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Message-Id: <1433248316-26320-5-git-send-email-daniel.lezcano@linaro.org>
Date: Tue, 2 Jun 2015 14:31:50 +0200
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: tglx@...utronix.de, mingo@...nel.org
Cc: Joachim Eastwood <manabian@...il.com>,
Arnd Bergmann <arnd@...db.de>,
linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 05/11] clocksource/drivers/lpc32xx: Add the lpc32xx timer driver
From: Joachim Eastwood <manabian@...il.com>
Add support for using the NXP LPC timer as clocksource and clock
event. These timers are present on many NXP devices including
LPC32xx, LPC17xx, LPC18xx and LPC43xx.
The timer has a 32-bit timer counter register with a programmable
32-bit prescaler. It supports up to 4 compare match values with
interrupt generation and reset/stop timer counter action.
Signed-off-by: Joachim Eastwood <manabian@...il.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Reviewed-by: Ezequiel Garcia <ezequiel@...guardiasur.com.ar>
Acked-by: Arnd Bergmann <arnd@...db.de>
---
drivers/clocksource/Kconfig | 5 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/time-lpc32xx.c | 272 +++++++++++++++++++++++++++++++++++++
3 files changed, 278 insertions(+)
create mode 100644 drivers/clocksource/time-lpc32xx.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 51d7865f..47f9f22 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -106,6 +106,11 @@ config CLKSRC_EFM32
Support to use the timers of EFM32 SoCs as clock source and clock
event device.
+config CLKSRC_LPC32XX
+ bool
+ select CLKSRC_MMIO
+ select CLKSRC_OF
+
config ARM_ARCH_TIMER
bool
select CLKSRC_OF if OF
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 5b85f6a..5928e35 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -37,6 +37,7 @@ 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_EXYNOS_MCT) += exynos_mct.o
+obj-$(CONFIG_CLKSRC_LPC32XX) += time-lpc32xx.o
obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o
obj-$(CONFIG_FSL_FTM_TIMER) += fsl_ftm_timer.o
obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o
diff --git a/drivers/clocksource/time-lpc32xx.c b/drivers/clocksource/time-lpc32xx.c
new file mode 100644
index 0000000..a1c06a2
--- /dev/null
+++ b/drivers/clocksource/time-lpc32xx.c
@@ -0,0 +1,272 @@
+/*
+ * Clocksource driver for NXP LPC32xx/18xx/43xx timer
+ *
+ * Copyright (C) 2015 Joachim Eastwood <manabian@...il.com>
+ *
+ * Based on:
+ * time-efm32 Copyright (C) 2013 Pengutronix
+ * mach-lpc32xx/timer.c Copyright (C) 2009 - 2010 NXP Semiconductors
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+
+#define LPC32XX_TIMER_IR 0x000
+#define LPC32XX_TIMER_IR_MR0INT BIT(0)
+#define LPC32XX_TIMER_TCR 0x004
+#define LPC32XX_TIMER_TCR_CEN BIT(0)
+#define LPC32XX_TIMER_TCR_CRST BIT(1)
+#define LPC32XX_TIMER_TC 0x008
+#define LPC32XX_TIMER_PR 0x00c
+#define LPC32XX_TIMER_MCR 0x014
+#define LPC32XX_TIMER_MCR_MR0I BIT(0)
+#define LPC32XX_TIMER_MCR_MR0R BIT(1)
+#define LPC32XX_TIMER_MCR_MR0S BIT(2)
+#define LPC32XX_TIMER_MR0 0x018
+#define LPC32XX_TIMER_CTCR 0x070
+
+struct lpc32xx_clock_event_ddata {
+ struct clock_event_device evtdev;
+ void __iomem *base;
+};
+
+/* Needed for the sched clock */
+static void __iomem *clocksource_timer_counter;
+
+static u64 notrace lpc32xx_read_sched_clock(void)
+{
+ return readl(clocksource_timer_counter);
+}
+
+static int lpc32xx_clkevt_next_event(unsigned long delta,
+ struct clock_event_device *evtdev)
+{
+ struct lpc32xx_clock_event_ddata *ddata =
+ container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
+
+ /*
+ * Place timer in reset and program the delta in the prescale
+ * register (PR). When the prescale counter matches the value
+ * in PR the counter register is incremented and the compare
+ * match will trigger. After setup the timer is released from
+ * reset and enabled.
+ */
+ writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
+ writel_relaxed(delta, ddata->base + LPC32XX_TIMER_PR);
+ writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);
+
+ return 0;
+}
+
+static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev)
+{
+ struct lpc32xx_clock_event_ddata *ddata =
+ container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
+
+ /* Disable the timer */
+ writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);
+
+ return 0;
+}
+
+static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev)
+{
+ /*
+ * When using oneshot, we must also disable the timer
+ * to wait for the first call to set_next_event().
