[PATCH/RFC 2/3] ethernet: add a PHY reset GPIO DT binding to sh_eth

Guennadi Liakhovetski
2013-01-25T10:34:55Z

Hi Laurent

On Fri, 25 Jan 2013, Laurent Pinchart wrote:

> Hi Guennadi,
>
> On Thursday 24 January 2013 17:07:32 Guennadi Liakhovetski wrote:
> > If an ethernet PHY can be reset by a GPIO, it can be specified in DT. Add
> > a binding and code to parse it, request the GPIO and take the PHY out of
> > reset.
> >
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > Cc: devicetree-discuss at lists.ozlabs.org
> > Cc: netdev at vger.kernel.org
> > ---
> > Documentation/devicetree/bindings/net/sh_ether.txt | 2 ++
> > drivers/net/ethernet/renesas/sh_eth.c | 9 ++++++++-
> > 2 files changed, 10 insertions(+), 1 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/net/sh_ether.txt
> > b/Documentation/devicetree/bindings/net/sh_ether.txt index c11e45d..edaf683
> > 100644
> > --- a/Documentation/devicetree/bindings/net/sh_ether.txt
> > +++ b/Documentation/devicetree/bindings/net/sh_ether.txt
> > @@ -12,6 +12,7 @@ Required properties:
> > - interrupts: Interrupt mapping for the sh_eth interrupt
> > sources (vector id).
> > - phy-mode: String, operation mode of the PHY interface.
> > +- phy-reset-gpios: PHY reset GPIO tuple
>
> If you can't have more than one GPIO here, what about calling it phy-reset-
> gpio ?

>From Documentation/devicetree/bindings/gpio/gpio.txt:

<quote>
GPIO properties should be named "[<name>-]gpios".
</quote>

> > - sh-eth,edmac-endian: String, endian of sh_eth dmac.
> > - sh-eth,register-type: String, register type of sh_eth.
> > Please select "gigabit", "fast-sh4" or
> > @@ -37,6 +38,7 @@ Example (armadillo800eva):
> > reg = <0xe9a00000 0x800>, <0xe9a01800 0x800>;
> > interrupts = <0x500>;
> > phy-mode = "mii";
> > + phy-reset-gpios = <&gpio 18 0>;
> > sh-eth,edmac-endian = "little";
> > sh-eth,register-type = "gigabit";
> > sh-eth,phy-id = <0>;
> > diff --git a/drivers/net/ethernet/renesas/sh_eth.c
> > b/drivers/net/ethernet/renesas/sh_eth.c index 1f64848..06035a2 100644
> > --- a/drivers/net/ethernet/renesas/sh_eth.c
> > +++ b/drivers/net/ethernet/renesas/sh_eth.c
> > @@ -20,6 +20,7 @@
> > * the file called "COPYING".
> > */
> >
> > +#include <linux/gpio.h>
> > #include <linux/init.h>
> > #include <linux/module.h>
> > #include <linux/kernel.h>
> > @@ -33,6 +34,7 @@
> > #include <linux/netdevice.h>
> > #include <linux/of.h>
> > #include <linux/of_device.h>
> > +#include <linux/of_gpio.h>
> > #include <linux/of_platform.h>
> > #include <linux/of_address.h>
> > #include <linux/of_irq.h>
> > @@ -2376,10 +2378,11 @@ sh_eth_of_get_register_type(struct device_node *np)
> > static struct sh_eth_plat_data *
> > sh_eth_parse_dt(struct device *dev, struct net_device *ndev)
> > {
> > - int ret;
> > + int ret, gpio;
> > const char *of_str;
> > struct device_node *np = dev->of_node;
> > struct sh_eth_plat_data *pdata;
> > + enum of_gpio_flags flags;
> >
> > pdata = devm_kzalloc(dev, sizeof(struct sh_eth_plat_data),
> > GFP_KERNEL);
> > @@ -2420,6 +2423,10 @@ sh_eth_parse_dt(struct device *dev, struct net_device
> > *ndev) else
> > pdata->needs_init = 0;
> >
> > + gpio = of_get_named_gpio_flags(np, "phy-reset-gpios", 0, &flags);
> > + if (gpio_is_valid(gpio) && !devm_gpio_request(dev, gpio, NULL))
> > + gpio_direction_output(gpio, !!(flags & OF_GPIO_ACTIVE_LOW));
>
> You could use devm_gpio_request_one() here.

Yes, but then the flag would look uglier, something like

devm_gpio_request_one(dev, gpio, flags &
OF_GPIO_ACTIVE_LOW ? GPIOF_OUT_INIT_HIGH :
GPIOF_OUT_INIT_LOW);

Does it really look like an improvement? :)

> Is there no need to reset the phy at runtime ?

No idea, I'm not developing the driver, I'm just porting one specific
feature from one API to another with no functional changes (apart from
postponing setting the GPIO).

Thanks
Guennadi

> > +
> > #ifdef CONFIG_OF_NET
> > if (!is_valid_ether_addr(ndev->dev_addr)) {
> > const char *macaddr = of_get_mac_address(np);
> --
> Regards,
>
> Laurent Pinchart
>

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer