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pwm: atmel-tcb: Support backup mode

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Save and restore registers for the PWM on suspend and resume, which
makes hibernation and backup modes possible.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Romain Izard 2017-10-19 18:44:10 +02:00 committed by Thierry Reding
parent ccb4e74aeb
commit 1b3d9a93ed
1 changed files with 61 additions and 2 deletions
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63
drivers/pwm/pwm-atmel-tcb.c
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@ -37,11 +37,20 @@ struct atmel_tcb_pwm_device {
unsigned period; /* PWM period expressed in clk cycles */
};
struct atmel_tcb_channel {
u32 enabled;
u32 cmr;
u32 ra;
u32 rb;
u32 rc;
};
struct atmel_tcb_pwm_chip {
struct pwm_chip chip;
spinlock_t lock;
struct atmel_tc *tc;
struct atmel_tcb_pwm_device *pwms[NPWM];
struct atmel_tcb_channel bkup[NPWM / 2];
};
static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip)
@ -175,12 +184,15 @@ static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
* Use software trigger to apply the new setting.
* If both PWM devices in this group are disabled we stop the clock.
*/
if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC)))
if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) {
__raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS,
regs + ATMEL_TC_REG(group, CCR));
else
tcbpwmc->bkup[group].enabled = 1;
} else {
__raw_writel(ATMEL_TC_SWTRG, regs +
ATMEL_TC_REG(group, CCR));
tcbpwmc->bkup[group].enabled = 0;
}
spin_unlock(&tcbpwmc->lock);
}
@ -263,6 +275,7 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
/* Use software trigger to apply the new setting */
__raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
regs + ATMEL_TC_REG(group, CCR));
tcbpwmc->bkup[group].enabled = 1;
spin_unlock(&tcbpwmc->lock);
return 0;
}
@ -445,10 +458,56 @@ static const struct of_device_id atmel_tcb_pwm_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);
#ifdef CONFIG_PM_SLEEP
static int atmel_tcb_pwm_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
void __iomem *base = tcbpwm->tc->regs;
int i;
for (i = 0; i < (NPWM / 2); i++) {
struct atmel_tcb_channel *chan = &tcbpwm->bkup[i];
chan->cmr = readl(base + ATMEL_TC_REG(i, CMR));
chan->ra = readl(base + ATMEL_TC_REG(i, RA));
chan->rb = readl(base + ATMEL_TC_REG(i, RB));
chan->rc = readl(base + ATMEL_TC_REG(i, RC));
}
return 0;
}
static int atmel_tcb_pwm_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
void __iomem *base = tcbpwm->tc->regs;
int i;
for (i = 0; i < (NPWM / 2); i++) {
struct atmel_tcb_channel *chan = &tcbpwm->bkup[i];
writel(chan->cmr, base + ATMEL_TC_REG(i, CMR));
writel(chan->ra, base + ATMEL_TC_REG(i, RA));
writel(chan->rb, base + ATMEL_TC_REG(i, RB));
writel(chan->rc, base + ATMEL_TC_REG(i, RC));
if (chan->enabled) {
writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
base + ATMEL_TC_REG(i, CCR));
}
}
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(atmel_tcb_pwm_pm_ops, atmel_tcb_pwm_suspend,
atmel_tcb_pwm_resume);
static struct platform_driver atmel_tcb_pwm_driver = {
.driver = {
.name = "atmel-tcb-pwm",
.of_match_table = atmel_tcb_pwm_dt_ids,
.pm = &atmel_tcb_pwm_pm_ops,
},
.probe = atmel_tcb_pwm_probe,
.remove = atmel_tcb_pwm_remove,