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path: root/drivers/pwm/pwm-meson.c
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Diffstat (limited to 'drivers/pwm/pwm-meson.c')
-rw-r--r--drivers/pwm/pwm-meson.c30
1 files changed, 17 insertions, 13 deletions
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index 9d5bd7d5c610..a196439ee14c 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -110,6 +110,10 @@ struct meson_pwm {
const struct meson_pwm_data *data;
void __iomem *base;
u8 inverter_mask;
+ /*
+ * Protects register (write) access to the REG_MISC_AB register
+ * that is shared between the two PWMs.
+ */
spinlock_t lock;
};
@@ -230,6 +234,7 @@ static void meson_pwm_enable(struct meson_pwm *meson,
{
u32 value, clk_shift, clk_enable, enable;
unsigned int offset;
+ unsigned long flags;
switch (id) {
case 0:
@@ -250,6 +255,8 @@ static void meson_pwm_enable(struct meson_pwm *meson,
return;
}
+ spin_lock_irqsave(&meson->lock, flags);
+
value = readl(meson->base + REG_MISC_AB);
value &= ~(MISC_CLK_DIV_MASK << clk_shift);
value |= channel->pre_div << clk_shift;
@@ -262,11 +269,14 @@ static void meson_pwm_enable(struct meson_pwm *meson,
value = readl(meson->base + REG_MISC_AB);
value |= enable;
writel(value, meson->base + REG_MISC_AB);
+
+ spin_unlock_irqrestore(&meson->lock, flags);
}
static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
{
u32 value, enable;
+ unsigned long flags;
switch (id) {
case 0:
@@ -281,9 +291,13 @@ static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
return;
}
+ spin_lock_irqsave(&meson->lock, flags);
+
value = readl(meson->base + REG_MISC_AB);
value &= ~enable;
writel(value, meson->base + REG_MISC_AB);
+
+ spin_unlock_irqrestore(&meson->lock, flags);
}
static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -291,29 +305,21 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
{
struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
struct meson_pwm *meson = to_meson_pwm(chip);
- unsigned long flags;
int err = 0;
if (!state)
return -EINVAL;
- spin_lock_irqsave(&meson->lock, flags);
-
if (!state->enabled) {
meson_pwm_disable(meson, pwm->hwpwm);
channel->state.enabled = false;
- goto unlock;
+ return 0;
}
if (state->period != channel->state.period ||
state->duty_cycle != channel->state.duty_cycle ||
state->polarity != channel->state.polarity) {
- if (channel->state.enabled) {
- meson_pwm_disable(meson, pwm->hwpwm);
- channel->state.enabled = false;
- }
-
if (state->polarity != channel->state.polarity) {
if (state->polarity == PWM_POLARITY_NORMAL)
meson->inverter_mask |= BIT(pwm->hwpwm);
@@ -324,7 +330,7 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
err = meson_pwm_calc(meson, channel, pwm->hwpwm,
state->duty_cycle, state->period);
if (err < 0)
- goto unlock;
+ return err;
channel->state.polarity = state->polarity;
channel->state.period = state->period;
@@ -336,9 +342,7 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
channel->state.enabled = true;
}
-unlock:
- spin_unlock_irqrestore(&meson->lock, flags);
- return err;
+ return 0;
}
static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,