[net-next,2/2] net: mdio: add amlogic gxl mdio mux support
Commit Message
Add support for the mdio mux and internal phy glue of the GXL SoC
family
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
drivers/net/mdio/Kconfig | 11 ++
drivers/net/mdio/Makefile | 1 +
drivers/net/mdio/mdio-mux-meson-gxl.c | 160 ++++++++++++++++++++++++++
3 files changed, 172 insertions(+)
create mode 100644 drivers/net/mdio/mdio-mux-meson-gxl.c
Comments
On Mon, Jan 16, 2023 at 10:16:36AM +0100, Jerome Brunet wrote:
> Add support for the mdio mux and internal phy glue of the GXL SoC
> family
>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
> drivers/net/mdio/Kconfig | 11 ++
> drivers/net/mdio/Makefile | 1 +
> drivers/net/mdio/mdio-mux-meson-gxl.c | 160 ++++++++++++++++++++++++++
> 3 files changed, 172 insertions(+)
> create mode 100644 drivers/net/mdio/mdio-mux-meson-gxl.c
Hi Jerome,
please run this patch through checkpatch.
...
> diff --git a/drivers/net/mdio/mdio-mux-meson-gxl.c b/drivers/net/mdio/mdio-mux-meson-gxl.c
> new file mode 100644
> index 000000000000..205095d845ea
> --- /dev/null
> +++ b/drivers/net/mdio/mdio-mux-meson-gxl.c
...
> +static int gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
> +{
nit: I think void would be a more appropriate return type for this
function. Likewise gxl_enable_external_mdio()
...
> +static int gxl_mdio_mux_probe(struct platform_device *pdev){
nit: '{' should be at the beginning of a new line
> + struct device *dev = &pdev->dev;
> + struct clk *rclk;
> + struct gxl_mdio_mux *priv;
nit: reverse xmas tree for local variable declarations.
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
nit: may be it is nicer to use dev_err_probe() here for consistency.
> + platform_set_drvdata(pdev, priv);
> +
> + priv->regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(priv->regs))
> + return PTR_ERR(priv->regs);
And here.
...
On Mon 16 Jan 2023 at 13:11, Simon Horman <simon.horman@corigine.com> wrote:
> On Mon, Jan 16, 2023 at 10:16:36AM +0100, Jerome Brunet wrote:
>> Add support for the mdio mux and internal phy glue of the GXL SoC
>> family
>>
>> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
>> ---
>> drivers/net/mdio/Kconfig | 11 ++
>> drivers/net/mdio/Makefile | 1 +
>> drivers/net/mdio/mdio-mux-meson-gxl.c | 160 ++++++++++++++++++++++++++
>> 3 files changed, 172 insertions(+)
>> create mode 100644 drivers/net/mdio/mdio-mux-meson-gxl.c
>
> Hi Jerome,
>
> please run this patch through checkpatch.
Shame ... I really thought I did, but I forgot indeed.
I am really sorry for this. I'll fix everything.
>
> ...
>
>> diff --git a/drivers/net/mdio/mdio-mux-meson-gxl.c b/drivers/net/mdio/mdio-mux-meson-gxl.c
>> new file mode 100644
>> index 000000000000..205095d845ea
>> --- /dev/null
>> +++ b/drivers/net/mdio/mdio-mux-meson-gxl.c
>
> ...
>
>> +static int gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
>> +{
>
> nit: I think void would be a more appropriate return type for this
> function. Likewise gxl_enable_external_mdio()
>
> ...
>
>> +static int gxl_mdio_mux_probe(struct platform_device *pdev){
>
> nit: '{' should be at the beginning of a new line
>
>> + struct device *dev = &pdev->dev;
>> + struct clk *rclk;
>> + struct gxl_mdio_mux *priv;
>
> nit: reverse xmas tree for local variable declarations.
>
>> + int ret;
>> +
>> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> + if (!priv)
>> + return -ENOMEM;
>
> nit: may be it is nicer to use dev_err_probe() here for consistency.
That was on purpose. I only use the `dev_err_probe()` when the probe may
defer, which I don't expect here.
I don't mind changing if you prefer it this way.
>
>> + platform_set_drvdata(pdev, priv);
>> +
>> + priv->regs = devm_platform_ioremap_resource(pdev, 0);
>> + if (IS_ERR(priv->regs))
>> + return PTR_ERR(priv->regs);
>
> And here.
