Re: [PATCH v2] Input: analog: Always use ktime functions

On 9/7/21 2:40 AM, Geert Uytterhoeven wrote:

Hi Günter,

On Tue, Sep 7, 2021 at 8:35 AM Guenter Roeck [off-list ref] wrote:

quoted

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@roeck-us.net>
---
v2: Drop helper functions and use ktime_get() and ktime_sub() directly
     Drop 'speed' variable and use NSEC_PER_MSEC directly

  drivers/input/joystick/analog.c | 103 ++++----------------------------
  1 file changed, 11 insertions(+), 92 deletions(-)

diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
index f798922a4598..a9ec41f48068 100644
--- a/drivers/input/joystick/analog.c
+++ b/drivers/input/joystick/analog.c

quoted

@@ -275,7 +210,7 @@ static int analog_cooked_read(struct analog_port *port)
                 this |= data[i];
                 for (j = 0; j < 4; j++)
                         if (data[i] & (1 << j))
-                               port->axes[j] = (delta(start, time[i]) << ANALOG_FUZZ_BITS) / port->loop;
+                               port->axes[j] = (ktime_sub(time[i], start) << ANALOG_FUZZ_BITS) / port->loop;

This is now a 64-by-32 division, triggering undefined references to __udivdi3
on some 32-bit platforms.

And I was sure I checked for those. Oh well. I'll send v3 later today.

Assumed deltas are small, the simple solution of truncating to
32 bit (like delta() did before):

-  port->axes[j] = (ktime_sub(time[i], start) << ANALOG_FUZZ_BITS) / port->loop;
+ port->axes[j] = ((u32)ktime_sub(time[i], start) << ANALOG_FUZZ_BITS)
/ port->loop;

Yes, I'll do that.

Thanks,
Guenter