Re: [PATCH] Input: analog: Always use ktime functions

[Guenter Roeck]

On 9/6/21 10:59 PM, Dmitry Torokhov wrote:
> Hi Guenter,
>
> On Mon, Sep 06, 2021 at 10:06:06PM -0700, Guenter Roeck wrote:
> > m68k, mips, s390, and sparc allmodconfig images fail to build with the
> > following error.
> >
> > drivers/input/joystick/analog.c:160:2: error:
> > 	#warning Precise timer not defined for this architecture.
> >
> > Remove architecture specific time handling code and always use ktime
> > functions to determine time deltas. Also remove the now useless use_ktime
> > kernel parameter.
> >
> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >   drivers/input/joystick/analog.c | 74 ++-------------------------------
> >   1 file changed, 3 insertions(+), 71 deletions(-)
> >
> > diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
> > index f798922a4598..4702982182fa 100644
> > --- a/drivers/input/joystick/analog.c
> > +++ b/drivers/input/joystick/analog.c
> > @@ -28,10 +28,6 @@ MODULE_AUTHOR("Vojtech Pavlik <vojtech@xxxxxx>");
> >   MODULE_DESCRIPTION(DRIVER_DESC);
> >   MODULE_LICENSE("GPL");
> >   
> > -static bool use_ktime = true;
> > -module_param(use_ktime, bool, 0400);
> > -MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed");
> > -
> >   /*
> >    * Option parsing.
> >    */
> > @@ -119,64 +115,14 @@ struct analog_port {
> >   	int axtime;
> >   };
> >   
> > -/*
> > - * Time macros.
> > - */
> > -
> > -#ifdef __i386__
> > -
> > -#include <linux/i8253.h>
> > -
> > -#define GET_TIME(x)	do { if (boot_cpu_has(X86_FEATURE_TSC)) x = (unsigned int)rdtsc(); else x = get_time_pit(); } while (0)
> > -#define DELTA(x,y)	(boot_cpu_has(X86_FEATURE_TSC) ? ((y) - (x)) : ((x) - (y) + ((x) < (y) ? PIT_TICK_RATE / HZ : 0)))
> > -#define TIME_NAME	(boot_cpu_has(X86_FEATURE_TSC)?"TSC":"PIT")
> > -static unsigned int get_time_pit(void)
> > -{
> > -        unsigned long flags;
> > -        unsigned int count;
> > -
> > -        raw_spin_lock_irqsave(&i8253_lock, flags);
> > -        outb_p(0x00, 0x43);
> > -        count = inb_p(0x40);
> > -        count |= inb_p(0x40) << 8;
> > -        raw_spin_unlock_irqrestore(&i8253_lock, flags);
> > -
> > -        return count;
> > -}
> > -#elif defined(__x86_64__)
> > -#define GET_TIME(x)	do { x = (unsigned int)rdtsc(); } while (0)
> > -#define DELTA(x,y)	((y)-(x))
> > -#define TIME_NAME	"TSC"
> > -#elif defined(__alpha__) || defined(CONFIG_ARM) || defined(CONFIG_ARM64) || defined(CONFIG_PPC) || defined(CONFIG_RISCV)
> > -#define GET_TIME(x)	do { x = get_cycles(); } while (0)
> > -#define DELTA(x,y)	((y)-(x))
> > -#define TIME_NAME	"get_cycles"
> > -#else
> > -#define FAKE_TIME
> > -static unsigned long analog_faketime = 0;
> > -#define GET_TIME(x)     do { x = analog_faketime++; } while(0)
> > -#define DELTA(x,y)	((y)-(x))
> > -#define TIME_NAME	"Unreliable"
> > -#warning Precise timer not defined for this architecture.
> > -#endif
> > -
> >   static inline u64 get_time(void)
> >   {
> > -	if (use_ktime) {
> > -		return ktime_get_ns();
> > -	} else {
> > -		unsigned int x;
> > -		GET_TIME(x);
> > -		return x;
> > -	}
> > +	return ktime_get_ns();
> >   }
> >   
> >   static inline unsigned int delta(u64 x, u64 y)
> >   {
> > -	if (use_ktime)
> > -		return y - x;
> > -	else
> > -		return DELTA((unsigned int)x, (unsigned int)y);
> > +	return y - x;
>
> I wonder if we should get rid of these wrappers and use ktime_t and
> ktime_get(), ktime_sub(), etc directly.

Will do.

> >   }
> >   
> >   /*
> > @@ -378,21 +324,7 @@ static void analog_calibrate_timer(struct analog_port *port)
> >   	u64 t1, t2, t3;
> >   	unsigned long flags;
> >   
> > -	if (use_ktime) {
> > -		port->speed = 1000000;
> > -	} else {
> > -		local_irq_save(flags);
> > -		t1 = get_time();
> > -#ifdef FAKE_TIME
> > -		analog_faketime += 830;
> > -#endif
> > -		mdelay(1);
> > -		t2 = get_time();
> > -		t3 = get_time();
> > -		local_irq_restore(flags);
> > -
> > -		port->speed = delta(t1, t2) - delta(t2, t3);
> > -	}
> > +	port->speed = 1000000;
>
> It seems we could get rid of port->speed.

Sure. I'll just use NSEC_PER_MSEC directly.

Thanks,
Guenter