From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753906AbcG2UoY (ORCPT ); Fri, 29 Jul 2016 16:44:24 -0400 Received: from mail-pf0-f178.google.com ([209.85.192.178]:34816 "EHLO mail-pf0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753754AbcG2UoR (ORCPT ); Fri, 29 Jul 2016 16:44:17 -0400 Subject: Re: [PATCH] clk: bcm: Add driver for Northstar ILP clock To: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Michael Turquette , Stephen Boyd References: <1469797120-29298-1-git-send-email-zajec5@gmail.com> Cc: linux-clk@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Florian Fainelli , Jon Mason , Eric Anholt , Stephen Warren , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list From: Ray Jui Message-ID: Date: Fri, 29 Jul 2016 13:44:13 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Thunderbird/47.0 MIME-Version: 1.0 In-Reply-To: <1469797120-29298-1-git-send-email-zajec5@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rafal, On 7/29/2016 5:58 AM, Rafał Miłecki wrote: > From: Rafał Miłecki > > This clock is present on cheaper Northstar devices like BCM53573 or > BCM47189 using Corex-A7. This driver uses PMU (Power Management Unit) > to calculate clock rate and allows using it in a generic (clk_*) way. > I thought Northstar uses Cortex A9 instead of A7? > Signed-off-by: Rafał Miłecki > --- > .../devicetree/bindings/clock/brcm,ns-ilp.txt | 28 ++++ > drivers/clk/bcm/Makefile | 1 + > drivers/clk/bcm/clk-ns-ilp.c | 146 +++++++++++++++++++++ > 3 files changed, 175 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..c4df38e > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt > @@ -0,0 +1,28 @@ > +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 on Broadcom Northstar devices using > +Corex-A7 CPU. ILP clock depends on ALP one and has to be calculated on > +runtime. > + Cortex-A9. > +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: should reference an ALP clock > +- clock-names: "alp", the only needed & supported clock right now clock-names must be "alp-clk" > +- #clock-cells: should be <0> > + > +Example: > + > +ilp: ilp { > + compatible = "brcm,ns-ilp"; > + reg = <0x18012000 0x1000>; > + reg-names = "pmu"; > + clocks = <&alp>; > + clock-names = "alp-clk"; > + #clock-cells = <0>; > +}; > 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..230458e8 > --- /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 > +#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; > + struct clk *alp_clk; > + 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; > + int err; > + > + err = clk_prepare_enable(ilp->alp_clk); > + if (err) > + return 0; > + > + /* Enable */ > + writel(XTAL_CTL_EN, pmu + PMU_XTAL_FREQ_RATIO); > + > + /* Read initial value */ > + last_val = readl(pmu + PMU_XTAL_FREQ_RATIO) & XTAL_ALP_PER_4ILP; > + > + /* Try getting 20 different values for calculating 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 */ > + writel(0x0, pmu + PMU_XTAL_FREQ_RATIO); > + > + avg = sum / num; > + > + return clk_get_rate(ilp->alp_clk) * 4 / avg; > +} > + > +const struct clk_ops ns_ilp_clk_ops = { static > + .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 }; > + int index; > + int err; > + > + ilp = kzalloc(sizeof(*ilp), GFP_KERNEL); > + if (!ilp) > + return; > + > + 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) { > + err = index; > + goto err_free_ilp; > + } > + ilp->pmu = ioremap_nocache(res.start, resource_size(&res)); > + if (IS_ERR(ilp->pmu)) { > + err = PTR_ERR(ilp->pmu); > + goto err_free_ilp; > + } > + > + ilp->alp_clk = of_clk_get_by_name(np, "alp-clk"); > + if (IS_ERR(ilp->alp_clk)) { > + err = PTR_ERR(ilp->alp_clk); > + goto err_unmap_pmu; > + } > + > + init.name = np->name; > + init.ops = &ns_ilp_clk_ops; > + init.flags = CLK_IS_ROOT; > + > + ilp->hw.init = &init; > + ilp->clk = clk_register(NULL, &ilp->hw); > + if (WARN_ON(IS_ERR(ilp->clk))) > + goto err_put_alp_clk; > + > + of_clk_add_provider(np, of_clk_src_simple_get, ilp->clk); Check return value and handle error conditions > + > + return; > + > +err_put_alp_clk: > + clk_put(ilp->alp_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); > Thanks, Ray