Hi Franklin,
On 2017/9/21 8:36, Franklin S Cooper Jr wrote:
On 08/24/2017 03:30 AM, Sekhar Nori wrote:
+ OMAP mailing list
On Tuesday 25 July 2017 04:21 AM, Franklin Cooper wrote:
Add support for PM Runtime which is the new way to handle managing clocks.
However, to avoid breaking SoCs not using PM_RUNTIME leave the old clk
management approach in place.
Since hclk is the interface clock, I think at a minimum there needs to
be an assumption that pm_runtime_get_sync() will enable that clock and
make the module ready for access.
The only in-kernel user of this driver seems to be an atmel SoC. I am
ccing folks who added support for M_CAN on that SoC to see if hclk
management can be left to pm_runtime*() on their SoC.
If they are okay, I think its a good to atleast drop explicit hclk
enable disable in the driver. That way, we avoid double enable/disable
of interface clock (hclk).
Wenyou,
Do you foresee this being a problem on your board? If not I can send a
v3 removing these clk_enable and clk_disable calls and it would be great
if you can test it out and provide your tested by.
Please send a v3 patch. I would like test it on my side.
PM_RUNTIME is required by OMAP based devices to handle clock management.
Therefore, this allows future Texas Instruments SoCs that have the MCAN IP
to work with this driver.
Signed-off-by: Franklin S Cooper Jr <fcooper@xxxxxx>
Thanks,
Sekhar
---
drivers/net/can/m_can/m_can.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index ea48e59..93e23f5 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -23,6 +23,7 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/iopoll.h>
#include <linux/can/dev.h>
@@ -633,11 +634,15 @@ static int m_can_clk_start(struct m_can_priv *priv)
if (err)
clk_disable_unprepare(priv->hclk);
+ pm_runtime_get_sync(priv->device);
+
return err;
}
static void m_can_clk_stop(struct m_can_priv *priv)
{
+ pm_runtime_put_sync(priv->device);
+
clk_disable_unprepare(priv->cclk);
clk_disable_unprepare(priv->hclk);
}
@@ -1582,6 +1587,8 @@ static int m_can_plat_probe(struct platform_device *pdev)
/* Enable clocks. Necessary to read Core Release in order to determine
* M_CAN version
*/
+ pm_runtime_enable(&pdev->dev);
+
ret = clk_prepare_enable(hclk);
if (ret)
goto disable_hclk_ret;
@@ -1626,6 +1633,8 @@ static int m_can_plat_probe(struct platform_device *pdev)
*/
tx_fifo_size = mram_config_vals[7];
+ pm_runtime_get_sync(&pdev->dev);
+
/* allocate the m_can device */
dev = alloc_m_can_dev(pdev, addr, tx_fifo_size);
if (!dev) {
@@ -1670,6 +1679,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
disable_hclk_ret:
clk_disable_unprepare(hclk);
failed_ret:
+ pm_runtime_put_sync(&pdev->dev);
return ret;
}
@@ -1726,6 +1736,9 @@ static int m_can_plat_remove(struct platform_device *pdev)
struct net_device *dev = platform_get_drvdata(pdev);
unregister_m_can_dev(dev);
+
+ pm_runtime_disable(&pdev->dev);
+
platform_set_drvdata(pdev, NULL);
free_m_can_dev(dev);
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Best Regards,
Wenyou Yang
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