Re: [Patch V8] i2c: imx: add runtime pm support to improve the performance

2015-10-15 Thread Shubhrajyoti Datta 
clk_enable is called here.
enables the clock here.
>
> The calling sequence is:
> pm_runtime_use_autosuspend(&pdev->dev);
> pm_runtime_set_active(&pdev->dev);
> pm_runtime_enable(&pdev->dev);
> pm_runtime_get_sync(&pdev->dev);
are we not enabling it again?

there by effectively disabling pm.

Or did I missing something.

>
> The cleanup order is:
> pm_runtime_put_noidle(&pdev->dev);
> pm_runtime_disable(&pdev->dev);
> pm_runtime_set_suspended(&pdev->dev);
>
> Is it that I miss pm_runtime_dont_use_autosuspend(&pdev->dev);
>
> Thank you!
>
> Best Reguards
> Gao Pan
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RE: [Patch V8] i2c: imx: add runtime pm support to improve the performance

2015-10-13 Thread Gao Pandy 
 From: Uwe Kleine-König <mailto:u.kleine-koe...@pengutronix.de> Sent: Tuesday, 
October 13, 2015 3:07 PM
> To: Gao Pan-B54642
> Cc: w...@the-dreams.de; linux-i2c@vger.kernel.org; Li Frank-B20596; Duan
> Fugang-B38611; ker...@pengutronix.de; hkallwe...@gmail.com
> Subject: Re: [Patch V8] i2c: imx: add runtime pm support to improve the
> performance
> 
> Hello,
> 
> On Fri, Sep 18, 2015 at 05:51:09PM +0800, Gao Pan wrote:
> > In our former i2c driver, i2c clk is enabled and disabled in xfer
> > function, which contributes to power saving. However, the clk enable
> > process brings a busy wait delay until the core is stable. As a
> > result, the performance is sacrificed.
> >
> > To weigh the power consumption and i2c bus performance, runtime pm is
> > the good solution for it. The clk is enabled when a i2c transfer
> > starts, and disabled after a specifically defined delay.
> >
> > Without the patch the test case (many eeprom reads) executes with
> approx:
> > real 1m7.735s
> > user 0m0.488s
> > sys 0m20.040s
> >
> > With the patch the same test case (many eeprom reads) executes with
> approx:
> > real 0m54.241s
> > user 0m0.440s
> > sys 0m5.920s
> >
> > Signed-off-by: Fugang Duan 
> > Signed-off-by: Gao Pan 
> 
> If runtime-pm is disabled the net result of this patch is that the clock
> is never disabled, right? I think this is ok, but I would have pointed
> that out in the commit log.
 
Yes, you are right, I will point that out in the commit log in next version.

> > @@ -1037,6 +1045,18 @@ static int i2c_imx_probe(struct platform_device
> *pdev)
> > /* Set up adapter data */
> > i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
> >
> > +   /* Set up platform driver data */
> > +   platform_set_drvdata(pdev, i2c_imx);
> > +
> > +   pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
> > +   pm_runtime_use_autosuspend(&pdev->dev);
> > +   pm_runtime_set_active(&pdev->dev);
> > +   pm_runtime_enable(&pdev->dev);
> > +
> > +   ret = pm_runtime_get_sync(&pdev->dev);
> > +   if (ret < 0)
> > +   goto rpm_disable;
> > +
> > /* Set up clock divider */
> > i2c_imx->bitrate = IMX_I2C_BIT_RATE;
> > ret = of_property_read_u32(pdev->dev.of_node,
> > @@ -1053,12 +1073,11 @@ static int i2c_imx_probe(struct platform_device
> *pdev)
> > ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
> > if (ret < 0) {
> > dev_err(&pdev->dev, "registration failed\n");
> > -   goto clk_disable;
> > +   goto rpm_disable;
> 
> Is it right, that here the same error path is taken as when
> pm_runtime_get_sync fails above? Even if it works now, not having the
> error cleanup path undo all things in reverse order is a danger to get it
> wrong in the next change. So if this is fixable, it would be nice to
> implement.
 
When i2c_add_numbered_adapter fails, the cleanup should include the runtime pm 
stuff. 
So it's ok to take the same error patch.

What do you mean by undo all things in reverse order, I think the cleanup is in 
reverse order.

