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[209.85.212.173]) by gmr-mx.google.com with ESMTPS id p12si366797wiv.1.2015.05.11.01.42.50 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 May 2015 01:42:50 -0700 (PDT) Received: by mail-wi0-f173.google.com with SMTP id k4so96205913wiz.1 for ; Mon, 11 May 2015 01:42:50 -0700 (PDT) Message-ID: <55506B87.3070807@linaro.org> Date: Mon, 11 May 2015 10:42:47 +0200 From: Daniel Lezcano MIME-Version: 1.0 To: Lee Jones , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org CC: kernel@stlinux.com, devicetree@vger.kernel.org, tglx@linutronix.de, wim@iguana.be, a.zummo@towertech.it, linux-watchdog@vger.kernel.org, rtc-linux@googlegroups.com, linux@roeck-us.net Subject: [rtc-linux] Re: [PATCH 02/12] clocksource: sti: Provide support for the ST LPC Clocksource IP References: <1431005924-21777-1-git-send-email-lee.jones@linaro.org> <1431005924-21777-3-git-send-email-lee.jones@linaro.org> In-Reply-To: <1431005924-21777-3-git-send-email-lee.jones@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Reply-To: rtc-linux@googlegroups.com List-ID: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , On 05/07/2015 03:38 PM, Lee Jones wrote: > This IP is shared with Watchdog and RTC functionality. Only one of > these IPs can be used at the same time. We use the device-driver > model combined with a DT 'mode' property to enforce this. > > The ST LPC Clocksource IP can be used as the system (tick) timer. > > Signed-off-by: Lee Jones > --- > drivers/clocksource/Kconfig | 8 +++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/clksrc_st_lpc.c | 123 +++++++++++++++++++++++++++++= +++++++ > 3 files changed, 132 insertions(+) > create mode 100644 drivers/clocksource/clksrc_st_lpc.c > > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index 68161f7..ac424cf 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -250,4 +250,12 @@ config CLKSRC_PXA > help > This enables OST0 support available on PXA and SA-11x0 > platforms. > + > +config CLKSRC_ST_LPC > + bool > + depends on ARCH_STI > + select CLKSRC_OF if OF > + help > + Enable this option to use the Low Power controller timer > + as clocksource. > endmenu > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index 752d5c7..e08da4d 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -51,3 +51,4 @@ obj-$(CONFIG_ARCH_INTEGRATOR_AP) +=3D timer-integrator-= ap.o > obj-$(CONFIG_CLKSRC_VERSATILE) +=3D versatile.o > obj-$(CONFIG_CLKSRC_MIPS_GIC) +=3D mips-gic-timer.o > obj-$(CONFIG_ASM9260_TIMER) +=3D asm9260_timer.o > +obj-$(CONFIG_CLKSRC_ST_LPC) +=3D clksrc_st_lpc.o > diff --git a/drivers/clocksource/clksrc_st_lpc.c b/drivers/clocksource/cl= ksrc_st_lpc.c > new file mode 100644 > index 0000000..18a7dcd0 > --- /dev/null > +++ b/drivers/clocksource/clksrc_st_lpc.c > @@ -0,0 +1,123 @@ > +/* > + * Clocksource using the Low Power Timer found in the Low Power Controll= er (LPC) > + * > + * Copyright (C) 2015 STMicroelectronics =E2=80=93 All Rights Reserved > + * > + * Author(s): Francesco Virlinzi > + * Ajit Pal Singh > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + */ > + > +#include > +#include > +#include > +#include > +#include > + > +#include > + > +/* Low Power Timer */ > +#define LPC_LPT_LSB_OFF 0x400 > +#define LPC_LPT_MSB_OFF 0x404 > +#define LPC_LPT_START_OFF 0x408 > + > +static struct st_clksrc_ddata { > + struct clk *clk; > + void __iomem *base; > +} ddata; > + > +static void st_clksrc_reset(void) > +{ > + writel_relaxed(0, ddata.base + LPC_LPT_START_OFF); > + writel_relaxed(0, ddata.base + LPC_LPT_MSB_OFF); > + writel_relaxed(0, ddata.base + LPC_LPT_LSB_OFF); > + writel_relaxed(1, ddata.base + LPC_LPT_START_OFF); > +} > + > +static int __init st_clksrc_init(void) > +{ > + unsigned long rate; > + int ret; > + > + st_clksrc_reset(); > + > + rate =3D clk_get_rate(ddata.clk); > + > + ret =3D clocksource_mmio_init(ddata.base + LPC_LPT_LSB_OFF, > + "clksrc-st-lpc", rate, 300, 32, > + clocksource_mmio_readl_up); > + if (ret) { > + pr_err("clksrc-st-lpc: Failed to register clocksource\n"); > + return ret; > + } > + > + return 0; > +} > + > +static int st_clksrc_setup_clk(struct device_node *np) > +{ > + struct clk *clk; > + int ret; > + > + clk =3D of_clk_get(np, 0); > + if (IS_ERR(clk)) { > + pr_err("clksrc-st-lpc: Failed to get LPC clock\n"); > + ret =3D PTR_ERR(clk); > + return ret; return PTR_ERR(clk); so you can get rid of the 'int ret' variable. > + } > + > + if (clk_prepare_enable(clk)) { > + pr_err("clksrc-st-lpc: Failed to enable LPC clock\n"); > + return -EINVAL; > + } > + > + if (!clk_get_rate(clk)) { > + pr_err("clksrc-st-lpc: Failed to get LPC clock rate\n"); > + clk_disable_unprepare(clk); > + return -EINVAL; > + } > + > + ddata.clk =3D clk; > + > + return 0; > +} > + > +static void __init st_clksrc_of_register(struct device_node *np) > +{ > + int ret; > + uint32_t mode; > + > + ret =3D of_property_read_u32(np, "st,lpc-mode", &mode); > + if (ret) { > + pr_err("clksrc-st-lpc: An LPC mode must be provided\n"); > + return; > + } > + > + /* LPC can either run as a Clocksource or in RTC or WDT mode */ > + if (mode !=3D ST_LPC_MODE_CLKSRC) > + return; I am confused with this patch description + comment and the patch 1's=20 description. For the former, I understand the LPC could be in RTC or WDT mode and=20 used as a clocksource (clksrc + rtc / clksrc + wdt), for the latter I=20 understand there are three modes clocksource, rtc and watchdog (mutually=20 exclusive). Could you clarify ? > + > + ddata.base =3D of_iomap(np, 0); > + if (!ddata.base) { > + pr_err("clksrc-st-lpc: Unable to map iomem\n"); > + return; > + } > + > + if (st_clksrc_setup_clk(np)) { > + iounmap(ddata.base); > + return; > + } > + > + if (st_clksrc_init()) { > + iounmap(ddata.base); > + return; > + } > + > + pr_info("clksrc-st-lpc: clocksource initialised - running @ %luHz\n", > + clk_get_rate(ddata.clk)); > +} > +CLOCKSOURCE_OF_DECLARE(ddata, "st,stih407-lpc", st_clksrc_of_register); > --=20 Linaro.org =E2=94=82 Open source software for AR= M SoCs Follow Linaro: Facebook | Twitter | Blog --=20 --=20 You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. ---=20 You received this message because you are subscribed to the Google Groups "= rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to rtc-linux+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.