From 1b3d9a93ed8313e42f108f871133346694de5ac3 Mon Sep 17 00:00:00 2001 From: Romain Izard Date: Thu, 19 Oct 2017 18:44:10 +0200 Subject: [PATCH] pwm: atmel-tcb: Support backup mode Save and restore registers for the PWM on suspend and resume, which makes hibernation and backup modes possible. Signed-off-by: Romain Izard Acked-by: Nicolas Ferre Signed-off-by: Thierry Reding --- 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,