From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933608AbcHJSR2 (ORCPT ); Wed, 10 Aug 2016 14:17:28 -0400 Received: from mail-it0-f54.google.com ([209.85.214.54]:36185 "EHLO mail-it0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933197AbcHJSRZ convert rfc822-to-8bit (ORCPT ); Wed, 10 Aug 2016 14:17:25 -0400 MIME-Version: 1.0 In-Reply-To: <1470830763-29189-1-git-send-email-zajec5@gmail.com> References: <1470830763-29189-1-git-send-email-zajec5@gmail.com> From: Jon Mason Date: Wed, 10 Aug 2016 13:22:09 -0400 Message-ID: Subject: Re: [PATCH V3] clk: bcm: Add driver for Northstar ILP clock To: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= Cc: Michael Turquette , Stephen Boyd , linux-clk@vger.kernel.org, BCM Kernel Feedback , =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Eric Anholt , Florian Fainelli , Jon Mason , Stephen Warren , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 10, 2016 at 8:05 AM, Rafał Miłecki wrote: > From: Rafał Miłecki > > This clock is present on cheaper Northstar devices like BCM53573 or > BCM47189 using Corex-A7. ILP is a part of PMU (Power Management Unit) > and so it should be defined as one of its subnodes (subdevices). For > more details see Documentation entry. > > Unfortunately there isn't a set of registers related to ILP clock only. > We use registers 0x66c, 0x674 and 0x6dc and between them there are e.g. > "retention*" and "control_ext" regs. This is why this driver maps all > 0x1000 B of space. > > Signed-off-by: Rafał Miłecki > --- > V2: Rebase on top of clk-next > Use ALP as parent clock > Improve comments > Switch from ioremap_nocache to ioremap > Check of_clk_add_provide result for error > V3: Drop #include > Make ILP DT entry part of PMU > Describe ILP as subdevice of PMU in Documentation > --- > .../devicetree/bindings/clock/brcm,ns-ilp.txt | 40 ++++++ > drivers/clk/bcm/Makefile | 1 + > drivers/clk/bcm/clk-ns-ilp.c | 146 +++++++++++++++++++++ > 3 files changed, 187 insertions(+) > create mode 100644 Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt > create mode 100644 drivers/clk/bcm/clk-ns-ilp.c > > diff --git a/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt > new file mode 100644 > index 0000000..a18c73f > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt > @@ -0,0 +1,40 @@ > +Broadcom Northstar ILP clock > +============================ > + > +This binding uses the common clock binding: > + Documentation/devicetree/bindings/clock/clock-bindings.txt > + > +This binding is used for ILP clock (sometimes referred as "slow clock") > +on Broadcom Northstar devices using Corex-A7 CPU. > + > +This clock is part of PMU (Power Management Unit), a Broadcom's device > +handing power-related aspects. Please note PMU contains more subdevices, > +ILP is only one of them. > + > +ILP's rate has to be calculated on runtime and it depends on ALP clock > +which has to be referenced. > + > +Required properties: > +- compatible: "brcm,ns-ilp" > +- reg: iomem address range of PMU (Power Management Unit) > +- reg-names: "pmu", the only needed & supported reg right now > +- clocks: has to reference an ALP clock > +- #clock-cells: should be <0> > + > +Example: > + > +pmu@18012000 { > + compatible = "simple-bus"; > + ranges = <0x00000000 0x18012000 0x00001000>; I don't see a corresponding DT entry in this patch, but 18012000 is the PCI block. So, I am concerned this will collide if used there. I looked at the NS register reference guide, and I cannot find the registers you are trying to reference. Is this supposed to be referencing the LCPLL clock registers in DMU? If so, there is already a driver in there for this (see drivers/clk/bcm/clk-nsp.c). > + #address-cells = <1>; > + #size-cells = <1>; > + > + ilp: ilp@0 { > + compatible = "brcm,ns-ilp"; > + reg = <0 0x1000>; > + reg-names = "pmu"; > + clocks = <&alp>; > + #clock-cells = <0>; > + clock-output-names = "ilp"; > + }; > +}; > diff --git a/drivers/clk/bcm/Makefile