Re: [PATCH v3 1/2] clocksource: npcm: add NPCM7xx timer driver

[Brendan Higgins]

On Fri, Nov 17, 2017 at 11:29 AM, Brendan Higgins
<brendanhiggins@xxxxxxxxxx> wrote:
> On Mon, Nov 6, 2017 at 8:28 AM, Tomer Maimon <tmaimon77@xxxxxxxxx> 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@xxxxxxxxx>
>> ---
>>  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@xxxxxxxxxx>

Any update on this?