On 01/21/2012 07:46 PM, Mark Brown wrote:
> Add stub runtime_pm calls which go through the flow of enabling and
> disabling but don't actually do anything with the device itself as
> there's nothing useful we can do. This provides the core PM framework
> with information about when the device is idle, enabling chip wide
> power savings.
>
> Signed-off-by: Mark Brown<[email protected]>
> Acked-by: Heiko Stuebner<[email protected]>
> ---
> drivers/i2c/busses/i2c-s3c2410.c | 8 ++++++++
> 1 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-s3c2410.c
> b/drivers/i2c/busses/i2c-s3c2410.c
> index e6f982b..3d80bab 100644
> --- a/drivers/i2c/busses/i2c-s3c2410.c
> +++ b/drivers/i2c/busses/i2c-s3c2410.c
> @@ -31,6 +31,7 @@
> #include<linux/errno.h>
> #include<linux/err.h>
> #include<linux/platform_device.h>
> +#include<linux/pm_runtime.h>
> #include<linux/clk.h>
> #include<linux/cpufreq.h>
> #include<linux/slab.h>
> @@ -564,6 +565,7 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
> int retry;
> int ret;
>
> + pm_runtime_get_sync(&adap->dev);
IMHO it's more appropriate to use i2c->dev here instead, i.e. to reference
the platform device we've enabled runtime PM for.
> clk_enable(i2c->clk);
>
> for (retry = 0; retry< adap->retries; retry++) {
> @@ -572,6 +574,7 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
>
> if (ret != -EAGAIN) {
> clk_disable(i2c->clk);
> + pm_runtime_put(&adap->dev);
Ditto.
> return ret;
> }
>
> @@ -581,6 +584,7 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
> }
>
> clk_disable(i2c->clk);
> + pm_runtime_put(&adap->dev);
Ditto.
> return -EREMOTEIO;
> }
>
> @@ -1013,6 +1017,8 @@ static int s3c24xx_i2c_probe(struct platform_device
> *pdev)
> of_i2c_register_devices(&i2c->adap);
> platform_set_drvdata(pdev, i2c);
>
> + pm_runtime_enable(&pdev->dev);
> +
> dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
> clk_disable(i2c->clk);
> return 0;
> @@ -1047,6 +1053,8 @@ static int s3c24xx_i2c_remove(struct platform_device
> *pdev)
> {
> struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
>
> + pm_runtime_disable(&pdev->dev);
> +
> s3c24xx_i2c_deregister_cpufreq(i2c);
>
> i2c_del_adapter(&i2c->adap);
How about the following patch (untested) ? It might be a better start for
proper power management implementation and would still allow the driver
to work on platforms that don't support runtime PM.
8<----------------------------------------------
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 4c17180..0f588bb 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -31,6 +31,7 @@
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
@@ -551,6 +552,26 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
return ret;
}
+static inline int s3c24xx_pm_runtime_get(struct s3c24xx_i2c *i2c)
+{
+ if (!pm_runtime_enabled(i2c->dev)) {
+ clk_enable(i2c->clk);
+ return 0;
+ }
+
+ return pm_runtime_get_sync(i2c->dev);
+}
+
+static inline int s3c24xx_pm_runtime_put(struct s3c24xx_i2c *i2c)
+{
+ if (!pm_runtime_enabled(i2c->dev)) {
+ clk_disable(i2c->clk);
+ return 0;
+ }
+
+ return pm_runtime_put(i2c->dev);
+}
+
/* s3c24xx_i2c_xfer
*
* first port of call from the i2c bus code when an message needs
@@ -564,14 +585,14 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
int retry;
int ret;
- clk_enable(i2c->clk);
+ s3c24xx_pm_runtime_get(i2c);
for (retry = 0; retry < adap->retries; retry++) {
ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
if (ret != -EAGAIN) {
- clk_disable(i2c->clk);
+ s3c24xx_pm_runtime_put(i2c);
return ret;
}
@@ -580,7 +601,7 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
udelay(100);
}
- clk_disable(i2c->clk);
+ s3c24xx_pm_runtime_put(i2c);
return -EREMOTEIO;
}
@@ -929,7 +950,9 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
- clk_enable(i2c->clk);
+ platform_set_drvdata(pdev, i2c);
+ pm_runtime_enable(i2c->dev);
+ s3c24xx_pm_runtime_get(i2c);
/* map the registers */
@@ -1011,10 +1034,9 @@ static int s3c24xx_i2c_probe(struct platform_device
*pdev)
}
of_i2c_register_devices(&i2c->adap);
- platform_set_drvdata(pdev, i2c);
dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
- clk_disable(i2c->clk);
+ s3c24xx_pm_runtime_put(i2c);
return 0;
err_cpufreq:
@@ -1048,6 +1070,8 @@ static int s3c24xx_i2c_remove(struct platform_device
*pdev)
{
struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
+ pm_runtime_disable(&pdev->dev);
+
s3c24xx_i2c_deregister_cpufreq(i2c);
i2c_del_adapter(&i2c->adap);
@@ -1066,7 +1090,28 @@ static int s3c24xx_i2c_remove(struct platform_device
*pdev)
return 0;
}
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_RUNTIME
+static int s3c24xx_i2c_runtime_suspend(struct device *dev)
+{
+ struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
+
+ clk_disable(i2c->clk);
+ return 0;
+}
+
+static int s3c24xx_i2c_runtime_resume(struct device *dev)
+{
+ struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
+
+ clk_enable(i2c->clk);
+ return 0;
+}
+#else
+#define s3c24xx_i2c_runtime_suspend NULL
+#define s3c24xx_i2c_runtime_resume NULL
+#endif
+
+#ifdef CONFIG_PM_SLEEP
static int s3c24xx_i2c_suspend_noirq(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
@@ -1089,17 +1134,18 @@ static int s3c24xx_i2c_resume(struct device *dev)
return 0;
}
+#else
+#define s3c24xx_i2c_suspend_noirq NULL
+#define s3c24xx_i2c_resume NULL
+#endif
static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
.suspend_noirq = s3c24xx_i2c_suspend_noirq,
.resume = s3c24xx_i2c_resume,
+ .runtime_suspend = s3c24xx_i2c_runtime_suspend,
+ .runtime_resume = s3c24xx_i2c_runtime_resume,
};
-#define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops)
-#else
-#define S3C24XX_DEV_PM_OPS NULL
-#endif
-
/* device driver for platform bus bits */
static struct platform_device_id s3c24xx_driver_ids[] = {
@@ -1131,7 +1177,7 @@ static struct platform_driver s3c24xx_i2c_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "s3c-i2c",
- .pm = S3C24XX_DEV_PM_OPS,
+ .pm = &s3c24xx_i2c_dev_pm_ops,
.of_match_table = s3c24xx_i2c_match,
},
};
8>----------------------------------------------
--
Thanks,
Sylwester
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