[PATCH v3 1/1] mfd: intel-lpss: save register context on suspend

[PATCH v3 1/1] mfd: intel-lpss: save register context on suspend

[Andy Shevchenko]

From: Heikki Krogerus <heikki.krogerus@linux.intel.com>

All configurations are lost and the registers will have
default values when the hardware is suspended and resumed,
so saving the private register space context on suspend, and
restoring it on resume.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
---
Since v2:
- add Ack
- remove Fixes tag
 drivers/mfd/intel-lpss.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
index 1bbbe87..807a3e3 100644
--- a/drivers/mfd/intel-lpss.c
+++ b/drivers/mfd/intel-lpss.c
@@ -34,6 +34,7 @@
 #define LPSS_DEV_SIZE		0x200
 #define LPSS_PRIV_OFFSET	0x200
 #define LPSS_PRIV_SIZE		0x100
+#define LPSS_PRIV_REG_COUNT	(LPSS_PRIV_SIZE / 4)
 #define LPSS_IDMA64_OFFSET	0x800
 #define LPSS_IDMA64_SIZE	0x800
 
@@ -76,6 +77,7 @@ struct intel_lpss {
 	struct mfd_cell *cell;
 	struct device *dev;
 	void __iomem *priv;
+	u32 priv_ctx[LPSS_PRIV_REG_COUNT];
 	int devid;
 	u32 caps;
 	u32 active_ltr;
@@ -493,6 +495,16 @@ EXPORT_SYMBOL_GPL(intel_lpss_prepare);
 
 int intel_lpss_suspend(struct device *dev)
 {
+	struct intel_lpss *lpss = dev_get_drvdata(dev);
+	unsigned int i;
+
+	/* Save device context */
+	for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
+		lpss->priv_ctx[i] = readl(lpss->priv + i * 4);
+
+	/* Put the device into reset state */
+	writel(0, lpss->priv + LPSS_PRIV_RESETS);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(intel_lpss_suspend);
@@ -500,8 +512,13 @@ EXPORT_SYMBOL_GPL(intel_lpss_suspend);
 int intel_lpss_resume(struct device *dev)
 {
 	struct intel_lpss *lpss = dev_get_drvdata(dev);
+	unsigned int i;
 
-	intel_lpss_init_dev(lpss);
+	intel_lpss_deassert_reset(lpss);
+
+	/* Restore device context */
+	for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
+		writel(lpss->priv_ctx[i], lpss->priv + i * 4);
 
 	return 0;
 }
-- 
2.8.0.rc3

Re: [PATCH v3 1/1] mfd: intel-lpss: save register context on suspend

[Heikki Krogerus]

Hi,

On Wed, Mar 30, 2016 at 04:35:46PM +0300, Andy Shevchenko wrote:
> From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> 
> All configurations are lost and the registers will have
> default values when the hardware is suspended and resumed,
> so saving the private register space context on suspend, and
> restoring it on resume.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Acked-by: Lee Jones <lee.jones@linaro.org>

Lee's Ack? I'm confused? Who is meant to take this patch?

> ---
> Since v2:
> - add Ack
> - remove Fixes tag

Why? This is a fix. And it also needs to go into the stable trees as
well, so we will also need tag it with "Cc: stable@vger.kernel.org".


Cheers,

-- 
heikki

Re: [PATCH v3 1/1] mfd: intel-lpss: save register context on suspend

[Andy Shevchenko]

On Wed, 2016-03-30 at 16:54 +0300, Heikki Krogerus wrote:
> Hi,
> 
> On Wed, Mar 30, 2016 at 04:35:46PM +0300, Andy Shevchenko wrote:
> > 
> > From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > 
> > All configurations are lost and the registers will have
> > default values when the hardware is suspended and resumed,
> > so saving the private register space context on suspend, and
> > restoring it on resume.
> > 
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > Acked-by: Lee Jones <lee.jones@linaro.org>
> Lee's Ack? I'm confused? Who is meant to take this patch?
> 
> > 
> > ---
> > Since v2:
> > - add Ack
> > - remove Fixes tag
> Why? This is a fix. And it also needs to go into the stable trees as
> well, so we will also need tag it with "Cc: stable@vger.kernel.org".

So, in that case v2 is what you want, right?

Lee, do I need to resend v2 as v4 or something else is required?

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

Re: [PATCH v3 1/1] mfd: intel-lpss: save register context on suspend

[Lee Jones]

On Fri, 15 Apr 2016, Andy Shevchenko wrote:

> On Wed, 2016-03-30 at 16:54 +0300, Heikki Krogerus wrote:
> > Hi,
> > 
> > On Wed, Mar 30, 2016 at 04:35:46PM +0300, Andy Shevchenko wrote:
> > > 
> > > From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > > 
> > > All configurations are lost and the registers will have
> > > default values when the hardware is suspended and resumed,
> > > so saving the private register space context on suspend, and
> > > restoring it on resume.
> > > 
> > > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > > Acked-by: Lee Jones <lee.jones@linaro.org>
> > Lee's Ack? I'm confused? Who is meant to take this patch?
> > 
> > > 
> > > ---
> > > Since v2:
> > > - add Ack
> > > - remove Fixes tag
> > Why? This is a fix. And it also needs to go into the stable trees as
> > well, so we will also need tag it with "Cc: stable@vger.kernel.org".
> 
> So, in that case v2 is what you want, right?
> 
> Lee, do I need to resend v2 as v4 or something else is required?

If you need a further change, please submit it as v4.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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