>
> ...
On Mon, Jan 16, 2023 at 02:27:57PM +0100, Jerome Brunet wrote:
>
> On Mon 16 Jan 2023 at 13:11, Simon Horman <simon.horman@corigine.com> wrote:
>
> > On Mon, Jan 16, 2023 at 10:16:36AM +0100, Jerome Brunet wrote:
> >> Add support for the mdio mux and internal phy glue of the GXL SoC
> >> family
> >>
> >> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> >> ---
> >> drivers/net/mdio/Kconfig | 11 ++
> >> drivers/net/mdio/Makefile | 1 +
> >> drivers/net/mdio/mdio-mux-meson-gxl.c | 160 ++++++++++++++++++++++++++
> >> 3 files changed, 172 insertions(+)
> >> create mode 100644 drivers/net/mdio/mdio-mux-meson-gxl.c
> >
> > Hi Jerome,
> >
> > please run this patch through checkpatch.
>
> Shame ... I really thought I did, but I forgot indeed.
> I am really sorry for this. I'll fix everything.
No problem, it happens.
> > ...
> >
> >> diff --git a/drivers/net/mdio/mdio-mux-meson-gxl.c b/drivers/net/mdio/mdio-mux-meson-gxl.c
> >> new file mode 100644
> >> index 000000000000..205095d845ea
> >> --- /dev/null
> >> +++ b/drivers/net/mdio/mdio-mux-meson-gxl.c
> >
> > ...
> >
> >> +static int gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
> >> +{
> >
> > nit: I think void would be a more appropriate return type for this
> > function. Likewise gxl_enable_external_mdio()
> >
> > ...
> >
> >> +static int gxl_mdio_mux_probe(struct platform_device *pdev){
> >
> > nit: '{' should be at the beginning of a new line
> >
> >> + struct device *dev = &pdev->dev;
> >> + struct clk *rclk;
> >> + struct gxl_mdio_mux *priv;
> >
> > nit: reverse xmas tree for local variable declarations.
> >
> >> + int ret;
> >> +
> >> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> >> + if (!priv)
> >> + return -ENOMEM;
> >
> > nit: may be it is nicer to use dev_err_probe() here for consistency.
>
> That was on purpose. I only use the `dev_err_probe()` when the probe may
> defer, which I don't expect here.
>
> I don't mind changing if you prefer it this way.
I have no strong opinion on this :)
> >> + platform_set_drvdata(pdev, priv);
> >> +
> >> + priv->regs = devm_platform_ioremap_resource(pdev, 0);
> >> + if (IS_ERR(priv->regs))
> >> + return PTR_ERR(priv->regs);
> >
> > And here.
> >
> > ...
>
> > >> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > >> + if (!priv)
> > >> + return -ENOMEM;
> > >
> > > nit: may be it is nicer to use dev_err_probe() here for consistency.
> >
> > That was on purpose. I only use the `dev_err_probe()` when the probe may
> > defer, which I don't expect here.
> >
> > I don't mind changing if you prefer it this way.
>
> I have no strong opinion on this :)
dev_err_probe() does not apply here, because devm_kzalloc does not
return an error code. Hence it cannot be EPROBE_DEFFER, which is what
dev_err_probe() is looking for.
Andrew
> +static int gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
> +{
> + u32 val;
> +
> + /* Setup the internal phy */
> + val = (REG3_ENH |
> + FIELD_PREP(REG3_CFGMODE, 0x7) |
> + REG3_AUTOMDIX |
> + FIELD_PREP(REG3_PHYADDR, 8) |
> + REG3_LEDPOL |
> + REG3_PHYMDI |
> + REG3_CLKINEN |
> + REG3_PHYIP);
> +
> + writel_relaxed(REG4_PWRUPRSTSIG, priv->regs + ETH_REG4);
> + writel_relaxed(val, priv->regs + ETH_REG3);
> + mdelay(10);
Probably the second _relaxed() should not be. You want it guaranteed
to be written out before you do the mdelay().
> +
> + /* Set the internal phy id */
> + writel_relaxed(FIELD_PREP(REG2_PHYID, 0x110181),
> + priv->regs + ETH_REG2);
So how does this play with what Heiner has been reporting recently?
