[PATCH V3 3/3] rtc: omap: Support regulator supply for RTC

On Friday 24 October 2014 06:56 PM, Nishanth Menon wrote:

On 10/23/2014 11:53 PM, Lokesh Vutla wrote:

quoted

On some Soc's RTC is powered by an external power regulator.

SoC ? -> could you rephrase this to indicate "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.

Ok. will do it.

quoted

e.g. RTC on DRA7 SoC. Make the OMAP RTC driver support a
power regulator.

Question ofcourse is what voltage would you like that regulator to be
at? As you are aware, certain LDOs and SMPS can drive varying voltage
and just enable/disable would do just the default voltage of the
SMPS/LDO, right? OR am i missing something here?

Yes I agree that enable/disable would just do the default voltage of SMPS/LDO.
If default voltage needs to be changed, driver should explicitly call regulator_set_voltage.
Currently this is missing. Ill update and repost it. Thanks for pointing it out.

quoted

Signed-off-by: Lokesh Vutla <redacted>
---
 Documentation/devicetree/bindings/rtc/rtc-omap.txt |  3 +++
 drivers/rtc/rtc-omap.c                             | 24 ++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/Documentation/devicetree/bindings/rtc/rtc-omap.txt b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
index 750efd4..e7ad12b 100644
--- a/Documentation/devicetree/bindings/rtc/rtc-omap.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc-omap.txt

@@ -15,6 +15,8 @@ Required properties:
 Optional properties:
 - ti,system-power-controller: whether the rtc is controlling the system power
   through pmic_power_en
+Optional Properties:

^^ already commented on..

quoted

+- vrtc-supply: phandle to the regulator device tree node if needed

"phandle to supply regulator" ? since it is optional, "if needed" is
redundant?

Okay. will update it in next version.

quoted

 
 Example:
 

@@ -25,4 +27,5 @@ rtc at 1c23000 {
 		      19>;
 	interrupt-parent = <&intc>;
 	ti,system-power-controller;
+	vrtc-supply = <&ldo9_reg>;
 };

diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index d9bb5e7..61fe630 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c

@@ -25,6 +25,7 @@
 #include <linux/of_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/io.h>
+#include <linux/regulator/consumer.h>
 
 /*
  * The OMAP RTC is a year/month/day/hours/minutes/seconds BCD clock

@@ -134,6 +135,7 @@ struct omap_rtc {
 	u8 interrupts_reg;
 	bool is_pmic_controller;
 	const struct omap_rtc_device_type *type;
+	struct regulator *supply;
 };
 
 static inline u8 rtc_read(struct omap_rtc *rtc, unsigned int reg)

@@ -516,6 +518,22 @@ static int omap_rtc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, rtc);
 
+	rtc->supply = devm_regulator_get_optional(&pdev->dev, "vrtc");
+	if (IS_ERR(rtc->supply)) {
+		if (PTR_ERR(rtc->supply) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		rtc->supply = NULL;
+	}
+
+	if (rtc->supply) {
+		ret = regulator_enable(rtc->supply);
+		if (ret) {
+			dev_err(&pdev->dev, "regulator enable failed\n");

would be nice to print the result as well - since it helps debug from
log a little easier.

Will update it in next version.

Thanks and regards,
Lokesh