[PATCH] rtc: tegra: Add ACPI support

[PATCH] rtc: tegra: Add ACPI support

[Kartik Rajput]

Add ACPI support for Tegra RTC, which is available on Tegra241 and
Tegra410. Both Tegra241 and Tegra410 use the same ACPI ID 'NVDA0280'.
The RTC clock is configured by UEFI before the kernel boots.

Signed-off-by: Kartik Rajput <kkartik@nvidia.com>
---
 drivers/rtc/rtc-tegra.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/rtc/rtc-tegra.c b/drivers/rtc/rtc-tegra.c
index 46788db89953..40617c82070f 100644
--- a/drivers/rtc/rtc-tegra.c
+++ b/drivers/rtc/rtc-tegra.c
@@ -5,6 +5,7 @@
  * Copyright (c) 2010-2019, NVIDIA Corporation.
  */
 
+#include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/init.h>
@@ -274,6 +275,12 @@ static const struct of_device_id tegra_rtc_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_rtc_dt_match);
 
+static const struct acpi_device_id tegra_rtc_acpi_match[] = {
+	{ "NVDA0280", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, tegra_rtc_acpi_match);
+
 static int tegra_rtc_probe(struct platform_device *pdev)
 {
 	struct tegra_rtc_info *info;
@@ -300,13 +307,15 @@ static int tegra_rtc_probe(struct platform_device *pdev)
 	info->rtc->ops = &tegra_rtc_ops;
 	info->rtc->range_max = U32_MAX;
 
-	info->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(info->clk))
-		return PTR_ERR(info->clk);
+	if (is_of_node(dev_fwnode(&pdev->dev))) {
+		info->clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(info->clk))
+			return PTR_ERR(info->clk);
 
-	ret = clk_prepare_enable(info->clk);
-	if (ret < 0)
-		return ret;
+		ret = clk_prepare_enable(info->clk);
+		if (ret < 0)
+			return ret;
+	}
 
 	/* set context info */
 	info->pdev = pdev;
@@ -338,7 +347,8 @@ static int tegra_rtc_probe(struct platform_device *pdev)
 	return 0;
 
 disable_clk:
-	clk_disable_unprepare(info->clk);
+	if (is_of_node(dev_fwnode(&pdev->dev)))
+		clk_disable_unprepare(info->clk);
 	return ret;
 }
 
@@ -346,7 +356,8 @@ static void tegra_rtc_remove(struct platform_device *pdev)
 {
 	struct tegra_rtc_info *info = platform_get_drvdata(pdev);
 
-	clk_disable_unprepare(info->clk);
+	if (is_of_node(dev_fwnode(&pdev->dev)))
+		clk_disable_unprepare(info->clk);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -404,6 +415,7 @@ static struct platform_driver tegra_rtc_driver = {
 	.driver = {
 		.name = "tegra_rtc",
 		.of_match_table = tegra_rtc_dt_match,
+		.acpi_match_table = tegra_rtc_acpi_match,
 		.pm = &tegra_rtc_pm_ops,
 	},
 };
-- 
2.43.0

Re: [PATCH] rtc: tegra: Add ACPI support

[kernel test robot]

Hi Kartik,

kernel test robot noticed the following build errors:

[auto build test ERROR on tegra/for-next]
[also build test ERROR on abelloni/rtc-next linus/master v6.17-rc6 next-20250919]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Kartik-Rajput/rtc-tegra-Add-ACPI-support/20250919-191553
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux.git for-next
patch link:    https://lore.kernel.org/r/20250919111232.605405-1-kkartik%40nvidia.com
patch subject: [PATCH] rtc: tegra: Add ACPI support
config: arm-randconfig-001-20250920 (https://download.01.org/0day-ci/archive/20250920/202509200953.uZOl24Is-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 12.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250920/202509200953.uZOl24Is-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509200953.uZOl24Is-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/rtc/rtc-tegra.c: In function 'tegra_rtc_probe':
>> drivers/rtc/rtc-tegra.c:310:13: error: implicit declaration of function 'is_of_node'; did you mean 'dev_of_node'? [-Werror=implicit-function-declaration]
     310 |         if (is_of_node(dev_fwnode(&pdev->dev))) {
         |             ^~~~~~~~~~
         |             dev_of_node
   cc1: some warnings being treated as errors


