From patchwork Fri Feb 20 18:01:08 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Coquelin X-Patchwork-Id: 442091 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id F031814017C for ; Sat, 21 Feb 2015 05:06:21 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932314AbbBTSF5 (ORCPT ); Fri, 20 Feb 2015 13:05:57 -0500 Received: from mail-wg0-f66.google.com ([74.125.82.66]:63463 "EHLO mail-wg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754805AbbBTSB5 (ORCPT ); Fri, 20 Feb 2015 13:01:57 -0500 Received: by mail-wg0-f66.google.com with SMTP id l18so4320772wgh.1; Fri, 20 Feb 2015 10:01:54 -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=dmKQuwLu/w6UnPCmPW8P9oNWs8NUJYuDoXSHSH7XZnU=; b=jK3HceQmGoyjYZ3cH/vYGCkDAaq/+BGkFNJR0/M8Bfdk4WdFiEpMSXQhj2Idpa7spn ZzUJCx7ERIO2MgOZHV7yRZw8WdJQH6kVtHKF2l7VFif9Hxmmxd7yWRPVLMl9a9cM9sl0 b5gCzqDTDWV1zPnjLQO1dxN8ES5MsaULQF7ix1NeaZ5AHKCdqRs6WdLYnAzW0boH3ld+ qYblIG6/VUMqQurYY9WdNlF+L0F4n+ViKNrbYDWK/ff6uepVOFL1lGFZm78Henexk8Nf p6M4NP3dzt9lI1NQRjF9CYHJD1IksZDJb414ukdElqHjEvJC/QC6qBbx39ZdnID9pV18 eLNQ== X-Received: by 10.194.133.68 with SMTP id pa4mr21801564wjb.26.1424455314541; Fri, 20 Feb 2015 10:01:54 -0800 (PST) Received: from lmecul0520.st.com. (169.20.90.92.rev.sfr.net. [92.90.20.169]) by mx.google.com with ESMTPSA id hs7sm3398370wib.4.2015.02.20.10.01.52 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 20 Feb 2015 10:01:54 -0800 (PST) From: Maxime Coquelin To: u.kleine-koenig@pengutronix.de, afaerber@suse.de, geert@linux-m68k.org, Rob Herring , Philipp Zabel , Jonathan Corbet , Maxime Coquelin , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , 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 v2 09/18] clockevent: Add STM32 Timer driver Date: Fri, 20 Feb 2015 19:01:08 +0100 Message-Id: <1424455277-29983-10-git-send-email-mcoquelin.stm32@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1424455277-29983-1-git-send-email-mcoquelin.stm32@gmail.com> References: <1424455277-29983-1-git-send-email-mcoquelin.stm32@gmail.com> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org STM32 MCUs feature 16 and 32 bits general purpose timers with prescalers. The drivers detects whether the time is 16 or 32 bits, and applies a 1024 prescaler value if it is 16 bits. Signed-off-by: Maxime Coquelin --- drivers/clocksource/Kconfig | 9 ++ drivers/clocksource/Makefile | 1 + drivers/clocksource/timer-stm32.c | 187 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 197 insertions(+) create mode 100644 drivers/clocksource/timer-stm32.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index fb6011e..f372329 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -91,6 +91,15 @@ config CLKSRC_EFM32 Support to use the timers of EFM32 SoCs as clock source and clock event device. +config CLKSRC_STM32 + bool "Clocksource for STM32 SoCs" if !ARCH_STM32 + depends on OF && ARM && (ARCH_STM32 || COMPILE_TEST) + select CLKSRC_MMIO + default ARCH_STM32 + help + Support to use the timers of STM32 SoCs as clock source and clock + event device. + config ARM_ARCH_TIMER bool select CLKSRC_OF if OF diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index eeea736..8078178 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -33,6 +33,7 @@ obj-$(CONFIG_ARCH_NSPIRE) += zevio-timer.o obj-$(CONFIG_ARCH_BCM_MOBILE) += bcm_kona_timer.o obj-$(CONFIG_CADENCE_TTC_TIMER) += cadence_ttc_timer.o obj-$(CONFIG_CLKSRC_EFM32) += time-efm32.o +obj-$(CONFIG_CLKSRC_STM32) += timer-stm32.o obj-$(CONFIG_CLKSRC_EXYNOS_MCT) += exynos_mct.o obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o obj-$(CONFIG_FSL_FTM_TIMER) += fsl_ftm_timer.o diff --git a/drivers/clocksource/timer-stm32.c b/drivers/clocksource/timer-stm32.c new file mode 100644 index 0000000..9839f57 --- /dev/null +++ b/drivers/clocksource/timer-stm32.c @@ -0,0 +1,187 @@ +/* + * Copyright (C) Maxime Coquelin 2015 + * Author: Maxime Coquelin + * License terms: GNU General Public License (GPL), version 2 + * + * Inspired by time-efm32.c from Uwe Kleine-Koenig + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define