From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Turquette Subject: Re: [PATCH 2/2] clk: ti: Add support for dm814x ADPLL Date: Wed, 17 Feb 2016 12:52:57 -0800 Message-ID: <20160217205257.2278.11639@quark.deferred.io> References: <1455312009-808-1-git-send-email-tony@atomide.com> <1455312009-808-3-git-send-email-tony@atomide.com> <20160217011930.2278.38316@quark.deferred.io> <20160217173949.GB21202@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160217173949.GB21202@atomide.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Tony Lindgren Cc: Russell King - ARM Linux , Delio Brignoli , Matthijs van Duin , Neil Armstrong , Stephen Boyd , Philipp Rosenberger , Brian Hutchinson , Tero Kristo , linux-omap@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: linux-omap@vger.kernel.org Quoting Tony Lindgren (2016-02-17 09:39:49) > * Michael Turquette [160216 17:32]: > > Quoting Tony Lindgren (2016-02-12 13:20:09) > > > > > > - Split the device tree binding into a separate patch as requested > > > by Mike for his conditional ack of the binding > > > > Just to make life fun for you, the clk tree is once more merging DT > > bindings descriptions and headers. You don't need to merge the patches, > > it doesn't matter to me, but just as a heads up for the future. > > OK :) > > > > --- /dev/null > > > +++ b/drivers/clk/ti/Kconfig > > > @@ -0,0 +1,6 @@ > > > +config COMMON_CLK_TI_ADPLL > > > + tristate "Clock driver for dm814x ADPLL" > > > + depends on ARCH_OMAP2PLUS > > > + default y if SOC_TI81XX > > > > Can we add COMPILE_TEST here? > > Good idea, will add. > > > > +static int ti_adpll_init_inputs(struct ti_adpll_data *d) > > > +{ > > > + const char *error = "need at least %i inputs"; > > > + struct clk *clock; > > > + int nr_inputs; > > > + > > > + nr_inputs = of_clk_get_parent_count(d->np); > > > + if (nr_inputs < d->c->nr_max_inputs) { > > > + dev_err(d->dev, error, nr_inputs); > > > + return -EINVAL; > > > + } > > > + of_clk_parent_fill(d->np, d->parent_names, nr_inputs); > > > + > > > + clock = devm_clk_get(d->dev, d->parent_names[0]); > > > + if (IS_ERR(clock)) { > > > + dev_err(d->dev, "could not get clkinp\n"); > > > + return PTR_ERR(clock); > > > + } > > > + d->parent_clocks[TI_ADPLL_CLKINP] = clock; > > > + > > > + clock = devm_clk_get(d->dev, d->parent_names[1]); > > > + if (IS_ERR(clock)) { > > > + dev_err(d->dev, "could not get clkinpulow clock\n"); > > > + return PTR_ERR(clock); > > > + } > > > + d->parent_clocks[TI_ADPLL_CLKINPULOW] = clock; > > > > Are the clock parents known at compile-time? Can we just put that data > > in C instead of whatever is going on here? > > No they can be board specific depending how the inputs for > clkin, clkinpulow and clkinphif are wired. > > > ... > > > +int __init dm814x_adpll_enable_init_clocks(void) > > > +{ > > > + int i, err; > > > + > > > + if (!timer_clocks_initialized) > > > + return -ENODEV; > > > + > > > + for (i = 0; i < ARRAY_SIZE(init_clocks); i++) { > > > + struct clk *clock; > > > + > > > + clock = clk_get(NULL, init_clocks[i]); > > > + if (WARN(IS_ERR(clock), "could not find init clock %s\n", > > > + init_clocks[i])) > > > + continue; > > > + err = clk_prepare_enable(clock); > > > + if (WARN(err, "could not enable init clock %s\n", > > > + init_clocks[i])) > > > + continue; > > > > We have a shiny new series that provides a standard way to do this: > > > > http://lkml.kernel.org/r/<1455225554-13267-1-git-send-email-mturquette@baylibre.com> > > OK nice, so tagging the MPU and DDR clocks with CLK_IS_CRITICAL or > "clock-critical" should allow removing this code. I think in this > case I still need to set CLK_IS_CRITICAL as the clock is output 1 > of the dts defined clock and does not have a separate dts node. In fact I hate clock-critical as a DT property and it's only there to support legacy DT bindings that store all clk data in DT and have zero clk data in C. So please use the CLK_IS_CRITICAL or CLK_ENABLE_HAND_OFF flags in C. Do you think you will ever have a driver that wants to gate these clocks? Probably not for MPU/DDR, but the HAND_OFF flag is a better fit if you do. It's the same as CRITICAL but transfers the prepare/enable reference counting to the consumer driver after that driver calls clk_get() and clk_prepare_enable() on the HAND_OFF clk. > > I can update when those patches hit Linux next, or I can do a > follow-up patch later on if we want to avoid the dependency > here. Which do you prefer? Well, testing is always welcome :-) If you rebase onto those patches then I'll add your patches to that series for testing and merge it that way. Regards, Mike > > Regards, > > Tony > -- > To unsubscribe from this list: send the line "unsubscribe linux-clk" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html