vim +310 drivers/rtc/rtc-tegra.c

   283	
   284	static int tegra_rtc_probe(struct platform_device *pdev)
   285	{
   286		struct tegra_rtc_info *info;
   287		int ret;
   288	
   289		info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
   290		if (!info)
   291			return -ENOMEM;
   292	
   293		info->base = devm_platform_ioremap_resource(pdev, 0);
   294		if (IS_ERR(info->base))
   295			return PTR_ERR(info->base);
   296	
   297		ret = platform_get_irq(pdev, 0);
   298		if (ret <= 0)
   299			return ret;
   300	
   301		info->irq = ret;
   302	
   303		info->rtc = devm_rtc_allocate_device(&pdev->dev);
   304		if (IS_ERR(info->rtc))
   305			return PTR_ERR(info->rtc);
   306	
   307		info->rtc->ops = &tegra_rtc_ops;
   308		info->rtc->range_max = U32_MAX;
   309	
 > 310		if (is_of_node(dev_fwnode(&pdev->dev))) {
   311			info->clk = devm_clk_get(&pdev->dev, NULL);
   312			if (IS_ERR(info->clk))
   313				return PTR_ERR(info->clk);
   314	
   315			ret = clk_prepare_enable(info->clk);
   316			if (ret < 0)
   317				return ret;
   318		}
   319	
   320		/* set context info */
   321		info->pdev = pdev;
   322		spin_lock_init(&info->lock);
   323	
   324		platform_set_drvdata(pdev, info);
   325	
   326		/* clear out the hardware */
   327		writel(0, info->base + TEGRA_RTC_REG_SECONDS_ALARM0);
   328		writel(0xffffffff, info->base + TEGRA_RTC_REG_INTR_STATUS);
   329		writel(0, info->base + TEGRA_RTC_REG_INTR_MASK);
   330	
   331		device_init_wakeup(&pdev->dev, true);
   332	
   333		ret = devm_request_irq(&pdev->dev, info->irq, tegra_rtc_irq_handler,
   334				       IRQF_TRIGGER_HIGH, dev_name(&pdev->dev),
   335				       &pdev->dev);
   336		if (ret) {
   337			dev_err(&pdev->dev, "failed to request interrupt: %d\n", ret);
   338			goto disable_clk;
   339		}
   340	
   341		ret = devm_rtc_register_device(info->rtc);
   342		if (ret)
   343			goto disable_clk;
   344	
   345		dev_notice(&pdev->dev, "Tegra internal Real Time Clock\n");
   346	
   347		return 0;
   348	
   349	disable_clk:
   350		if (is_of_node(dev_fwnode(&pdev->dev)))
   351			clk_disable_unprepare(info->clk);
   352		return ret;
   353	}
   354	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH] rtc: tegra: Add ACPI support

[Andy Shevchenko]

On Fri, Sep 19, 2025 at 04:42:32PM +0530, Kartik Rajput wrote:
> Add ACPI support for Tegra RTC, which is available on Tegra241 and
> Tegra410. Both Tegra241 and Tegra410 use the same ACPI ID 'NVDA0280'.
> The RTC clock is configured by UEFI before the kernel boots.

...

> +#include <linux/acpi.h>

No use.

...

> +static const struct acpi_device_id tegra_rtc_acpi_match[] = {
> +	{ "NVDA0280", 0 },

Drop redundant ', 0' part.

> +	{ }
> +};

...

> +	if (is_of_node(dev_fwnode(&pdev->dev))) {

Simple dev_of_node() will work here

> +		info->clk = devm_clk_get(&pdev->dev, NULL);
> +		if (IS_ERR(info->clk))
> +			return PTR_ERR(info->clk);
>  
> +		ret = clk_prepare_enable(info->clk);
> +		if (ret < 0)
> +			return ret;
> +	}

...

>  disable_clk:
> -	clk_disable_unprepare(info->clk);
> +	if (is_of_node(dev_fwnode(&pdev->dev)))
> +		clk_disable_unprepare(info->clk);

Redundant change. CLK APIs are NULL aware.

...

> -	clk_disable_unprepare(info->clk);
> +	if (is_of_node(dev_fwnode(&pdev->dev)))
> +		clk_disable_unprepare(info->clk);

Ditto.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] rtc: tegra: Add ACPI support

[Kartik Rajput]

Hi Andy,

Thanks for reviewing the patch!

On 15/10/25 13:34, Andy Shevchenko wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Fri, Sep 19, 2025 at 04:42:32PM +0530, Kartik Rajput wrote:
>> Add ACPI support for Tegra RTC, which is available on Tegra241 and
>> Tegra410. Both Tegra241 and Tegra410 use the same ACPI ID 'NVDA0280'.
>> The RTC clock is configured by UEFI before the kernel boots.
> 
> ...
> 
>> +#include <linux/acpi.h>
> 
> No use.
> 

Ack.

> ...
> 
>> +static const struct acpi_device_id tegra_rtc_acpi_match[] = {
>> +     { "NVDA0280", 0 },
> 
> Drop redundant ', 0' part.
> 

Ack.

>> +     { }
>> +};
> 
> ...
> 
>> +     if (is_of_node(dev_fwnode(&pdev->dev))) {
> 
> Simple dev_of_node() will work here
> 

Ack.

>> +             info->clk = devm_clk_get(&pdev->dev, NULL);
>> +             if (IS_ERR(info->clk))
>> +                     return PTR_ERR(info->clk);
>>
>> +             ret = clk_prepare_enable(info->clk);
>> +             if (ret < 0)
>> +                     return ret;
>> +     }
> 
> ...
> 
>>   disable_clk:
>> -     clk_disable_unprepare(info->clk);
>> +     if (is_of_node(dev_fwnode(&pdev->dev)))
>> +             clk_disable_unprepare(info->clk);
> 
> Redundant change. CLK APIs are NULL aware.
> 

Ack. I will drop this check.

> ...
> 
>> -     clk_disable_unprepare(info->clk);
>> +     if (is_of_node(dev_fwnode(&pdev->dev)))
>> +             clk_disable_unprepare(info->clk);
> 
> Ditto.
> 

Ack.

> --
> With Best Regards,
> Andy Shevchenko
> 
> 

Thanks,
Kartik