Re: [PATCH v4 1/6] rtc: arm: imx: snvs: change use syscon to access register

[Shawn Guo <shawn.guo@linaro.org>]

On Fri, May 22, 2015 at 10:36:34PM +0800, Frank.Li@freescale.com wrote:
> From: Frank Li <Frank.Li@freescale.com>
> 
> snvs included rtc, on/off key, power-off module
> change to syscon to access register
> 
> Signed-off-by: Frank Li <Frank.Li@freescale.com>

Did you test it with both existing and new DTBs?

> ---
>  drivers/rtc/rtc-snvs.c | 136 +++++++++++++++++++++++++------------------------
>  1 file changed, 70 insertions(+), 66 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
> index 0479e80..42e55da 100644
> --- a/drivers/rtc/rtc-snvs.c
> +++ b/drivers/rtc/rtc-snvs.c
> @@ -18,6 +18,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/rtc.h>
>  #include <linux/clk.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
>  
>  /* These register offsets are relative to LP (Low Power) range */
>  #define SNVS_LPCR		0x04
> @@ -37,31 +39,35 @@
>  
>  struct snvs_rtc_data {
>  	struct rtc_device *rtc;
> -	void __iomem *ioaddr;
> +	struct regmap *regmap;
> +	int offset;
>  	int irq;
> -	spinlock_t lock;
>  	struct clk *clk;
>  };
>  
> -static u32 rtc_read_lp_counter(void __iomem *ioaddr)
> +static u32 rtc_read_lp_counter(struct snvs_rtc_data *snvs)

All the pointers to struct snvs_rtc_data are named 'data'.  Please keep
it consistent.

>  {
>  	u64 read1, read2;
> -
> +	u32 val;

Please keep the new line here.

