rtc: omap: Add support for regulator supply

Certain SoCs such as DRA7, RTC is an independent voltage domain of it's own and on platforms such as DRA7-evm, this may be supplied by individual regulator on it's own.
So make the OMAP RTC driver support a power regulator.

Signed-off-by Lokesh Vutla <[email protected]>

---
- Dropped the Reviewed-by tags as this patch is changed from previous version.

 Documentation/devicetree/bindings/rtc/rtc-omap.txt |  6 ++++
 drivers/rtc/rtc-omap.c                             | 41 +++++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

Documentation/devicetree/bindings/rtc/rtc-omap.txt +3 -0

index 750efd4..c1d84ac 100644
@@ -15,6 +15,9 @@ Required properties:
 Optional properties:
 - ti,system-power-controller: whether the rtc is controlling the system power
   through pmic_power_en
+- vrtc-supply: phandle to the regulator device tree node.
+- vrtc-minuV: Minimum required voltage in uV, If default voltage needs to be changed
+- vrtc-maxuV: Maximum acceptable voltage in uV, If default voltage needs to be changed
 
 Example:
 

Certain SoCs such as DRA7, RTC is an independent voltage domain of it's own and on platforms such as DRA7-evm, this may be supplied by individual regulator on it's own.
So make the OMAP RTC driver support a power regulator.

Signed-off-by Lokesh Vutla <[email protected]>

---
- Dropped the Reviewed-by tags as this patch is changed from previous version.

 Documentation/devicetree/bindings/rtc/rtc-omap.txt |  6 ++++
 drivers/rtc/rtc-omap.c                             | 41 +++++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

Documentation/devicetree/bindings/rtc/rtc-omap.txt +0 -0

index 750efd4..c1d84ac 100644

Documentation/devicetree/bindings/rtc/rtc-omap.txt +11 -0

+	if (IS_ERR(rtc->supply)) {
+		if (PTR_ERR(rtc->supply) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		rtc->supply = NULL;
+	}
+
+	if (rtc->supply) {
+		of_property_read_u32(pdev->dev.of_node, "vrtc-minuV",
+				     &vrtc_minuV);
+		of_property_read_u32(pdev->dev.of_node, "vrtc-maxuV",

Documentation/devicetree/bindings/rtc/rtc-omap.txt +15 -0

+
+		ret = regulator_enable(rtc->supply);
+		if (ret) {
+			dev_err(&pdev->dev, "regulator enable failed %d\n",
+				ret);
+			return ret;
+		}
+	}
+
 	platform_set_drvdata(pdev, rtc);
 
 	/* Enable the clock/module so that we can access the registers */

@@ -624,6 +657,9 @@ err:
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
+	if (rtc->supply)
+		regulator_disable(rtc->supply);
+
 	return ret;
 }
 

@@ -649,6 +685,9 @@ static int __exit omap_rtc_remove(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
+	if (rtc->supply)
+		regulator_disable(rtc->supply);
+
 	return 0;
 }
 

Signature · 1 line

1.9.1

Quoted 2 lines · Lokesh Vutla

+- vrtc-minuV: Minimum required voltage in uV, If default voltage needs to be changed
+- vrtc-maxuV: Maximum acceptable voltage in uV, If default voltage needs to be changed

huh ? minuV and maxuV is already part of the regulator binding itself.

drivers/rtc/rtc-omap.c static int omap_rtc_probe(struct platform_device *pdev) · line 519

Quoted 5 lines

drivers/rtc/rtc-omap.c +1 -0

@@ -514,6 +516,37 @@ static int omap_rtc_probe(struct platform_device *pdev)
 	if (IS_ERR(rtc->base))
 		return PTR_ERR(rtc->base);
 
+	rtc->supply = devm_regulator_get_optional(&pdev->dev, "vrtc");

I'm not sure if this is optional either, it's just that many of our current DTS don't really pass a regulator to RTC, right ?

Quoted 5 lines

drivers/rtc/rtc-omap.c +5 -0

+		if (vrtc_minuV && vrtc_maxuV) {
+			ret = regulator_set_voltage(rtc->supply,
+						    vrtc_minuV, vrtc_maxuV);
+			if (ret) {
+				dev_err(&pdev->dev, "failed to set volt %d\n",

drivers/rtc/rtc-omap.c static int omap_rtc_probe(struct platform_device *pdev) · line 540

Quoted 4 lines

drivers/rtc/rtc-omap.c +4 -0

+					ret);
+				return ret;
+			}
+		}

I'd really like to Mark's comments here but I was under the impression that if the binding already gives min_microvolt == max_microvolt then driver shouldn't really care about a set_voltage. Mark ?