These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / drivers / pwm / pwm-bcm-kona.c

diff --git a/kernel/drivers/pwm/pwm-bcm-kona.c b/kernel/drivers/pwm/pwm-bcm-kona.c
index 02bc048..c634183 100644 (file)
--- a/kernel/drivers/pwm/pwm-bcm-kona.c
+++ b/kernel/drivers/pwm/pwm-bcm-kona.c
@@ -76,19 +76,36 @@ static inline struct kona_pwmc *to_kona_pwmc(struct pwm_chip *_chip)
        return container_of(_chip, struct kona_pwmc, chip);
 }
 
-static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan)
+/*
+ * Clear trigger bit but set smooth bit to maintain old output.
+ */
+static void kona_pwmc_prepare_for_settings(struct kona_pwmc *kp,
+       unsigned int chan)
 {
        unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET);
 
-       /* Clear trigger bit but set smooth bit to maintain old output */
        value |= 1 << PWM_CONTROL_SMOOTH_SHIFT(chan);
        value &= ~(1 << PWM_CONTROL_TRIGGER_SHIFT(chan));
        writel(value, kp->base + PWM_CONTROL_OFFSET);
 
+       /*
+        * There must be a min 400ns delay between clearing trigger and setting
+        * it. Failing to do this may result in no PWM signal.
+        */
+       ndelay(400);
+}
+
+static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan)
+{
+       unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET);
+
        /* Set trigger bit and clear smooth bit to apply new settings */
        value &= ~(1 << PWM_CONTROL_SMOOTH_SHIFT(chan));
        value |= 1 << PWM_CONTROL_TRIGGER_SHIFT(chan);
        writel(value, kp->base + PWM_CONTROL_OFFSET);
+
+       /* Trigger bit must be held high for at least 400 ns. */
+       ndelay(400);
 }
 
 static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -133,8 +150,14 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
                        return -EINVAL;
        }
 
-       /* If the PWM channel is enabled, write the settings to the HW */
-       if (test_bit(PWMF_ENABLED, &pwm->flags)) {
+       /*
+        * Don't apply settings if disabled. The period and duty cycle are
+        * always calculated above to ensure the new values are
+        * validated immediately instead of on enable.
+        */
+       if (pwm_is_enabled(pwm)) {
+               kona_pwmc_prepare_for_settings(kp, chan);
+
                value = readl(kp->base + PRESCALE_OFFSET);
                value &= ~PRESCALE_MASK(chan);
                value |= prescale << PRESCALE_SHIFT(chan);
@@ -164,6 +187,8 @@ static int kona_pwmc_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
                return ret;
        }
 
+       kona_pwmc_prepare_for_settings(kp, chan);
+
        value = readl(kp->base + PWM_CONTROL_OFFSET);
 
        if (polarity == PWM_POLARITY_NORMAL)
@@ -175,9 +200,6 @@ static int kona_pwmc_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
 
        kona_pwmc_apply_settings(kp, chan);
 
-       /* Wait for waveform to settle before gating off the clock */
-       ndelay(400);
-
        clk_disable_unprepare(kp->clk);
 
        return 0;
@@ -194,7 +216,8 @@ static int kona_pwmc_enable(struct pwm_chip *chip, struct pwm_device *pwm)
                return ret;
        }
 
-       ret = kona_pwmc_config(chip, pwm, pwm->duty_cycle, pwm->period);
+       ret = kona_pwmc_config(chip, pwm, pwm_get_duty_cycle(pwm),
+                              pwm_get_period(pwm));
        if (ret < 0) {
                clk_disable_unprepare(kp->clk);
                return ret;
@@ -207,13 +230,20 @@ static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
        struct kona_pwmc *kp = to_kona_pwmc(chip);
        unsigned int chan = pwm->hwpwm;
+       unsigned int value;
+
+       kona_pwmc_prepare_for_settings(kp, chan);
 
        /* Simulate a disable by configuring for zero duty */
        writel(0, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan));
-       kona_pwmc_apply_settings(kp, chan);
+       writel(0, kp->base + PERIOD_COUNT_OFFSET(chan));
 
-       /* Wait for waveform to settle before gating off the clock */
-       ndelay(400);
+       /* Set prescale to 0 for this channel */
+       value = readl(kp->base + PRESCALE_OFFSET);
+       value &= ~PRESCALE_MASK(chan);
+       writel(value, kp->base + PRESCALE_OFFSET);
+
+       kona_pwmc_apply_settings(kp, chan);
 
        clk_disable_unprepare(kp->clk);
 }
@@ -266,18 +296,15 @@ static int kona_pwmc_probe(struct platform_device *pdev)
                return ret;
        }
 
-       /* Set smooth mode, push/pull, and normal polarity for all channels */
-       for (chan = 0; chan < kp->chip.npwm; chan++) {
-               value |= (1 << PWM_CONTROL_SMOOTH_SHIFT(chan));
+       /* Set push/pull for all channels */
+       for (chan = 0; chan < kp->chip.npwm; chan++)
                value |= (1 << PWM_CONTROL_TYPE_SHIFT(chan));
-               value |= (1 << PWM_CONTROL_POLARITY_SHIFT(chan));
-       }
 
        writel(value, kp->base + PWM_CONTROL_OFFSET);
 
        clk_disable_unprepare(kp->clk);
 
-       ret = pwmchip_add(&kp->chip);
+       ret = pwmchip_add_with_polarity(&kp->chip, PWM_POLARITY_INVERSED);
        if (ret < 0)
                dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 
@@ -290,7 +317,7 @@ static int kona_pwmc_remove(struct platform_device *pdev)
        unsigned int chan;
 
        for (chan = 0; chan < kp->chip.npwm; chan++)
-               if (test_bit(PWMF_ENABLED, &kp->chip.pwms[chan].flags))
+               if (pwm_is_enabled(&kp->chip.pwms[chan]))
                        clk_disable_unprepare(kp->clk);
 
        return pwmchip_remove(&kp->chip);