static int vt8500_pwm_config()

in pwm-vt8500.c [72:124]

• 43 lines of code
• 5 McCabe index (conditional complexity)

static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
		int duty_ns, int period_ns)
{
	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
	unsigned long long c;
	unsigned long period_cycles, prescale, pv, dc;
	int err;
	u32 val;

	err = clk_enable(vt8500->clk);
	if (err < 0) {
		dev_err(chip->dev, "failed to enable clock\n");
		return err;
	}

	c = clk_get_rate(vt8500->clk);
	c = c * period_ns;
	do_div(c, 1000000000);
	period_cycles = c;

	if (period_cycles < 1)
		period_cycles = 1;
	prescale = (period_cycles - 1) / 4096;
	pv = period_cycles / (prescale + 1) - 1;
	if (pv > 4095)
		pv = 4095;

	if (prescale > 1023) {
		clk_disable(vt8500->clk);
		return -EINVAL;
	}

	c = (unsigned long long)pv * duty_ns;
	do_div(c, period_ns);
	dc = c;

	writel(prescale, vt8500->base + REG_SCALAR(pwm->hwpwm));
	vt8500_pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_SCALAR_UPDATE);

	writel(pv, vt8500->base + REG_PERIOD(pwm->hwpwm));
	vt8500_pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_PERIOD_UPDATE);

	writel(dc, vt8500->base + REG_DUTY(pwm->hwpwm));
	vt8500_pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_DUTY_UPDATE);

	val = readl(vt8500->base + REG_CTRL(pwm->hwpwm));
	val |= CTRL_AUTOLOAD;
	writel(val, vt8500->base + REG_CTRL(pwm->hwpwm));
	vt8500_pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_CTRL_UPDATE);

	clk_disable(vt8500->clk);
	return 0;
}