diff mbox series

[1/2] dt-bindings: rtc: new binding for Amlogic VRTC

Message ID 20190607194343.18359-1-khilman@kernel.org
State New
Headers show
Series [1/2] dt-bindings: rtc: new binding for Amlogic VRTC | expand

Commit Message

Kevin Hilman June 7, 2019, 7:43 p.m. UTC
From: Kevin Hilman <khilman@baylibre.com>


Add binding fo the new VRTC driver for Amlogic SoCs.  The 64-bit
family of SoCs only has an RTC managed by firmware, and this VRTC
driver provides the simple, one-register firmware interface.

Signed-off-by: Kevin Hilman <khilman@baylibre.com>

---
 .../devicetree/bindings/rtc/rtc-meson-vrtc.txt   | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-meson-vrtc.txt

-- 
2.21.0

Comments

Alexandre Belloni June 20, 2019, 9:17 p.m. UTC | #1
Hello Kevin,

On 07/06/2019 12:43:43-0700, Kevin Hilman wrote:
> +static int meson_vrtc_read_time(struct device *dev, struct rtc_time *tm)

> +{

> +	unsigned long local_time;

> +	struct timespec64 time;

> +

> +	ktime_get_raw_ts64(&time);

> +	local_time = time.tv_sec - (sys_tz.tz_minuteswest * 60);

The RTC is supposed to be set to UTC so the TZ adjustment is not
necessary.

> +	rtc_time_to_tm(local_time, tm);

> +


Please use the 64 bit version.

> +	return 0;

> +}

> +

> +static void meson_vrtc_set_wakeup_time(struct meson_vrtc_data *vrtc,

> +				       unsigned long time)

> +{

> +	writel_relaxed(time, vrtc->io_alarm);

> +

> +	dev_dbg(&vrtc->pdev->dev, "set_wakeup_time: %lu\n", time);

> +}

> +

> +static int meson_vrtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)

> +{

> +	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);

> +	struct timespec64 time;

> +	unsigned long local_time;

> +	unsigned long alarm_secs;

> +	int ret;

> +

> +	if (alarm->enabled) {

> +		ret = rtc_tm_to_time(&alarm->time, &alarm_secs);

> +		if (ret)

> +			return ret;

> +


Use the 64bit version which makes it clear that it never fails (checking
ret is useless).

> +		ktime_get_raw_ts64(&time);

> +		local_time = time.tv_sec - (sys_tz.tz_minuteswest * 60);

> +

> +		vrtc->alarm_time = alarm_secs;

> +

> +		if (alarm_secs >= local_time) {


This is already ensured by the core so no need to check here.

> +			alarm_secs = alarm_secs - local_time;

> +

> +			meson_vrtc_set_wakeup_time(vrtc, alarm_secs);

> +

> +			pr_debug("system will wakeup %lus later\n", alarm_secs);

> +		}

> +	} else {

> +		vrtc->alarm_time = 0;

> +		meson_vrtc_set_wakeup_time(vrtc, 0);

> +	}

> +

> +	return 0;

> +}

> +

> +static int meson_vrtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)

> +{

> +	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);

> +

> +	if (!vrtc->alarm_time) {


I think this test is inverted.

> +		alm->enabled = true;

> +

> +		rtc_time_to_tm(vrtc->alarm_time, &alm->time);

> +	}

> +

> +	return 0;

> +}

> +

> +static const struct rtc_class_ops meson_vrtc_ops = {

> +	.read_time = meson_vrtc_read_time,

> +	.set_alarm = meson_vrtc_set_alarm,

> +	.read_alarm = meson_vrtc_read_alarm,

> +};

> +

> +static int meson_vrtc_probe(struct platform_device *pdev)

> +{

> +	struct meson_vrtc_data *vrtc;

> +	struct resource *res;

> +

> +	vrtc = devm_kzalloc(&pdev->dev, sizeof(*vrtc), GFP_KERNEL);

> +	if (!vrtc)

> +		return -ENOMEM;

> +

> +	vrtc->pdev = pdev;

> +

> +	/* Alarm registers */

> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

> +	vrtc->io_alarm = devm_ioremap_resource(&pdev->dev, res);

> +	if (IS_ERR(vrtc->io_alarm))

> +		return PTR_ERR(vrtc->io_alarm);

> +

> +	device_init_wakeup(&pdev->dev, 1);

> +

> +	platform_set_drvdata(pdev, vrtc);

> +

> +	vrtc->rtc = devm_rtc_device_register(&pdev->dev, "meson-vrtc",

> +					     &meson_vrtc_ops, THIS_MODULE);

> +	if (IS_ERR(vrtc->rtc))

> +		return PTR_ERR(vrtc->rtc);

> +


Please use devm_rtc_allocate_device and rtc_register_device. This
doesn't help much but my plan is to get rid of devm_rtc_device_register.

I suppose you don't get any interrupt for the alarm?


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Rob Herring (Arm) July 9, 2019, 2:07 a.m. UTC | #2
On Fri,  7 Jun 2019 12:43:42 -0700, Kevin Hilman wrote:
> From: Kevin Hilman <khilman@baylibre.com>

> 

> Add binding fo the new VRTC driver for Amlogic SoCs.  The 64-bit

> family of SoCs only has an RTC managed by firmware, and this VRTC

> driver provides the simple, one-register firmware interface.

> 

> Signed-off-by: Kevin Hilman <khilman@baylibre.com>

> ---

>  .../devicetree/bindings/rtc/rtc-meson-vrtc.txt   | 16 ++++++++++++++++

>  1 file changed, 16 insertions(+)

>  create mode 100644 Documentation/devicetree/bindings/rtc/rtc-meson-vrtc.txt

> 


Reviewed-by: Rob Herring <robh@kernel.org>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/rtc/rtc-meson-vrtc.txt b/Documentation/devicetree/bindings/rtc/rtc-meson-vrtc.txt
new file mode 100644
index 000000000000..f02886179788
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-meson-vrtc.txt
@@ -0,0 +1,16 @@ 
+* Amlogic Virtual RTC (VRTC)
+
+This is a Linux interface to an RTC managed by firmware, hence it's
+virtual from a Linux perspective.  The interface is 1 register where
+an alarm time is to be written.
+
+Required properties:
+- compatible: should be "amlogic,meson-vrtc"
+- reg: physical address for the alarm register
+
+Example:
+
+	vrtc: rtc@0a8 {
+		compatible = "amlogic,meson-vrtc";
+		reg = <0x0 0x000a8 0x0 0x4>;
+	};