO reset, the divider is restored to the requested value to prevent
any kind of downclocking caused by the divider reverting to a default
value.

To follow 802.3 spec of 2.5MHz of default value, if divider is set at
/256 and "clock-frequency" is not set in DT, assume nobody set the
divider and try to find the closest MDC rate to 2.5MHz. (in the case of
AHB set to 100MHz, it's 1.5625MHz)

While at is also document other bits of the MDIO_MODE reg to have a
clear idea of what is actually applied there.

Documentation of some BITs is skipped as they are marked as reserved and
their usage is not clear (RES 11:9 GENPHY 16:13 RES1 19:17)

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio: ipq4019: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio: ipq4019: Separate C22 and C45 transactions

The ipq4019 driver can perform both C22 and C45 transfers. Create
separate functions for each and register the C45 versions using the
new driver API calls.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: mdio-ipq4019: add delay after clock enable

Experimentation shows that PHY detect might fail when the code attempts
MDIO bus read immediately after clock enable. Add delay to stabilize the
clock before bus access.

PHY detect failure started to show after commit 7590fc6f80ac ("net:
mdio: Demote probed message to debug print") that removed coincidental
delay between clock enable and bus access.

10ms is meant to match the time it take to send the probed message over
UART at 115200 bps. This might be a far overshoot.

Fixes: 23a890d493e3 ("net: mdio: Add the reset function for IPQ MDIO driver")
Signed-off-by: Baruch Siach <baruch.siach@siklu.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio-ipq4019: Fix the error for an optional regs resource

The second resource is optional which is only provided on the chipset
IPQ5018. But the blamed commit ignores that and if the resource is
not there it just fails.

the resource is used like this,
if (priv->eth_ldo_rdy) {
val = readl(priv->eth_ldo_rdy);
val |= BIT(0);
writel(val, priv->eth_ldo_rdy);
fsleep(IPQ_PHY_SET_DELAY_US);
}

This patch reverts that to still allow the second resource to be optional
because other SoC have the some MDIO controller and doesn't need to
second resource.

Fixes: fa14d03e014a ("net: mdio-ipq4019: Make use of devm_platform_ioremap_resource()")
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210928134849.2092-1-caihuoqing@baidu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: mdio-ipq4019: Make use of devm_platform_ioremap_resource()

Use the devm_platform_ioremap_resource() helper instead of
calling platform_get_resource() and devm_ioremap_resource()
separately

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MDIO: Kconfig: Specify more IPQ chipset supported

The IPQ MDIO driver currently supports the chipset IPQ40xx, IPQ807x,
IPQ60xx and IPQ50xx.

Add the compatible 'qcom,ipq5018-mdio' because of ethernet LDO dedicated
to the IPQ5018 platform.

Signed-off-by: Luo Jie <luoj@codeaurora.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio: Add the reset function for IPQ MDIO driver

1. configure the MDIO clock source frequency.
2. the LDO resource is needed to configure the ethernet LDO available
for CMN_PLL.

Signed-off-by: Luo Jie <luoj@codeaurora.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio: Alphabetically sort header inclusion

Alphabetically sort header inclusion

Signed-off-by: Calvin Johnson <calvin.johnson@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio-ipq4019: add Clause 45 support

While up-streaming the IPQ4019 driver it was thought that the controller had no Clause 45 support,
but it actually does and its activated by writing a bit to the mode register.

So lets add it as newer SoC-s use the same controller and Clause 45 compliant PHY-s.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio-ipq4019: change defines to upper case

In the commit adding the IPQ4019 MDIO driver, defines for timeout and sleep partially used lower case.
Lets change it to upper case in line with the rest of driver defines.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mdio: Move MDIO drivers into a new subdirectory

Move all the MDIO drivers and multiplexers into drivers/net/mdio. The
mdio core is however left in the phy directory, due to mutual
dependencies between the MDIO core and the PHY core.

Take this opportunity to sort the Kconfig based on the menuconfig
strings, and move the multiplexers to the end with a separating
comment.

v2:
Fix typo in commit message

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>