diff mbox

[07/12] rtc: omap: silence bogus power-up reset message at probe

Message ID 1412881594-25678-8-git-send-email-johan@kernel.org (mailing list archive)
State New, archived
Headers show

Commit Message

Johan Hovold Oct. 9, 2014, 7:06 p.m. UTC
Some legacy RTC IP revisions has a power-up reset flag in the status
register that later revisions lack.

As this flag is always read back as set on later revisions (or is
overloaded with a different flag), make sure to only clear the flag and
print the info message on legacy platforms.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/rtc/rtc-omap.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

Comments

Felipe Balbi Oct. 10, 2014, 6 p.m. UTC | #1
On Thu, Oct 09, 2014 at 09:06:29PM +0200, Johan Hovold wrote:
> Some legacy RTC IP revisions has a power-up reset flag in the status
> register that later revisions lack.
> 
> As this flag is always read back as set on later revisions (or is
> overloaded with a different flag), make sure to only clear the flag and
> print the info message on legacy platforms.
> 
> Signed-off-by: Johan Hovold <johan@kernel.org>

Reviewed-by: Felipe Balbi <balbi@ti.com>

> ---
>  drivers/rtc/rtc-omap.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
> index 1c58920b0c88..0ef016553a97 100644
> --- a/drivers/rtc/rtc-omap.c
> +++ b/drivers/rtc/rtc-omap.c
> @@ -118,6 +118,12 @@
>   */
>  #define OMAP_RTC_HAS_32KCLK_EN		BIT(2)
>  
> +/*
> + * Some legacy RTC IP revisions has a power-up reset flag which later
> + * revisions lack.
> + */
> +#define OMAP_RTC_HAS_POWER_UP_RESET	BIT(3)
> +
>  static void __iomem	*rtc_base;
>  
>  #define rtc_read(addr)		readb(rtc_base + (addr))
> @@ -347,6 +353,7 @@ static int omap_rtc_timer;
>  static struct platform_device_id omap_rtc_devtype[] = {
>  	{
>  		.name	= DRIVER_NAME,
> +		.driver_data = OMAP_RTC_HAS_POWER_UP_RESET,
>  	},
>  	[OMAP_RTC_DATA_AM3352_IDX] = {
>  		.name	= "am3352-rtc",
> @@ -376,7 +383,7 @@ static int __init omap_rtc_probe(struct platform_device *pdev)
>  {
>  	struct resource		*res;
>  	struct rtc_device	*rtc;
> -	u8			reg, new_ctrl;
> +	u8			reg, mask, new_ctrl;
>  	const struct platform_device_id *id_entry;
>  	const struct of_device_id *of_id;
>  
> @@ -429,12 +436,16 @@ static int __init omap_rtc_probe(struct platform_device *pdev)
>  
>  	/* clear old status */
>  	reg = rtc_read(OMAP_RTC_STATUS_REG);
> -	if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
> -		dev_info(&pdev->dev, "RTC power up reset detected\n");
> -		rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
> +
> +	mask = OMAP_RTC_STATUS_ALARM;
> +	if (id_entry->driver_data & OMAP_RTC_HAS_POWER_UP_RESET) {
> +		mask |= OMAP_RTC_STATUS_POWER_UP;
> +		if (reg & OMAP_RTC_STATUS_POWER_UP)
> +			dev_info(&pdev->dev, "RTC power up reset detected\n");
>  	}
> -	if (reg & (u8) OMAP_RTC_STATUS_ALARM)
> -		rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
> +
> +	if (reg & mask)
> +		rtc_write(reg & mask, OMAP_RTC_STATUS_REG);
>  
>  	/* handle periodic and alarm irqs */
>  	if (devm_request_irq(&pdev->dev, omap_rtc_timer, rtc_irq, 0,
> -- 
> 2.0.4
>
Felipe Balbi Oct. 10, 2014, 6:02 p.m. UTC | #2
On Fri, Oct 10, 2014 at 01:00:54PM -0500, Felipe Balbi wrote:
> On Thu, Oct 09, 2014 at 09:06:29PM +0200, Johan Hovold wrote:
> > Some legacy RTC IP revisions has a power-up reset flag in the status
> > register that later revisions lack.
> > 
> > As this flag is always read back as set on later revisions (or is
> > overloaded with a different flag), make sure to only clear the flag and
> > print the info message on legacy platforms.
> > 
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> 
> Reviewed-by: Felipe Balbi <balbi@ti.com>