b/drivers/clk/bcm/Makefile > index 1d79bd2..1389379 100644 > --- a/drivers/clk/bcm/Makefile > +++ b/drivers/clk/bcm/Makefile > @@ -10,3 +10,4 @@ obj-$(CONFIG_COMMON_CLK_IPROC) += clk-ns2.o > obj-$(CONFIG_ARCH_BCM_CYGNUS) += clk-cygnus.o > obj-$(CONFIG_ARCH_BCM_NSP) += clk-nsp.o > obj-$(CONFIG_ARCH_BCM_5301X) += clk-nsp.o > +obj-$(CONFIG_ARCH_BCM_5301X) += clk-ns-ilp.o > diff --git a/drivers/clk/bcm/clk-ns-ilp.c b/drivers/clk/bcm/clk-ns-ilp.c > new file mode 100644 > index 0000000..53b4a23 > --- /dev/null > +++ b/drivers/clk/bcm/clk-ns-ilp.c > @@ -0,0 +1,146 @@ > +/* > + * Copyright (C) 2016 Rafał Miłecki > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define PMU_XTAL_FREQ_RATIO 0x66c > +#define XTAL_ALP_PER_4ILP 0x00001fff > +#define XTAL_CTL_EN 0x80000000 > +#define PMU_SLOW_CLK_PERIOD 0x6dc > + > +struct ns_ilp { > + struct clk *clk; > + struct clk_hw hw; > + void __iomem *pmu; > +}; > + > +static int ns_ilp_enable(struct clk_hw *hw) > +{ > + struct ns_ilp *ilp = container_of(hw, struct ns_ilp, hw); > + > + writel(0x10199, ilp->pmu + PMU_SLOW_CLK_PERIOD); > + writel(0x10000, ilp->pmu + 0x674); > + > + return 0; > +} > + > +static unsigned long ns_ilp_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ > + struct ns_ilp *ilp = container_of(hw, struct ns_ilp, hw); > + void __iomem *pmu = ilp->pmu; > + u32 last_val, cur_val; > + u32 sum = 0, num = 0, loop_num = 0; > + u32 avg; > + > + /* Enable measurement */ > + writel(XTAL_CTL_EN, pmu + PMU_XTAL_FREQ_RATIO); > + > + /* Read initial value */ > + last_val = readl(pmu + PMU_XTAL_FREQ_RATIO) & XTAL_ALP_PER_4ILP; > + > + /* > + * At minimum we should loop for a bit to let hardware do the > + * measurement. This isn't very accurate however, so for a better > + * precision lets try getting 20 different values for and use average. > + */ > + while (num < 20) { > + cur_val = readl(pmu + PMU_XTAL_FREQ_RATIO) & XTAL_ALP_PER_4ILP; > + > + if (cur_val != last_val) { > + /* Got different value, use it */ > + sum += cur_val; > + num++; > + loop_num = 0; > + last_val = cur_val; > + } else if (++loop_num > 5000) { > + /* Same value over and over, give up */ > + sum += cur_val; > + num++; > + break; > + } > + } > + > + /* Disable measurement to save power */ > + writel(0x0, pmu + PMU_XTAL_FREQ_RATIO); > + > + avg = sum / num; > + > + return parent_rate * 4 / avg; > +} > + > +static const struct clk_ops ns_ilp_clk_ops = { > + .enable = ns_ilp_enable, > + .recalc_rate = ns_ilp_recalc_rate, > +}; > + > +static void ns_ilp_init(struct device_node *np) > +{ > + struct ns_ilp *ilp; > + struct resource res; > + struct clk_init_data init = { 0 }; > + const char *parent_name; > + int index; > + int err; > + > + ilp = kzalloc(sizeof(*ilp), GFP_KERNEL); > + if (!ilp) > + return; > + > + parent_name = of_clk_get_parent_name(np, 0); > + if (!parent_name) { > + err = -ENOENT; > + goto err_free_ilp; > + } > + > + /* TODO: This looks generic, try making it OF helper. */ > + index = of_property_match_string(np, "reg-names", "pmu"); > + if (index < 0) { > + err = index; > + goto err_free_ilp; > + } > + err = of_address_to_resource(np, index, &res); > + if (err) > + goto err_free_ilp; > + ilp->pmu = ioremap(res.start, resource_size(&res)); > + if (IS_ERR(ilp->pmu)) { > + err = PTR_ERR(ilp->pmu); > + goto err_free_ilp; > + } > + > + init.name = np->name; > + init.ops = &ns_ilp_clk_ops; > + init.parent_names = &parent_name; > + init.num_parents = 1; > + > + ilp->hw.init = &init; > + ilp->clk = clk_register(NULL, &ilp->hw); > + if (WARN_ON(IS_ERR(ilp->clk))) > + goto err_unmap_pmu; > + > + err = of_clk_add_provider(np, of_clk_src_simple_get, ilp->clk); > + if (err) > + goto err_clk_unregister; > + > + return; > + > +err_clk_unregister: > + clk_unregister(ilp->clk); > +err_unmap_pmu: > + iounmap(ilp->pmu); > +err_free_ilp: > + kfree(ilp); > + pr_err("Failed to init ILP clock: %d\n", err); > +} > +CLK_OF_DECLARE(ns_ilp_clk, "brcm,ns-ilp", ns_ilp_init); > -- > 1.8.4.5 >