Re: [PATCH v8 11/26] pwm: jz4740: Use regmap and clocks from TCU driver

[Paul Cercueil]

Hi,

Le jeu. 13 déc. 2018 à 10:30, Uwe Kleine-König 
<u.kleine-koenig@xxxxxxxxxxxxxx> a écrit :
> Hello,
>
> On Wed, Dec 12, 2018 at 11:09:06PM +0100, Paul Cercueil wrote:
> >  [...]
> >   static int jz4740_pwm_enable(struct pwm_chip *chip, struct 
> > pwm_device *pwm)
> >   {
> >  -	uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
> >  +	struct jz4740_pwm_chip *jz = to_jz4740(chip);
> >
> >  -	ctrl |= JZ_TIMER_CTRL_PWM_ENABLE;
> >  -	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
> >  -	jz4740_timer_enable(pwm->hwpwm);
> >  +	/* Enable PWM output */
> >  +	regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
> >  +				TCU_TCSR_PWM_EN, TCU_TCSR_PWM_EN);
>
> Usually follow-up lines are indented to the matching parenthesis.

OK.

> >  [...]
> >   static int jz4740_pwm_config(struct pwm_chip *chip, struct 
> > pwm_device *pwm,
> >   			     int duty_ns, int period_ns)
> >   {
> >   	struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
> >  +	struct clk *clk = jz4740->clks[pwm->hwpwm];
> >  +	unsigned long rate, new_rate, period, duty;
> >   	unsigned long long tmp;
> >  -	unsigned long period, duty;
> >  -	unsigned int prescaler = 0;
> >  -	uint16_t ctrl;
> >  +	unsigned int tcsr;
> >   	bool is_enabled;
> >
> >  -	tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns;
> >  -	do_div(tmp, 1000000000);
> >  -	period = tmp;
> >  +	rate = clk_get_rate(clk);
> >  +
> >  +	for (;;) {
> >  +		tmp = (unsigned long long) rate * period_ns;
> >  +		do_div(tmp, 1000000000);
> >
> >  -	while (period > 0xffff && prescaler < 6) {
> >  -		period >>= 2;
> >  -		++prescaler;
> >  +		if (tmp <= 0xffff)
> >  +			break;
> >  +
> >  +		new_rate = clk_round_rate(clk, rate / 2);
> >  +
> >  +		if (new_rate < rate)
> >  +			rate = new_rate;
> >  +		else
> >  +			return -EINVAL;
> >   	}
> >
> >  -	if (prescaler == 6)
> >  -		return -EINVAL;
> >  +	clk_set_rate(clk, rate);
>
> Maybe this could better live in a separate patch. If you split still
> further to have the conversion to regmap in a single patch, then the
> conversion to the clk_* functions and then improve the algorithm for 
> the
> clk settings each of the patches is easier to review than this one 
> patch
> that does all three things at once.

I can try.

> Best regards
> Uwe
>
> --
> Pengutronix e.K.                           | Uwe Kleine-König        
>     |
> Industrial Linux Solutions                 | 
> http://www.pengutronix.de/  |