From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: tglx@linutronix.de, mingo@kernel.org
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Chanwoo Choi <cw00.choi@samsung.com>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH 08/11] clocksource/drivers/armv7m_systick: Add ARM System timer driver
Date: Tue, 2 Jun 2015 14:31:53 +0200 [thread overview]
Message-ID: <1433248316-26320-8-git-send-email-daniel.lezcano@linaro.org> (raw)
In-Reply-To: <1433248316-26320-1-git-send-email-daniel.lezcano@linaro.org>
From: Maxime Coquelin <mcoquelin.stm32@gmail.com>
This patch adds clocksource support for ARMv7-M's System timer,
also known as SysTick.
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
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 47f9f22..2c67ca9 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -144,6 +144,13 @@ 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 5928e35..ebfb5dc 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -46,6 +46,7 @@ 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 <mcoquelin.stm32@gmail.com>
+ * License terms: GNU General Public License (GPL), version 2
+ */
+
+#include <linux/kernel.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk.h>
+#include <linux/bitops.h>
+
+#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);
--
1.9.1
next prev parent reply other threads:[~2015-06-02 12:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <556DA1E5.1030601@linaro.org>
2015-06-02 12:31 ` [PATCH 01/11] clocksource/drivers/qcom: Remove dead code Daniel Lezcano
2015-06-02 12:31 ` [PATCH 02/11] clocksource/drivers/exynos_mct: Change exynos4_mct_tick_clear return type to void Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` [PATCH 03/11] clocksource/drivers/exynos_mct: Staticize struct clocksource Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` [PATCH 04/11] clocksource/drivers/exynos_mct: Remove old platform mct_init() Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` [PATCH 05/11] clocksource/drivers/lpc32xx: Add the lpc32xx timer driver Daniel Lezcano
2015-06-02 12:31 ` [PATCH 06/11] doc: dt: Add documentation for lpc3220-timer Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` [PATCH 07/11] dt-bindings: Document the ARM System timer bindings Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano [this message]
2015-06-02 12:31 ` [PATCH 09/11] dt-bindings: Document the STM32 " Daniel Lezcano
2015-06-02 12:31 ` Daniel Lezcano
2015-06-02 12:31 ` [PATCH 10/11] clockevents/drivers: Add STM32 Timer driver Daniel Lezcano
2015-06-02 12:31 ` [PATCH 11/11] clockevents/drivers/timer-stm32: Fix build warning spotted by kbuild test robot Daniel Lezcano
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