>  	do {
> -		read1 = readl(ioaddr + SNVS_LPSRTCMR);
> +		regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCMR, &val);
> +		read1 = val;
>  		read1 <<= 32;
> -		read1 |= readl(ioaddr + SNVS_LPSRTCLR);
> +		regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCLR, &val);
> +		read1 |= val;
>  
> -		read2 = readl(ioaddr + SNVS_LPSRTCMR);
> +		regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCMR, &val);
> +		read2 = val;
>  		read2 <<= 32;
> -		read2 |= readl(ioaddr + SNVS_LPSRTCLR);
> +		regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCLR, &val);
> +		read2 |= val;
>  	} while (read1 != read2);
>  
>  	/* Convert 47-bit counter to 32-bit raw second count */
>  	return (u32) (read1 >> CNTR_TO_SECS_SH);
>  }
>  
> -static void rtc_write_sync_lp(void __iomem *ioaddr)
> +static void rtc_write_sync_lp(struct snvs_rtc_data *snvs)
>  {
>  	u32 count1, count2, count3;
>  	int i;
> @@ -69,15 +75,15 @@ static void rtc_write_sync_lp(void __iomem *ioaddr)
>  	/* Wait for 3 CKIL cycles */
>  	for (i = 0; i < 3; i++) {
>  		do {
> -			count1 = readl(ioaddr + SNVS_LPSRTCLR);
> -			count2 = readl(ioaddr + SNVS_LPSRTCLR);
> +			regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCLR, &count1);
> +			regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCLR, &count2);
>  		} while (count1 != count2);
>  
>  		/* Now wait until counter value changes */
>  		do {
>  			do {
> -				count2 = readl(ioaddr + SNVS_LPSRTCLR);
> -				count3 = readl(ioaddr + SNVS_LPSRTCLR);
> +				regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCLR, &count2);
> +				regmap_read(snvs->regmap, snvs->offset + SNVS_LPSRTCLR, &count3);
>  			} while (count2 != count3);
>  		} while (count3 == count1);
>  	}
> @@ -85,23 +91,14 @@ static void rtc_write_sync_lp(void __iomem *ioaddr)
>  
>  static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable)
>  {
> -	unsigned long flags;
>  	int timeout = 1000;
>  	u32 lpcr;
>  
> -	spin_lock_irqsave(&data->lock, flags);
> -
> -	lpcr = readl(data->ioaddr + SNVS_LPCR);
> -	if (enable)
> -		lpcr |= SNVS_LPCR_SRTC_ENV;
> -	else
> -		lpcr &= ~SNVS_LPCR_SRTC_ENV;
> -	writel(lpcr, data->ioaddr + SNVS_LPCR);
> -
> -	spin_unlock_irqrestore(&data->lock, flags);
> +	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_SRTC_ENV,
> +			   enable ? SNVS_LPCR_SRTC_ENV : 0);
>  
>  	while (--timeout) {
> -		lpcr = readl(data->ioaddr + SNVS_LPCR);
> +		regmap_read(data->regmap, data->offset + SNVS_LPCR, &lpcr);
>  
>  		if (enable) {
>  			if (lpcr & SNVS_LPCR_SRTC_ENV)
> @@ -121,7 +118,7 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable)
>  static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm)
>  {
>  	struct snvs_rtc_data *data = dev_get_drvdata(dev);
> -	unsigned long time = rtc_read_lp_counter(data->ioaddr);
> +	unsigned long time = rtc_read_lp_counter(data);
>  
>  	rtc_time_to_tm(time, tm);
>  
> @@ -139,8 +136,8 @@ static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
>  	snvs_rtc_enable(data, false);
>  
>  	/* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */
> -	writel(time << CNTR_TO_SECS_SH, data->ioaddr + SNVS_LPSRTCLR);
> -	writel(time >> (32 - CNTR_TO_SECS_SH), data->ioaddr + SNVS_LPSRTCMR);
> +	regmap_write(data->regmap, data->offset + SNVS_LPSRTCLR, time << CNTR_TO_SECS_SH);
> +	regmap_write(data->regmap, data->offset + SNVS_LPSRTCMR, time >> (32 - CNTR_TO_SECS_SH));
>  
>  	/* Enable RTC again */
>  	snvs_rtc_enable(data, true);
> @@ -153,10 +150,10 @@ static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	struct snvs_rtc_data *data = dev_get_drvdata(dev);
>  	u32 lptar, lpsr;
>  
> -	lptar = readl(data->ioaddr + SNVS_LPTAR);
> +	regmap_read(data->regmap, data->offset + SNVS_LPTAR, &lptar);
>  	rtc_time_to_tm(lptar, &alrm->time);
>  
> -	lpsr = readl(data->ioaddr + SNVS_LPSR);
> +	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
>  	alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0;
>  
>  	return 0;
> @@ -165,21 +162,12 @@ static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>  static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
>  {
>  	struct snvs_rtc_data *data = dev_get_drvdata(dev);
> -	u32 lpcr;
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&data->lock, flags);
> -
> -	lpcr = readl(data->ioaddr + SNVS_LPCR);
> -	if (enable)
> -		lpcr |= (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
> -	else
> -		lpcr &= ~(SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
> -	writel(lpcr, data->ioaddr + SNVS_LPCR);
>  
> -	spin_unlock_irqrestore(&data->lock, flags);
> +	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR,
> +			   (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN),
> +			   enable ? (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN) : 0);
>  
> -	rtc_write_sync_lp(data->ioaddr);
> +	rtc_write_sync_lp(data);
>  
>  	return 0;
>  }
> @@ -189,24 +177,14 @@ static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	struct snvs_rtc_data *data = dev_get_drvdata(dev);
>  	struct rtc_time *alrm_tm = &alrm->time;
>  	unsigned long time;
> -	unsigned long flags;
> -	u32 lpcr;
>  
>  	rtc_tm_to_time(alrm_tm, &time);
>  
> -	spin_lock_irqsave(&data->lock, flags);
> -
> -	/* Have to clear LPTA_EN before programming new alarm time in LPTAR */
> -	lpcr = readl(data->ioaddr + SNVS_LPCR);
> -	lpcr &= ~SNVS_LPCR_LPTA_EN;
> -	writel(lpcr, data->ioaddr + SNVS_LPCR);
> -
> -	spin_unlock_irqrestore(&data->lock, flags);
> -
> -	writel(time, data->ioaddr + SNVS_LPTAR);
> +	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_LPTA_EN, 0);
> +	regmap_write(data->regmap, data->offset + SNVS_LPTAR, time);
>  
>  	/* Clear alarm interrupt status bit */
> -	writel(SNVS_LPSR_LPTA, data->ioaddr + SNVS_LPSR);
> +	regmap_write(data->regmap, data->offset + SNVS_LPSR, SNVS_LPSR_LPTA);
>  
>  	return snvs_rtc_alarm_irq_enable(dev, alrm->enabled);
>  }
> @@ -226,7 +204,7 @@ static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
>  	u32 lpsr;
>  	u32 events = 0;
>  
> -	lpsr = readl(data->ioaddr + SNVS_LPSR);
> +	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
>  
>  	if (lpsr & SNVS_LPSR_LPTA) {
>  		events |= (RTC_AF | RTC_IRQF);
> @@ -238,25 +216,53 @@ static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
>  	}
>  
>  	/* clear interrupt status */
> -	writel(lpsr, data->ioaddr + SNVS_LPSR);
> +	regmap_write(data->regmap, data->offset + SNVS_LPSR, lpsr);
>  
>  	return events ? IRQ_HANDLED : IRQ_NONE;
>  }
>  
> +static const struct regmap_config snvs_rtc_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +};
> +
>  static int snvs_rtc_probe(struct platform_device *pdev)
>  {
>  	struct snvs_rtc_data *data;
>  	struct resource *res;
>  	int ret;
> +	struct device_node *snvs_np;