oh, btw. This should be done for DT probes too.
Johan Hovold Oct. 11, 2014, 10:20 a.m. UTC | #3
On Fri, Oct 10, 2014 at 01:02:56PM -0500, Felipe Balbi wrote:
> On Fri, Oct 10, 2014 at 01:00:54PM -0500, Felipe Balbi wrote:
> > On Thu, Oct 09, 2014 at 09:06:29PM +0200, Johan Hovold wrote:
> > > Some legacy RTC IP revisions has a power-up reset flag in the status
> > > register that later revisions lack.
> > > 
> > > As this flag is always read back as set on later revisions (or is
> > > overloaded with a different flag), make sure to only clear the flag and
> > > print the info message on legacy platforms.
> > > 
> > > Signed-off-by: Johan Hovold <johan@kernel.org>
> > 
> > Reviewed-by: Felipe Balbi <balbi@ti.com>
> 
> oh, btw. This should be done for DT probes too.

What do you mean? This is for DT probes (of "ti,da830-rtc" and
"ti,am3352-rtc"). DT probing of legacy RTC IPs is currently not
supported.

Are you suggesting I should add a new compatible string for that?

Johan
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Felipe Balbi Oct. 12, 2014, 12:50 a.m. UTC | #4
Hi,

On Sat, Oct 11, 2014 at 12:20:04PM +0200, Johan Hovold wrote:
> On Fri, Oct 10, 2014 at 01:02:56PM -0500, Felipe Balbi wrote:
> > On Fri, Oct 10, 2014 at 01:00:54PM -0500, Felipe Balbi wrote:
> > > On Thu, Oct 09, 2014 at 09:06:29PM +0200, Johan Hovold wrote:
> > > > Some legacy RTC IP revisions has a power-up reset flag in the status
> > > > register that later revisions lack.
> > > > 
> > > > As this flag is always read back as set on later revisions (or is
> > > > overloaded with a different flag), make sure to only clear the flag and
> > > > print the info message on legacy platforms.
> > > > 
> > > > Signed-off-by: Johan Hovold <johan@kernel.org>
> > > 
> > > Reviewed-by: Felipe Balbi <balbi@ti.com>
> > 
> > oh, btw. This should be done for DT probes too.
> 
> What do you mean? This is for DT probes (of "ti,da830-rtc" and
> "ti,am3352-rtc"). DT probing of legacy RTC IPs is currently not
> supported.
> 
> Are you suggesting I should add a new compatible string for that?

it seemed to me that you're only passing the new flag through
platform_device_id table, not DT table. Did I miss something ?
Johan Hovold Oct. 12, 2014, 6:42 p.m. UTC | #5
On Sat, Oct 11, 2014 at 07:50:07PM -0500, Felipe Balbi wrote:
> Hi,
> 
> On Sat, Oct 11, 2014 at 12:20:04PM +0200, Johan Hovold wrote:
> > On Fri, Oct 10, 2014 at 01:02:56PM -0500, Felipe Balbi wrote:
> > > On Fri, Oct 10, 2014 at 01:00:54PM -0500, Felipe Balbi wrote:
> > > > On Thu, Oct 09, 2014 at 09:06:29PM +0200, Johan Hovold wrote:
> > > > > Some legacy RTC IP revisions has a power-up reset flag in the status
> > > > > register that later revisions lack.
> > > > > 
> > > > > As this flag is always read back as set on later revisions (or is
> > > > > overloaded with a different flag), make sure to only clear the flag and
> > > > > print the info message on legacy platforms.
> > > > > 
> > > > > Signed-off-by: Johan Hovold <johan@kernel.org>
> > > > 
> > > > Reviewed-by: Felipe Balbi <balbi@ti.com>
> > > 
> > > oh, btw. This should be done for DT probes too.
> > 
> > What do you mean? This is for DT probes (of "ti,da830-rtc" and
> > "ti,am3352-rtc"). DT probing of legacy RTC IPs is currently not
> > supported.
> > 
> > Are you suggesting I should add a new compatible string for that?
> 
> it seemed to me that you're only passing the new flag through
> platform_device_id table, not DT table. Did I miss something ?

Ah, that's just the way the driver currently encodes the IP revision
differences. The platform_device_id entries are references from
of_device_id data. Should probably clean that up as well.

Thanks again for the review. I'll post a new version when I'm back from
Düsseldorf and ELC-E/Plumbers.