What is the reset default? Who determined this value?
> + /* Enable the internal phy */
> + val |= REG3_PHYEN;
> + writel_relaxed(val, priv->regs + ETH_REG3);
> + writel_relaxed(0, priv->regs + ETH_REG4);
> +
> + /* The phy needs a bit of time to come up */
> + mdelay(10);
What do you mean by 'come up'? Not link up i assume. But maybe it will
not respond to MDIO requests?
Andrew
On Wed, Jan 18, 2023 at 03:56:32AM +0100, Andrew Lunn wrote:
> > > >> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > > >> + if (!priv)
> > > >> + return -ENOMEM;
> > > >
> > > > nit: may be it is nicer to use dev_err_probe() here for consistency.
> > >
> > > That was on purpose. I only use the `dev_err_probe()` when the probe may
> > > defer, which I don't expect here.
> > >
> > > I don't mind changing if you prefer it this way.
> >
> > I have no strong opinion on this :)
>
> dev_err_probe() does not apply here, because devm_kzalloc does not
> return an error code. Hence it cannot be EPROBE_DEFFER, which is what
> dev_err_probe() is looking for.
Sure, there is no EPROBE_DEFFER.
But, FWIIW, my reading of the documentation for dev_err_probe()
is that it's use in such cases is acceptable.
Anyway, let's pass on my suggestion.
On Wed 18 Jan 2023 at 04:02, Andrew Lunn <andrew@lunn.ch> wrote:
>> +static int gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
>> +{
>> + u32 val;
>> +
>> + /* Setup the internal phy */
>> + val = (REG3_ENH |
>> + FIELD_PREP(REG3_CFGMODE, 0x7) |
>> + REG3_AUTOMDIX |
>> + FIELD_PREP(REG3_PHYADDR, 8) |
>> + REG3_LEDPOL |
>> + REG3_PHYMDI |
>> + REG3_CLKINEN |
>> + REG3_PHYIP);
>> +
>> + writel_relaxed(REG4_PWRUPRSTSIG, priv->regs + ETH_REG4);
>> + writel_relaxed(val, priv->regs + ETH_REG3);
>> + mdelay(10);
>
> Probably the second _relaxed() should not be. You want it guaranteed
> to be written out before you do the mdelay().
Good point, I'll have a look
>
>> +
>> + /* Set the internal phy id */
>> + writel_relaxed(FIELD_PREP(REG2_PHYID, 0x110181),
>> + priv->regs + ETH_REG2);
>
> So how does this play with what Heiner has been reporting recently?
What Heiner reported recently is related to the g12 family, not the gxl
which this driver address.
That being said, the g12 does things in a similar way - the glue
is just a bit different:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/mdio/mdio-mux-meson-g12a.c?h=v6.2-rc4#n165
> What is the reset default? Who determined this value?
It's the problem, the reset value is 0. That is why GXL does work with the
internal PHY if the bootloader has not initialized it before the kernel
comes up ... and there is no guarantee that it will.
The phy id value is arbitrary, same as the address. They match what AML
is using internally.
They have been kept to avoid making a mess if a vendor bootloader is
used with the mainline kernel, I guess.
I suppose any value could be used here, as long as it matches the value
in the PHY driver:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/phy/meson-gxl.c?h=v6.2-rc4#n253
>
>> + /* Enable the internal phy */
>> + val |= REG3_PHYEN;
>> + writel_relaxed(val, priv->regs + ETH_REG3);
>> + writel_relaxed(0, priv->regs + ETH_REG4);
>> +
>> + /* The phy needs a bit of time to come up */
>> + mdelay(10);
>
> What do you mean by 'come up'? Not link up i assume. But maybe it will
> not respond to MDIO requests?
Yes this MDIO multiplexer is also the glue that provides power and
clocks to the internal PHY. Once the internal PHY is selected, it needs
a bit a of time before it is usuable.
>
> Andrew
> >> +
> >> + /* Set the internal phy id */
> >> + writel_relaxed(FIELD_PREP(REG2_PHYID, 0x110181),
> >> + priv->regs + ETH_REG2);
> >
> > So how does this play with what Heiner has been reporting recently?
>
> What Heiner reported recently is related to the g12 family, not the gxl
> which this driver address.
