Re: [RFC][PATCH 3/3] clocksource: Add Freescale FlexTimer Module (FTM) timer support
From: Daniel Lezcano
Date: Thu Apr 17 2014 - 10:22:53 EST
On 04/16/2014 04:19 AM, Xiubo Li wrote:
The Freescale FlexTimer Module time reference is a 16-bit counter
that can be used as an unsigned or signed counter.one 16-bits
increase counter.
Here using the FTM0 as clock event device and the FTM1 as clock
source device.
As it is a new driver, please add a more elaborated description of the
timer.
Signed-off-by: Xiubo Li <Li.Xiubo@xxxxxxxxxxxxx>
Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
Cc: Jingchang Lu <b35083@xxxxxxxxxxxxx>
---
drivers/clocksource/Kconfig | 5 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/fsl_ftm_timer.c | 238 ++++++++++++++++++++++++++++++++++++
3 files changed, 244 insertions(+)
create mode 100644 drivers/clocksource/fsl_ftm_timer.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index cd6950f..28321c5 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -136,6 +136,11 @@ config CLKSRC_SAMSUNG_PWM
for all devicetree enabled platforms. This driver will be
needed only on systems that do not have the Exynos MCT available.
+config FSL_FTM_TIMER
+ bool
+ help
+ Support for Freescale FlexTimer Module (FTM) timer.
+
config VF_PIT_TIMER
bool
help
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index c7ca50a..ce0a967 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -31,6 +31,7 @@ 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_SAMSUNG_PWM) += samsung_pwm_timer.o
+obj-$(CONFIG_FSL_FTM_TIMER) += fsl_ftm_timer.o
obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o
obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
diff --git a/drivers/clocksource/fsl_ftm_timer.c b/drivers/clocksource/fsl_ftm_timer.c
new file mode 100644
index 0000000..988449e
--- /dev/null
+++ b/drivers/clocksource/fsl_ftm_timer.c
@@ -0,0 +1,238 @@
+/*
+ * Freescale FlexTimer Module (FTM) timer driver.
+ *
+ * Copyright 2014 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
Could you check all these headers are effectively needed ?
+#define FTM_OFFSET(n) (0x1000 * n)
+
+#define FTM_SC 0x00
+#define FTM_SC_CLK_SHIFT 3
+#define FTM_SC_CLK_MASK (0x3 << FTM_SC_CLK_SHIFT)
+#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_SHIFT)
+#define FTM_SC_PS_MASK 0x7
+#define FTM_SC_TOIE BIT(6)
+#define FTM_SC_TOF BIT(7)
+
+#define FTM_CNT 0x04
+#define FTM_MOD 0x08
+
+#define FTM_CSC_BASE 0x0C
+#define FTM_CSC_MSB BIT(5)
+#define FTM_CSC_MSA BIT(4)
+#define FTM_CSC_ELSB BIT(3)
+#define FTM_CSC_ELSA BIT(2)
+
+#define FTM_CV_BASE 0x10
+#define FTM_CNTIN 0x4C
+#define FTM_STATUS 0x50
+
+#define FTM_MODE 0x54
+#define FTM_MODE_FTMEN BIT(0)
+#define FTM_MODE_WPDIS BIT(2)
+#define FTM_MODE_PWMSYNC BIT(3)
+
+#define FTM_SYNC 0x58
+#define FTM_OUTINIT 0x5C
+#define FTM_OUTMASK 0x60
+#define FTM_COMBINE 0x64
+#define FTM_DEADTIME 0x68
+#define FTM_EXTTRIG 0x6C
+#define FTM_POL 0x70
+#define FTM_FMS 0x74
+#define FTM_FILTER 0x78
+#define FTM_FLTCTRL 0x7C
+#define FTM_QDCTRL 0x80
+#define FTM_CONF 0x84
+#define FTM_FLTPOL 0x88
+#define FTM_SYNCONF 0x8C
+#define FTM_INVCTRL 0x90
+#define FTM_SWOCTRL 0x94
+#define FTM_PWMLOAD 0x98
Please remove the unused macros.
