Merge tag 'mac80211-for-davem-2015-05-19' of git://git.kernel.org/pub/scm/linux/kerne...

[cascardo/linux.git] / drivers / pwm / pwm-samsung.c

diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
index 3e9b583..ff201e1 100644 (file)
--- a/drivers/pwm/pwm-samsung.c
+++ b/drivers/pwm/pwm-samsung.c
@@ -269,12 +269,31 @@ static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
        spin_unlock_irqrestore(&samsung_pwm_lock, flags);
 }
 
+static void pwm_samsung_manual_update(struct samsung_pwm_chip *chip,
+                                     struct pwm_device *pwm)
+{
+       unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
+       u32 tcon;
+       unsigned long flags;
+
+       spin_lock_irqsave(&samsung_pwm_lock, flags);
+
+       tcon = readl(chip->base + REG_TCON);
+       tcon |= TCON_MANUALUPDATE(tcon_chan);
+       writel(tcon, chip->base + REG_TCON);
+
+       tcon &= ~TCON_MANUALUPDATE(tcon_chan);
+       writel(tcon, chip->base + REG_TCON);
+
+       spin_unlock_irqrestore(&samsung_pwm_lock, flags);
+}
+
 static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
                              int duty_ns, int period_ns)
 {
        struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
        struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
-       u32 tin_ns = chan->tin_ns, tcnt, tcmp;
+       u32 tin_ns = chan->tin_ns, tcnt, tcmp, oldtcmp;
 
        /*
         * We currently avoid using 64bit arithmetic by using the
@@ -288,6 +307,7 @@ static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
                return 0;
 
        tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
+       oldtcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm));
 
        /* We need tick count for calculation, not last tick. */
        ++tcnt;
@@ -335,6 +355,16 @@ static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
        writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
        writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
 
+       /*
+        * In case the PWM is currently at 100% duty cycle, force a manual
+        * update to prevent the signal staying high if the PWM is disabled
+        * shortly afer this update (before it autoreloaded the new values).
+        */
+       if (oldtcmp == (u32) -1) {
+               dev_dbg(our_chip->chip.dev, "Forcing manual update");
+               pwm_samsung_manual_update(our_chip, pwm);
+       }
+
        chan->period_ns = period_ns;
        chan->tin_ns = tin_ns;
        chan->duty_ns = duty_ns;