Since you have only one pointer to device_node in this function, name
'np' is probably just fine.

> +	void __iomem *mmio;
>  
>  	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
>  		return -ENOMEM;
>  
> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	data->ioaddr = devm_ioremap_resource(&pdev->dev, res);
> -	if (IS_ERR(data->ioaddr))
> -		return PTR_ERR(data->ioaddr);
> +	snvs_np = of_get_parent(pdev->dev.of_node);
> +	if (!snvs_np)
> +		return -ENODEV;
> +
> +	if (of_device_is_compatible(snvs_np, "syscon")) {
> +		data->regmap = syscon_node_to_regmap(snvs_np);
> +		data->offset = 0x34;

You should at least have a macro for this magic number to tell what it
is?

> +	} else {
> +		pr_warn("snvs rtc: you use old dts file, please update it\n");
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> +		mmio = devm_ioremap_resource(&pdev->dev, res);
> +		if (IS_ERR(mmio))
> +			return PTR_ERR(mmio);

So if it fails out from here, of_node_put() call will be skipped.

> +
> +		data->regmap = devm_regmap_init_mmio(&pdev->dev, mmio, &snvs_rtc_config);
> +	}
> +
> +	of_node_put(snvs_np);
> +
> +	if (!data->regmap) {
> +		pr_err("Can't snvs syscon\n");

dev_err(), and "Can't find" or something?

Shawn

> +		return -ENODEV;
> +	}
>  
>  	data->irq = platform_get_irq(pdev, 0);
>  	if (data->irq < 0)
> @@ -276,13 +282,11 @@ static int snvs_rtc_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, data);
>  
> -	spin_lock_init(&data->lock);
> -
>  	/* Initialize glitch detect */
> -	writel(SNVS_LPPGDR_INIT, data->ioaddr + SNVS_LPPGDR);
> +	regmap_write(data->regmap, data->offset + SNVS_LPPGDR, SNVS_LPPGDR_INIT);
>  
>  	/* Clear interrupt status */
> -	writel(0xffffffff, data->ioaddr + SNVS_LPSR);
> +	regmap_write(data->regmap, data->offset + SNVS_LPSR, 0xffffffff);
>  
>  	/* Enable RTC */
>  	snvs_rtc_enable(data, true);
> -- 
> 1.9.1
>