linux-kernel - Re: [PATCH v2 1/4] clocksource: fttmr010: Parametrise shutdown

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Date:   Wed, 29 Jan 2020 12:25:24 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Joel Stanley <joel@....id.au>, Rob Herring <robh+dt@...nel.org>
Cc:     Cédric Le Goater <clg@...d.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH v2 1/4] clocksource: fttmr010: Parametrise shutdown

On 07/11/2019 10:42, Joel Stanley wrote:
> In preparation for supporting the ast2600 which uses a different method
> to clear bits in the control register, use a callback for performing the
> shutdown sequence.
> 
> Reviewed-by: Cédric Le Goater <clg@...d.org>
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
> Signed-off-by: Joel Stanley <joel@....id.au>

It will be cleaner if you create a struct of_device_id array where you
store the different variant data.

eg.
struct myops {
	int (*shutdown)(struct clock_event_device *evt);
};

struct fttmr010 {
	...
	struct myops *ops;
};

...

static const struct of_device_id fttmr010_of_match[] = {
	{ .compatible = "faraday,fttmr010",     .data = &fttmr010_ops },
	...
	{ .compatible = "aspeed,ast2600-timer", .data = &as2600_ops, },
	{ /* sentinel */ }
};

Keep the generic timer_shutdown function, get the ops from there and
then call the shutdown callback.

At init time:

...

const struct of_device_id *match;

...

match = of_match_node(fttmr010_of_match, node);
fttmr010->ops = (struct myops *)match->data;

...

(also if you have time, remove the is_aspeed boolean test by a
corresponding callback).

> ---
>  drivers/clocksource/timer-fttmr010.c | 19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clocksource/timer-fttmr010.c b/drivers/clocksource/timer-fttmr010.c
> index fadff7915dd9..c2d30eb9dc72 100644
> --- a/drivers/clocksource/timer-fttmr010.c
> +++ b/drivers/clocksource/timer-fttmr010.c
> @@ -97,6 +97,7 @@ struct fttmr010 {
>  	bool is_aspeed;
>  	u32 t1_enable_val;
>  	struct clock_event_device clkevt;
> +	int (*timer_shutdown)(struct clock_event_device *evt);
>  #ifdef CONFIG_ARM
>  	struct delay_timer delay_timer;
>  #endif
> @@ -140,9 +141,7 @@ static int fttmr010_timer_set_next_event(unsigned long cycles,
>  	u32 cr;
>  
>  	/* Stop */
> -	cr = readl(fttmr010->base + TIMER_CR);
> -	cr &= ~fttmr010->t1_enable_val;
> -	writel(cr, fttmr010->base + TIMER_CR);
> +	fttmr010->timer_shutdown(evt);
>  
>  	if (fttmr010->is_aspeed) {
>  		/*
> @@ -183,9 +182,7 @@ static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
>  	u32 cr;
>  
>  	/* Stop */
> -	cr = readl(fttmr010->base + TIMER_CR);
> -	cr &= ~fttmr010->t1_enable_val;
> -	writel(cr, fttmr010->base + TIMER_CR);
> +	fttmr010->timer_shutdown(evt);
>  
>  	/* Setup counter start from 0 or ~0 */
>  	writel(0, fttmr010->base + TIMER1_COUNT);
> @@ -211,9 +208,7 @@ static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
>  	u32 cr;
>  
>  	/* Stop */
> -	cr = readl(fttmr010->base + TIMER_CR);
> -	cr &= ~fttmr010->t1_enable_val;
> -	writel(cr, fttmr010->base + TIMER_CR);
> +	fttmr010->timer_shutdown(evt);
>  
>  	/* Setup timer to fire at 1/HZ intervals. */
>  	if (fttmr010->is_aspeed) {
> @@ -350,6 +345,8 @@ static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
>  				     fttmr010->tick_rate);
>  	}
>  
> +	fttmr010->timer_shutdown = fttmr010_timer_shutdown;
> +
>  	/*
>  	 * Setup clockevent timer (interrupt-driven) on timer 1.
>  	 */
> @@ -370,10 +367,10 @@ static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
>  	fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
>  		CLOCK_EVT_FEAT_ONESHOT;
>  	fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
> -	fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
> +	fttmr010->clkevt.set_state_shutdown = fttmr010->timer_shutdown;
>  	fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
>  	fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
> -	fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
> +	fttmr010->clkevt.tick_resume = fttmr010->timer_shutdown;
>  	fttmr010->clkevt.cpumask = cpumask_of(0);
>  	fttmr010->clkevt.irq = irq;
>  	clockevents_config_and_register(&fttmr010->clkevt,
> 


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