From patchwork Thu Feb 12 17:45:53 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Coquelin X-Patchwork-Id: 439305 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 1D86B140187 for ; Fri, 13 Feb 2015 04:49:44 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751696AbbBLRt2 (ORCPT ); Thu, 12 Feb 2015 12:49:28 -0500 Received: from mail-wg0-f66.google.com ([74.125.82.66]:53800 "EHLO mail-wg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751637AbbBLRqW (ORCPT ); Thu, 12 Feb 2015 12:46:22 -0500 Received: by mail-wg0-f66.google.com with SMTP id l18so3543715wgh.1; Thu, 12 Feb 2015 09:46:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:subject:date:message-id:in-reply-to:references; bh=acfoGnhV9EzDCwB7/ttLm+DmkKyR3wCwxyIg9WuRsBo=; b=Vbmxe9KGxOKNaSDTeKAJ0sgcDRVFJKOB43I84DU0GcZJ/47bsRalMni9z7QX6NAXRz ipE5gD/lnqCvP9T7FVgNAHERPkUWbM4ONnHfaC60RUFJC1cjl8EUWboBmzc1ii3QXpYO uoRsIeFo8yQRddeWRu50Fd0MZ9xpZ2OfP0ALNt9SLg2YWO6RvyxftwjdaMPsH9Z5BXBU Gci6Opl0XNxkD8vHTrp4IEv1At6VqnmSdDIPpJFhUhkwfUSLI5FBi1kTDeF5O+Y90e5X SnqwuJZO2X6LGP3j3iWltvviOfc39kdjI0yyVemSNaXqt6npKqJURu7Vf+eE/fMqBT3t Riig== X-Received: by 10.180.99.42 with SMTP id en10mr8518350wib.26.1423763180687; Thu, 12 Feb 2015 09:46:20 -0800 (PST) Received: from lmecul0520.st.com. (157.162.113.78.rev.sfr.net. [78.113.162.157]) by mx.google.com with ESMTPSA id ka1sm6614924wjc.2.2015.02.12.09.46.16 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 12 Feb 2015 09:46:20 -0800 (PST) From: Maxime Coquelin To: Jonathan Corbet , Maxime Coquelin , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Philipp Zabel , Russell King , Daniel Lezcano , Thomas Gleixner , Linus Walleij , Greg Kroah-Hartman , Jiri Slaby , Arnd Bergmann , Andrew Morton , "David S. Miller" , Mauro Carvalho Chehab , Joe Perches , Antti Palosaari , Tejun Heo , Will Deacon , Nikolay Borisov , Rusty Russell , Kees Cook , Michal Marek , linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-gpio@vger.kernel.org, linux-serial@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH 03/14] clocksource: Add ARM System timer driver Date: Thu, 12 Feb 2015 18:45:53 +0100 Message-Id: <1423763164-5606-4-git-send-email-mcoquelin.stm32@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1423763164-5606-1-git-send-email-mcoquelin.stm32@gmail.com> References: <1423763164-5606-1-git-send-email-mcoquelin.stm32@gmail.com> Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This patch adds clocksource support for ARMv7-M's System timer, also known as SysTick. Signed-off-by: Maxime Coquelin --- .../devicetree/bindings/arm/system_timer.txt | 15 +++++ drivers/clocksource/Kconfig | 7 ++ drivers/clocksource/Makefile | 1 + drivers/clocksource/arm_system_timer.c | 74 ++++++++++++++++++++++ 4 files changed, 97 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/system_timer.txt create mode 100644 drivers/clocksource/arm_system_timer.c diff --git a/Documentation/devicetree/bindings/arm/system_timer.txt b/Documentation/devicetree/bindings/arm/system_timer.txt new file mode 100644 index 0000000..35268b7 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/system_timer.txt @@ -0,0 +1,15 @@ +* ARM System Timer + +ARMv7-M includes a system timer, known as SysTick. Current driver only +implements the clocksource feature. + +Required properties: +- compatible : Should be "arm,armv7m-systick" +- reg : The address range of the timer +- clocks : The input clock of the timer + +systick: system-timer { + compatible = "arm,armv7m-systick"; + reg = <0xe000e010 0x10>; + clocks = <&clk_systick>; +}; diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index fc01ec2..f9fe4ac 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -124,6 +124,13 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK help Use ARM global timer clock source as sched_clock +config ARM_SYSTEM_TIMER + bool + select CLKSRC_OF if OF + select CLKSRC_MMIO + help + This options enables support for the ARM system timer unit + config ATMEL_PIT select CLKSRC_OF if OF def_bool SOC_AT91SAM9 || SOC_SAMA5 diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 94d90b2..194400b 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -42,6 +42,7 @@ obj-$(CONFIG_MTK_TIMER) += mtk_timer.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o +obj-$(CONFIG_ARM_SYSTEM_TIMER) += arm_system_timer.o obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o diff --git a/drivers/clocksource/arm_system_timer.c b/drivers/clocksource/arm_system_timer.c new file mode 100644 index 0000000..69e6ef9 --- /dev/null +++ b/drivers/clocksource/arm_system_timer.c @@ -0,0 +1,74 @@ +/* + * Copyright (C) Maxime Coquelin 2015 + * Author: Maxime Coquelin + * License terms: GNU General Public License (GPL), version 2 + */ + +#include +#include +#include +#include +#include +#include +#include + +#define SYST_CSR 0x00 +#define SYST_RVR 0x04 +#define SYST_CVR 0x08 +#define SYST_CALIB 0x0c + +#define SYST_CSR_ENABLE BIT(0) + +#define SYSTICK_LOAD_RELOAD_MASK 0x00FFFFFF + +static void __init system_timer_of_register(struct device_node *np) +{ + struct clk *clk; + void __iomem *base; + unsigned long rate; + int ret; + + base = of_iomap(np, 0); + if (!base) { + pr_warn("system-timer: invalid base address\n"); + return; + } + + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + pr_warn("system-timer: clk not found\n"); + ret = PTR_ERR(clk); + goto out_unmap; + } + + ret = clk_prepare_enable(clk); + if (ret) + goto out_clk_put; + + rate = clk_get_rate(clk); + + writel_relaxed(SYSTICK_LOAD_RELOAD_MASK, base + SYST_RVR); + writel_relaxed(SYST_CSR_ENABLE, base + SYST_CSR); + + ret = clocksource_mmio_init(base + SYST_CVR, "arm_system_timer", rate, + 200, 24, clocksource_mmio_readl_down); + if (ret) { + pr_err("failed to init clocksource (%d)\n", ret); + goto out_clk_disable; + } + + pr_info("ARM System timer initialized as clocksource\n"); + + return; + +out_clk_disable: + clk_disable_unprepare(clk); +out_clk_put: + clk_put(clk); +out_unmap: + iounmap(base); + WARN(ret, "ARM System timer register failed (%d)\n", ret); +} + +CLOCKSOURCE_OF_DECLARE(arm_systick, "arm,armv7m-systick", + system_timer_of_register);