Messages in this thread | | | Subject | Re: [v2,3/3] can: m_can: Add PM Runtime | From | "Yang, Wenyou" <> | Date | Fri, 22 Sep 2017 09:54:47 +0800 |
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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@ti.com> >> 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); >>> > -- > To unsubscribe from this list: send the line "unsubscribe linux-can" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
Best Regards, Wenyou Yang
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