>
> That being said, the g12 does things in a similar way - the glue
> is just a bit different:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/mdio/mdio-mux-meson-g12a.c?h=v6.2-rc4#n165
>
> > What is the reset default? Who determined this value?
>
> It's the problem, the reset value is 0. That is why GXL does work with the
> internal PHY if the bootloader has not initialized it before the kernel
> comes up ... and there is no guarantee that it will.
>
> The phy id value is arbitrary, same as the address. They match what AML
> is using internally.
Please document where these values have come from. In the future we
might need to point a finger when it all goes horribly wrong.
> They have been kept to avoid making a mess if a vendor bootloader is
> used with the mainline kernel, I guess.
>
> I suppose any value could be used here, as long as it matches the value
> in the PHY driver:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/phy/meson-gxl.c?h=v6.2-rc4#n253
Some Marvell Ethernet switches with integrated PHYs have IDs with the
vendor part set to Marvell, but the lower part is 0. The date sheet
even says this is deliberate, you need to look at some other register
in the switches address space to determine what the part is. That
works O.K in the vendor crap monolithic driver, but not for Linux
which separates the drivers up. So we have to intercept the reads and
fill in the lower part. And we have no real knowledge if the PHYs are
all the same, or there are differences. So we put in the switch ID,
and the PHY driver then has an entry per switch. That gives us some
future wiggle room if we find the PHYs are actually different.
Is there any indication in the datasheets that the PHY is the exact
same one as in the g12? Are we really safe to reuse this value between
different SoCs?
I actually find it an odd feature. Does the datasheet say anything
about Why you can set the ID in software? The ID describes the
hardware, and software configuration should not be able to change the
hardware in any meaningful way.
> >> + /* Enable the internal phy */
> >> + val |= REG3_PHYEN;
> >> + writel_relaxed(val, priv->regs + ETH_REG3);
> >> + writel_relaxed(0, priv->regs + ETH_REG4);
> >> +
> >> + /* The phy needs a bit of time to come up */
> >> + mdelay(10);
> >
> > What do you mean by 'come up'? Not link up i assume. But maybe it will
> > not respond to MDIO requests?
>
> Yes this MDIO multiplexer is also the glue that provides power and
> clocks to the internal PHY. Once the internal PHY is selected, it needs
> a bit a of time before it is usuable.
O.K, please reword it to indicate power up, not link up.
Andrew
On Thu 19 Jan 2023 at 18:17, Andrew Lunn <andrew@lunn.ch> wrote:
>> >> +
>> >> + /* Set the internal phy id */
>> >> + writel_relaxed(FIELD_PREP(REG2_PHYID, 0x110181),
>> >> + priv->regs + ETH_REG2);
>> >
>> > So how does this play with what Heiner has been reporting recently?
>>
>> What Heiner reported recently is related to the g12 family, not the gxl
>> which this driver address.
>>
>> That being said, the g12 does things in a similar way - the glue
>> is just a bit different:
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/mdio/mdio-mux-meson-g12a.c?h=v6.2-rc4#n165
>>
>> > What is the reset default? Who determined this value?
>>
>> It's the problem, the reset value is 0. That is why GXL does work with the
>> internal PHY if the bootloader has not initialized it before the kernel
>> comes up ... and there is no guarantee that it will.
>>
>> The phy id value is arbitrary, same as the address. They match what AML
>> is using internally.
>
> Please document where these values have come from. In the future we
> might need to point a finger when it all goes horribly wrong.
>
OK
>> They have been kept to avoid making a mess if a vendor bootloader is
>> used with the mainline kernel, I guess.
>>
>> I suppose any value could be used here, as long as it matches the value
>> in the PHY driver:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/phy/meson-gxl.c?h=v6.2-rc4#n253
>
> Some Marvell Ethernet switches with integrated PHYs have IDs with the
> vendor part set to Marvell, but the lower part is 0. The date sheet
> even says this is deliberate, you need to look at some other register
> in the switches address space to determine what the part is. That
> works O.K in the vendor crap monolithic driver, but not for Linux
> which separates the drivers up. So we have to intercept the reads and
> fill in the lower part. And we have no real knowledge if the PHYs are
> all the same, or there are differences. So we put in the switch ID,
> and the PHY driver then has an entry per switch. That gives us some
> future wiggle room if we find the PHYs are actually different.
