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SubjectRe: [PATCH v2 7/9] pwm: atmel-tcb: Support backup mode
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On 15/09/2017 at 16:04, Romain Izard wrote:
> 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>

Seems good to me:
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

> ---
> drivers/pwm/pwm-atmel-tcb.c | 63 +++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 61 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c
> index 75db585a2a94..acd3ce8ecf3f 100644
> --- a/drivers/pwm/pwm-atmel-tcb.c
> +++ b/drivers/pwm/pwm-atmel-tcb.c
> @@ -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,
>


--
Nicolas Ferre

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