Johan
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Felipe Balbi Oct. 13, 2014, 3:56 p.m. UTC | #6
Hi,

On Sun, Oct 12, 2014 at 08:42:40PM +0200, Johan Hovold wrote:
> On Sat, Oct 11, 2014 at 07:50:07PM -0500, Felipe Balbi wrote:
> > Hi,
> > 
> > On Sat, Oct 11, 2014 at 12:20:04PM +0200, Johan Hovold wrote:
> > > On Fri, Oct 10, 2014 at 01:02:56PM -0500, Felipe Balbi wrote:
> > > > On Fri, Oct 10, 2014 at 01:00:54PM -0500, Felipe Balbi wrote:
> > > > > On Thu, Oct 09, 2014 at 09:06:29PM +0200, Johan Hovold wrote:
> > > > > > Some legacy RTC IP revisions has a power-up reset flag in the status
> > > > > > register that later revisions lack.
> > > > > > 
> > > > > > As this flag is always read back as set on later revisions (or is
> > > > > > overloaded with a different flag), make sure to only clear the flag and
> > > > > > print the info message on legacy platforms.
> > > > > > 
> > > > > > Signed-off-by: Johan Hovold <johan@kernel.org>
> > > > > 
> > > > > Reviewed-by: Felipe Balbi <balbi@ti.com>
> > > > 
> > > > oh, btw. This should be done for DT probes too.
> > > 
> > > What do you mean? This is for DT probes (of "ti,da830-rtc" and
> > > "ti,am3352-rtc"). DT probing of legacy RTC IPs is currently not
> > > supported.
> > > 
> > > Are you suggesting I should add a new compatible string for that?
> > 
> > it seemed to me that you're only passing the new flag through
> > platform_device_id table, not DT table. Did I miss something ?
> 
> Ah, that's just the way the driver currently encodes the IP revision
> differences. The platform_device_id entries are references from
> of_device_id data. Should probably clean that up as well.

oh, alright :-)

> Thanks again for the review. I'll post a new version when I'm back from

no problem.
diff mbox

Patch

diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index 1c58920b0c88..0ef016553a97 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -118,6 +118,12 @@ 
  */
 #define OMAP_RTC_HAS_32KCLK_EN		BIT(2)
 
+/*
+ * Some legacy RTC IP revisions has a power-up reset flag which later
+ * revisions lack.
+ */
+#define OMAP_RTC_HAS_POWER_UP_RESET	BIT(3)
+
 static void __iomem	*rtc_base;
 
 #define rtc_read(addr)		readb(rtc_base + (addr))
@@ -347,6 +353,7 @@  static int omap_rtc_timer;
 static struct platform_device_id omap_rtc_devtype[] = {
 	{
 		.name	= DRIVER_NAME,
+		.driver_data = OMAP_RTC_HAS_POWER_UP_RESET,
 	},
 	[OMAP_RTC_DATA_AM3352_IDX] = {
 		.name	= "am3352-rtc",
@@ -376,7 +383,7 @@  static int __init omap_rtc_probe(struct platform_device *pdev)
 {
 	struct resource		*res;
 	struct rtc_device	*rtc;
-	u8			reg, new_ctrl;
+	u8			reg, mask, new_ctrl;
 	const struct platform_device_id *id_entry;
 	const struct of_device_id *of_id;
 
@@ -429,12 +436,16 @@  static int __init omap_rtc_probe(struct platform_device *pdev)
 
 	/* clear old status */
 	reg = rtc_read(OMAP_RTC_STATUS_REG);
-	if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
-		dev_info(&pdev->dev, "RTC power up reset detected\n");
-		rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
+
+	mask = OMAP_RTC_STATUS_ALARM;
+	if (id_entry->driver_data & OMAP_RTC_HAS_POWER_UP_RESET) {
+		mask |= OMAP_RTC_STATUS_POWER_UP;
+		if (reg & OMAP_RTC_STATUS_POWER_UP)
+			dev_info(&pdev->dev, "RTC power up reset detected\n");
 	}
-	if (reg & (u8) OMAP_RTC_STATUS_ALARM)
-		rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
+
+	if (reg & mask)
+		rtc_write(reg & mask, OMAP_RTC_STATUS_REG);
 
 	/* handle periodic and alarm irqs */
 	if (devm_request_irq(&pdev->dev, omap_rtc_timer, rtc_irq, 0,