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@@ -67,49 +67,55 @@ static int sunxi_pwm_set_config(struct udevice *dev, uint channel,
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{
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struct sunxi_pwm_priv *priv = dev_get_priv(dev);
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struct sunxi_pwm *regs = priv->regs;
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- int prescaler;
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- u32 v, period = 0, duty;
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- u64 scaled_freq = 0;
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+ int best_prescaler = 0;
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+ u32 v, best_period = 0, duty;
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+ u64 best_scaled_freq = 0;
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const u32 nsecs_per_sec = 1000000000U;
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debug("%s: period_ns=%u, duty_ns=%u\n", __func__, period_ns, duty_ns);
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- for (prescaler = 0; prescaler <= SUNXI_PWM_CTRL_PRESCALE0_MASK;
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+ for (int prescaler = 0; prescaler <= SUNXI_PWM_CTRL_PRESCALE0_MASK;
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prescaler++) {
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+ u32 period = 0;
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+ u64 scaled_freq = 0;
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if (!prescaler_table[prescaler])
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continue;
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scaled_freq = lldiv(OSC_24MHZ, prescaler_table[prescaler]);
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period = lldiv(scaled_freq * period_ns, nsecs_per_sec);
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- if (period - 1 <= SUNXI_PWM_CH0_PERIOD_MAX)
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- break;
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+ if ((period - 1 <= SUNXI_PWM_CH0_PERIOD_MAX) &&
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+ best_period < period) {
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+ best_period = period;
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+ best_scaled_freq = scaled_freq;
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+ best_prescaler = prescaler;
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+ }
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}
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- if (period - 1 > SUNXI_PWM_CH0_PERIOD_MAX) {
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+ if (best_period - 1 > SUNXI_PWM_CH0_PERIOD_MAX) {
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debug("%s: failed to find prescaler value\n", __func__);
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return -EINVAL;
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}
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- duty = lldiv(scaled_freq * duty_ns, nsecs_per_sec);
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+ duty = lldiv(best_scaled_freq * duty_ns, nsecs_per_sec);
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- if (priv->prescaler != prescaler) {
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+ if (priv->prescaler != best_prescaler) {
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/* Mask clock to update prescaler */
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v = readl(®s->ctrl);
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v &= ~SUNXI_PWM_CTRL_CLK_GATE;
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writel(v, ®s->ctrl);
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v &= ~SUNXI_PWM_CTRL_PRESCALE0_MASK;
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- v |= (prescaler & SUNXI_PWM_CTRL_PRESCALE0_MASK);
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+ v |= (best_prescaler & SUNXI_PWM_CTRL_PRESCALE0_MASK);
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writel(v, ®s->ctrl);
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v |= SUNXI_PWM_CTRL_CLK_GATE;
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writel(v, ®s->ctrl);
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- priv->prescaler = prescaler;
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+ priv->prescaler = best_prescaler;
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}
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- writel(SUNXI_PWM_CH0_PERIOD_PRD(period) |
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+ writel(SUNXI_PWM_CH0_PERIOD_PRD(best_period) |
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SUNXI_PWM_CH0_PERIOD_DUTY(duty), ®s->ch0_period);
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debug("%s: prescaler: %d, period: %d, duty: %d\n",
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__func__, priv->prescaler,
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- period, duty);
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+ best_period, duty);
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return 0;
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}
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