TIM_CR1 0x00 +#define TIM_DIER 0x0c +#define TIM_SR 0x10 +#define TIM_EGR 0x14 +#define TIM_PSC 0x28 +#define TIM_ARR 0x2c + +#define TIM_CR1_CEN BIT(0) +#define TIM_CR1_OPM BIT(3) +#define TIM_CR1_ARPE BIT(7) + +#define TIM_DIER_UIE BIT(0) + +#define TIM_SR_UIF BIT(0) + +#define TIM_EGR_UG BIT(0) + +struct stm32_clock_event_ddata { + struct clock_event_device evtdev; + unsigned periodic_top; + void __iomem *base; +}; + +static void stm32_clock_event_set_mode(enum clock_event_mode mode, + struct clock_event_device *evtdev) +{ + struct stm32_clock_event_ddata *data = + container_of(evtdev, struct stm32_clock_event_ddata, evtdev); + void *base = data->base; + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + writel_relaxed(data->periodic_top, base + TIM_ARR); + writel_relaxed(TIM_CR1_ARPE | TIM_CR1_CEN, base + TIM_CR1); + break; + + case CLOCK_EVT_MODE_ONESHOT: + default: + writel_relaxed(0, base + TIM_CR1); + break; + } +} + +static int stm32_clock_event_set_next_event(unsigned long evt, + struct clock_event_device *evtdev) +{ + struct stm32_clock_event_ddata *data = + container_of(evtdev, struct stm32_clock_event_ddata, evtdev); + + writel_relaxed(evt, data->base + TIM_ARR); + writel_relaxed(TIM_CR1_ARPE | TIM_CR1_OPM | TIM_CR1_CEN, + data->base + TIM_CR1); + + return 0; +} + +static irqreturn_t stm32_clock_event_handler(int irq, void *dev_id) +{ + struct stm32_clock_event_ddata *data = dev_id; + + writel_relaxed(0, data->base + TIM_SR); + + data->evtdev.event_handler(&data->evtdev); + + return IRQ_HANDLED; +} + +static struct stm32_clock_event_ddata clock_event_ddata = { + .evtdev = { + .name = "stm32 clockevent", + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, + .set_mode = stm32_clock_event_set_mode, + .set_next_event = stm32_clock_event_set_next_event, + .rating = 200, + }, +}; + +static void __init stm32_clockevent_init(struct device_node *np) +{ + struct stm32_clock_event_ddata *data = &clock_event_ddata; + struct clk *clk; + struct reset_control *rstc; + unsigned long rate, max_delta; + int irq, ret, bits, prescaler = 1; + + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + pr_err("failed to get clock for clockevent (%d)\n", ret); + goto err_clk_get; + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("failed to enable timer clock for clockevent (%d)\n", + ret); + goto err_clk_enable; + } + + rate = clk_get_rate(clk); + + rstc = of_reset_control_get(np, NULL); + if (IS_ERR(rstc)) { + pr_err("%s: Failed to get reset\n", np->full_name); + return; + } + + reset_control_assert(rstc); + reset_control_deassert(rstc); + + data->base = of_iomap(np, 0); + if (!data->base) { + pr_err("failed to map registers for clockevent\n"); + goto err_iomap; + } + + irq = irq_of_parse_and_map(np, 0); + if (!irq) { + pr_err("%s: failed to get irq.\n", np->full_name); + goto err_get_irq; + } + + /* Detect whether the timer is 16 or 32 bits */ + writel_relaxed(~0UL, data->base + TIM_ARR); + max_delta = readl_relaxed(data->base + TIM_ARR); + if (max_delta == ~0UL) { + prescaler = 1; + bits = 32; + } else { + prescaler = 1024; + bits = 16; + } + writel_relaxed(0, data->base + TIM_ARR); + + writel_relaxed(prescaler - 1, data->base + TIM_PSC); + writel_relaxed(TIM_EGR_UG, data->base + TIM_EGR); + writel_relaxed(TIM_DIER_UIE, data->base + TIM_DIER); + writel_relaxed(0, data->base + TIM_SR); + + data->periodic_top = DIV_ROUND_CLOSEST(rate, prescaler * HZ); + + clockevents_config_and_register(&data->evtdev, + DIV_ROUND_CLOSEST(rate, prescaler), + 0x1, max_delta); + + ret = request_irq(irq, stm32_clock_event_handler, IRQF_TIMER, + "stm32 clockevent", data); + if (ret) { + pr_err("%s: failed to request irq.\n", np->full_name); + goto err_get_irq; + } + + pr_info("%s: STM32 clockevent driver initialized (%d bits)\n", + np->full_name, bits); + + return; + +err_get_irq: + iounmap(data->base); +err_iomap: + clk_disable_unprepare(clk); +err_clk_enable: + clk_put(clk); +err_clk_get: + return; +} + +CLOCKSOURCE_OF_DECLARE(stm32, "st,stm32-timer", stm32_clockevent_init);