>
> Is there any indication in the datasheets that the PHY is the exact
> same one as in the g12? Are we really safe to reuse this value between
> different SoCs?
There is zero information about the PHY in the datasheet.
The gxl and g12 don't use the same ID values.
The PHY ip is very similar but slightly different between the 2.
(see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/phy/meson-gxl.c)
My guess is the g12 as another version of the IP, with some bug fixed.
The integration (clocking scheme mostly) is also different, which is why
the mux/glue is different.
>
> I actually find it an odd feature. Does the datasheet say anything
> about Why you can set the ID in software? The ID describes the
> hardware, and software configuration should not be able to change the
> hardware in any meaningful way.
Again, zero information.
It is a bought IP (similar to the Rockchip judging by the PHY driver).
I'm not surprised the provider of the IP would make the ID
easy to configure. AML chose to keep that configurable through the glue,
instead of fixing it. This is how it is.
>
>> >> + /* Enable the internal phy */
>> >> + val |= REG3_PHYEN;
>> >> + writel_relaxed(val, priv->regs + ETH_REG3);
>> >> + writel_relaxed(0, priv->regs + ETH_REG4);
>> >> +
>> >> + /* The phy needs a bit of time to come up */
>> >> + mdelay(10);
>> >
>> > What do you mean by 'come up'? Not link up i assume. But maybe it will
>> > not respond to MDIO requests?
>>
>> Yes this MDIO multiplexer is also the glue that provides power and
>> clocks to the internal PHY. Once the internal PHY is selected, it needs
>> a bit a of time before it is usuable.
>
> O.K, please reword it to indicate power up, not link up.
>
Sure
> Andrew
@@ -215,6 +215,17 @@ config MDIO_BUS_MUX_MESON_G12A
the amlogic g12a SoC. The multiplexers connects either the external
or the internal MDIO bus to the parent bus.
+config MDIO_BUS_MUX_MESON_GXL
+ tristate "Amlogic GXL based MDIO bus multiplexer"
+ depends on ARCH_MESON || COMPILE_TEST
+ depends on OF_MDIO && HAS_IOMEM && COMMON_CLK
+ select MDIO_BUS_MUX
+ default m if ARCH_MESON
+ help
+ This module provides a driver for the MDIO multiplexer/glue of
+ the amlogic gxl SoC. The multiplexers connects either the external
+ or the internal MDIO bus to the parent bus.
+
config MDIO_BUS_MUX_BCM6368
tristate "Broadcom BCM6368 MDIO bus multiplexers"
depends on OF && OF_MDIO && (BMIPS_GENERIC || COMPILE_TEST)
@@ -28,5 +28,6 @@ obj-$(CONFIG_MDIO_BUS_MUX_BCM6368) += mdio-mux-bcm6368.o
obj-$(CONFIG_MDIO_BUS_MUX_BCM_IPROC) += mdio-mux-bcm-iproc.o
obj-$(CONFIG_MDIO_BUS_MUX_GPIO) += mdio-mux-gpio.o
obj-$(CONFIG_MDIO_BUS_MUX_MESON_G12A) += mdio-mux-meson-g12a.o
+obj-$(CONFIG_MDIO_BUS_MUX_MESON_GXL) += mdio-mux-meson-gxl.o
obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) += mdio-mux-mmioreg.o
obj-$(CONFIG_MDIO_BUS_MUX_MULTIPLEXER) += mdio-mux-multiplexer.o
new file mode 100644
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Baylibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/mdio-mux.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define ETH_REG2 0x0
+#define REG2_PHYID GENMASK(21, 0)
+#define EPHY_GXL_ID 0x110181
+#define REG2_LEDACT GENMASK(23, 22)
+#define REG2_LEDLINK GENMASK(25, 24)
+#define REG2_DIV4SEL BIT(27)
+#define REG2_ADCBYPASS BIT(30)
