From: Felipe Balbi <balbi@ti.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>,
Felipe Balbi <balbi@ti.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, 13 Feb 2015 10:01:23 -0600 [thread overview]
Message-ID: <20150213160123.GC22238@saruman.tx.rr.com> (raw)
In-Reply-To: <20150213123516.GB27695@kuha.fi.intel.com>
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On Fri, Feb 13, 2015 at 02:35:16PM +0200, Heikki Krogerus wrote:
> Hi,
>
> On Thu, Feb 12, 2015 at 05:52:42PM -0800, David Cohen wrote:
> > Hi Heikki,
> >
> > Sorry I am starting a new branch on this thread.
> > I need to go back to another topic on this same patch.
> >
> > On Fri, Jan 23, 2015 at 05:12:58PM +0200, Heikki Krogerus wrote:
> > > TUSB1210 ULPI PHY has vendor specific register for eye
> > > diagram tuning. On some platforms the system firmware has
> > > set optimized value to it. In order to not loose the
> > > optimized value, the driver stores it during probe and
> > > restores it every time the PHY is powered back on.
> > >
> > > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > > Cc: Kishon Vijay Abraham I <kishon@ti.com>
> > > ---
> >
> > [snip]
> >
> > > + /* Store initial eye diagram optimisation value */
> > > + ret = ulpi_read(ulpi, TUSB1210_VENDOR_SPECIFIC2);
> >
> > We can't rely on eye diagram optimization value here. It's possible the
> > phy went through reset (e.g. module unloading/loading).
> > We need a more consistent method. Could we use _DSD instead? That would
> > be more compatible with DT too.
>
> I'm don't have any problem with getting the value from a property.
> Sounds like the correct thing to do. Are you thinking about putting
> that _DSD method to the ACPI device object for the dwc3? The correct
> place would probable be separate device object for the PHY, but if we
> do that we need to consider how that object is bound to the ulpi
> device. There are few ways we can do that, so it requires some
> thinking.
>
> In any case this driver we can already implement so that it expects to
> get the value from property. We just need the name for it.
>
> The register has actually separate fields for High speed output
> impedance configuration and High speed output driver strength
> configuration for eye diagram tuning, plus control bit for DP/DM swap.
>
> Maybe we should actually get them from three separate properties:
>
> device_property_read_u8(dev, "datapolarity", &val);
> ...
> device_property_read_u8(dev, "zhsdrv", &val);
> ...
> device_property_read_u8(dev, "ihstx", &val);
> ...
>
> What do you think?
it's probably better to pass each value and let the driver calculate the
register contents like this.
--
balbi
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prev parent reply other threads:[~2015-02-13 16:01 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
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 [this message]
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