From mboxrd@z Thu Jan 1 00:00:00 1970 From: Charles Keepax Subject: Re: [PATCH v2 3/5] clk: lochnagar: Add support for the Cirrus Logic Lochnagar Date: Mon, 15 Oct 2018 11:49:05 +0100 Message-ID: <20181015104905.GF1653@imbe.wolfsonmicro.main> References: <20181008132542.19775-1-ckeepax@opensource.cirrus.com> <20181008132542.19775-3-ckeepax@opensource.cirrus.com> <153924124658.207691.10370075148426001371@swboyd.mtv.corp.google.com> <20181011132602.GD1653@imbe.wolfsonmicro.main> <153935999691.5275.1587207165396958375@swboyd.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <153935999691.5275.1587207165396958375@swboyd.mtv.corp.google.com> Sender: linux-kernel-owner@vger.kernel.org To: Stephen Boyd 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 List-Id: devicetree@vger.kernel.org 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