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SubjectRe: [PATCH v6 3/6] can: m_can: Add PM Runtime
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On 12/22/2017 02:31 PM, Faiz Abbas wrote:
> From: Franklin S Cooper Jr <fcooper@ti.com>
>
> 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.

There is no PM_RUNTIME anymore since 464ed18ebdb6 ("PM: Eliminate
CONFIG_PM_RUNTIME")

Have a look at the discussion: https://patchwork.kernel.org/patch/9436507/ :

>> Well, I admit it would be nicer if drivers didn't have to worry about
>> whether or not CONFIG_PM was enabled. A slightly cleaner approach
>> from the one outlined above would have the probe routine do this:
>>
>> my_power_up(dev);
>> pm_runtime_set_active(dev);
>> pm_runtime_get_noresume(dev);
>> pm_runtime_enable(dev);

> 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.

Who will set the SET_RUNTIME_PM_OPS in this case?

> Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
> [nsekhar@ti.com: handle pm_runtime_get_sync() failure, fix some bugs]
> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
> Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
> ---
> drivers/net/can/m_can/m_can.c | 38 ++++++++++++++++++++++++++++++++++----
> 1 file changed, 34 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index f72116e..53e764f 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>
>
> @@ -625,19 +626,33 @@ static int m_can_clk_start(struct m_can_priv *priv)
> {
> int err;
>
> + err = pm_runtime_get_sync(priv->device);
> + if (err) {
> + pm_runtime_put_noidle(priv->device);

Why do you call this in case of an error?

> + return err;
> + }
> +
> err = clk_prepare_enable(priv->hclk);
> if (err)
> - return err;
> + goto pm_runtime_put;
>
> err = clk_prepare_enable(priv->cclk);
> if (err)
> - clk_disable_unprepare(priv->hclk);
> + goto disable_hclk;
>
> return err;
> +
> +disable_hclk:
> + clk_disable_unprepare(priv->hclk);
> +pm_runtime_put:
> + pm_runtime_put_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);
> }
> @@ -1577,13 +1592,20 @@ 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 = pm_runtime_get_sync(&pdev->dev);
> + if (ret) {
> + pm_runtime_put_noidle(&pdev->dev);

Why do you call this in case of error?

> + goto pm_runtime_fail;
> + }
> +
> ret = clk_prepare_enable(hclk);
> if (ret)
> - goto disable_hclk_ret;
> + goto pm_runtime_put;
>
> ret = clk_prepare_enable(cclk);
> if (ret)
> - goto disable_cclk_ret;
> + goto disable_hclk_ret;
>
> res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "m_can");
> addr = devm_ioremap_resource(&pdev->dev, res);
> @@ -1666,6 +1688,11 @@ static int m_can_plat_probe(struct platform_device *pdev)
> clk_disable_unprepare(cclk);
> disable_hclk_ret:
> clk_disable_unprepare(hclk);
> +pm_runtime_put:
> + pm_runtime_put_sync(&pdev->dev);
> +pm_runtime_fail:
> + if (ret)
> + pm_runtime_disable(&pdev->dev);
> failed_ret:
> return ret;
> }
> @@ -1723,6 +1750,9 @@ 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);
>

regards,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
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