Subject: [PATCH] rtc: omap: Support regulator supply for RTC

From: [email-masked] (Nishanth Menon)
Date: Fri, 19 Sep 2014 07:54:46 -0500

On 09/19/2014 04:48 AM, Lokesh Vutla wrote:
> +linux-omap, linux-arm-kernel, devicetree
> On Friday 19 September 2014 03:16 PM, Lokesh Vutla wrote:
>> On some Soc's RTC is powered by an external power regulator.
>> e.g. RTC on DRA7 SoC. Make the OMAP RTC driver support a
>> power regulator.
>> And also making the driver as module_platform_driver to
>> support probe deferal.
>>
>> Signed-off-by: Lokesh Vutla <[email-masked]>
>> ---
>> Tested on DRA7. Logs here: http://fpaste.org/134804/11200041/

Is that the only platform using rtc-omap.c?

>>
>>  Documentation/devicetree/bindings/rtc/rtc-omap.txt |  3 +++
>>  drivers/rtc/rtc-omap.c                             | 28 ++++++++++++++++++++--
>>  2 files changed, 29 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/rtc/rtc-omap.txt b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
>> index 5a0f02d..c9f963a 100644
>> --- a/Documentation/devicetree/bindings/rtc/rtc-omap.txt
>> +++ b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
>> @@ -10,6 +10,9 @@ Required properties:
>>  - interrupts: rtc timer, alarm interrupts in order
>>  - interrupt-parent: phandle for the interrupt controller
>>  
>> +Optional Properties:
>> + - rtc-supply : phandle to the regulator device tree node if needed.
>> +
>>  Example:
>>  
>>  rtc at 1c23000 {
>> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
>> index 21142e6..4473d1d 100644
>> --- a/drivers/rtc/rtc-omap.c
>> +++ b/drivers/rtc/rtc-omap.c
>> @@ -24,6 +24,7 @@
>>  #include <linux/of_device.h>
>>  #include <linux/pm_runtime.h>
>>  #include <linux/io.h>
>> +#include <linux/regulator/consumer.h>
>>  
>>  /* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock
>>   * with century-range alarm matching, driven by the 32kHz clock.
>> @@ -121,6 +122,7 @@
>>  #define OMAP_RTC_HAS_32KCLK_EN		BIT(2)
>>  
>>  static void __iomem	*rtc_base;

^^ this can easily be removed by allocating data in probe.

>> +static struct regulator	*rtc_reg;

So, two instances cannot have different RTC supplies? we dont need to
do this.

>>  
>>  #define rtc_read(addr)		readb(rtc_base + (addr))
>>  #define rtc_write(val, addr)	writeb(val, rtc_base + (addr))
>> @@ -372,11 +374,12 @@ static const struct of_device_id omap_rtc_of_match[] = {
>>  };
>>  MODULE_DEVICE_TABLE(of, omap_rtc_of_match);
>>  
>> -static int __init omap_rtc_probe(struct platform_device *pdev)
>> +static int omap_rtc_probe(struct platform_device *pdev)
>>  {
>>  	struct resource		*res;
>>  	struct rtc_device	*rtc;
>>  	u8			reg, new_ctrl;
>> +	int			ret;
>>  	const struct platform_device_id *id_entry;
>>  	const struct of_device_id *of_id;
>>  
>> @@ -402,6 +405,23 @@ static int __init omap_rtc_probe(struct platform_device *pdev)
>>  		return -ENOENT;
>>  	}
>>  
>> +	rtc_reg =  devm_regulator_get_optional(&pdev->dev, "rtc");
>> +	if (IS_ERR(rtc_reg)) {
>> +		if (PTR_ERR(rtc_reg) == -EPROBE_DEFER) {
>> +			dev_err(&pdev->dev, "regulator not ready, retry\n");
>> +			return -EPROBE_DEFER;
>> +		}
>> +		rtc_reg = NULL;
>> +	}
>> +
>> +	if (rtc_reg) {
>> +		ret = regulator_enable(rtc_reg);
>> +		if (ret) {
>> +			dev_dbg(&pdev->dev, "regulator enable failed\n");
>> +			return ret;
>> +		}
>> +	}
>> +

Do you have a specific voltage you need for your rtc device?

>>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>  	rtc_base = devm_ioremap_resource(&pdev->dev, res);
>>  	if (IS_ERR(rtc_base))
>> @@ -517,6 +537,9 @@ static int __exit omap_rtc_remove(struct platform_device *pdev)
>>  	pm_runtime_put_sync(&pdev->dev);
>>  	pm_runtime_disable(&pdev->dev);
>>  
>> +	if (rtc_reg)
>> +		regulator_disable(rtc_reg);
>> +
>>  	return 0;
>>  }
>>  
>> @@ -565,6 +588,7 @@ static void omap_rtc_shutdown(struct platform_device *pdev)
>>  
>>  MODULE_ALIAS("platform:omap_rtc");
>>  static struct platform_driver omap_rtc_driver = {
>> +	.probe		= omap_rtc_probe,
>>  	.remove		= __exit_p(omap_rtc_remove),
>>  	.shutdown	= omap_rtc_shutdown,
>>  	.driver		= {
>> @@ -576,7 +600,7 @@ static struct platform_driver omap_rtc_driver = {
>>  	.id_table	= omap_rtc_devtype,
>>  };
>>  
>> -module_platform_driver_probe(omap_rtc_driver, omap_rtc_probe);
>> +module_platform_driver(omap_rtc_driver);

>>  
>>  MODULE_AUTHOR("George G. Davis (and others)");
>>  MODULE_LICENSE("GPL");
>>
> 

-- 
Regards,
Nishanth Menon