linux-kernel - RE: [PATCH v16] pwm: opencores: Add PWM driver support

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Message-ID:
 <ZQ0PR01MB12530DDB9AF830296773C7AF9F03A@ZQ0PR01MB1253.CHNPR01.prod.partner.outlook.cn>
Date: Tue, 24 Dec 2024 01:53:03 +0000
From: William Qiu <william.qiu@...rfivetech.com>
To: Uwe Kleine-König <ukleinek@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-pwm@...r.kernel.org" <linux-pwm@...r.kernel.org>, Hal Feng
	<hal.feng@...rfivetech.com>, Philipp Zabel <p.zabel@...gutronix.de>
Subject: RE: [PATCH v16] pwm: opencores: Add PWM driver support

> -----Original Message-----
> From: Uwe Kleine-König <ukleinek@...nel.org>
> Sent: 2024年12月24日 1:12
> To: William Qiu <william.qiu@...rfivetech.com>
> Cc: linux-kernel@...r.kernel.org; linux-pwm@...r.kernel.org; Hal Feng
> <hal.feng@...rfivetech.com>; Philipp Zabel <p.zabel@...gutronix.de>
> Subject: Re: [PATCH v16] pwm: opencores: Add PWM driver support
> 
> Hello William,
> 
> On Mon, Dec 23, 2024 at 02:47:59AM +0000, William Qiu wrote:
> > > > +	duty_data = mul_u64_u32_div(state->duty_cycle, ddata->clk_rate,
> > > NSEC_PER_SEC);
> > > > +	if (!duty_data)
> > > > +		return -EINVAL;
> > >
> > > I can understand that period_data == 0 is an error, but duty_data ==
> > > 0 could/should just work?!
> >
> > It means no need to check whether the duty is valid?
> 
> No, it means that I expect that duty_data == 0 is a valid setting and most
> controllers support it.
> 
> Best regards
> Uwe

So we just need to check duty < 0?

Best Regards,
William