From: Felipe Balbi <balbi@ti.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Felipe Balbi <balbi@ti.com>,
David Cohen <david.a.cohen@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Baolu Lu <baolu.lu@linux.intel.com>, <linux-usb@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Kishon Vijay Abraham I <kishon@ti.com>
Subject: Re: [PATCH 8/8] phy: add driver for TI TUSB1210 ULPI PHY
Date: Fri, 30 Jan 2015 10:14:12 -0600 [thread overview]
Message-ID: <20150130161412.GD15318@saruman.tx.rr.com> (raw)
In-Reply-To: <20150130092956.GE2570@kuha.fi.intel.com>
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On Fri, Jan 30, 2015 at 11:29:56AM +0200, Heikki Krogerus wrote:
> Hi,
>
> > > You can't really compare a bus like i2c, which can't enumerate devices
> > > natively, to ULPI which can.
> >
> > why not ? The BIOS might not need to use the PHY (or USB) at all, it can
> > very well decide to never turn it on, right ?
>
> If ULPI was seen as a bus, then no. BIOS would have definitely left
> the PHY on. In fact, if we would have just asked the BIOS writers to
> leave it on, they would not have any problem with that, even without
> the bus.
it doesn't make sense, what you say just doesn't make sense. You're
assuming that a) only intel writes BIOS and b) you *always* have access
to BIOS writers. You forget that companies other than Intel make x86
devices too.
If the BIOS left the thing switched off, there's no "oh man, if only I
had asked them to leave it on"... that's nonsense, just have the kernel
deal with it.
> > > I don't agree with PM arguments if it means that we should be ready to
> > > accept loosing possibility for a generic solution in OS with a single
> > > device like our PHY. I seriously doubt it would prevent the products
> > > using these boards of achieving their PM requirements. But this
> > > conversation is outside our topic.
> >
> > we're not loosing anything. We're just considering what's the best way
> > to tackle that ulpi_read() inside probe(). TUSB1210 driver _has_ to cope
> > with situations where reset_gpio/cs_gpio are in unexpected state. Saying
> > we will just "fix the firmware", as if that was a simple feat, is
> > counter-productive.
>
> You know guys, we shouldn't always just lay down and say, "we just
> have to accept it can be anything" or "we just have to try to prepare
> for everything". We can influence these things, and we should. We can
sure Heikki, no arguments there. But the fact of the matter is that the
product David mentioned is *already* in the market.
> influence these things inside our own companies before any products is
> launched using our SoCs, and since more and more companies are
> releasing their code into the public before their product are
> launched, we even have a change to influence others. Lack of standards
> does not mean we should not try to achieve consistency.
>
> For example, now I should probable write to Documentation that "ULPI
> PHY needs to be in condition where it's register can be accessed
> before the interface is registered.", and I'm pretty sure it would be
> enough to have an effect on many of the new platforms that use ULPI
> PHYs.
until then, we just have to deal with current state of affairs.
> > > Because of the need to write to the ULPI registers, I don't think we
> > > should try anything else except to use ULPI bus straight away. We'll
> >
> > I'll agree with this.
> >
> > > start by making use of ULPI bus possible by adding the quirk for BYT
> > > (attached), which to me is perfectly OK solution. I would appreciate
> > > if you gave it a review.
> >
> > it's not perfectly ok for dwc3 to toggle PHY's GPIOs. Have the PHY
> > driver to that.
>
> Oh, I agree with that..
>
> > > diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
> > > index 8d95056..53902ea 100644
> > > --- a/drivers/usb/dwc3/dwc3-pci.c
> > > +++ b/drivers/usb/dwc3/dwc3-pci.c
> > > @@ -21,6 +21,7 @@
> > > #include <linux/slab.h>
> > > #include <linux/pci.h>
> > > #include <linux/platform_device.h>
> > > +#include <linux/gpio/consumer.h>
> > >
> > > #include "platform_data.h"
> > >
> > > @@ -35,6 +36,24 @@
> > >
> > > static int dwc3_pci_quirks(struct pci_dev *pdev)
> > > {
> > > + if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
> > > + pdev->device == PCI_DEVICE_ID_INTEL_BYT) {
> > > + struct gpio_desc *gpio;
> > > +
> > > + gpio = gpiod_get_index(&pdev->dev, "reset", 0);
> > > + if (!IS_ERR(gpio)) {
> > > + gpiod_direction_output(gpio, 0);
> > > + gpiod_set_value_cansleep(gpio, 1);
> > > + gpiod_put(gpio);
> > > + }
> > > + gpio = gpiod_get_index(&pdev->dev, "cs", 1);
> > > + if (!IS_ERR(gpio)) {
> > > + gpiod_direction_output(gpio, 0);
> > > + gpiod_set_value_cansleep(gpio, 1);
> > > + gpiod_put(gpio);
> > > + }
> > > + }
> >
> > why would you have dwc3 mess around with the PHY's gpios ? Doesn't look
> > very good.
