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Groups > linux.kernel > #1627173
| From | Roger Quadros <rogerq@ti.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. |
| Date | 2017-04-20 10:00 +0200 |
| Message-ID | <tyfap-6aM-15@gated-at.bofh.it> (permalink) |
| References | <tsODU-f3-17@gated-at.bofh.it> <txU5X-1Gt-7@gated-at.bofh.it> <txWhr-2Xi-9@gated-at.bofh.it> <txWr7-30n-9@gated-at.bofh.it> <txXZT-40g-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 19/04/17 16:38, Andrew Lunn wrote:
> On Wed, Apr 19, 2017 at 02:56:48PM +0300, Roger Quadros wrote:
>> Hi,
>>
>> On 19/04/17 14:39, Andrew Lunn wrote:
>>> On Wed, Apr 19, 2017 at 12:24:26PM +0300, Roger Quadros wrote:
>>>> Some boards [1] leave the PHYs at an invalid state
>>>> during system power-up or reset thus causing unreliability
>>>> issues with the PHY which manifests as PHY not being detected
>>>> or link not functional. To fix this, these PHYs need to be RESET
>>>> via a GPIO connected to the PHY's RESET pin.
>>>>
>>>> Some boards have a single GPIO controlling the PHY RESET pin of all
>>>> PHYs on the bus whereas some others have separate GPIOs controlling
>>>> individual PHY RESETs.
>>>>
>>>> In both cases, the RESET de-assertion cannot be done in the PHY driver
>>>> as the PHY will not probe till its reset is de-asserted.
>>>> So do the RESET de-assertion in the MDIO bus driver.
>>>>
>>>> [1] - am572x-idk, am571x-idk, a437x-idk
>>>>
>>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>>> ---
>>>> drivers/net/phy/mdio_bus.c | 26 ++++++++++++++++++++++++++
>>>> drivers/of/of_mdio.c | 4 ++++
>>>> include/linux/phy.h | 5 +++++
>>>> 3 files changed, 35 insertions(+)
>>>
>>> Hi Roger
>>>
>>> Thanks for making this generic.
>>>
>>> Please add device tree binding documentation. I think that actually
>>> means you have to document MDIO in general, since there currently is
>>> not a binding document.
>>
>> OK.
>>
>>>
>>>> diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
>>>> index fa7d51f..25fda2b 100644
>>>> --- a/drivers/net/phy/mdio_bus.c
>>>> +++ b/drivers/net/phy/mdio_bus.c
>>>> @@ -22,8 +22,11 @@
>>>> #include <linux/init.h>
>>>> #include <linux/delay.h>
>>>> #include <linux/device.h>
>>>> +#include <linux/gpio.h>
>>>> +#include <linux/gpio/consumer.h>
>>>> #include <linux/of_device.h>
>>>> #include <linux/of_mdio.h>
>>>> +#include <linux/of_gpio.h>
>>>> #include <linux/netdevice.h>
>>>> #include <linux/etherdevice.h>
>>>> #include <linux/skbuff.h>
>>>> @@ -43,6 +46,8 @@
>>>>
>>>> #include "mdio-boardinfo.h"
>>>>
>>>> +#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */
>>>> +
>>>> int mdiobus_register_device(struct mdio_device *mdiodev)
>>>> {
>>>> if (mdiodev->bus->mdio_map[mdiodev->addr])
>>>> @@ -307,6 +312,7 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner)
>>>> {
>>>> struct mdio_device *mdiodev;
>>>> int i, err;
>>>> + struct gpio_desc *gpiod;
>>>>
>>>> if (NULL == bus || NULL == bus->name ||
>>>> NULL == bus->read || NULL == bus->write)
>>>> @@ -333,6 +339,26 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner)
>>>> if (bus->reset)
>>>> bus->reset(bus);
>>>>
>>>> + /* de-assert bus level PHY GPIO resets */
>>>> + for (i = 0; i < bus->num_reset_gpios; i++) {
>>>> + gpiod = devm_gpiod_get_index(&bus->dev, "reset", i,
>>>> + GPIOD_OUT_LOW);
>>>> + if (IS_ERR(gpiod)) {
>>>> + err = PTR_ERR(gpiod);
>>>> + if (err != -ENOENT) {
>>>> + pr_err("mii_bus %s couldn't get reset GPIO\n",
>>>> + bus->id);
>>>> + return err;
>>>> + }
>>>> + } else {
>>>> + gpiod_set_value_cansleep(gpiod, 1);
>>>
>>>
>>>> + if (!bus->reset_delay_us)
>>>> + bus->reset_delay_us = DEFAULT_GPIO_RESET_DELAY;
>>>
>>> Maybe do this once, where you read the device tree property.
>>
>> I was thinking from point of view that GPIO RESET code should work even without
>> device tree. Although I'm not sure if there would be any users or not.
>
> Hi Roger
>
> I don't see how this would work. What would devm_gpiod_get_index()
> return? Something from ACPI? But then there would be something
Yes or just lookup tables based on platform data.
> equivalent for getting the delay.
I'm not sure about delay part.
>
> Lets keep it simple and OF only. If there is a real need for something
> in addition to OF, it can be added later.
OK. I'll revise the patch based on your comments.
cheers,
-roger
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[PATCH] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-19 11:30 +0200
Re: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. Andrew Lunn <andrew@lunn.ch> - 2017-04-19 13:50 +0200
Re: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-19 14:00 +0200
Re: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. Andrew Lunn <andrew@lunn.ch> - 2017-04-19 15:40 +0200
Re: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-20 10:00 +0200
[PATCH v2] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-20 10:40 +0200
Re: [PATCH v2] mdio_bus: Issue GPIO RESET to PHYs. Andrew Lunn <andrew@lunn.ch> - 2017-04-20 15:20 +0200
Re: [PATCH v2] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-20 16:00 +0200
[PATCH v3 net-next] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-20 16:20 +0200
Re: [PATCH v3 net-next] mdio_bus: Issue GPIO RESET to PHYs. Andrew Lunn <andrew@lunn.ch> - 2017-04-21 03:20 +0200
Re: [PATCH v3 net-next] mdio_bus: Issue GPIO RESET to PHYs. Florian Fainelli <f.fainelli@gmail.com> - 2017-04-21 03:30 +0200
Re: [PATCH v3 net-next] mdio_bus: Issue GPIO RESET to PHYs. Andrew Lunn <andrew@lunn.ch> - 2017-04-21 03:40 +0200
Re: [PATCH v3 net-next] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-21 10:10 +0200
[PATCH v4 net-next] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-21 15:20 +0200
Re: [PATCH v4 net-next] mdio_bus: Issue GPIO RESET to PHYs. Lars-Peter Clausen <lars@metafoo.de> - 2017-04-21 15:40 +0200
Re: [PATCH v4 net-next] mdio_bus: Issue GPIO RESET to PHYs. Andrew Lunn <andrew@lunn.ch> - 2017-04-24 01:40 +0200
Re: [PATCH v4 net-next] mdio_bus: Issue GPIO RESET to PHYs. Roger Quadros <rogerq@ti.com> - 2017-04-24 11:10 +0200
Re: [PATCH v4 net-next] mdio_bus: Issue GPIO RESET to PHYs. Florian Fainelli <f.fainelli@gmail.com> - 2017-04-24 18:40 +0200
Re: [PATCH v4 net-next] mdio_bus: Issue GPIO RESET to PHYs. David Miller <davem@davemloft.net> - 2017-04-24 18:50 +0200
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