Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933410AbbDIKxO (ORCPT ); Thu, 9 Apr 2015 06:53:14 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:34182 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933348AbbDIKxA (ORCPT ); Thu, 9 Apr 2015 06:53:00 -0400 Message-ID: <55265A06.5020902@linaro.org> Date: Thu, 09 Apr 2015 12:52:54 +0200 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Maxime Coquelin , u.kleine-koenig@pengutronix.de, afaerber@suse.de, geert@linux-m68k.org, Rob Herring , Philipp Zabel , Linus Walleij , Arnd Bergmann , stefan@agner.ch, pmeerw@pmeerw.net, pebolle@tiscali.nl, peter@hurleysoftware.com, andy.shevchenko@gmail.com, cw00.choi@samsung.com, Russell King , joe@perches.com CC: Jonathan Corbet , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Thomas Gleixner , Greg Kroah-Hartman , Jiri Slaby , Andrew Morton , "David S. Miller" , Mauro Carvalho Chehab , 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: Re: [PATCH v6 04/15] clocksource/drivers: Add ARM System timer driver References: <1428424234-28572-1-git-send-email-mcoquelin.stm32@gmail.com> <1428424234-28572-5-git-send-email-mcoquelin.stm32@gmail.com> In-Reply-To: <1428424234-28572-5-git-send-email-mcoquelin.stm32@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 Content-Length: 4388 Lines: 146 On 04/07/2015 06:30 PM, Maxime Coquelin wrote: > This patch adds clocksource support for ARMv7-M's System timer, > also known as SysTick. > > Tested-by: Chanwoo Choi > Signed-off-by: Maxime Coquelin Acked-by: Daniel Lezcano > --- > drivers/clocksource/Kconfig | 7 ++++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/armv7m_systick.c | 79 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 87 insertions(+) > create mode 100644 drivers/clocksource/armv7m_systick.c > > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index 1c2506f..b82e58b 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -134,6 +134,13 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK > help > Use ARM global timer clock source as sched_clock > > +config ARMV7M_SYSTICK > + bool > + select CLKSRC_OF if OF > + select CLKSRC_MMIO > + help > + This options enables support for the ARMv7M 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 752d5c7..1c9a643 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -44,6 +44,7 @@ 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_ARMV7M_SYSTICK) += armv7m_systick.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/armv7m_systick.c b/drivers/clocksource/armv7m_systick.c > new file mode 100644 > index 0000000..addfd2c > --- /dev/null > +++ b/drivers/clocksource/armv7m_systick.c > @@ -0,0 +1,79 @@ > +/* > + * 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 = NULL; > + void __iomem *base; > + u32 rate; > + int ret; > + > + base = of_iomap(np, 0); > + if (!base) { > + pr_warn("system-timer: invalid base address\n"); > + return; > + } > + > + ret = of_property_read_u32(np, "clock-frequency", &rate); > + if (ret) { > + clk = of_clk_get(np, 0); > + if (IS_ERR(clk)) > + goto out_unmap; > + > + ret = clk_prepare_enable(clk); > + if (ret) > + goto out_clk_put; > + > + rate = clk_get_rate(clk); > + if (!rate) > + goto out_clk_disable; > + } > + > + 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); > + if (clk) > + goto out_clk_disable; > + else > + goto out_unmap; > + } > + > + 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); > + pr_warn("ARM System timer register failed (%d)\n", ret); > +} > + > +CLOCKSOURCE_OF_DECLARE(arm_systick, "arm,armv7m-systick", > + system_timer_of_register); > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/