On Saturday 04 June 2016 11:58 AM, Boris Brezillon wrote:
On Fri, 3 Jun 2016 13:50:28 -0700
Brian Norris <briannorris@xxxxxxxxxxxx> wrote:
+ Laxman
Hi,
On Fri, Jun 03, 2016 at 10:23:08AM +0200, Boris Brezillon wrote:
- * calculation loss.
- */
- req_period = req_diff * pargs.period;
- div_u64_rem(req_period, diff, &rem);
- if (!rem) {
- do_div(req_period, diff);
- duty_pulse = (unsigned int)req_period;
- } else {
- duty_pulse = (pargs.period / 100) * ((req_diff * 100) / diff);
- }
+ /* We pass diff as the scale to get a uV precision. */
+ pwm_set_relative_duty_cycle(&pstate, req_diff, diff);
Notably, you're dropping much of Laxman's commit fd786fb0276a ("regulator:
pwm: Try to avoid voltage error in duty cycle calculation"), but I
believe the DIV_ROUND_CLOSEST_ULL() in pwm_set_relative_duty_cycle()
solves his problem better.
Oops, forgot to comment on that in the commit message. Indeed, the use
of pwm_set_relative_duty_cycle() solves the problem Laxman was seeing.
Yaah, the issue which I was seeing and had fix will be resolved with
this also.
I wanted to do req_diff * period first before any scaling/division.
Function pwm_set_relative_duty_cycle() does the same, and hence it is fine.
state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)val * state->period,
+ scale);
Acked-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
Thanks,
Laxman
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