From: Charles Keepax <ckeepax@opensource.cirrus.com>
To: Stephen Boyd <sboyd@kernel.org>
Cc: <broonie@kernel.org>, <lee.jones@linaro.org>,
<linus.walleij@linaro.org>, <mturquette@baylibre.com>,
<robh+dt@kernel.org>, <mark.rutland@arm.com>,
<lgirdwood@gmail.com>, <devicetree@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <patches@opensource.cirrus.com>,
<linux-clk@vger.kernel.org>, <linux-gpio@vger.kernel.org>
Subject: Re: [PATCH v2 3/5] clk: lochnagar: Add support for the Cirrus Logic Lochnagar
Date: Mon, 15 Oct 2018 11:49:05 +0100 [thread overview]
Message-ID: <20181015104905.GF1653@imbe.wolfsonmicro.main> (raw)
In-Reply-To: <153935999691.5275.1587207165396958375@swboyd.mtv.corp.google.com>
On Fri, Oct 12, 2018 at 08:59:56AM -0700, Stephen Boyd wrote:
> Quoting Charles Keepax (2018-10-11 06:26:02)
> > On Thu, Oct 11, 2018 at 12:00:46AM -0700, Stephen Boyd wrote:
> > > Quoting Charles Keepax (2018-10-08 06:25:40)
> > > > +struct lochnagar_clk_priv {
> > > > + struct device *dev;
> > > > + struct lochnagar *lochnagar;
> > >
> > > Is this used for anything besides getting the regmap? Can you get the
> > > pointer to the parent in probe and use that to get the regmap pointer
> > > from dev_get_remap() and also use the of_node of the parent to register
> > > a clk provider? It would be nice to avoid including the mfd header file
> > > unless it's providing something useful.
> > >
> >
> > It is also used to find out which type of Lochnagar we have
> > connected, which determines which clocks we should register. I
>
> Can that be done through some device ID? So the driver can be untangled
> from the MFD part.
>
> > could perhaps pass that using another mechanism but we would
> > still want to include the MFD stuff to get the register
> > definitions. So this approach seems simplest.
>
> Can the register definitions be moved to this clk driver?
>
> Maybe you now get the hint, but I'd really like to be able to merge and
> compile the clk driver all by itself without relying on the parent MFD
> device to provide anything at compile time.
>
If you feel strongly but since the MFD needs to hold the regmap
(which needs to define the read/volatile regs and defaults)
these will need to be duplicate defines and personally i would
rather only have one copy as it makes updating things much less
error prone.
> > > > + if (lclk->regmap.dir_mask) {
> > > > + ret = regmap_update_bits(regmap, lclk->regmap.cfg_reg,
> > > > + lclk->regmap.dir_mask,
> > > > + lclk->regmap.dir_mask);
> > > > + if (ret < 0) {
> > > > + dev_err(priv->dev, "Failed to set %s direction: %d\n",
> > >
> > > What does direction mean?
> > >
> >
> > Some of the clocks can both generate and receive a clock. For
> > example the PSIA (external audio interface) MCLKs, the attached
> > device could be expecting or providing a master audio clock. If
> > the user assigns a parent to the clock we assume the attached
> > device is providing a clock to us, otherwise we assume we are
> > providing the clock.
>
> And this directionality is determined by dir_mask? It would be great if
> this sort of information was in the commit text or in a comment in the
> driver so we know what's going on here.
>
No problem will make this more clear.
Thanks,
Charles
next prev parent reply other threads:[~2018-10-15 10:49 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-08 13:25 [PATCH v2 1/5] mfd: lochnagar: Add initial binding documentation Charles Keepax
2018-10-08 13:25 ` [PATCH v2 2/5] mfd: lochnagar: Add support for the Cirrus Logic Lochnagar Charles Keepax
2018-10-25 7:44 ` Lee Jones
2018-10-25 8:26 ` Charles Keepax
2018-10-25 9:28 ` Richard Fitzgerald
2018-10-25 10:12 ` Mark Brown
2018-10-25 10:56 ` Charles Keepax
2018-10-25 11:42 ` Lee Jones
2018-10-25 12:49 ` Charles Keepax
2018-10-25 13:20 ` Charles Keepax
2018-10-25 13:47 ` Richard Fitzgerald
2018-10-26 15:49 ` Mark Brown
2018-10-26 7:33 ` Lee Jones
2018-10-26 15:47 ` Mark Brown
2018-10-25 13:40 ` Richard Fitzgerald
2018-10-26 8:00 ` Lee Jones
2018-10-26 20:32 ` Mark Brown
2018-10-29 11:04 ` Lee Jones
2018-10-29 11:52 ` Richard Fitzgerald
2018-10-29 12:36 ` Richard Fitzgerald
2018-10-29 12:57 ` Mark Brown
2018-11-01 10:28 ` Charles Keepax
2018-11-01 11:40 ` Richard Fitzgerald
2018-11-01 12:04 ` Mark Brown
2018-11-01 12:01 ` Mark Brown
2018-11-01 14:17 ` Richard Fitzgerald
2018-10-08 13:25 ` [PATCH v2 3/5] clk: " Charles Keepax
2018-10-11 7:00 ` Stephen Boyd
2018-10-11 13:26 ` Charles Keepax
2018-10-12 15:59 ` Stephen Boyd
2018-10-15 10:49 ` Charles Keepax [this message]
2018-10-15 16:39 ` Stephen Boyd
2018-10-15 16:55 ` Mark Brown
2018-10-15 21:53 ` Stephen Boyd
2018-10-11 14:54 ` Mark Brown
2018-10-11 19:36 ` Stephen Boyd
2018-10-12 16:52 ` Mark Brown
2018-10-08 13:25 ` [PATCH v2 4/5] regulator: " Charles Keepax
2018-10-08 13:25 ` [PATCH v2 5/5] pinctrl: " Charles Keepax
2018-10-12 22:08 ` [PATCH v2 1/5] mfd: lochnagar: Add initial binding documentation Rob Herring
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