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pwm: sti: Sync between enable/disable calls

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ST PWM IP has a common enable/disable control for all the PWM
channels on a PWM cell. Disables PWM output on the PWM HW only
when disable is called for the last channel.

Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Ajit Pal Singh 2014-07-14 15:33:31 +01:00 committed by Thierry Reding
parent 5165166e8a
commit 6ad6b838e1
1 changed files with 30 additions and 14 deletions
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44
drivers/pwm/pwm-sti.c
View file

@ -59,6 +59,8 @@ struct sti_pwm_chip {
unsigned long *pwm_periods;
struct pwm_chip chip;
struct pwm_device *cur;
unsigned int en_count;
struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
void __iomem *mmio;
};
@ -236,32 +238,44 @@ static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
struct device *dev = pc->dev;
int ret;
int ret = 0;
ret = clk_enable(pc->clk);
if (ret)
return ret;
ret = regmap_field_write(pc->pwm_en, 1);
if (ret)
dev_err(dev, "%s,pwm_en write failed\n", __func__);
/*
* Since we have a common enable for all PWM channels,
* do not enable if already enabled.
*/
mutex_lock(&pc->sti_pwm_lock);
if (!pc->en_count) {
ret = clk_enable(pc->clk);
if (ret)
goto out;
ret = regmap_field_write(pc->pwm_en, 1);
if (ret) {
dev_err(dev, "failed to enable PWM device:%d\n",
pwm->hwpwm);
goto out;
}
}
pc->en_count++;
out:
mutex_unlock(&pc->sti_pwm_lock);
return ret;
}
static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
struct device *dev = pc->dev;
unsigned int val;
mutex_lock(&pc->sti_pwm_lock);
if (--pc->en_count) {
mutex_unlock(&pc->sti_pwm_lock);
return;
}
regmap_field_write(pc->pwm_en, 0);
regmap_read(pc->regmap, STI_CNT, &val);
dev_dbg(dev, "pwm counter :%u\n", val);
clk_disable(pc->clk);
mutex_unlock(&pc->sti_pwm_lock);
}
static const struct pwm_ops sti_pwm_ops = {
@ -352,6 +366,8 @@ static int sti_pwm_probe(struct platform_device *pdev)
pc->cdata = cdata;
pc->dev = dev;
pc->en_count = 0;
mutex_init(&pc->sti_pwm_lock);
ret = sti_pwm_probe_dt(pc);
if (ret)