Re: [PATCH] i2c: busses: remove superfluous ignoring of children for RPM

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On 29 April 2018 at 20:41, Wolfram Sang
<wsa+renesas@xxxxxxxxxxxxxxxxxxxx> wrote:
> These days, the I2C core ensures that the embedded adapter device
> ignores the PM states of its children already. Because the adapter
> device is an opaque logical device, there is no need for drivers to
> repeat that again.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>

Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

Kind regards
Uffe

> ---
>
> I tested it using a Renesas Salvator-X board (M3-W) which has an EEPROM
> connected to a bus driven by the i2c-sh_mobile driver. The EEPROM driver (at24)
> immediately sets the RPM state to 'active'. Even with this patch applied, it
> does not affect the state of the parent platform_device. Only if I remove
> 'pm_suspend_ignore_children' from the I2C core, too, then the 'active' state
> from the client is passed on to the host adapter.
>
> I think this is a sufficient test, but please double check.
>
>  drivers/i2c/busses/i2c-hix5hd2.c   |  1 -
>  drivers/i2c/busses/i2c-nomadik.c   |  2 --
>  drivers/i2c/busses/i2c-sh_mobile.c | 11 -----------
>  3 files changed, 14 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-hix5hd2.c b/drivers/i2c/busses/i2c-hix5hd2.c
> index bb68957d3da5..1504c3c1a1c0 100644
> --- a/drivers/i2c/busses/i2c-hix5hd2.c
> +++ b/drivers/i2c/busses/i2c-hix5hd2.c
> @@ -471,7 +471,6 @@ static int hix5hd2_i2c_probe(struct platform_device *pdev)
>                 goto err_clk;
>         }
>
> -       pm_suspend_ignore_children(&pdev->dev, true);
>         pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
>         pm_runtime_use_autosuspend(priv->dev);
>         pm_runtime_set_active(priv->dev);
> diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
> index 49c7c0c91486..0ed5a41804dc 100644
> --- a/drivers/i2c/busses/i2c-nomadik.c
> +++ b/drivers/i2c/busses/i2c-nomadik.c
> @@ -1012,8 +1012,6 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>                 goto err_no_mem;
>         }
>
> -       pm_suspend_ignore_children(&adev->dev, true);
> -
>         dev->clk = devm_clk_get(&adev->dev, NULL);
>         if (IS_ERR(dev->clk)) {
>                 dev_err(&adev->dev, "could not get i2c clock\n");
> diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
> index d856bc211715..5fda4188a9e5 100644
> --- a/drivers/i2c/busses/i2c-sh_mobile.c
> +++ b/drivers/i2c/busses/i2c-sh_mobile.c
> @@ -899,17 +899,6 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
>         if (resource_size(res) > 0x17)
>                 pd->flags |= IIC_FLAG_HAS_ICIC67;
>
> -       /* Enable Runtime PM for this device.
> -        *
> -        * Also tell the Runtime PM core to ignore children
> -        * for this device since it is valid for us to suspend
> -        * this I2C master driver even though the slave devices
> -        * on the I2C bus may not be suspended.
> -        *
> -        * The state of the I2C hardware bus is unaffected by
> -        * the Runtime PM state.
> -        */
> -       pm_suspend_ignore_children(&dev->dev, true);
>         pm_runtime_enable(&dev->dev);
>         pm_runtime_get_sync(&dev->dev);
>
> --
> 2.11.0
>



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