From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH v6 04/15] clocksource/drivers: Add ARM System timer driver Date: Thu, 09 Apr 2015 12:52:54 +0200 Message-ID: <55265A06.5020902@linaro.org> References: <1428424234-28572-1-git-send-email-mcoquelin.stm32@gmail.com> <1428424234-28572-5-git-send-email-mcoquelin.stm32@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1428424234-28572-5-git-send-email-mcoquelin.stm32-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Maxime Coquelin , u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, afaerber-l3A5Bk7waGM@public.gmane.org, geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org, Rob Herring , Philipp Zabel , Linus Walleij , Arnd Bergmann , stefan-XLVq0VzYD2Y@public.gmane.org, pmeerw-jW+XmwGofnusTnJN9+BGXg@public.gmane.org, pebolle-IWqWACnzNjzz+pZb47iToQ@public.gmane.org, peter-WaGBZJeGNqdsbIuE7sb01tBPR1lH4CV8@public.gmane.org, andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, cw00.choi-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, Russell King , joe-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arch-u79uwXL29TZNg+MwTxZMZA@public.gmane.org List-Id: linux-gpio@vger.kernel.org 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/Kconfi= g > 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/Makef= ile > index 752d5c7..1c9a643 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -44,6 +44,7 @@ obj-$(CONFIG_MTK_TIMER) +=3D mtk_timer.o > > obj-$(CONFIG_ARM_ARCH_TIMER) +=3D arm_arch_timer.o > obj-$(CONFIG_ARM_GLOBAL_TIMER) +=3D arm_global_timer.o > +obj-$(CONFIG_ARMV7M_SYSTICK) +=3D armv7m_systick.o > obj-$(CONFIG_CLKSRC_METAG_GENERIC) +=3D metag_generic.o > obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) +=3D dummy_timer.o > obj-$(CONFIG_ARCH_KEYSTONE) +=3D timer-keystone.o > diff --git a/drivers/clocksource/armv7m_systick.c b/drivers/clocksour= ce/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 =3D NULL; > + void __iomem *base; > + u32 rate; > + int ret; > + > + base =3D of_iomap(np, 0); > + if (!base) { > + pr_warn("system-timer: invalid base address\n"); > + return; > + } > + > + ret =3D of_property_read_u32(np, "clock-frequency", &rate); > + if (ret) { > + clk =3D of_clk_get(np, 0); > + if (IS_ERR(clk)) > + goto out_unmap; > + > + ret =3D clk_prepare_enable(clk); > + if (ret) > + goto out_clk_put; > + > + rate =3D 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 =3D 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); > --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog