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authorJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-11 10:41:07 +0300
committerJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-13 08:17:18 +0300
commite09b41010ba33a20a87472ee821fa407a5b8da36 (patch)
treed10dc367189862e7ca5c592f033dc3726e1df4e3 /kernel/drivers/pwm/pwm-bcm-kona.c
parentf93b97fd65072de626c074dbe099a1fff05ce060 (diff)
These changes are the raw update to linux-4.4.6-rt14. Kernel sources
are taken from kernel.org, and rt patch from the rt wiki download page. During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'kernel/drivers/pwm/pwm-bcm-kona.c')
-rw-r--r--kernel/drivers/pwm/pwm-bcm-kona.c63
1 files changed, 45 insertions, 18 deletions
diff --git a/kernel/drivers/pwm/pwm-bcm-kona.c b/kernel/drivers/pwm/pwm-bcm-kona.c
index 02bc04889..c63418322 100644
--- 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);