On 05/07/2017 04:35, Dong Aisheng wrote:
> IMX Timer/PWM Module (TPM) supports both timer and pwm function while
> this patch only adds the timer support. PWM would be added later.
>
> The TPM counter, compare and capture registers are clocked by an
> asynchronous clock that can remain enabled in low power modes.
>
> NOTE: We observed in a very small probability, the bus fabric
> contention between GPU and A7 may results a few cycles delay
> of writing CNT registers which may cause the min_delta event got
> missed, so we need add a ETIME check here in case it happened.
>
> Cc: Daniel Lezcano <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Shawn Guo <[email protected]>
> Cc: Anson Huang <[email protected]>
> Cc: Bai Ping <[email protected]>
> Signed-off-by: Dong Aisheng <[email protected]>
>
> ---
> ChangeLog:
> v3->v4:
> * also add ETIME explanation in function
> v2->v3:
> * address all comments from Daniel Lezcano
> * add more explaination on ETIME check in commit message
> v1->v2:
> * change to readl/writel from __raw_readl/writel according to Arnd's
> suggestion to avoid endian issue
> * add help information in Kconfig
> * add more error checking
> ---
> drivers/clocksource/Kconfig | 8 ++
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/timer-imx-tpm.c | 239
> ++++++++++++++++++++++++++++++++++++
> 3 files changed, 248 insertions(+)
> create mode 100644 drivers/clocksource/timer-imx-tpm.c
[ ... ]
> +static struct irqaction tpm_timer_irq = {
> + .name = "i.MX7ULP TPM Timer",
> + .flags = IRQF_TIMER | IRQF_IRQPOLL,
> + .handler = tpm_timer_interrupt,
> + .dev_id = &clockevent_tpm,
> +};
>
Please remove the structure above and use request_irq instead of
setup_irq below + return code checking.
> +static int __init tpm_clockevent_init(unsigned long rate, int irq)
> +{
> + setup_irq(irq, &tpm_timer_irq);
> +
> + clockevent_tpm.cpumask = cpumask_of(0);
> + clockevent_tpm.irq = irq;
> + clockevents_config_and_register(&clockevent_tpm,
> + rate, 300, 0xfffffffe);
> +
> + return 0;
> +}
> +
> +static int __init tpm_timer_init(struct device_node *np)
> +{
[ ... ]
> + rate = clk_get_rate(per) >> 3;
Why ?
> + tpm_clocksource_init(rate);
> + tpm_clockevent_init(rate, irq);
Check.
> + return 0;
> +
> +err_per_clk_enable:
> + clk_disable_unprepare(ipg);
> +err_ipg_clk_enable:
No need to add an extra label.
> +err_clk_get:
> + clk_put(per);
> + clk_put(ipg);
> +err_iomap:
> + iounmap(timer_base);
> + return ret;
> +}
> +CLOCKSOURCE_OF_DECLARE(imx7ulp, "fsl,imx7ulp-tpm", tpm_timer_init);
CLOCKSOURCE_OF_DECLARE is renamed to TIMER_OF_DECLARE.
Thanks!
-- Daniel
--
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