The calling sequence is: 
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);  
pm_runtime_get_sync(&pdev->dev);

The cleanup order is:
pm_runtime_put_noidle(&pdev->dev);
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);

Is it that I miss pm_runtime_dont_use_autosuspend(&pdev->dev);

Thank you!

Best Reguards
Gao Pan
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Re: [Patch V8] i2c: imx: add runtime pm support to improve the performance

2015-10-13 Thread Uwe Kleine-König 
Hello,

On Fri, Sep 18, 2015 at 05:51:09PM +0800, Gao Pan wrote:
> In our former i2c driver, i2c clk is enabled and disabled in
> xfer function, which contributes to power saving. However,
> the clk enable process brings a busy wait delay until the core
> is stable. As a result, the performance is sacrificed.
> 
> To weigh the power consumption and i2c bus performance, runtime
> pm is the good solution for it. The clk is enabled when a i2c
> transfer starts, and disabled after a specifically defined delay.
> 
> Without the patch the test case (many eeprom reads) executes with approx:
> real 1m7.735s
> user 0m0.488s
> sys 0m20.040s
> 
> With the patch the same test case (many eeprom reads) executes with approx:
> real 0m54.241s
> user 0m0.440s
> sys 0m5.920s
> 
> Signed-off-by: Fugang Duan 
> Signed-off-by: Gao Pan 

If runtime-pm is disabled the net result of this patch is that the clock
is never disabled, right? I think this is ok, but I would have pointed
that out in the commit log.

> @@ -1037,6 +1045,18 @@ static int i2c_imx_probe(struct platform_device *pdev)
>   /* Set up adapter data */
>   i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
>  
> + /* Set up platform driver data */
> + platform_set_drvdata(pdev, i2c_imx);
> +
> + pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
> + pm_runtime_use_autosuspend(&pdev->dev);
> + pm_runtime_set_active(&pdev->dev);
> + pm_runtime_enable(&pdev->dev);
> +
> + ret = pm_runtime_get_sync(&pdev->dev);
> + if (ret < 0)
> + goto rpm_disable;
> +
>   /* Set up clock divider */
>   i2c_imx->bitrate = IMX_I2C_BIT_RATE;
>   ret = of_property_read_u32(pdev->dev.of_node,
> @@ -1053,12 +1073,11 @@ static int i2c_imx_probe(struct platform_device *pdev)
>   ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
>   if (ret < 0) {
>   dev_err(&pdev->dev, "registration failed\n");
> - goto clk_disable;
> + goto rpm_disable;

Is it right, that here the same error path is taken as when
pm_runtime_get_sync fails above? Even if it works now, not having the
error cleanup path undo all things in reverse order is a danger to get
it wrong in the next change. So if this is fixable, it would be nice to
implement.

Best regards
Uwe

-- 
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Industrial Linux Solutions | http://www.pengutronix.de/  |
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Re: [Patch V8] i2c: imx: add runtime pm support to improve the performance

2015-10-10 Thread Wolfram Sang 
On Fri, Sep 18, 2015 at 05:51:09PM +0800, Gao Pan wrote:
> In our former i2c driver, i2c clk is enabled and disabled in
> xfer function, which contributes to power saving. However,
> the clk enable process brings a busy wait delay until the core
> is stable. As a result, the performance is sacrificed.
> 
> To weigh the power consumption and i2c bus performance, runtime
> pm is the good solution for it. The clk is enabled when a i2c
> transfer starts, and disabled after a specifically defined delay.
> 
> Without the patch the test case (many eeprom reads) executes with approx:
> real 1m7.735s
> user 0m0.488s
> sys 0m20.040s
> 
> With the patch the same test case (many eeprom reads) executes with approx:
> real 0m54.241s
> user 0m0.440s
> sys 0m5.920s
> 
> Signed-off-by: Fugang Duan 
> Signed-off-by: Gao Pan 

Uwe? Sascha?