+
+static void __iomem *clksrc_base;
+static void __iomem *clkevt_base;
+static unsigned long peroidic_cyc;
+
+static inline void __init ftm_timer_enable(void __iomem *base)
+{
+ u32 val;
+
+ /* select and enable counter clock source */
+ val = __raw_readl(base + FTM_SC);
+ val &= ~FTM_SC_CLK_MASK;
+ val |= FTM_SC_CLK(1);
+ __raw_writel(val, base + FTM_SC);
+}
+
+static u64 ftm_read_sched_clock(void)
+{
+ return __raw_readl(clksrc_base + FTM_CNT);
+}
+
+static int __init ftm_clocksource_init(unsigned long freq)
+{
+ int ret;
+
+ __raw_writel(0x00, clksrc_base + FTM_CNTIN);
+ __raw_writel(~0UL, clksrc_base + FTM_MOD);
+ __raw_writel(0x1, clksrc_base + FTM_CNT);
+
+ sched_clock_register(ftm_read_sched_clock, 16, freq);
+ ret = clocksource_mmio_init(clksrc_base + FTM_CNT, "fsl-ftm",
+ freq, 300, 16, clocksource_mmio_readl_up);
+ if (ret)
+ return ret;
+
+ ftm_timer_enable(clksrc_base);
+
+ return 0;
+}
+
+static inline void ftm_irq_acknowledge(void)
+{
+ u32 val;
+
+ val = __raw_readl(clkevt_base + FTM_SC);
+ val &= ~FTM_SC_TOF;
+ __raw_writel(val, clkevt_base + FTM_SC);
+}
+
+static int ftm_set_next_event(unsigned long delta,
+ struct clock_event_device *unused)
+{
+ __raw_writel(delta, clkevt_base + FTM_MOD);
+
+ return 0;
+}
+
+static void ftm_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ ftm_set_next_event(peroidic_cyc, evt);
+ break;
+ default:
+ break;
+ }
+}
+
+static irqreturn_t ftm_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ ftm_irq_acknowledge();
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct clock_event_device clockevent_ftm = {
+ .name = "Freescale ftm timer",
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+ .set_mode = ftm_set_mode,
+ .set_next_event = ftm_set_next_event,
+ .rating = 300,
+};
+
+static struct irqaction ftm_timer_irq = {
+ .name = "Freescale ftm timer",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = ftm_timer_interrupt,
+ .dev_id = &clockevent_ftm,
+};
+
+static int __init ftm_clockevent_init(unsigned long freq, int irq)
+{
+ u32 val;
+
+ __raw_writel(0x00, clkevt_base + FTM_CNTIN);
+ __raw_writel(~0UL, clkevt_base + FTM_MOD);
+ __raw_writel(0x1, clksrc_base + FTM_CNT);
+
+ val = __raw_readl(clkevt_base + FTM_SC);
+ val |= FTM_SC_TOIE;
+ __raw_writel(val, clkevt_base + FTM_SC);
+
+ BUG_ON(setup_irq(irq, &ftm_timer_irq));
+
+ clockevent_ftm.cpumask = cpumask_of(0);
+ clockevent_ftm.irq = irq;
+
+ clockevents_config_and_register(&clockevent_ftm, freq, 1, 0xffff);
+
+ ftm_timer_enable(clkevt_base);
+
+ return 0;
+}
+
+static void __init calc_closest_cound_cyc(unsigned long freq)
+{
+ unsigned long ps = 0;
+
+ do {
+ peroidic_cyc = DIV_ROUND_CLOSEST(freq, HZ * (1 << ps++));
+ } while (peroidic_cyc > 0xFFFF);
+
+}
+
+static void __init ftm_timer_init(struct device_node *np)
+{
+ struct clk *ftm_clk;
+ void __iomem *timer_base;
+ unsigned long freq;
+ int irq;
+
+ timer_base = of_iomap(np, 0);
+ BUG_ON(!timer_base);
+
+ clksrc_base = timer_base + FTM_OFFSET(1);
+ clkevt_base = timer_base + FTM_OFFSET(0);
+
+ irq = irq_of_parse_and_map(np, 0);
+ BUG_ON(irq <= 0);
+
+ ftm_clk = of_clk_get_by_name(np, "ftm0_counter_en");
+ BUG_ON(IS_ERR(ftm_clk));
+ BUG_ON(clk_prepare_enable(ftm_clk));
+
+ ftm_clk = of_clk_get_by_name(np, "ftm1_counter_en");
+ BUG_ON(IS_ERR(ftm_clk));
+ BUG_ON(clk_prepare_enable(ftm_clk));
+
+ ftm_clk = of_clk_get_by_name(np, "ftm0");
+ BUG_ON(IS_ERR(ftm_clk));
+ BUG_ON(clk_prepare_enable(ftm_clk));
+
+ ftm_clk = of_clk_get_by_name(np, "ftm1");
+ BUG_ON(IS_ERR(ftm_clk));
+ BUG_ON(clk_prepare_enable(ftm_clk));
+
+ freq = clk_get_rate(ftm_clk);
+
+ calc_closest_cound_cyc(freq);
+
+ BUG_ON(ftm_clocksource_init(freq));
+
+ BUG_ON(ftm_clockevent_init(freq, irq));
+}
+CLOCKSOURCE_OF_DECLARE(vf610, "fsl,vf610-ftm-timer", ftm_timer_init);
I am not a big fan of those BUG_ON every line. Could you please replace
it by dev_err().
That is also not in the logic of a single zImage.
Thanks
-- Daniel
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