+ */
+ return lpc32xx_clkevt_shutdown(evtdev);
+}
+
+static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
+{
+ struct lpc32xx_clock_event_ddata *ddata = dev_id;
+
+ /* Clear match on channel 0 */
+ writel_relaxed(LPC32XX_TIMER_IR_MR0INT, ddata->base + LPC32XX_TIMER_IR);
+
+ ddata->evtdev.event_handler(&ddata->evtdev);
+
+ return IRQ_HANDLED;
+}
+
+static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = {
+ .evtdev = {
+ .name = "lpc3220 clockevent",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 300,
+ .set_next_event = lpc32xx_clkevt_next_event,
+ .set_state_shutdown = lpc32xx_clkevt_shutdown,
+ .set_state_oneshot = lpc32xx_clkevt_oneshot,
+ },
+};
+
+static int __init lpc32xx_clocksource_init(struct device_node *np)
+{
+ void __iomem *base;
+ unsigned long rate;
+ struct clk *clk;
+ int ret;
+
+ clk = of_clk_get_by_name(np, "timerclk");
+ if (IS_ERR(clk)) {
+ pr_err("clock get failed (%lu)\n", PTR_ERR(clk));
+ return PTR_ERR(clk);
+ }
+
+ ret = clk_prepare_enable(clk);
+ if (ret) {
+ pr_err("clock enable failed (%d)\n", ret);
+ goto err_clk_enable;
+ }
+
+ base = of_iomap(np, 0);
+ if (!base) {
+ pr_err("unable to map registers\n");
+ ret = -EADDRNOTAVAIL;
+ goto err_iomap;
+ }
+
+ /*
+ * Disable and reset timer then set it to free running timer
+ * mode (CTCR) with no prescaler (PR) or match operations (MCR).
+ * After setup the timer is released from reset and enabled.
+ */
+ writel_relaxed(LPC32XX_TIMER_TCR_CRST, base + LPC32XX_TIMER_TCR);
+ writel_relaxed(0, base + LPC32XX_TIMER_PR);
+ writel_relaxed(0, base + LPC32XX_TIMER_MCR);
+ writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
+ writel_relaxed(LPC32XX_TIMER_TCR_CEN, base + LPC32XX_TIMER_TCR);
+
+ rate = clk_get_rate(clk);
+ ret = clocksource_mmio_init(base + LPC32XX_TIMER_TC, "lpc3220 timer",
+ rate, 300, 32, clocksource_mmio_readl_up);
+ if (ret) {
+ pr_err("failed to init clocksource (%d)\n", ret);
+ goto err_clocksource_init;
+ }
+
+ clocksource_timer_counter = base + LPC32XX_TIMER_TC;
+ sched_clock_register(lpc32xx_read_sched_clock, 32, rate);
+
+ return 0;
+
+err_clocksource_init:
+ iounmap(base);
+err_iomap:
+ clk_disable_unprepare(clk);
+err_clk_enable:
+ clk_put(clk);
+ return ret;
+}
+
+static int __init lpc32xx_clockevent_init(struct device_node *np)
+{
+ void __iomem *base;
+ unsigned long rate;
+ struct clk *clk;
+ int ret, irq;
+
+ clk = of_clk_get_by_name(np, "timerclk");
+ if (IS_ERR(clk)) {
+ pr_err("clock get failed (%lu)\n", PTR_ERR(clk));
+ return PTR_ERR(clk);
+ }
+
+ ret = clk_prepare_enable(clk);
+ if (ret) {
+ pr_err("clock enable failed (%d)\n", ret);
+ goto err_clk_enable;
+ }
+
+ base = of_iomap(np, 0);
+ if (!base) {
+ pr_err("unable to map registers\n");
+ ret = -EADDRNOTAVAIL;
+ goto err_iomap;
+ }
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (!irq) {
+ pr_err("get irq failed\n");
+ ret = -ENOENT;
+ goto err_irq;
+ }
+
+ /*
+ * Disable timer and clear any pending interrupt (IR) on match
+ * channel 0 (MR0). Configure a compare match value of 1 on MR0
+ * and enable interrupt, reset on match and stop on match (MCR).
+ */
+ writel_relaxed(0, base + LPC32XX_TIMER_TCR);
+ writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
+ writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR);
+ writel_relaxed(1, base + LPC32XX_TIMER_MR0);
+ writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R |
+ LPC32XX_TIMER_MCR_MR0S, base + LPC32XX_TIMER_MCR);
+
+ rate = clk_get_rate(clk);
+ lpc32xx_clk_event_ddata.base = base;
+ clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev,
+ rate, 1, -1);
+
+ ret = request_irq(irq, lpc32xx_clock_event_handler,
+ IRQF_TIMER | IRQF_IRQPOLL, "lpc3220 clockevent",
+ &lpc32xx_clk_event_ddata);
+ if (ret) {
+ pr_err("request irq failed\n");
+ goto err_irq;
+ }
+
+ return 0;
+
+err_irq:
+ iounmap(base);
+err_iomap:
+ clk_disable_unprepare(clk);
+err_clk_enable:
+ clk_put(clk);
+ return ret;
+}
+
+/*
+ * This function asserts that we have exactly one clocksource and one
+ * clock_event_device in the end.
+ */
+static void __init lpc32xx_timer_init(struct device_node *np)
+{
+ static int has_clocksource, has_clockevent;
+ int ret;
+
+ if (!has_clocksource) {
+ ret = lpc32xx_clocksource_init(np);
+ if (!ret) {
+ has_clocksource = 1;
+ return;
+ }
+ }
+
+ if (!has_clockevent) {
+ ret = lpc32xx_clockevent_init(np);
+ if (!ret) {
+ has_clockevent = 1;
+ return;
+ }
+ }
+}
+CLOCKSOURCE_OF_DECLARE(lpc32xx_timer, "nxp,lpc3220-timer", lpc32xx_timer_init);
--
1.9.1
--
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