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Commit 1b3d9a93 authored by Romain Izard's avatar Romain Izard Committed by Thierry Reding
Browse files

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: default avatarRomain Izard <romain.izard.pro@gmail.com>
Acked-by: default avatarNicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent ccb4e74a

drivers/pwm/pwm-atmel-tcb.c

+61 −2
Original line number Diff line number Diff line
@@ -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,