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SubjectRe: [PATCH v3 1/2] clocksource: npcm: add NPCM7xx timer driver
On Fri, Nov 17, 2017 at 11:29 AM, Brendan Higgins
<brendanhiggins@google.com> wrote:
> On Mon, Nov 6, 2017 at 8:28 AM, Tomer Maimon <tmaimon77@gmail.com> wrote:
>> Add Nuvoton BMC NPCM7xx timer driver.
>>
>> the clocksource Enable 24-bit TIMER0 and TIMER1 counters,
>> while TIMER0 serves as clockevent and TIMER1 serves as clocksource.
>>
>> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
>> ---
>> drivers/clocksource/Kconfig | 8 ++
>> drivers/clocksource/Makefile | 1 +
>> drivers/clocksource/npcm7xx-timer.c | 239 ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 248 insertions(+)
>> create mode 100644 drivers/clocksource/npcm7xx-timer.c
>>
>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>> index cc6062049170..46184af75d6c 100644
>> --- a/drivers/clocksource/Kconfig
>> +++ b/drivers/clocksource/Kconfig
>> @@ -140,6 +140,14 @@ 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 72711f1491e3..ff2b30b75b5b 100644
>> --- a/drivers/clocksource/Makefile
>> +++ b/drivers/clocksource/Makefile
>> @@ -54,6 +54,7 @@ obj-$(CONFIG_CLKSRC_TI_32K) += timer-ti-32k.o
>> obj-$(CONFIG_CLKSRC_NPS) += timer-nps.o
>> obj-$(CONFIG_OXNAS_RPS_TIMER) += timer-oxnas-rps.o
>> obj-$(CONFIG_OWL_TIMER) += owl-timer.o
>> +obj-$(CONFIG_NPCM7XX_TIMER) += npcm7xx-timer.o
>>
>> obj-$(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..b9b468da4560
>> --- /dev/null
>> +++ b/drivers/clocksource/npcm7xx-timer.c
>> @@ -0,0 +1,239 @@
>> +
>> +/*
>> + * Copyright (c) 2017 Nuvoton Technology corporation.
>> + * Copyright 2017 Google, 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;version 2 of the License.
>> + */
>> +
>> +#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 to_npcm7xx = {
>
> nit: the prefix should be npcm7xx_*
>
>> + .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(&to_npcm7xx) + NPCM7XX_REG_TCSR0);
>> +
>> + writel(NPCM7XX_Tx_RESETINT,
>> + timer_of_base(&to_npcm7xx) + NPCM7XX_REG_TISR);
>> +
>> + to_npcm7xx.clkevt.cpumask = cpumask_of(0);
>> + clockevents_config_and_register(&to_npcm7xx.clkevt, rate,
>> + 0x1, NPCM7XX_Tx_MAX_CNT);
>> +}
>> +
>> +static void __init npcm7xx_clocksource_init(u32 rate)
>> +{
>> + u32 val;
>> +
>> + writel(NPCM7XX_DEFAULT_CSR,
>> + timer_of_base(&to_npcm7xx) + NPCM7XX_REG_TCSR1);
>> + writel(NPCM7XX_Tx_MAX_CNT,
>> + timer_of_base(&to_npcm7xx) + NPCM7XX_REG_TICR1);
>> +
>> + val = readl(timer_of_base(&to_npcm7xx) + NPCM7XX_REG_TCSR1);
>> + val |= NPCM7XX_START_Tx;
>> + writel(val, timer_of_base(&to_npcm7xx) + NPCM7XX_REG_TCSR1);
>> +
>> + clocksource_mmio_init(timer_of_base(&to_npcm7xx) +
>> + NPCM7XX_REG_TDR1,
>> + "npcm7xx-timer1", rate,
>> + 300, (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);
>> + to_npcm7xx.of_clk.clk = clk;
>> + }
>> +
>> + ret = timer_of_init(np, &to_npcm7xx);
>> + 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);
>> + to_npcm7xx.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(&to_npcm7xx), timer_of_irq(&to_npcm7xx));
>> +
>> + 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
>>
>
> Reviewed-by: Brendan Higgins <brendanhiggins@google.com>

Any update on this?

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