[PATCH v4 2/2] clocksource: npcm: add NPCM7xx timer driver
From: Tomer Maimon
Date: Mon Feb 26 2018 - 09:37:29 EST
Add Nuvoton BMC NPCM7xx timer driver.
the clocksource Enable 24-bit TIMER0 and TIMER1 counters,
while TIMER0 serve as clockevent and TIMER1 serve as clocksource.
Signed-off-by: Tomer Maimon <tmaimon77@xxxxxxxxx>
Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
---
drivers/clocksource/Kconfig | 8 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/npcm7xx-timer.c | 237 ++++++++++++++++++++++++++++++++++++
3 files changed, 246 insertions(+)
create mode 100644 drivers/clocksource/npcm7xx-timer.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index b3b4ed9b6874..bfc80653d89f 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -130,6 +130,14 @@ config VT8500_TIMER
help
Enables support for the VT8500 driver.
+config NPCM7XX_TIMER
+ bool "NPCM7xx timer driver" if COMPILE_TEST
+ depends on HAS_IOMEM
+ select CLKSRC_MMIO
+ help
+ Enable 24-bit TIMER0 and TIMER1 counters in the NPCM7xx arcithcture,
+ While TIMER0 serves as clockevent and TIMER1 serves as clocksource.
+
config CADENCE_TTC_TIMER
bool "Cadence TTC timer driver" if COMPILE_TEST
depends on COMMON_CLK
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index d6dec4489d66..b16c1a2b9e0d 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_CLKSRC_NPS) += timer-nps.o
obj-$(CONFIG_OXNAS_RPS_TIMER) += timer-oxnas-rps.o
obj-$(CONFIG_OWL_TIMER) += owl-timer.o
obj-$(CONFIG_SPRD_TIMER) += timer-sprd.o
+obj-$(CONFIG_NPCM7XX_TIMER) += npcm7xx-timer.o
obj-$(CONFIG_ARC_TIMERS) += arc_timer.o
obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
diff --git a/drivers/clocksource/npcm7xx-timer.c b/drivers/clocksource/npcm7xx-timer.c
new file mode 100644
index 000000000000..ab27fc82d8ef
--- /dev/null
+++ b/drivers/clocksource/npcm7xx-timer.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014-2018 Nuvoton Technologies tomer.maimon@xxxxxxxxxxx
+ * All rights reserved.
+ *
+ * Copyright 2017 Google, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/clockchips.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include "timer-of.h"
+
+/* Timers registers */
+#define NPCM7XX_REG_TCSR0 0x0 /* Timer 0 Control and Status Register */
+#define NPCM7XX_REG_TICR0 0x8 /* Timer 0 Initial Count Register */
+#define NPCM7XX_REG_TCSR1 0x4 /* Timer 1 Control and Status Register */
+#define NPCM7XX_REG_TICR1 0xc /* Timer 1 Initial Count Register */
+#define NPCM7XX_REG_TDR1 0x14 /* Timer 1 Data Register */
+#define NPCM7XX_REG_TISR 0x18 /* Timer Interrupt Status Register */
+
+/* Timers control */
+#define NPCM7XX_Tx_RESETINT 0x1f
+#define NPCM7XX_Tx_PERIOD BIT(27)
+#define NPCM7XX_Tx_INTEN BIT(29)
+#define NPCM7XX_Tx_COUNTEN BIT(30)
+#define NPCM7XX_Tx_ONESHOT 0x0
+#define NPCM7XX_Tx_OPER GENMASK(3, 27)
+#define NPCM7XX_Tx_MIN_PRESCALE 0x1
+#define NPCM7XX_Tx_TDR_MASK_BITS 24
+#define NPCM7XX_Tx_MAX_CNT 0xFFFFFF
+#define NPCM7XX_T0_CLR_INT 0x1
+#define NPCM7XX_Tx_CLR_CSR 0x0
+
+/* Timers operating mode */
+#define NPCM7XX_START_PERIODIC_Tx (NPCM7XX_Tx_PERIOD | NPCM7XX_Tx_COUNTEN | \
+ NPCM7XX_Tx_INTEN | \
+ NPCM7XX_Tx_MIN_PRESCALE)
+
+#define NPCM7XX_START_ONESHOT_Tx (NPCM7XX_Tx_ONESHOT | NPCM7XX_Tx_COUNTEN | \
+ NPCM7XX_Tx_INTEN | \
+ NPCM7XX_Tx_MIN_PRESCALE)
+
+#define NPCM7XX_START_Tx (NPCM7XX_Tx_COUNTEN | NPCM7XX_Tx_PERIOD | \
+ NPCM7XX_Tx_MIN_PRESCALE)
+
+#define NPCM7XX_DEFAULT_CSR (NPCM7XX_Tx_CLR_CSR | NPCM7XX_Tx_MIN_PRESCALE)
+
+static int npcm7xx_timer_resume(struct clock_event_device *evt)
+{
+ struct timer_of *to = to_timer_of(evt);
+ u32 val;
+
+ val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
+ val |= NPCM7XX_Tx_COUNTEN;
+ writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
+
+ return 0;
+}
+
+static int npcm7xx_timer_shutdown(struct clock_event_device *evt)
+{
+ struct timer_of *to = to_timer_of(evt);
+ u32 val;
+
+ val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
+ val &= ~NPCM7XX_Tx_COUNTEN;
+ writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
+
+ return 0;
+}
+
+static int npcm7xx_timer_oneshot(struct clock_event_device *evt)
+{
+ struct timer_of *to = to_timer_of(evt);
+ u32 val;
+
+ val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
+ val &= ~NPCM7XX_Tx_OPER;
+
+ val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
+ val |= NPCM7XX_START_ONESHOT_Tx;
+ writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
+
+ return 0;
+}
+
+static int npcm7xx_timer_periodic(struct clock_event_device *evt)
+{
+ struct timer_of *to = to_timer_of(evt);
+ u32 val;
+
+ val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
+ val &= ~NPCM7XX_Tx_OPER;
+
+ writel((timer_of_rate(to) / HZ),
+ timer_of_base(to) + NPCM7XX_REG_TICR0);
+ val |= NPCM7XX_START_PERIODIC_Tx;
+
+ writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
+
+ return 0;
+}
+
+static int npcm7xx_clockevent_setnextevent(unsigned long evt,
+ struct clock_event_device *clk)
+{
+ struct timer_of *to = to_timer_of(clk);
+ u32 val;
+
+ writel(evt, timer_of_base(to) + NPCM7XX_REG_TICR0);
+ val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
+ val |= NPCM7XX_START_Tx;
+ writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
+
+ return 0;
+}
+
+static irqreturn_t npcm7xx_timer0_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+ struct timer_of *to = to_timer_of(evt);
+
+ writel(NPCM7XX_T0_CLR_INT, timer_of_base(to) + NPCM7XX_REG_TISR);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct timer_of npcm7xx_to = {
+ .flags = TIMER_OF_IRQ | TIMER_OF_BASE,
+
+ .clkevt = {
+ .name = "npcm7xx-timer0",
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = npcm7xx_clockevent_setnextevent,
+ .set_state_shutdown = npcm7xx_timer_shutdown,
+ .set_state_periodic = npcm7xx_timer_periodic,
+ .set_state_oneshot = npcm7xx_timer_oneshot,
+ .tick_resume = npcm7xx_timer_resume,
+ .rating = 300,
+ },
+
+ .of_irq = {
+ .handler = npcm7xx_timer0_interrupt,
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ },
+};
+
+static void __init npcm7xx_clockevents_init(u32 rate)
+{
+ writel(NPCM7XX_DEFAULT_CSR,
+ timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR0);
+
+ writel(NPCM7XX_Tx_RESETINT,
+ timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TISR);
+
+ npcm7xx_to.clkevt.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&npcm7xx_to.clkevt, rate,
+ 0x1, NPCM7XX_Tx_MAX_CNT);
+}
+
+static void __init npcm7xx_clocksource_init(u32 rate)
+{
+ u32 val;
+
+ writel(NPCM7XX_DEFAULT_CSR,
+ timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
+ writel(NPCM7XX_Tx_MAX_CNT,
+ timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TICR1);
+
+ val = readl(timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
+ val |= NPCM7XX_START_Tx;
+ writel(val, timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
+
+ clocksource_mmio_init(timer_of_base(&npcm7xx_to) +
+ NPCM7XX_REG_TDR1,
+ "npcm7xx-timer1", rate,
+ 200, (unsigned int)NPCM7XX_Tx_TDR_MASK_BITS,
+ clocksource_mmio_readl_down);
+}
+
+static int __init npcm7xx_timer_init(struct device_node *np)
+{
+ struct clk *clk;
+ int ret;
+ u32 rate;
+
+ clk = of_clk_get(np, 0);
+
+ if (IS_ERR(clk)) {
+ ret = of_property_read_u32(np, "clock-frequency", &rate);
+ if (ret)
+ return ret;
+ } else {
+ clk_prepare_enable(clk);
+ rate = clk_get_rate(clk);
+ npcm7xx_to.of_clk.clk = clk;
+ }
+
+ ret = timer_of_init(np, &npcm7xx_to);
+ if (ret)
+ goto err_timer_of_init;
+
+ /* Clock input is divided by PRESCALE + 1 before it is fed */
+ /* to the counter */
+ rate = rate / (NPCM7XX_Tx_MIN_PRESCALE + 1);
+ npcm7xx_to.of_clk.rate = rate;
+
+ npcm7xx_clocksource_init(rate);
+ npcm7xx_clockevents_init(rate);
+
+ pr_info("Enabling NPCM7xx clocksource timer base: %p, IRQ: %d\n",
+ timer_of_base(&npcm7xx_to), timer_of_irq(&npcm7xx_to));
+
+ return 0;
+
+err_timer_of_init:
+ if (!IS_ERR(clk)) {
+ clk_disable_unprepare(clk);
+ clk_put(clk);
+ }
+
+ return ret;
+}
+
+TIMER_OF_DECLARE(npcm7xx, "nuvoton,npcm750-timer", npcm7xx_timer_init);
+
--
2.14.1