+#define REG2_CLKINSEL BIT(31)
+#define ETH_REG3 0x4
+#define REG3_ENH BIT(3)
+#define REG3_CFGMODE GENMASK(6, 4)
+#define REG3_AUTOMDIX BIT(7)
+#define REG3_PHYADDR GENMASK(12, 8)
+#define REG3_PWRUPRST BIT(21)
+#define REG3_PWRDOWN BIT(22)
+#define REG3_LEDPOL BIT(23)
+#define REG3_PHYMDI BIT(26)
+#define REG3_CLKINEN BIT(29)
+#define REG3_PHYIP BIT(30)
+#define REG3_PHYEN BIT(31)
+#define ETH_REG4 0x8
+#define REG4_PWRUPRSTSIG BIT(0)
+
+#define MESON_GXL_MDIO_EXTERNAL_ID 0
+#define MESON_GXL_MDIO_INTERNAL_ID 1
+
+struct gxl_mdio_mux {
+ void __iomem *regs;
+ void *mux_handle;
+};
+
+static int gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
+{
+ u32 val;
+
+ /* Setup the internal phy */
+ val = (REG3_ENH |
+ FIELD_PREP(REG3_CFGMODE, 0x7) |
+ REG3_AUTOMDIX |
+ FIELD_PREP(REG3_PHYADDR, 8) |
+ REG3_LEDPOL |
+ REG3_PHYMDI |
+ REG3_CLKINEN |
+ REG3_PHYIP);
+
+ writel_relaxed(REG4_PWRUPRSTSIG, priv->regs + ETH_REG4);
+ writel_relaxed(val, priv->regs + ETH_REG3);
+ mdelay(10);
+
+ /* Set the internal phy id */
+ writel_relaxed(FIELD_PREP(REG2_PHYID, 0x110181),
+ priv->regs + ETH_REG2);
+
+ /* Enable the internal phy */
+ val |= REG3_PHYEN;
+ writel_relaxed(val, priv->regs + ETH_REG3);
+ writel_relaxed(0, priv->regs + ETH_REG4);
+
+ /* The phy needs a bit of time to come up */
+ mdelay(10);
+
+ return 0;
+}
+
+static int gxl_enable_external_mdio(struct gxl_mdio_mux *priv)
+{
+ /* Reset the mdio bus mux to the external phy */
+ writel_relaxed(0, priv->regs + ETH_REG3);
+
+ return 0;
+}
+
+static int gxl_mdio_switch_fn(int current_child, int desired_child,
+ void *data)
+{
+ struct gxl_mdio_mux *priv = dev_get_drvdata(data);
+
+ if (current_child == desired_child)
+ return 0;
+
+ switch (desired_child) {
+ case MESON_GXL_MDIO_EXTERNAL_ID:
+ return gxl_enable_external_mdio(priv);
+ case MESON_GXL_MDIO_INTERNAL_ID:
+ return gxl_enable_internal_mdio(priv);
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct of_device_id gxl_mdio_mux_match[] = {
+ { .compatible = "amlogic,gxl-mdio-mux", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gxl_mdio_mux_match);
+
+
+static int gxl_mdio_mux_probe(struct platform_device *pdev){
+ struct device *dev = &pdev->dev;
+ struct clk *rclk;
+ struct gxl_mdio_mux *priv;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, priv);
+
+ priv->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->regs))
+ return PTR_ERR(priv->regs);
+
+ rclk = devm_clk_get_enabled(dev, "ref");
+ if (IS_ERR(rclk))
+ return dev_err_probe(dev, PTR_ERR(rclk),
+ "failed to get reference clock\n");
+
+ ret = mdio_mux_init(dev, dev->of_node, gxl_mdio_switch_fn,
+ &priv->mux_handle, dev, NULL);
+ if (ret)
+ dev_err_probe(dev, ret, "mdio multiplexer init failed\n");
+
+ return ret;
+}
+
+static int gxl_mdio_mux_remove(struct platform_device *pdev)
+{
+ struct gxl_mdio_mux *priv = platform_get_drvdata(pdev);
+
+ mdio_mux_uninit(priv->mux_handle);
+
+ return 0;
+}
+
+static struct platform_driver gxl_mdio_mux_driver = {
+ .probe = gxl_mdio_mux_probe,
+ .remove = gxl_mdio_mux_remove,
+ .driver = {
+ .name = "gxl-mdio-mux",
+ .of_match_table = gxl_mdio_mux_match,
+ },
+};
+module_platform_driver(gxl_mdio_mux_driver);
+
+MODULE_DESCRIPTION("Amlogic GXL MDIO multiplexer driver");
+MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
+MODULE_LICENSE("GPL v2");