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RE: [Patch V8] i2c: imx: add runtime pm support to improve the performance

2015-09-25 Thread Gao Pandy 
Ping...
From: Gao Pan <mailto:b54...@freescale.com> Sent: Friday, September 18, 2015 
5:51 PM
> To: w...@the-dreams.de
> Cc: linux-i2c@vger.kernel.org; Li Frank-B20596; Duan Fugang-B38611; Gao
> Pan-B54642; u.kleine-koe...@pengutronix.de; ker...@pengutronix.de;
> hkallwe...@gmail.com
> Subject: [Patch V8] i2c: imx: add runtime pm support to improve the
> performance
> 
> In our former i2c driver, i2c clk is enabled and disabled in xfer
> function, which contributes to power saving. However, the clk enable
> process brings a busy wait delay until the core is stable. As a result,
> the performance is sacrificed.
> 
> To weigh the power consumption and i2c bus performance, runtime pm is the
> good solution for it. The clk is enabled when a i2c transfer starts, and
> disabled after a specifically defined delay.
> 
> Without the patch the test case (many eeprom reads) executes with approx:
> real 1m7.735s
> user 0m0.488s
> sys 0m20.040s
> 
> With the patch the same test case (many eeprom reads) executes with
> approx:
> real 0m54.241s
> user 0m0.440s
> sys 0m5.920s
> 
> Signed-off-by: Fugang Duan 
> Signed-off-by: Gao Pan 
> ---
> V2:
> As Uwe Kleine-König's suggestion, the version do below changes:
>  -call clk_prepare_enable in probe to avoid never enabling clock
>   if CONFIG_PM is disabled
>  -enable clock before request IRQ in probe  -remove the pm staff in
> i2c_imx_isr
> 
> V3:
>  -pm_runtime_get_sync returns < 0 as error
> 
> V4:
>  -add pm_runtime_set_active before pm_runtime_enable  -replace
> pm_runtime_put_autosuspend with pm_runtime_autosuspend
>   in probe
>  -add error disposal when i2c_add_numbered_adapter fails
> 
> V5:
>  -clean up and disable runtime PM when i2c_add_numbered_adapter fails  -
> use pm_runtime_get and pm_runtime_put_autosuspend in probe
> 
> V6:
>  -disable the clock manually and set the state to suspended explicitly
> with
>   pm_runtime_set_suspended
> 
> V7:
>  -manually disabling the clock and use pm_runtime_put_noidle in the
> remove callback
> 
> V8:
>  -move out label after the two runtime pm calls in i2c_imx_xfer
> 
>  drivers/i2c/busses/i2c-imx.c | 90
> ++--
>  1 file changed, 78 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 785aa67..91bdf28 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -53,6 +53,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
> 
>  /** Defines
> 
> 
> *
> **/
> @@ -118,6 +119,8 @@
>  #define I2CR_IEN_OPCODE_00x0
>  #define I2CR_IEN_OPCODE_1I2CR_IEN
> 
> +#define I2C_PM_TIMEOUT   10 /* ms */
> +
>  /** Variables
> **
> 
> *
> **/
> 
> @@ -520,9 +523,6 @@ static int i2c_imx_start(struct imx_i2c_struct
> *i2c_imx)
> 
>   i2c_imx_set_clk(i2c_imx);
> 
> - result = clk_prepare_enable(i2c_imx->clk);
> - if (result)
> - return result;
>   imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
>   /* Enable I2C controller */
>   imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx,
> IMX_I2C_I2SR); @@ -575,7 +575,6 @@ static void i2c_imx_stop(struct
> imx_i2c_struct *i2c_imx)
>   /* Disable I2C controller */
>   temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
>   imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> - clk_disable_unprepare(i2c_imx->clk);
>  }
> 
>  static irqreturn_t i2c_imx_isr(int irq, void *dev_id) @@ -894,6 +893,10
> @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
> 
>   dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> 
> + result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
> + if (result < 0)
> + goto out;
> +
>   /* Start I2C transfer */
>   result = i2c_imx_start(i2c_imx);
>   if (result)
> @@ -950,6 +953,10 @@ fail0:
>   /* Stop I2C transfer */
>   i2c_imx_stop(i2c_imx);
> 
> + pm_runtime_mark_last_busy(i2c_imx->adapter.dev.parent);
> + pm_runtime_put_autosuspend(i2c_imx->adapter.dev.parent);
> +
> +out:
>   dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
>   (result < 0) ? "error" : "success msg",
>

[Patch V8] i2c: imx: add runtime pm support to improve the performance

2015-09-18 Thread Gao Pan 
In our former i2c driver, i2c clk is enabled and disabled in
xfer function, which contributes to power saving. However,
the clk enable process brings a busy wait delay until the core
is stable. As a result, the performance is sacrificed.

