From: mcoquelin.stm32@gmail.com (Maxime Coquelin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 08/15] clockevent: Add STM32 Timer driver
Date: Thu, 12 Mar 2015 22:55:54 +0100 [thread overview]
Message-ID: <1426197361-19290-9-git-send-email-maxime.coquelin@st.com> (raw)
In-Reply-To: <1426197361-19290-1-git-send-email-maxime.coquelin@st.com>
From: Maxime Coquelin <mcoquelin.stm32@gmail.com>
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.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
---
drivers/clocksource/Kconfig | 8 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-stm32.c | 184 ++++++++++++++++++++++++++++++++++++++
3 files changed, 193 insertions(+)
create mode 100644 drivers/clocksource/timer-stm32.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index b82e58b..519304b 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -101,6 +101,14 @@ 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 event device.
+
config ARM_ARCH_TIMER
bool
select CLKSRC_OF if OF
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 1c9a643..525dafe 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -35,6 +35,7 @@ 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..fad2e2e
--- /dev/null
+++ b/drivers/clocksource/timer-stm32.c
@@ -0,0 +1,184 @@
+/*
+ * Copyright (C) Maxime Coquelin 2015
+ * Author: Maxime Coquelin <mcoquelin.stm32@gmail.com>
+ * License terms: GNU General Public License (GPL), version 2
+ *
+ * Inspired by time-efm32.c from Uwe Kleine-Koenig
+ */
+
+#include <linux/kernel.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+
+#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)) {
+ 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);
--
1.9.1
next prev parent reply other threads:[~2015-03-12 21:55 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-12 21:55 [PATCH v3 00/15] Add support to STMicroelectronics STM32 family Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 01/15] scripts: link-vmlinux: Don't pass page offset to kallsyms if XIP Kernel Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 02/15] ARM: ARMv7-M: Enlarge vector table up to 256 entries Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 03/15] dt-bindings: Document the ARM System timer bindings Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 04/15] clocksource: Add ARM System timer driver Maxime Coquelin
2015-03-26 9:50 ` Daniel Lezcano
2015-03-26 20:19 ` Maxime Coquelin
2015-03-27 8:36 ` Daniel Lezcano
2015-03-27 12:33 ` Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 05/15] dt-bindings: Document the STM32 reset bindings Maxime Coquelin
2015-03-13 0:09 ` Chanwoo Choi
2015-03-17 16:57 ` Maxime Coquelin
2015-03-13 8:50 ` Philipp Zabel
2015-03-17 17:13 ` Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 06/15] drivers: reset: Add STM32 reset driver Maxime Coquelin
2015-03-13 0:11 ` Chanwoo Choi
2015-03-13 8:54 ` Philipp Zabel
2015-03-17 17:23 ` Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 07/15] dt-bindings: Document the STM32 timer bindings Maxime Coquelin
2015-03-12 21:55 ` Maxime Coquelin [this message]
2015-03-12 21:55 ` [PATCH v3 09/15] dt-bindings: Document the STM32 USART bindings Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 10/15] serial: stm32-usart: Add STM32 USART Driver Maxime Coquelin
2015-03-13 9:41 ` Paul Bolle
2015-03-17 17:39 ` Maxime Coquelin
2015-03-13 14:19 ` Andy Shevchenko
2015-03-17 17:32 ` Maxime Coquelin
2015-03-17 17:56 ` Andy Shevchenko
2015-03-19 13:55 ` Maxime Coquelin
2015-03-19 14:58 ` Peter Hurley
2015-03-19 17:35 ` Maxime Coquelin
2015-03-24 17:21 ` Maxime Coquelin
2015-03-24 17:44 ` Peter Hurley
2015-03-24 18:23 ` Peter Hurley
2015-03-26 15:46 ` Russell King - ARM Linux
2015-03-26 22:05 ` Maxime Coquelin
2015-03-26 22:03 ` Maxime Coquelin
2015-03-27 11:32 ` Peter Hurley
2015-03-27 12:30 ` Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 11/15] ARM: Add STM32 family machine Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 12/15] ARM: dts: Add ARM System timer as clockevent in armv7m Maxime Coquelin
2015-03-12 21:55 ` [PATCH v3 13/15] ARM: dts: Introduce STM32F429 MCU Maxime Coquelin
2015-03-12 21:56 ` [PATCH v3 14/15] ARM: configs: Add STM32 defconfig Maxime Coquelin
2015-03-12 21:56 ` [PATCH v3 15/15] MAINTAINERS: Add entry for STM32 MCUs Maxime Coquelin
2015-03-12 23:45 ` [PATCH v3 00/15] Add support to STMicroelectronics STM32 family Chanwoo Choi
2015-03-18 23:35 ` Chanwoo Choi
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