Re: [RFC 2/4] pwm: sifive: Add a driver for SiFive SoC PWM

From: Christoph Hellwig
Date: Wed Oct 10 2018 - 09:11:32 EST


Thanks for getting these drivers submitted upstream!

I don't really know anything about PWM, so just some random nitpicking
below..

> + iowrite32(frac, pwm->regs + REG_PWMCMP0 + (dev->hwpwm * SIZE_PWMCMP));

* already has a higher precedence than +, so no need for the inner
braces.

> + duty = ioread32(pwm->regs + REG_PWMCMP0 + (dev->hwpwm * SIZE_PWMCMP));

Same here.

> + /* (1 << (16+scale)) * 10^9/rate = real_period */
unsigned long scalePow = (pwm->approx_period * (u64)rate) / 1000000000;

no camcel case, please.

> + int scale = ilog2(scalePow) - 16;
> +
> + scale = clamp(scale, 0, 0xf);

Why not:

int scale = clamp(ilog2(scale_pow) - 16, 0, 0xf);

> +static int sifive_pwm_clock_notifier(struct notifier_block *nb,
> + unsigned long event, void *data)
> +{
> + struct clk_notifier_data *ndata = data;
> + struct sifive_pwm_device *pwm = container_of(nb,
> + struct sifive_pwm_device,
> + notifier);

I don't think there are any guidlines, but I always prefer to just move
the whole container_of onto a new line:

struct sifive_pwm_device *pwm =
container_of(nb, struct sifive_pwm_device, notifier);

> +static struct platform_driver sifive_pwm_driver = {
> + .probe = sifive_pwm_probe,
> + .remove = sifive_pwm_remove,
> + .driver = {
> + .name = "pwm-sifivem",
> + .of_match_table = of_match_ptr(sifive_pwm_of_match),
> + },
> +};

What about using tabs to align this a little more nicely?

static struct platform_driver sifive_pwm_driver = {
.probe = sifive_pwm_probe,
.remove = sifive_pwm_remove,
.driver = {
.name = "pwm-sifivem",
.of_match_table = of_match_ptr(sifive_pwm_of_match),
},
};