To weigh the power consumption and i2c bus performance, runtime
pm is the good solution for it. The clk is enabled when a i2c
transfer starts, and disabled after a specifically defined delay.

Without the patch the test case (many eeprom reads) executes with approx:
real 1m7.735s
user 0m0.488s
sys 0m20.040s

With the patch the same test case (many eeprom reads) executes with approx:
real 0m54.241s
user 0m0.440s
sys 0m5.920s

Signed-off-by: Fugang Duan 
Signed-off-by: Gao Pan 
---
V2:
As Uwe Kleine-König's suggestion, the version do below changes:
 -call clk_prepare_enable in probe to avoid never enabling clock
  if CONFIG_PM is disabled
 -enable clock before request IRQ in probe
 -remove the pm staff in i2c_imx_isr

V3:
 -pm_runtime_get_sync returns < 0 as error

V4:
 -add pm_runtime_set_active before pm_runtime_enable
 -replace pm_runtime_put_autosuspend with pm_runtime_autosuspend
  in probe
 -add error disposal when i2c_add_numbered_adapter fails

V5:
 -clean up and disable runtime PM when i2c_add_numbered_adapter fails
 -use pm_runtime_get and pm_runtime_put_autosuspend in probe

V6:
 -disable the clock manually and set the state to suspended explicitly with
  pm_runtime_set_suspended

V7:
 -manually disabling the clock and use pm_runtime_put_noidle in the remove 
callback

V8:
 -move out label after the two runtime pm calls in i2c_imx_xfer

 drivers/i2c/busses/i2c-imx.c | 90 ++--
 1 file changed, 78 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 785aa67..91bdf28 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -53,6 +53,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /** Defines 

 
***/
@@ -118,6 +119,8 @@
 #define I2CR_IEN_OPCODE_0  0x0
 #define I2CR_IEN_OPCODE_1  I2CR_IEN
 
+#define I2C_PM_TIMEOUT 10 /* ms */
+
 /** Variables 
**
 
***/
 
@@ -520,9 +523,6 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
 
i2c_imx_set_clk(i2c_imx);
 
-   result = clk_prepare_enable(i2c_imx->clk);
-   if (result)
-   return result;
imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
/* Enable I2C controller */
imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, 
IMX_I2C_I2SR);
@@ -575,7 +575,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
/* Disable I2C controller */
temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
-   clk_disable_unprepare(i2c_imx->clk);
 }
 
 static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
@@ -894,6 +893,10 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
 
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 
+   result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
+   if (result < 0)
+   goto out;
+
/* Start I2C transfer */
result = i2c_imx_start(i2c_imx);
if (result)
@@ -950,6 +953,10 @@ fail0:
/* Stop I2C transfer */
i2c_imx_stop(i2c_imx);
 
+   pm_runtime_mark_last_busy(i2c_imx->adapter.dev.parent);
+   pm_runtime_put_autosuspend(i2c_imx->adapter.dev.parent);
+
+out:
dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
(result < 0) ? "error" : "success msg",
(result < 0) ? result : num);
@@ -1020,9 +1027,10 @@ static int i2c_imx_probe(struct platform_device *pdev)
 
ret = clk_prepare_enable(i2c_imx->clk);
if (ret) {
-   dev_err(&pdev->dev, "can't enable I2C clock\n");
+   dev_err(&pdev->dev, "can't enable I2C clock, ret=%d\n", ret);
return ret;
}
+
/* Request IRQ */
ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0,
pdev->name, i2c_imx);
@@ -1037,6 +1045,18 @@ static int i2c_imx_probe(struct platform_device *pdev)
/* Set up adapter data */
i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
 
+   /* Set up platform driver data */
+   platform_set_drvdata(pdev, i2c_imx);
+
+   pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
+   pm_runtime_use_autosuspend(&pdev->dev);
+   pm_runtime_set_active(&pdev->dev);
+   pm_runtime_enable(&pdev->dev);
+
+   ret = pm_runtime_get_sync(&pdev->dev);
+   if (ret < 0)
+   goto rpm_disable;
+