>
> ..but unfortunately we can't use the bus without it :(. We depend on
> being able to read the vendor and product id's in the bus driver.
and what's the problem on doing this within PHY's probe ? The solution
is simple:
tusb1210_phy_probe()
{
...
gpiod_get(...);
gpiod_direction_output(reset, 0);
gpiod_set_value_cansleep(reset, 1);
gpiod_get(...);
gpiod_direction_output(cs, 0);
gpiod_set_value_cansleep(cs, 1);
eye = ulpi_read();
gpiod_set_value_cansleep(cs, 0);
gpiod_put(cs);
gpiod_set_value_cansleep(reset, 0);
gpiod_put(reset);
...
return 0;
}
This will have no effect on devices where PHY is already turned on and
will cope with the device David mentioned. If, however, there's a way to
get that eye diagram optimization without needing a ulpi_read() that's
*even* better, otherwise, above should fine in all cases.
cheers
--
balbi
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next prev parent reply other threads:[~2015-01-30 16:14 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-23 15:12 [PATCH 0/8] usb: ulpi bus Heikki Krogerus
2015-01-23 15:12 ` [PATCH 1/8] usb: add bus type for USB ULPI Heikki Krogerus
2015-01-29 5:02 ` Felipe Balbi
2015-01-29 14:18 ` Heikki Krogerus
2015-02-13 1:44 ` Stephen Boyd
2015-02-13 11:24 ` Heikki Krogerus
2015-01-23 15:12 ` [PATCH 2/8] usb: dwc3: USB2 PHY register access bits Heikki Krogerus
2015-01-23 15:12 ` [PATCH 3/8] usb: dwc3: store driver data earlier Heikki Krogerus
2015-01-23 15:12 ` [PATCH 4/8] usb: dwc3: cache hwparams earlier Heikki Krogerus
2015-01-23 15:12 ` [PATCH 5/8] usb: dwc3: ULPI or UTMI+ select Heikki Krogerus
2015-01-23 15:12 ` [PATCH 6/8] usb: dwc3: add ULPI interface support Heikki Krogerus
2015-01-23 16:24 ` Felipe Balbi
2015-01-26 11:46 ` Heikki Krogerus
2015-01-26 19:35 ` Felipe Balbi
2015-01-27 11:09 ` Heikki Krogerus
2015-01-27 15:24 ` Felipe Balbi
2015-02-11 19:34 ` David Cohen
2015-02-12 12:12 ` Heikki Krogerus
2015-02-13 1:41 ` David Cohen
2015-02-13 1:54 ` David Cohen
2015-02-13 13:16 ` Heikki Krogerus
2015-02-13 22:03 ` David Cohen
2015-02-13 22:04 ` Felipe Balbi
2015-01-23 15:12 ` [PATCH 7/8] phy: helpers for USB ULPI PHY registering Heikki Krogerus
2015-01-29 5:03 ` Felipe Balbi
2015-01-29 14:34 ` Heikki Krogerus
2015-01-29 16:11 ` Felipe Balbi
2015-01-30 10:33 ` Heikki Krogerus
2015-01-30 16:03 ` Felipe Balbi
2015-01-23 15:12 ` [PATCH 8/8] phy: add driver for TI TUSB1210 ULPI PHY Heikki Krogerus
2015-01-24 23:58 ` David Cohen
2015-01-26 12:55 ` Heikki Krogerus
2015-01-26 19:23 ` David Cohen
2015-01-27 9:28 ` Heikki Krogerus
2015-01-27 12:57 ` Heikki Krogerus
2015-01-27 17:38 ` David Cohen
2015-01-28 14:20 ` Heikki Krogerus
2015-01-28 18:02 ` David Cohen
2015-01-29 14:14 ` Heikki Krogerus
2015-01-29 16:20 ` Felipe Balbi
2015-01-29 18:02 ` David Cohen
2015-01-30 12:18 ` Heikki Krogerus
2015-01-30 16:09 ` David Cohen
2015-02-02 12:50 ` Heikki Krogerus
2015-01-30 9:29 ` Heikki Krogerus
2015-01-30 16:14 ` Felipe Balbi [this message]
2015-01-30 16:25 ` David Cohen
2015-01-30 16:30 ` Felipe Balbi
2015-01-30 16:20 ` David Cohen
2015-01-30 16:33 ` Felipe Balbi
2015-02-02 12:59 ` Heikki Krogerus
2015-02-03 11:37 ` Heikki Krogerus
2015-02-10 18:33 ` David Cohen
2015-02-10 19:05 ` David Cohen
2015-02-10 19:23 ` David Cohen
2015-02-11 13:12 ` Heikki Krogerus
2015-02-11 19:36 ` David Cohen
2015-02-13 22:02 ` David Cohen
2015-02-13 22:03 ` Felipe Balbi
2015-02-13 22:13 ` David Cohen
2015-01-29 5:09 ` Felipe Balbi
2015-01-29 14:30 ` Heikki Krogerus
2015-01-29 16:20 ` Felipe Balbi
2015-01-29 18:04 ` David Cohen
2015-01-29 18:25 ` David Cohen
2015-01-29 18:47 ` David Cohen
2015-01-30 10:30 ` Heikki Krogerus
2015-02-13 1:52 ` David Cohen
2015-02-13 12:35 ` Heikki Krogerus
2015-02-13 16:01 ` Felipe Balbi
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